build(rechner): exact expression engine, keypad, scientific panel, history, memory; README

Co-Authored-By: Claude Opus 5.5 <[email protected]>

README.md

@@ -8,6 +8,7 @@
 
 | App | Replaces | Status | Install |
 | --- | --- | --- | --- |
+| **Rechner** (`rechner/`) | Google Calculator | alpha | [Obtainium](https://apps.obtainium.imranr.dev/redirect?r=obtainium://app/%7B%22id%22%3A%22app.rechner%22%2C%22url%22%3A%22https%3A%2F%2Fgit.mrblake.cc%2FMrBlake%2FNoGooleApps%22%2C%22author%22%3A%22MrBlake%22%2C%22name%22%3A%22Rechner%22%2C%22overrideSource%22%3A%22Codeberg%22%2C%22preferredApkIndex%22%3A0%2C%22additionalSettings%22%3A%22%7B%5C%22appId%5C%22%3A%5C%22app.rechner%5C%22%2C%5C%22includePrereleases%5C%22%3Atrue%2C%5C%22fallbackToOlderReleases%5C%22%3Atrue%2C%5C%22filterReleaseTitlesByRegEx%5C%22%3A%5C%22%5ERechner%20%5C%22%2C%5C%22apkFilterRegEx%5C%22%3A%5C%22%5Erechner-.%2A%5C%5C%5C%5C.apk%24%5C%22%2C%5C%22autoApkFilterByArch%5C%22%3Afalse%2C%5C%22verifyLatestTag%5C%22%3Afalse%2C%5C%22releaseTitleAsVersion%5C%22%3Afalse%7D%22%7D) · F-Droid: not yet |
 | **Uhr** (`uhr/`) | Google Clock / Pixel Clock | alpha, in daily testing | [Obtainium](https://apps.obtainium.imranr.dev/redirect?r=obtainium://app/%7B%22id%22%3A%22app.uhr%22%2C%22url%22%3A%22https%3A%2F%2Fgit.mrblake.cc%2FMrBlake%2FNoGooleApps%22%2C%22author%22%3A%22MrBlake%22%2C%22name%22%3A%22Uhr%22%2C%22overrideSource%22%3A%22Codeberg%22%2C%22preferredApkIndex%22%3A0%2C%22additionalSettings%22%3A%22%7B%5C%22appId%5C%22%3A%5C%22app.uhr%5C%22%2C%5C%22includePrereleases%5C%22%3Atrue%2C%5C%22fallbackToOlderReleases%5C%22%3Atrue%2C%5C%22filterReleaseTitlesByRegEx%5C%22%3A%5C%22%5EUhr%20%5C%22%2C%5C%22apkFilterRegEx%5C%22%3A%5C%22%5Euhr-.%2A%5C%5C%5C%5C.apk%24%5C%22%2C%5C%22autoApkFilterByArch%5C%22%3Afalse%2C%5C%22verifyLatestTag%5C%22%3Afalse%2C%5C%22releaseTitleAsVersion%5C%22%3Afalse%7D%22%7D) · F-Droid: not yet |
 | **Wetter** (`wetter/`) | Google Weather / Pixel Weather | alpha, in daily testing | [Obtainium](https://apps.obtainium.imranr.dev/redirect?r=obtainium://app/%7B%22id%22%3A%22app.wetter%22%2C%22url%22%3A%22https%3A%2F%2Fgit.mrblake.cc%2FMrBlake%2FNoGooleApps%22%2C%22author%22%3A%22MrBlake%22%2C%22name%22%3A%22Wetter%22%2C%22overrideSource%22%3A%22Codeberg%22%2C%22preferredApkIndex%22%3A0%2C%22additionalSettings%22%3A%22%7B%5C%22appId%5C%22%3A%5C%22app.wetter%5C%22%2C%5C%22includePrereleases%5C%22%3Atrue%2C%5C%22fallbackToOlderReleases%5C%22%3Atrue%2C%5C%22filterReleaseTitlesByRegEx%5C%22%3A%5C%22%5EWetter%20%5C%22%2C%5C%22apkFilterRegEx%5C%22%3A%5C%22%5Ewetter-.%2A%5C%5C%5C%5C.apk%24%5C%22%2C%5C%22autoApkFilterByArch%5C%22%3Afalse%2C%5C%22verifyLatestTag%5C%22%3Afalse%2C%5C%22releaseTitleAsVersion%5C%22%3Afalse%7D%22%7D) · F-Droid: not yet |
 
@@ -43,6 +44,24 @@ A weather app with the look and feel of Pixel Weather: an animated sky that chan
 
 Requires Android 10 (API 29) or newer.
 
+### Rechner
+
+A calculator with the flow of the Pixel calculator: live result while typing, a scientific row that expands into a full panel, and the history in a sheet you pull down from the display.
+
+- **Exact arithmetic.** Numbers are decimal, not floating point: 0,1 + 0,2 is 0,3, 1 ÷ 3 × 3 is 1, 100! is exact. Trigonometry snaps exact angles (sin 30° = 0,5, cos π = −1). The engine is covered by unit tests.
+- **Smart input:** one key for parentheses that opens or closes as needed, operators replace each other, implicit multiplication (2π, 3(4)), percent the way people expect (50 + 10 % = 55), unfinished input still shows a preview.
+- **Scientific:** √ π ^ ! · Deg/Rad · sin cos tan and their inverses (Inv) · e ln log · eˣ 10ˣ x².
+- **History** grouped by day, tap to reuse; copy, paste and a memory (MS/MR) from a long press on the display; wallpaper colours, light and dark.
+- **No permissions** except vibration for key feedback. No network.
+
+<p align="center">
+  <img src="docs/screenshots/rechner/S01-typing-light.png" width="200" alt="Typing with live result">
+  <img src="docs/screenshots/rechner/S02-scientific-dark.png" width="200" alt="Scientific panel">
+  <img src="docs/screenshots/rechner/S03-history-dark.png" width="200" alt="History">
+</p>
+
+Requires Android 10 (API 29) or newer.
+
 ### Uhr
 
 A clock and alarm app with the look and flow of the Pixel clock: alarms in expandable cards, world clock, several timers at once, stopwatch with laps, and a bedtime schedule.
@@ -51,7 +70,8 @@ A clock and alarm app with the look and flow of the Pixel clock: alarms in expan
 - **Ringing done right:** a full-screen screen over the lock screen with slide to snooze or stop, alarm-stream audio that gets louder gradually, vibration, automatic silence after a set time, and notifications for upcoming, snoozed and missed alarms. Volume keys can snooze or stop.
 - **No network permission at all.** World clock cities come from the system time zone database (names localised offline), sounds from the device, the app's own tone, or your own audio files.
 - **Also:** days and labels per alarm, pause until a date, skip the next ring, timers with ring progress and +1:00 that keep running in the background with a live countdown notification, stopwatch with fastest/slowest laps, analog or digital clock, wallpaper colours (Material You), three home-screen widgets (live digital clock, analog clock, next alarm).
-- **Coming next:** widget style options like Wetter, screensaver/night clock, sunrise alarm, sleep sounds, reordering world clocks.
+- **Bedtime extras:** own sleep sounds (rain, waves, deep noise) with a sleep timer that fades out, and a sunrise option that slowly brightens the screen 15 minutes before the wake-up alarm.
+- **Coming next:** widget style options like Wetter, screensaver/night clock.
 
 <p align="center">
   <img src="docs/screenshots/uhr/S01-alarms-dark.png" width="200" alt="Alarm list">
@@ -101,6 +121,16 @@ Same setup as Wetter, with the filters `^Uhr ` (release titles) and `^uhr-.*\.ap
 obtainium://app/%7B%22id%22%3A%22app.uhr%22%2C%22url%22%3A%22https%3A%2F%2Fgit.mrblake.cc%2FMrBlake%2FNoGooleApps%22%2C%22author%22%3A%22MrBlake%22%2C%22name%22%3A%22Uhr%22%2C%22overrideSource%22%3A%22Codeberg%22%2C%22preferredApkIndex%22%3A0%2C%22additionalSettings%22%3A%22%7B%5C%22appId%5C%22%3A%5C%22app.uhr%5C%22%2C%5C%22includePrereleases%5C%22%3Atrue%2C%5C%22fallbackToOlderReleases%5C%22%3Atrue%2C%5C%22filterReleaseTitlesByRegEx%5C%22%3A%5C%22%5EUhr%20%5C%22%2C%5C%22apkFilterRegEx%5C%22%3A%5C%22%5Euhr-.%2A%5C%5C%5C%5C.apk%24%5C%22%2C%5C%22autoApkFilterByArch%5C%22%3Afalse%2C%5C%22verifyLatestTag%5C%22%3Afalse%2C%5C%22releaseTitleAsVersion%5C%22%3Afalse%7D%22%7D
 ```
 
+### Rechner
+
+[<img src="https://raw.githubusercontent.com/ImranR98/Obtainium/main/assets/graphics/badge_obtainium.png" alt="Get it on Obtainium" height="54">](https://apps.obtainium.imranr.dev/redirect?r=obtainium://app/%7B%22id%22%3A%22app.rechner%22%2C%22url%22%3A%22https%3A%2F%2Fgit.mrblake.cc%2FMrBlake%2FNoGooleApps%22%2C%22author%22%3A%22MrBlake%22%2C%22name%22%3A%22Rechner%22%2C%22overrideSource%22%3A%22Codeberg%22%2C%22preferredApkIndex%22%3A0%2C%22additionalSettings%22%3A%22%7B%5C%22appId%5C%22%3A%5C%22app.rechner%5C%22%2C%5C%22includePrereleases%5C%22%3Atrue%2C%5C%22fallbackToOlderReleases%5C%22%3Atrue%2C%5C%22filterReleaseTitlesByRegEx%5C%22%3A%5C%22%5ERechner%20%5C%22%2C%5C%22apkFilterRegEx%5C%22%3A%5C%22%5Erechner-.%2A%5C%5C%5C%5C.apk%24%5C%22%2C%5C%22autoApkFilterByArch%5C%22%3Afalse%2C%5C%22verifyLatestTag%5C%22%3Afalse%2C%5C%22releaseTitleAsVersion%5C%22%3Afalse%7D%22%7D)
+
+Filters: `^Rechner ` (release titles) and `^rechner-.*\.apk$` (APKs). Raw link:
+
+```
+obtainium://app/%7B%22id%22%3A%22app.rechner%22%2C%22url%22%3A%22https%3A%2F%2Fgit.mrblake.cc%2FMrBlake%2FNoGooleApps%22%2C%22author%22%3A%22MrBlake%22%2C%22name%22%3A%22Rechner%22%2C%22overrideSource%22%3A%22Codeberg%22%2C%22preferredApkIndex%22%3A0%2C%22additionalSettings%22%3A%22%7B%5C%22appId%5C%22%3A%5C%22app.rechner%5C%22%2C%5C%22includePrereleases%5C%22%3Atrue%2C%5C%22fallbackToOlderReleases%5C%22%3Atrue%2C%5C%22filterReleaseTitlesByRegEx%5C%22%3A%5C%22%5ERechner%20%5C%22%2C%5C%22apkFilterRegEx%5C%22%3A%5C%22%5Erechner-.%2A%5C%5C%5C%5C.apk%24%5C%22%2C%5C%22autoApkFilterByArch%5C%22%3Afalse%2C%5C%22verifyLatestTag%5C%22%3Afalse%2C%5C%22releaseTitleAsVersion%5C%22%3Afalse%7D%22%7D
+```
+
 **Releases.** Every app is published as a release titled `<App> <version>` (for example `Wetter 0.1.0`, tag `wetter-v0.1.0`) with one asset named `<app>-<version>.apk`. Obtainium shows *"no matching version"* until the first release of an app exists.
 
 **F-Droid:** not available yet. The apps contain no proprietary libraries, so an F-Droid build is planned (either the main repository or a self-hosted F-Droid repo).
@@ -119,6 +149,8 @@ Every app is rebuilt with **[Replica](https://github.com/Jakeschincariol/replica
 | 4 | `replica-build` | The app itself, screen by screen, with a [build log](replica/wetter/build-log.md) and [screenshots](replica/wetter/clone-screens/) rendered from a real API response |
 | next | `replica-test`, `replica-diff`, `replica-entrepreneur`, `replica-brand`, `replica-launch`, `replica-deploy`, `replica-backend` | QA, parity scoring against the original, reading real user reviews for improvements, naming and branding, store listing, release |
 
+**Rechner** too: [recon](replica/rechner/recon.md), [architecture](replica/rechner/architecture.md), [tokens](replica/rechner/design/tokens.json) (24 pairs AA), [build log](replica/rechner/build-log.md), [screenshots](replica/rechner/clone-screens/).
+
 **Uhr** went through the same steps from scratch: [recon](replica/uhr/recon.md) (17 screens, 9 flows), [architecture](replica/uhr/architecture.md), [design tokens](replica/uhr/design/tokens.json) (39 pairs AA), [build log](replica/uhr/build-log.md) and [screenshots](replica/uhr/clone-screens/).
 
 The rules Replica enforces, and that this project follows:
@@ -142,7 +174,7 @@ Each commit says what changed and carries a `Co-Authored-By` line for the AI.
 Requirements: JDK 17 or newer and the Android SDK (platform 36).
 
 ```bash
-cd wetter        # or: cd uhr
+cd wetter        # or: cd uhr, cd rechner
 ./gradlew :app:assembleRelease            # APK in app/build/outputs/apk/release/
 ./gradlew :app:testDebugUnitTest          # unit + screenshot tests
 ./gradlew :app:recordRoborazziDebug       # re-render replica/wetter/clone-screens/
@@ -155,6 +187,7 @@ Release builds are signed with the project key from `~/.android/nogoogleapps-rel
 ```
 replica/<app>/    recon, architecture, design system, build log, screenshots (one folder per app)
 wetter/           the weather app (Kotlin, Jetpack Compose, Glance widgets, Room, WorkManager)
+rechner/          the calculator (Kotlin, Jetpack Compose, own exact expression engine)
 uhr/              the clock and alarm app (Kotlin, Jetpack Compose, AlarmManager, Glance, Room)
 ```
 

rechner/.gitignore

@@ -0,0 +1,6 @@
+.gradle/
+build/
+local.properties
+.idea/
+*.iml
+.kotlin/

rechner/app/build.gradle.kts

@@ -0,0 +1,93 @@
+import java.util.Properties
+
+plugins {
+    id("com.android.application")
+    id("org.jetbrains.kotlin.android")
+    id("org.jetbrains.kotlin.plugin.compose")
+    id("com.google.devtools.ksp")
+    id("io.github.takahirom.roborazzi")
+}
+
+android {
+    namespace = "app.rechner"
+    compileSdk = 36
+
+    defaultConfig {
+        applicationId = "app.rechner"
+        minSdk = 29
+        targetSdk = 36
+        versionCode = 1
+        versionName = "0.1.0"
+    }
+
+    // Release key lives outside the repo; without it, release builds fall back to the debug key (local only).
+    val keyProps = Properties().apply {
+        val f = file(System.getProperty("user.home") + "/.android/nogoogleapps-release.properties")
+        if (f.exists()) f.inputStream().use { load(it) }
+    }
+    signingConfigs {
+        if (keyProps.isNotEmpty()) create("release") {
+            storeFile = file(keyProps.getProperty("storeFile"))
+            storePassword = keyProps.getProperty("storePassword")
+            keyAlias = keyProps.getProperty("keyAlias")
+            keyPassword = keyProps.getProperty("keyPassword")
+        }
+    }
+
+    buildTypes {
+        debug {
+            // installs next to the release app from Obtainium
+            applicationIdSuffix = ".debug"
+            resValue("string", "app_name", "Rechner (Debug)")
+        }
+        release {
+            resValue("string", "app_name", "Rechner")
+            isMinifyEnabled = true
+            isShrinkResources = true
+            signingConfig = signingConfigs.findByName("release") ?: signingConfigs.getByName("debug")
+            proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
+        }
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+    buildFeatures { compose = true }
+    testOptions { unitTests { isIncludeAndroidResources = true } }
+}
+
+kotlin { compilerOptions { jvmTarget.set(org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17) } }
+
+ksp { arg("room.schemaLocation", "$projectDir/schemas") }
+
+dependencies {
+    val composeBom = platform("androidx.compose:compose-bom:2025.10.01")
+    implementation(composeBom)
+    implementation("androidx.compose.ui:ui")
+    implementation("androidx.compose.ui:ui-tooling-preview")
+    implementation("androidx.compose.foundation:foundation")
+    implementation("androidx.compose.material3:material3")
+    implementation("androidx.compose.material:material-icons-extended")
+    debugImplementation("androidx.compose.ui:ui-tooling")
+
+    implementation("androidx.activity:activity-compose:1.11.0")
+    implementation("androidx.core:core-ktx:1.17.0")
+    implementation("androidx.lifecycle:lifecycle-runtime-compose:2.9.4")
+    implementation("androidx.lifecycle:lifecycle-viewmodel-compose:2.9.4")
+
+    implementation("androidx.room:room-runtime:2.7.0")
+    implementation("androidx.room:room-ktx:2.7.0")
+    ksp("androidx.room:room-compiler:2.7.0")
+    implementation("androidx.datastore:datastore-preferences:1.1.7")
+
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.10.2")
+
+    testImplementation("junit:junit:4.13.2")
+    testImplementation("org.robolectric:robolectric:4.15.1")
+    testImplementation("androidx.compose.ui:ui-test-junit4")
+    debugImplementation("androidx.compose.ui:ui-test-manifest")
+    testImplementation("io.github.takahirom.roborazzi:roborazzi:1.46.1")
+    testImplementation("io.github.takahirom.roborazzi:roborazzi-compose:1.46.1")
+}
+
+roborazzi { outputDir.set(rootProject.file("../replica/rechner/clone-screens")) }

rechner/app/schemas/app.rechner.data.CalcDb/1.json

@@ -0,0 +1,60 @@
+{
+  "formatVersion": 1,
+  "database": {
+    "version": 1,
+    "identityHash": "68577f81880de5c04e4721ad8ba32e4e",
+    "entities": [
+      {
+        "tableName": "history",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, `expression` TEXT NOT NULL, `result` TEXT NOT NULL, `created_at` INTEGER NOT NULL)",
+        "fields": [
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "expression",
+            "columnName": "expression",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "result",
+            "columnName": "result",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "createdAt",
+            "columnName": "created_at",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": true,
+          "columnNames": [
+            "id"
+          ]
+        },
+        "indices": [
+          {
+            "name": "index_history_created_at",
+            "unique": false,
+            "columnNames": [
+              "created_at"
+            ],
+            "orders": [],
+            "createSql": "CREATE INDEX IF NOT EXISTS `index_history_created_at` ON `${TABLE_NAME}` (`created_at`)"
+          }
+        ]
+      }
+    ],
+    "setupQueries": [
+      "CREATE TABLE IF NOT EXISTS room_master_table (id INTEGER PRIMARY KEY,identity_hash TEXT)",
+      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, '68577f81880de5c04e4721ad8ba32e4e')"
+    ]
+  }
+}

rechner/app/src/main/AndroidManifest.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- no INTERNET: a calculator has nothing to send anywhere -->
+    <uses-permission android:name="android.permission.VIBRATE" />
+    <application
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:roundIcon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:supportsRtl="true"
+        android:theme="@android:style/Theme.Material.NoActionBar">
+        <activity android:name=".MainActivity" android:exported="true" android:windowSoftInputMode="stateAlwaysHidden">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+                <category android:name="android.intent.category.APP_CALCULATOR" />
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>

rechner/app/src/main/java/app/rechner/MainActivity.kt

@@ -0,0 +1,26 @@
+package app.rechner
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.activity.enableEdgeToEdge
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import app.rechner.data.Graph
+import app.rechner.data.Prefs
+import app.rechner.ui.CalculatorScreen
+import app.rechner.ui.CalculatorViewModel
+import app.rechner.ui.theme.CalcTheme
+
+class MainActivity : ComponentActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        enableEdgeToEdge()
+        Graph.init(this)
+        val vm = CalculatorViewModel.get(this)
+        setContent {
+            val prefs by Graph.store.prefs.collectAsState(initial = Prefs())
+            CalcTheme(prefs.theme) { CalculatorScreen(vm, prefs) }
+        }
+    }
+}

rechner/app/src/main/java/app/rechner/data/Data.kt

@@ -0,0 +1,79 @@
+package app.rechner.data
+
+import android.content.Context
+import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.core.stringPreferencesKey
+import androidx.datastore.preferences.preferencesDataStore
+import androidx.room.ColumnInfo
+import androidx.room.Dao
+import androidx.room.Database
+import androidx.room.Entity
+import androidx.room.Index
+import androidx.room.Insert
+import androidx.room.PrimaryKey
+import androidx.room.Query
+import androidx.room.Room
+import androidx.room.RoomDatabase
+import app.rechner.engine.Angle
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.map
+
+@Entity(tableName = "history", indices = [Index("created_at")])
+data class HistoryEntry(
+    @PrimaryKey(autoGenerate = true) val id: Long = 0,
+    val expression: String,
+    val result: String,
+    @ColumnInfo(name = "created_at") val createdAt: Long = System.currentTimeMillis(),
+)
+
+@Dao
+interface HistoryDao {
+    @Query("SELECT * FROM history ORDER BY created_at") fun all(): Flow<List<HistoryEntry>>
+    @Insert suspend fun insert(e: HistoryEntry)
+    @Query("DELETE FROM history") suspend fun clear()
+    /** keep the list bounded */
+    @Query("DELETE FROM history WHERE id NOT IN (SELECT id FROM history ORDER BY created_at DESC LIMIT 500)") suspend fun trim()
+}
+
+@Database(entities = [HistoryEntry::class], version = 1, exportSchema = true)
+abstract class CalcDb : RoomDatabase() {
+    abstract fun history(): HistoryDao
+}
+
+enum class ThemeMode { SYSTEM, LIGHT, DARK }
+
+data class Prefs(val angle: Angle = Angle.DEG, val memory: String? = null, val expression: String = "", val theme: ThemeMode = ThemeMode.SYSTEM)
+
+private val Context.store by preferencesDataStore("calc")
+
+class Store(private val context: Context) {
+    private val kAngle = stringPreferencesKey("angle")
+    private val kMemory = stringPreferencesKey("memory")
+    private val kExpr = stringPreferencesKey("expression")
+    private val kTheme = stringPreferencesKey("theme")
+
+    val prefs: Flow<Prefs> = context.store.data.map { p ->
+        Prefs(
+            angle = p[kAngle]?.let { runCatching { Angle.valueOf(it) }.getOrNull() } ?: Angle.DEG,
+            memory = p[kMemory],
+            expression = p[kExpr] ?: "",
+            theme = p[kTheme]?.let { runCatching { ThemeMode.valueOf(it) }.getOrNull() } ?: ThemeMode.SYSTEM,
+        )
+    }
+
+    suspend fun setAngle(a: Angle) = context.store.edit { it[kAngle] = a.name }
+    suspend fun setMemory(v: String?) = context.store.edit { if (v == null) it.remove(kMemory) else it[kMemory] = v }
+    suspend fun setExpression(v: String) = context.store.edit { it[kExpr] = v }
+    suspend fun setTheme(t: ThemeMode) = context.store.edit { it[kTheme] = t.name }
+}
+
+object Graph {
+    lateinit var history: HistoryDao private set
+    lateinit var store: Store private set
+    fun init(context: Context) {
+        if (::store.isInitialized) return
+        val app = context.applicationContext
+        history = Room.databaseBuilder(app, CalcDb::class.java, "calc.db").build().history()
+        store = Store(app)
+    }
+}

rechner/app/src/main/java/app/rechner/engine/Editor.kt

@@ -0,0 +1,51 @@
+package app.rechner.engine
+
+/**
+ * Keypad editing on the expression text. Operators replace a trailing operator, the
+ * parenthesis key opens or closes depending on context, backspace removes whole tokens.
+ */
+object Editor {
+    private val binary = setOf('+', '−', '×', '÷', '^')
+    private val functionTokens = listOf("sin⁻¹(", "cos⁻¹(", "tan⁻¹(", "sin(", "cos(", "tan(", "ln(", "log(")
+
+    fun input(expr: String, key: String, decimal: Char): String {
+        val last = expr.lastOrNull()
+        return when {
+            key.length == 1 && key[0].isDigit() -> expr + key
+            key == decimal.toString() -> {
+                val number = expr.takeLastWhile { it.isDigit() || it == decimal || it == '.' }
+                when {
+                    decimal in number -> expr
+                    number.isEmpty() -> expr + "0" + decimal
+                    else -> expr + decimal
+                }
+            }
+            key.length == 1 && key[0] in binary -> {
+                val op = key[0]
+                when {
+                    expr.isEmpty() -> if (op == '−') "−" else expr
+                    last != null && last in binary -> {
+                        // "×−" is allowed for a negative factor, otherwise replace the operator
+                        if (op == '−' && last != '−' && last != '+') expr + op else expr.dropLast(1) + op
+                    }
+                    last == '(' -> if (op == '−') expr + op else expr
+                    else -> expr + op
+                }
+            }
+            key == "()" -> {
+                val open = expr.count { it == '(' } - expr.count { it == ')' }
+                val closeable = open > 0 && last != null && last != '(' && last !in binary
+                if (closeable) "$expr)" else "$expr("
+            }
+            key == "%" || key == "!" -> if (last != null && (last.isDigit() || last == ')' || last == 'π' || last == 'e' || last == '!' || last == '%')) expr + key else expr
+            key == "√" || key == "π" || key == "e" -> expr + key
+            key.endsWith("(") -> expr + key
+            else -> expr + key
+        }
+    }
+
+    fun backspace(expr: String): String {
+        functionTokens.firstOrNull { expr.endsWith(it) }?.let { return expr.dropLast(it.length) }
+        return expr.dropLast(1)
+    }
+}

rechner/app/src/main/java/app/rechner/engine/Engine.kt

@@ -0,0 +1,297 @@
+package app.rechner.engine
+
+import java.math.BigDecimal
+import java.math.BigInteger
+import java.math.MathContext
+import java.math.RoundingMode
+import kotlin.math.PI
+
+enum class Angle { DEG, RAD }
+
+sealed interface Outcome {
+    data class Value(val value: BigDecimal) : Outcome
+    data class Error(val kind: ErrorKind) : Outcome
+    /** Nothing to show yet (empty or only an operator). */
+    data object Empty : Outcome
+}
+
+enum class ErrorKind { DIV_ZERO, DOMAIN, TOO_BIG, SYNTAX }
+
+class CalcException(val kind: ErrorKind) : Exception(kind.name)
+
+/**
+ * Parser and evaluator for the expressions the keypad produces.
+ * Display symbols: digits, decimal separator, + − × ÷ ^ ! % √ π e ( ), and the functions
+ * sin cos tan sin⁻¹ cos⁻¹ tan⁻¹ ln log. Unfinished input is tolerated: open parentheses are
+ * closed and a trailing operator is ignored, so the live preview always has something to show.
+ */
+class Engine(private val decimalSeparator: Char = ',') {
+    private val mc = MathContext(50, RoundingMode.HALF_EVEN)
+
+    fun evaluate(expression: String, angle: Angle = Angle.DEG, lenient: Boolean = true): Outcome {
+        var tokens = runCatching { tokenize(expression) }.getOrElse { return Outcome.Error(ErrorKind.SYNTAX) }
+        if (lenient) while (tokens.isNotEmpty() && tokens.last().let { it is Tok.Op || it is Tok.Func || it == Tok.Sqrt || it == Tok.Open }) tokens = tokens.dropLast(1)
+        if (tokens.isEmpty()) return Outcome.Empty
+        val open = tokens.count { it == Tok.Open } - tokens.count { it == Tok.Close }
+        if (open > 0) tokens = tokens + List(open) { Tok.Close }
+        return try {
+            val p = Parser(tokens, angle)
+            val v = p.parseExpression()
+            if (!p.atEnd()) throw CalcException(ErrorKind.SYNTAX)
+            if (v.abs() > LIMIT) throw CalcException(ErrorKind.TOO_BIG)
+            Outcome.Value(v)
+        } catch (e: CalcException) {
+            Outcome.Error(e.kind)
+        } catch (e: ArithmeticException) {
+            Outcome.Error(ErrorKind.DOMAIN)
+        }
+    }
+
+    // --- tokens --------------------------------------------------------------------------------
+
+    sealed interface Tok {
+        data class Num(val v: BigDecimal) : Tok
+        data class Op(val c: Char) : Tok
+        data class Func(val name: String) : Tok
+        data object Open : Tok
+        data object Close : Tok
+        data object Fact : Tok
+        data object Percent : Tok
+        data object Sqrt : Tok
+        data object Pi : Tok
+        data object E : Tok
+    }
+
+    private val functions = listOf("sin⁻¹", "cos⁻¹", "tan⁻¹", "sin", "cos", "tan", "ln", "log")
+
+    fun tokenize(s: String): List<Tok> {
+        val out = mutableListOf<Tok>()
+        var i = 0
+        while (i < s.length) {
+            val c = s[i]
+            when {
+                c.isWhitespace() || c == '.' && decimalSeparator == ',' -> i++ // grouping dots are cosmetic
+                c.isDigit() || c == decimalSeparator -> {
+                    val start = i
+                    while (i < s.length && (s[i].isDigit() || s[i] == decimalSeparator || (s[i] == '.' && decimalSeparator == ','))) i++
+                    val raw = s.substring(start, i).filter { it != '.' || decimalSeparator == '.' }.replace(decimalSeparator, '.')
+                    if (raw.count { it == '.' } > 1) throw CalcException(ErrorKind.SYNTAX)
+                    // "E" exponent from pasted scientific results
+                    var text = if (raw == ".") "0" else raw
+                    if (i < s.length && s[i] == 'E' && i + 1 < s.length && (s[i + 1].isDigit() || s[i + 1] == '−' || s[i + 1] == '-')) {
+                        val e0 = i + 1
+                        i += 2
+                        while (i < s.length && s[i].isDigit()) i++
+                        text += "E" + s.substring(e0, i).replace('−', '-')
+                    }
+                    out += Tok.Num(BigDecimal(text))
+                }
+                c == '+' -> { out += Tok.Op('+'); i++ }
+                c == '−' || c == '-' -> { out += Tok.Op('−'); i++ }
+                c == '×' || c == '*' -> { out += Tok.Op('×'); i++ }
+                c == '÷' || c == '/' -> { out += Tok.Op('÷'); i++ }
+                c == '^' -> { out += Tok.Op('^'); i++ }
+                c == '(' -> { out += Tok.Open; i++ }
+                c == ')' -> { out += Tok.Close; i++ }
+                c == '!' -> { out += Tok.Fact; i++ }
+                c == '%' -> { out += Tok.Percent; i++ }
+                c == '√' -> { out += Tok.Sqrt; i++ }
+                c == 'π' -> { out += Tok.Pi; i++ }
+                c == 'e' -> { out += Tok.E; i++ }
+                else -> {
+                    val f = functions.firstOrNull { s.startsWith(it, i) } ?: throw CalcException(ErrorKind.SYNTAX)
+                    out += Tok.Func(f); i += f.length
+                    if (i < s.length && s[i] == '(') { out += Tok.Open; i++ } else out += Tok.Open
+                }
+            }
+        }
+        return out
+    }
+
+    // --- parser --------------------------------------------------------------------------------
+
+    private inner class Parser(private val t: List<Tok>, private val angle: Angle) {
+        private var p = 0
+        fun atEnd() = p >= t.size
+        private fun peek() = t.getOrNull(p)
+        private fun next() = t[p++]
+
+        /** additive: a + b% means a + a·b/100 */
+        fun parseExpression(): BigDecimal {
+            var v = parseTerm()
+            while (true) {
+                val op = (peek() as? Tok.Op)?.c ?: break
+                if (op != '+' && op != '−') break
+                next()
+                val (rhs, wasPercent) = parseTermWithPercent()
+                val r = if (wasPercent) v.multiply(rhs, mc) else rhs
+                v = if (op == '+') v.add(r, mc) else v.subtract(r, mc)
+            }
+            return v
+        }
+
+        private fun parseTermWithPercent(): Pair<BigDecimal, Boolean> {
+            val start = p
+            val v = parseTerm()
+            // a term that is just "x%" counts as a percentage of the left side
+            val plainPercent = p - start >= 2 && t[p - 1] == Tok.Percent && t.subList(start, p - 1).none { it is Tok.Op || it == Tok.Percent }
+            return v to plainPercent
+        }
+
+        private fun startsPrimary(k: Tok?) = k is Tok.Num || k == Tok.Open || k is Tok.Func || k == Tok.Sqrt || k == Tok.Pi || k == Tok.E
+
+        private fun parseTerm(): BigDecimal {
+            var v = parseUnary()
+            while (true) {
+                val k = peek()
+                v = when {
+                    k is Tok.Op && k.c == '×' -> { next(); v.multiply(parseUnary(), mc) }
+                    k is Tok.Op && k.c == '÷' -> {
+                        next()
+                        val d = parseUnary()
+                        if (d.signum() == 0) throw CalcException(ErrorKind.DIV_ZERO)
+                        v.divide(d, mc)
+                    }
+                    startsPrimary(k) -> v.multiply(parseUnary(), mc) // implicit: 2π, 3(4), 2√9
+                    else -> return v
+                }
+            }
+        }
+
+        private fun parseUnary(): BigDecimal {
+            val k = peek()
+            if (k is Tok.Op && k.c == '−') { next(); return parseUnary().negate() }
+            if (k is Tok.Op && k.c == '+') { next(); return parseUnary() }
+            return parsePower()
+        }
+
+        /** right associative, binds tighter than unary minus on the left: −2^2 = −4 */
+        private fun parsePower(): BigDecimal {
+            val base = parsePostfix()
+            val k = peek()
+            if (k is Tok.Op && k.c == '^') {
+                next()
+                return pow(base, parseUnary())
+            }
+            return base
+        }
+
+        private fun parsePostfix(): BigDecimal {
+            var v = parsePrimary()
+            while (true) {
+                v = when (peek()) {
+                    Tok.Fact -> { next(); factorial(v) }
+                    Tok.Percent -> { next(); v.divide(BigDecimal(100), mc) }
+                    else -> return v
+                }
+            }
+        }
+
+        private fun parsePrimary(): BigDecimal {
+            return when (val k = next()) {
+                is Tok.Num -> k.v
+                Tok.Pi -> PI_BIG
+                Tok.E -> E_BIG
+                Tok.Open -> {
+                    if (peek() == Tok.Close) throw CalcException(ErrorKind.SYNTAX)
+                    val v = parseExpression()
+                    if (peek() != Tok.Close) throw CalcException(ErrorKind.SYNTAX)
+                    next(); v
+                }
+                Tok.Sqrt -> {
+                    val x = parsePostfix()
+                    if (x.signum() < 0) throw CalcException(ErrorKind.DOMAIN)
+                    x.sqrt(mc)
+                }
+                is Tok.Func -> {
+                    if (peek() != Tok.Open) throw CalcException(ErrorKind.SYNTAX)
+                    next()
+                    val x = parseExpression()
+                    if (peek() != Tok.Close) throw CalcException(ErrorKind.SYNTAX)
+                    next()
+                    applyFunction(k.name, x)
+                }
+                else -> throw CalcException(ErrorKind.SYNTAX)
+            }
+        }
+
+        private fun toRad(x: Double) = if (angle == Angle.DEG) x * PI / 180 else x
+        private fun fromRad(x: Double) = if (angle == Angle.DEG) x * 180 / PI else x
+
+        private fun applyFunction(name: String, x: BigDecimal): BigDecimal {
+            val d = x.toDouble()
+            val r = when (name) {
+                "sin" -> exactTrig(x, 0) ?: kotlin.math.sin(toRad(d))
+                "cos" -> exactTrig(x, 1) ?: kotlin.math.cos(toRad(d))
+                "tan" -> {
+                    if (angle == Angle.DEG && x.remainder(BigDecimal(180)).abs().compareTo(BigDecimal(90)) == 0) throw CalcException(ErrorKind.DOMAIN)
+                    exactTrig(x, 2) ?: kotlin.math.tan(toRad(d))
+                }
+                "sin⁻¹" -> { if (d < -1 || d > 1) throw CalcException(ErrorKind.DOMAIN); fromRad(kotlin.math.asin(d)) }
+                "cos⁻¹" -> { if (d < -1 || d > 1) throw CalcException(ErrorKind.DOMAIN); fromRad(kotlin.math.acos(d)) }
+                "tan⁻¹" -> fromRad(kotlin.math.atan(d))
+                "ln" -> { if (d <= 0) throw CalcException(ErrorKind.DOMAIN); kotlin.math.ln(d) }
+                "log" -> { if (d <= 0) throw CalcException(ErrorKind.DOMAIN); exactLog10(x) ?: kotlin.math.log10(d) }
+                else -> throw CalcException(ErrorKind.SYNTAX)
+            }
+            if (r.isNaN() || r.isInfinite()) throw CalcException(ErrorKind.DOMAIN)
+            return clean(r)
+        }
+
+        /** sin/cos/tan of multiples of 30° and 45° (and π fractions in radians) are exact. */
+        private fun exactTrig(x: BigDecimal, which: Int): Double? {
+            val deg = if (angle == Angle.DEG) x else return null
+            val r = deg.remainder(BigDecimal(360)).let { if (it.signum() < 0) it.add(BigDecimal(360)) else it }
+            if (r.stripTrailingZeros().scale() > 0) return null
+            val a = r.toInt()
+            val table = mapOf(0 to Triple(0.0, 1.0, 0.0), 30 to Triple(.5, Double.NaN, Double.NaN), 90 to Triple(1.0, 0.0, Double.NaN),
+                150 to Triple(.5, Double.NaN, Double.NaN), 180 to Triple(0.0, -1.0, 0.0), 210 to Triple(-.5, Double.NaN, Double.NaN),
+                270 to Triple(-1.0, 0.0, Double.NaN), 330 to Triple(-.5, Double.NaN, Double.NaN),
+                45 to Triple(Double.NaN, Double.NaN, 1.0), 135 to Triple(Double.NaN, Double.NaN, -1.0), 225 to Triple(Double.NaN, Double.NaN, 1.0), 315 to Triple(Double.NaN, Double.NaN, -1.0),
+                60 to Triple(Double.NaN, .5, Double.NaN), 120 to Triple(Double.NaN, -.5, Double.NaN), 240 to Triple(Double.NaN, -.5, Double.NaN), 300 to Triple(Double.NaN, .5, Double.NaN))
+            val e = table[a] ?: return null
+            val v = when (which) { 0 -> e.first; 1 -> e.second; else -> e.third }
+            return v.takeIf { !it.isNaN() }
+        }
+
+        private fun exactLog10(x: BigDecimal): Double? {
+            val s = x.stripTrailingZeros()
+            if (s.unscaledValue() == BigInteger.ONE) return (-s.scale()).toDouble()
+            return null
+        }
+
+        private fun pow(base: BigDecimal, exp: BigDecimal): BigDecimal {
+            val e = exp.stripTrailingZeros()
+            if (e.scale() <= 0 && e.abs() <= BigDecimal(9999)) {
+                val n = e.toInt()
+                if (base.signum() == 0 && n < 0) throw CalcException(ErrorKind.DIV_ZERO)
+                val r = base.pow(kotlin.math.abs(n), mc)
+                return if (n < 0) BigDecimal.ONE.divide(r, mc) else r
+            }
+            if (base.signum() < 0) throw CalcException(ErrorKind.DOMAIN)
+            val r = Math.pow(base.toDouble(), exp.toDouble())
+            if (r.isNaN() || r.isInfinite()) throw CalcException(ErrorKind.TOO_BIG)
+            return clean(r)
+        }
+
+        private fun factorial(x: BigDecimal): BigDecimal {
+            val s = x.stripTrailingZeros()
+            if (s.signum() < 0 || s.scale() > 0) throw CalcException(ErrorKind.DOMAIN)
+            if (s > BigDecimal(1000)) throw CalcException(ErrorKind.TOO_BIG)
+            var r = BigInteger.ONE
+            for (i in 2..s.toInt()) r = r.multiply(BigInteger.valueOf(i.toLong()))
+            return BigDecimal(r)
+        }
+
+        /** Floating results get 15 significant digits, so cos(π) is −1 and not −0.9999999999999999. */
+        private fun clean(d: Double): BigDecimal = BigDecimal(d).round(MathContext(15, RoundingMode.HALF_EVEN)).let {
+            if (it.abs() < BigDecimal("1E-14")) BigDecimal.ZERO else it
+        }
+    }
+
+    companion object {
+        val PI_BIG = BigDecimal("3.14159265358979323846264338327950288419716939937510")
+        val E_BIG = BigDecimal("2.71828182845904523536028747135266249775724709369995")
+        private val LIMIT = BigDecimal("1E5000")
+    }
+}

rechner/app/src/main/java/app/rechner/engine/Format.kt

@@ -0,0 +1,36 @@
+package app.rechner.engine
+
+import java.math.BigDecimal
+import java.math.MathContext
+import java.math.RoundingMode
+
+/** Turns exact results into display text: locale separators, no trailing zeros, scientific when huge or tiny. */
+class NumberFormat(private val decimal: Char = ',', private val grouping: Char = '.') {
+    fun format(v: BigDecimal, maxDigits: Int = 12): String {
+        if (v.signum() == 0) return "0"
+        val abs = v.abs()
+        val sci = abs >= BigDecimal.TEN.pow(maxDigits) || abs < BigDecimal("1E-6")
+        if (sci) {
+            val r = v.round(MathContext(maxDigits - 3, RoundingMode.HALF_EVEN))
+            val exp = r.precision() - r.scale() - 1
+            val mant = r.movePointLeft(exp).stripTrailingZeros()
+            return plain(mant) + "E" + (if (exp < 0) "−" else "") + kotlin.math.abs(exp)
+        }
+        val intDigits = abs.setScale(0, RoundingMode.DOWN).toPlainString().length
+        val r = v.setScale((maxDigits - intDigits).coerceAtLeast(0), RoundingMode.HALF_EVEN).stripTrailingZeros()
+        return plain(r)
+    }
+
+    /** Every digit, for copy, scrolling and the history. */
+    fun full(v: BigDecimal): String = plain(v.round(MathContext(40, RoundingMode.HALF_EVEN)).stripTrailingZeros())
+
+    private fun plain(v: BigDecimal): String {
+        val s = v.toPlainString()
+        val neg = s.startsWith("-")
+        val body = s.removePrefix("-")
+        val int = body.substringBefore('.')
+        val frac = body.substringAfter('.', "")
+        val grouped = int.reversed().chunked(3).joinToString(grouping.toString()).reversed()
+        return (if (neg) "−" else "") + grouped + if (frac.isNotEmpty()) decimal + frac else ""
+    }
+}

rechner/app/src/main/java/app/rechner/ui/CalculatorScreen.kt

@@ -0,0 +1,379 @@
+package app.rechner.ui
+
+import android.content.ClipData
+import android.content.ClipboardManager
+import android.content.Context
+import android.view.HapticFeedbackConstants
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.core.Animatable
+import androidx.compose.animation.core.animateDpAsState
+import androidx.compose.animation.core.spring
+import androidx.compose.animation.expandVertically
+import androidx.compose.animation.shrinkVertically
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.combinedClickable
+import androidx.compose.foundation.gestures.Orientation
+import androidx.compose.foundation.gestures.draggable
+import androidx.compose.foundation.gestures.rememberDraggableState
+import androidx.compose.foundation.horizontalScroll
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.interaction.collectIsPressedAsState
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.BoxWithConstraints
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.RowScope
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.aspectRatio
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.navigationBarsPadding
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.statusBarsPadding
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.rounded.Backspace
+import androidx.compose.material.icons.rounded.ExpandLess
+import androidx.compose.material.icons.rounded.ExpandMore
+import androidx.compose.material.icons.rounded.History
+import androidx.compose.material.icons.rounded.MoreVert
+import androidx.compose.material3.DropdownMenu
+import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.layout.onGloballyPositioned
+import androidx.compose.ui.layout.positionInParent
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.platform.LocalView
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.semantics.contentDescription
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import app.rechner.R
+import app.rechner.data.Graph
+import app.rechner.data.HistoryEntry
+import app.rechner.data.Prefs
+import app.rechner.data.ThemeMode
+import app.rechner.engine.Angle
+import app.rechner.engine.ErrorKind
+import app.rechner.ui.theme.LocalCalcColors
+import app.rechner.ui.theme.WType
+import kotlinx.coroutines.launch
+import java.time.Instant
+import java.time.LocalDate
+import java.time.ZoneId
+import java.time.format.DateTimeFormatter
+import java.time.format.FormatStyle
+
+@Composable
+fun CalculatorScreen(vm: CalculatorViewModel, prefs: Prefs) {
+    val state by vm.state.collectAsState()
+    val history by vm.history.collectAsState()
+    CalculatorContent(
+        state = state, history = history, prefs = prefs, decimal = vm.decimal,
+        onKey = vm::key, onBackspace = vm::backspace, onClear = vm::clear, onEquals = vm::equals,
+        onInsert = vm::insert, onAngle = vm::setAngle, onClearHistory = { vm.clearHistory() },
+        onMemoryStore = { vm.memoryStore(it) }, currentValue = vm::currentValue,
+    )
+}
+
+@Composable
+fun CalculatorContent(
+    state: CalcState,
+    history: List<HistoryEntry>,
+    prefs: Prefs,
+    decimal: Char,
+    onKey: (String) -> Unit,
+    onBackspace: () -> Unit,
+    onClear: () -> Unit,
+    onEquals: () -> Unit,
+    onInsert: (String) -> Unit,
+    onAngle: (Angle) -> Unit,
+    onClearHistory: () -> Unit,
+    onMemoryStore: (String) -> Unit,
+    currentValue: () -> String,
+    initialHistoryOpen: Boolean = false,
+    initialScientific: Boolean = false,
+) {
+    val c = LocalCalcColors.current
+    var scientific by rememberSaveable { mutableStateOf(initialScientific) }
+    var inverse by rememberSaveable { mutableStateOf(false) }
+    val scope = rememberCoroutineScope()
+    val view = LocalView.current
+    val tap: (() -> Unit) -> () -> Unit = { f -> { view.performHapticFeedback(HapticFeedbackConstants.KEYBOARD_TAP); f() } }
+
+    BoxWithConstraints(Modifier.fillMaxSize().background(c.bg)) {
+        val density = LocalDensity.current
+        val fullPx = with(density) { maxHeight.toPx() }
+        // the display is a sheet: collapsed above the keypad, pulled down it shows the history
+        val sheet = remember { Animatable(if (initialHistoryOpen) 1f else 0f) }
+        var keypadTop by remember { mutableStateOf(maxHeight * .4f) }
+        Column(Modifier.fillMaxSize()) {
+            Spacer(Modifier.weight(1f))
+            Column(Modifier.onGloballyPositioned { keypadTop = with(density) { it.positionInParent().y.toDp() } - 8.dp }) {
+            FunctionArea(scientific, inverse, prefs.angle, { scientific = !scientific }, { inverse = !inverse }, onAngle, onKey, tap)
+            Keypad(decimal, onKey, onBackspace, onClear, onEquals, tap, Modifier.navigationBarsPadding())
+            }
+        }
+        // the display reaches down to the function row; pulled down it covers the keypad
+        val collapsed by animateDpAsState(keypadTop, spring(.9f, 500f), label = "top")
+        val height = collapsed + (maxHeight - collapsed - 24.dp) * sheet.value
+        Column(
+            Modifier.fillMaxWidth().height(height).clip(RoundedCornerShape(bottomStart = 32.dp, bottomEnd = 32.dp)).background(c.display)
+                .draggable(
+                    rememberDraggableState { d -> scope.launch { sheet.snapTo((sheet.value + d / (fullPx * .6f)).coerceIn(0f, 1f)) } },
+                    Orientation.Vertical,
+                    onDragStopped = { v -> scope.launch { sheet.animateTo(if (v > 300 || (v > -300 && sheet.value > .4f)) 1f else 0f, spring(.9f, 400f)) } },
+                )
+                .statusBarsPadding(),
+        ) {
+            TopBar(
+                historyOpen = sheet.value > .5f,
+                onHistory = { scope.launch { sheet.animateTo(if (sheet.value > .5f) 0f else 1f, spring(.9f, 400f)) } },
+                onClearHistory = onClearHistory, theme = prefs.theme,
+            )
+            if (sheet.value > 0.01f) {
+                HistoryList(history, Modifier.weight(1f)) { onInsert(it); scope.launch { sheet.animateTo(0f, spring(.9f, 400f)) } }
+                Text(stringResource(R.string.current_expression), style = WType.label, color = c.muted, modifier = Modifier.padding(horizontal = 24.dp))
+            } else Spacer(Modifier.weight(1f))
+            Display(state, prefs, onInsert, onMemoryStore, currentValue)
+            // drag handle
+            Box(Modifier.fillMaxWidth().padding(vertical = 10.dp), contentAlignment = Alignment.Center) {
+                Box(Modifier.size(32.dp, 4.dp).clip(RoundedCornerShape(2.dp)).background(c.muted.copy(alpha = .6f)))
+            }
+        }
+    }
+}
+
+@Composable
+private fun TopBar(historyOpen: Boolean, onHistory: () -> Unit, onClearHistory: () -> Unit, theme: ThemeMode) {
+    val c = LocalCalcColors.current
+    var menu by remember { mutableStateOf(false) }
+    val scope = rememberCoroutineScope()
+    Row(Modifier.fillMaxWidth().padding(horizontal = 8.dp), verticalAlignment = Alignment.CenterVertically) {
+        IconButton(onClick = onHistory) {
+            Box(Modifier.size(36.dp).clip(CircleShape).background(if (historyOpen) c.op else Color.Transparent), contentAlignment = Alignment.Center) {
+                Icon(Icons.Rounded.History, stringResource(R.string.history), tint = if (historyOpen) c.onOp else c.muted)
+            }
+        }
+        Spacer(Modifier.weight(1f))
+        IconButton(onClick = { menu = true }) { Icon(Icons.Rounded.MoreVert, stringResource(R.string.more), tint = c.muted) }
+        DropdownMenu(menu, { menu = false }) {
+            DropdownMenuItem(text = { Text(stringResource(R.string.clear_history)) }, onClick = { menu = false; onClearHistory() })
+            val next = when (theme) { ThemeMode.SYSTEM -> ThemeMode.DARK; ThemeMode.DARK -> ThemeMode.LIGHT; ThemeMode.LIGHT -> ThemeMode.SYSTEM }
+            val label = mapOf(ThemeMode.SYSTEM to R.string.theme_system, ThemeMode.DARK to R.string.theme_dark, ThemeMode.LIGHT to R.string.theme_light)
+            DropdownMenuItem(
+                text = { Text(stringResource(R.string.theme) + ": " + stringResource(label.getValue(theme))) },
+                onClick = { scope.launch { Graph.store.setTheme(next) } },
+            )
+        }
+    }
+}
+
+@Composable
+private fun HistoryList(history: List<HistoryEntry>, modifier: Modifier, onPick: (String) -> Unit) {
+    val c = LocalCalcColors.current
+    val state = rememberLazyListState()
+    LaunchedEffect(history.size) { if (history.isNotEmpty()) state.scrollToItem(history.size + countDays(history)) }
+    if (history.isEmpty()) {
+        Box(modifier.fillMaxWidth(), contentAlignment = Alignment.Center) { Text(stringResource(R.string.no_history), style = WType.body, color = c.muted) }
+        return
+    }
+    val res = LocalContext.current.resources
+    LazyColumn(modifier.fillMaxWidth(), state = state, verticalArrangement = Arrangement.Bottom) {
+        var lastDay: LocalDate? = null
+        history.forEach { h ->
+            val day = Instant.ofEpochMilli(h.createdAt).atZone(ZoneId.systemDefault()).toLocalDate()
+            if (day != lastDay) {
+                val d = day
+                item(key = "d$d") {
+                    val label = when (d) {
+                        LocalDate.now() -> res.getString(R.string.today)
+                        LocalDate.now().minusDays(1) -> res.getString(R.string.yesterday)
+                        else -> d.format(DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM))
+                    }
+                    Text(label, style = WType.label, color = c.muted, modifier = Modifier.padding(start = 24.dp, top = 16.dp, bottom = 4.dp))
+                }
+                lastDay = day
+            }
+            item(key = h.id) {
+                Column(
+                    Modifier.fillMaxWidth().clickable { onPick(h.result) }.padding(horizontal = 24.dp, vertical = 8.dp),
+                    horizontalAlignment = Alignment.End,
+                ) {
+                    Text(h.expression, style = WType.historyExpr, color = c.muted, maxLines = 1)
+                    Text(h.result, style = WType.historyResult, color = c.text, maxLines = 1)
+                }
+            }
+        }
+    }
+}
+
+private fun countDays(h: List<HistoryEntry>) = h.map { Instant.ofEpochMilli(it.createdAt).atZone(ZoneId.systemDefault()).toLocalDate() }.distinct().size
+
+@Composable
+private fun Display(state: CalcState, prefs: Prefs, onInsert: (String) -> Unit, onMemoryStore: (String) -> Unit, currentValue: () -> String) {
+    val c = LocalCalcColors.current
+    val context = LocalContext.current
+    var menu by remember { mutableStateOf(false) }
+    val clipboard = context.getSystemService(ClipboardManager::class.java)
+    val scroll = rememberScrollState()
+    LaunchedEffect(state.expression) { scroll.scrollTo(scroll.maxValue) }
+    Column(Modifier.fillMaxWidth().padding(horizontal = 24.dp), horizontalAlignment = Alignment.End) {
+        Box {
+            val text = state.expression.ifEmpty { " " }
+            // shrink with length, then scroll
+            val size = when { text.length <= 7 -> 72.sp; text.length <= 10 -> 56.sp; text.length <= 14 -> 44.sp; else -> 36.sp }
+            Row(Modifier.horizontalScroll(scroll)) {
+                Text(
+                    text, style = WType.expr.copy(fontSize = size, lineHeight = size * 1.1f, fontFeatureSettings = "tnum"), color = c.text, maxLines = 1,
+                    modifier = Modifier.combinedClickable(onClick = {}, onLongClick = { menu = true }).semantics { contentDescription = speak(state.expression) },
+                )
+            }
+            DropdownMenu(menu, { menu = false }, shape = RoundedCornerShape(24.dp)) {
+                DropdownMenuItem(text = { Text(stringResource(R.string.copy)) }, onClick = {
+                    menu = false; clipboard.setPrimaryClip(ClipData.newPlainText("Ergebnis", currentValue()))
+                })
+                DropdownMenuItem(text = { Text(stringResource(R.string.paste)) }, onClick = {
+                    menu = false; clipboard.primaryClip?.getItemAt(0)?.coerceToText(context)?.toString()?.let(onInsert)
+                })
+                DropdownMenuItem(text = { Text("MS") }, onClick = { menu = false; onMemoryStore(currentValue()) })
+                if (prefs.memory != null) DropdownMenuItem(text = { Text("MR  " + prefs.memory) }, onClick = { menu = false; onInsert(prefs.memory) })
+            }
+        }
+        val second = when {
+            state.error != null -> errorText(state.error)
+            state.showingResult -> ""
+            else -> state.preview
+        }
+        Text(
+            second.ifEmpty { " " }, style = if (state.error != null) WType.fn else WType.result.copy(fontFeatureSettings = "tnum"),
+            color = if (state.error != null) c.error else c.result, maxLines = 1, textAlign = TextAlign.End,
+        )
+    }
+}
+
+@Composable
+private fun errorText(e: ErrorKind) = stringResource(
+    when (e) { ErrorKind.DIV_ZERO -> R.string.err_div_zero; ErrorKind.DOMAIN -> R.string.err_domain; ErrorKind.TOO_BIG -> R.string.err_too_big; ErrorKind.SYNTAX -> R.string.err_syntax },
+)
+
+private fun speak(e: String) = e.replace("×", " mal ").replace("÷", " geteilt durch ").replace("−", " minus ").replace("+", " plus ").replace("√", " Wurzel ").replace("π", " Pi ")
+
+@Composable
+private fun FunctionArea(
+    expanded: Boolean, inverse: Boolean, angle: Angle,
+    onToggle: () -> Unit, onInverse: () -> Unit, onAngle: (Angle) -> Unit, onKey: (String) -> Unit, tap: (() -> Unit) -> () -> Unit,
+) {
+    val c = LocalCalcColors.current
+    Column(Modifier.fillMaxWidth().padding(horizontal = 12.dp)) {
+        Row(verticalAlignment = Alignment.CenterVertically) {
+            listOf("√" to "√", "π" to "π", "^" to "^", "!" to "!").forEach { (label, key) ->
+                FnKey(label, expanded, tap { onKey(key) })
+            }
+            Box(Modifier.padding(start = 6.dp).size(40.dp).clip(CircleShape).background(c.fn).clickable(onClick = onToggle), contentAlignment = Alignment.Center) {
+                Icon(if (expanded) Icons.Rounded.ExpandLess else Icons.Rounded.ExpandMore, stringResource(R.string.more_functions), tint = c.onFn)
+            }
+        }
+        AnimatedVisibility(expanded, enter = expandVertically(spring(.9f, 500f)), exit = shrinkVertically(spring(.9f, 500f))) {
+            Column {
+                Row {
+                    FnKey(if (angle == Angle.DEG) "Deg" else "Rad", true, tap { onAngle(if (angle == Angle.DEG) Angle.RAD else Angle.DEG) })
+                    if (inverse) { FnKey("sin⁻¹", true, tap { onKey("sin⁻¹(") }); FnKey("cos⁻¹", true, tap { onKey("cos⁻¹(") }); FnKey("tan⁻¹", true, tap { onKey("tan⁻¹(") }) }
+                    else { FnKey("sin", true, tap { onKey("sin(") }); FnKey("cos", true, tap { onKey("cos(") }); FnKey("tan", true, tap { onKey("tan(") }) }
+                    Spacer(Modifier.width(46.dp))
+                }
+                Row {
+                    FnKey("Inv", true, onInverse, selected = inverse)
+                    if (inverse) { FnKey("eˣ", true, tap { onKey("e^") }); FnKey("10ˣ", true, tap { onKey("10^") }); FnKey("x²", true, tap { onKey("^2") }) }
+                    else { FnKey("e", true, tap { onKey("e") }); FnKey("ln", true, tap { onKey("ln(") }); FnKey("log", true, tap { onKey("log(") }) }
+                    Spacer(Modifier.width(46.dp))
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun RowScope.FnKey(label: String, tonal: Boolean, onClick: () -> Unit, selected: Boolean = false) {
+    val c = LocalCalcColors.current
+    Box(
+        Modifier.weight(1f).padding(4.dp).height(44.dp).clip(RoundedCornerShape(22.dp))
+            .background(if (selected) c.op else if (tonal) c.fn else Color.Transparent).clickable(onClick = onClick),
+        contentAlignment = Alignment.Center,
+    ) { Text(label, style = WType.fn, color = if (selected) c.onOp else c.onFn) }
+}
+
+@Composable
+private fun Keypad(
+    decimal: Char, onKey: (String) -> Unit, onBackspace: () -> Unit, onClear: () -> Unit, onEquals: () -> Unit,
+    tap: (() -> Unit) -> () -> Unit, modifier: Modifier,
+) {
+    val c = LocalCalcColors.current
+    data class K(val label: String, val bg: Color, val fg: Color, val action: () -> Unit, val icon: ImageVector? = null, val long: (() -> Unit)? = null, val desc: String = label)
+    val d = K("", c.digit, c.onDigit, {})
+    fun digit(s: String) = d.copy(label = s, action = tap { onKey(s) })
+    fun op(s: String, desc: String) = K(s, c.op, c.onOp, tap { onKey(s) }, desc = desc)
+    val rows = listOf(
+        listOf(K("AC", c.ac, c.onAc, tap(onClear), desc = "Alles löschen"), op("()", "Klammer"), op("%", "Prozent"), op("÷", "geteilt durch")),
+        listOf(digit("7"), digit("8"), digit("9"), op("×", "mal")),
+        listOf(digit("4"), digit("5"), digit("6"), op("−", "minus")),
+        listOf(digit("1"), digit("2"), digit("3"), op("+", "plus")),
+        listOf(digit("0"), digit(decimal.toString()), K("", c.digit, c.onDigit, tap(onBackspace), Icons.AutoMirrored.Rounded.Backspace, long = onClear, desc = "Löschen"),
+            K("=", c.eq, c.onEq, tap(onEquals), desc = "gleich")),
+    )
+    Column(modifier.padding(12.dp), verticalArrangement = Arrangement.spacedBy(10.dp)) {
+        rows.forEach { row ->
+            Row(horizontalArrangement = Arrangement.spacedBy(10.dp)) {
+                row.forEach { k -> Key(k.label, k.bg, k.fg, k.icon, k.desc, k.action, k.long, Modifier.weight(1f)) }
+            }
+        }
+    }
+}
+
+/** Circle at rest, squircle while pressed: the expressive press. */
+@Composable
+private fun Key(label: String, bg: Color, fg: Color, icon: ImageVector?, desc: String, onClick: () -> Unit, onLong: (() -> Unit)?, modifier: Modifier) {
+    val source = remember { MutableInteractionSource() }
+    val pressed by source.collectIsPressedAsState()
+    val radius by animateDpAsState(if (pressed) 22.dp else 100.dp, spring(.6f, 800f), label = "r")
+    Box(
+        modifier.aspectRatio(1.18f).clip(RoundedCornerShape(radius)).background(bg)
+            .combinedClickable(interactionSource = source, indication = null, onClick = onClick, onLongClick = onLong)
+            .semantics { contentDescription = desc },
+        contentAlignment = Alignment.Center,
+    ) {
+        if (icon != null) Icon(icon, null, tint = fg, modifier = Modifier.size(30.dp))
+        else Text(label, style = WType.key, color = fg)
+    }
+}

rechner/app/src/main/java/app/rechner/ui/CalculatorViewModel.kt

@@ -0,0 +1,115 @@
+package app.rechner.ui
+
+import androidx.activity.ComponentActivity
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewModelScope
+import app.rechner.data.Graph
+import app.rechner.data.HistoryEntry
+import app.rechner.engine.Angle
+import app.rechner.engine.Editor
+import app.rechner.engine.Engine
+import app.rechner.engine.ErrorKind
+import app.rechner.engine.NumberFormat
+import app.rechner.engine.Outcome
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+import java.text.DecimalFormatSymbols
+
+data class CalcState(
+    val expression: String = "",
+    /** live preview, empty when there is nothing new to show */
+    val preview: String = "",
+    val error: ErrorKind? = null,
+    /** after "=": the expression is a result and the next digit starts over */
+    val showingResult: Boolean = false,
+    val previous: String = "",
+)
+
+class CalculatorViewModel : ViewModel() {
+    val decimal: Char = DecimalFormatSymbols.getInstance().decimalSeparator
+    private val grouping: Char = DecimalFormatSymbols.getInstance().groupingSeparator.let { if (it == decimal) ' ' else it }
+    private val engine = Engine(decimal)
+    val format = NumberFormat(decimal, grouping)
+    private var angle = Angle.DEG
+
+    private val _state = MutableStateFlow(CalcState())
+    val state: StateFlow<CalcState> = _state
+    val history: StateFlow<List<HistoryEntry>> = Graph.history.all().stateIn(viewModelScope, SharingStarted.Eagerly, emptyList())
+
+    init {
+        viewModelScope.launch {
+            val p = Graph.store.prefs.first()
+            angle = p.angle
+            update(p.expression)
+        }
+    }
+
+    fun setAngle(a: Angle) {
+        angle = a
+        viewModelScope.launch { Graph.store.setAngle(a) }
+        update(_state.value.expression, keepResult = _state.value.showingResult)
+    }
+
+    fun key(k: String) {
+        val s = _state.value
+        val base = when {
+            // a digit or function after "=" starts a new calculation; an operator continues with the result
+            s.showingResult && (k.first().isDigit() || k == decimal.toString() || k.endsWith("(") || k in setOf("√", "π", "e", "()")) -> ""
+            s.error != null && s.showingResult -> ""
+            else -> s.expression
+        }
+        update(Editor.input(base, k, decimal))
+    }
+
+    fun backspace() = update(if (_state.value.showingResult) "" else Editor.backspace(_state.value.expression))
+    fun clear() = update("")
+    fun insert(text: String) = update(_state.value.let { if (it.showingResult) "" else it.expression } + sanitize(text))
+
+    fun equals() {
+        val s = _state.value
+        if (s.expression.isEmpty() || s.showingResult) return
+        when (val r = engine.evaluate(s.expression, angle, lenient = true)) {
+            is Outcome.Value -> {
+                val result = format.format(r.value, 15)
+                viewModelScope.launch { Graph.history.insert(HistoryEntry(expression = s.expression, result = result)); Graph.history.trim() }
+                _state.value = CalcState(expression = result, previous = s.expression, showingResult = true)
+                persist(result)
+            }
+            is Outcome.Error -> _state.value = s.copy(error = r.kind, preview = "")
+            Outcome.Empty -> Unit
+        }
+    }
+
+    fun clearHistory() = viewModelScope.launch { Graph.history.clear() }
+    fun memoryStore(value: String) = viewModelScope.launch { Graph.store.setMemory(value) }
+
+    /** The value currently shown: result after "=", else the live preview, else the expression. */
+    fun currentValue(): String = _state.value.let { if (it.showingResult) it.expression else it.preview.ifEmpty { it.expression } }
+
+    private fun update(expr: String, keepResult: Boolean = false) {
+        val r = engine.evaluate(expr, angle, lenient = true)
+        val preview = when (r) {
+            is Outcome.Value -> format.format(r.value).takeIf { it != expr && hasOperation(expr) } ?: ""
+            else -> ""
+        }
+        _state.value = CalcState(expression = expr, preview = preview, showingResult = keepResult)
+        persist(expr)
+    }
+
+    private fun hasOperation(e: String) = e.any { it in "+−×÷^!%√πe(" } || e.contains("sin") || e.contains("cos") || e.contains("tan") || e.contains("ln") || e.contains("log")
+
+    private fun persist(expr: String) = viewModelScope.launch { Graph.store.setExpression(expr) }
+
+    /** Paste keeps only what the keypad could type. */
+    private fun sanitize(t: String) = t.replace('*', '×').replace('/', '÷').replace('-', '−')
+        .filter { it.isDigit() || it == decimal || it == grouping || it in "+−×÷^!%√πe()E" || it.isLetter() }
+
+    companion object {
+        fun get(activity: ComponentActivity) = ViewModelProvider(activity)[CalculatorViewModel::class.java]
+    }
+}

rechner/app/src/main/java/app/rechner/ui/theme/Theme.kt

@@ -0,0 +1,61 @@
+package app.rechner.ui.theme
+
+import android.os.Build
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.material3.ColorScheme
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.darkColorScheme
+import androidx.compose.material3.dynamicDarkColorScheme
+import androidx.compose.material3.dynamicLightColorScheme
+import androidx.compose.material3.lightColorScheme
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.runtime.Immutable
+import androidx.compose.runtime.staticCompositionLocalOf
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.platform.LocalContext
+import app.rechner.data.ThemeMode
+
+/** Key and display roles; from the wallpaper on Android 12+, from tokens otherwise. */
+@Immutable
+data class CalcColors(
+    val bg: Color, val display: Color, val text: Color, val muted: Color, val result: Color, val error: Color,
+    val digit: Color, val onDigit: Color, val op: Color, val onOp: Color, val ac: Color, val onAc: Color,
+    val eq: Color, val onEq: Color, val fn: Color, val onFn: Color,
+)
+
+private val LightCalc = CalcColors(
+    WColor.bg, WColor.display, WColor.text, WColor.textMuted, WColor.result, WColor.error,
+    WColor.keyDigit, WColor.onKeyDigit, WColor.keyOp, WColor.onKeyOp, WColor.keyAc, WColor.onKeyAc,
+    WColor.keyEq, WColor.onKeyEq, WColor.keyFn, WColor.onKeyFn,
+)
+private val DarkCalc = CalcColors(
+    WColor.darkBg, WColor.darkDisplay, WColor.darkText, WColor.darkTextMuted, WColor.darkResult, WColor.darkError,
+    WColor.darkKeyDigit, WColor.darkOnKeyDigit, WColor.darkKeyOp, WColor.darkOnKeyOp, WColor.darkKeyAc, WColor.darkOnKeyAc,
+    WColor.darkKeyEq, WColor.darkOnKeyEq, WColor.darkKeyFn, WColor.darkOnKeyFn,
+)
+
+private fun fromScheme(s: ColorScheme, dark: Boolean) = CalcColors(
+    bg = s.surface, display = s.surfaceContainerHigh, text = s.onSurface, muted = s.onSurfaceVariant, result = s.onSurfaceVariant, error = s.error,
+    digit = if (dark) s.surfaceContainer else s.surfaceContainerLow, onDigit = s.onSurface,
+    op = s.secondaryContainer, onOp = s.onSecondaryContainer,
+    ac = s.tertiaryContainer, onAc = s.onTertiaryContainer,
+    eq = if (dark) s.primary else s.primaryContainer, onEq = if (dark) s.onPrimary else s.onPrimaryContainer,
+    fn = s.surfaceContainerHighest, onFn = s.onSurface,
+)
+
+val LocalCalcColors = staticCompositionLocalOf { LightCalc }
+
+@Composable
+fun CalcTheme(mode: ThemeMode = ThemeMode.SYSTEM, dynamic: Boolean = true, content: @Composable () -> Unit) {
+    val dark = when (mode) { ThemeMode.SYSTEM -> isSystemInDarkTheme(); ThemeMode.LIGHT -> false; ThemeMode.DARK -> true }
+    val context = LocalContext.current
+    val useDynamic = dynamic && Build.VERSION.SDK_INT >= 31
+    val scheme = when {
+        useDynamic -> if (dark) dynamicDarkColorScheme(context) else dynamicLightColorScheme(context)
+        dark -> darkColorScheme()
+        else -> lightColorScheme()
+    }
+    val calc = if (useDynamic) fromScheme(scheme, dark) else if (dark) DarkCalc else LightCalc
+    CompositionLocalProvider(LocalCalcColors provides calc) { MaterialTheme(colorScheme = scheme, content = content) }
+}

rechner/app/src/main/java/app/rechner/ui/theme/Tokens.kt

@@ -0,0 +1,75 @@
+// Generated from tokens.json by gen_theme.py. Do not edit by hand.
+package app.rechner.ui.theme
+
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+
+object WColor {
+    val bg = Color(0xFFF9F9FF)
+    val display = Color(0xFFE1E5EE)
+    val sheet = Color(0xFFE8EBF2)
+    val text = Color(0xFF191C20)
+    val textMuted = Color(0xFF43474E)
+    val result = Color(0xFF5A5F68)
+    val keyDigit = Color(0xFFEEF0F5)
+    val onKeyDigit = Color(0xFF191C20)
+    val keyOp = Color(0xFFD6E3F5)
+    val onKeyOp = Color(0xFF0E1D2E)
+    val keyAc = Color(0xFFEAD9FF)
+    val onKeyAc = Color(0xFF25113D)
+    val keyEq = Color(0xFFCDE3FB)
+    val onKeyEq = Color(0xFF06233D)
+    val keyFn = Color(0xFFDDE3EC)
+    val onKeyFn = Color(0xFF191C20)
+    val error = Color(0xFFBA1A1A)
+    val darkBg = Color(0xFF0B1414)
+    val darkDisplay = Color(0xFF283535)
+    val darkSheet = Color(0xFF1E2A2A)
+    val darkText = Color(0xFFE0E6E6)
+    val darkTextMuted = Color(0xFFBEC8C8)
+    val darkResult = Color(0xFF9FB0B0)
+    val darkKeyDigit = Color(0xFF172121)
+    val darkOnKeyDigit = Color(0xFFDDE4E4)
+    val darkKeyOp = Color(0xFFA3D1D3)
+    val darkOnKeyOp = Color(0xFF002F31)
+    val darkKeyAc = Color(0xFF8FD5E8)
+    val darkOnKeyAc = Color(0xFF00303B)
+    val darkKeyEq = Color(0xFF00E0CC)
+    val darkOnKeyEq = Color(0xFF00332E)
+    val darkKeyFn = Color(0xFF253232)
+    val darkOnKeyFn = Color(0xFFDDE4E4)
+    val darkError = Color(0xFFFFB4AB)
+}
+
+object WType {
+    val label = TextStyle(fontSize = 14.sp, lineHeight = 20.sp, fontWeight = FontWeight.W500)
+    val body = TextStyle(fontSize = 16.sp, lineHeight = 24.sp, fontWeight = FontWeight.W400)
+    val fn = TextStyle(fontSize = 22.sp, lineHeight = 28.sp, fontWeight = FontWeight.W400)
+    val key = TextStyle(fontSize = 34.sp, lineHeight = 40.sp, fontWeight = FontWeight.W400)
+    val result = TextStyle(fontSize = 36.sp, lineHeight = 44.sp, fontWeight = FontWeight.W400)
+    val expr = TextStyle(fontSize = 72.sp, lineHeight = 80.sp, fontWeight = FontWeight.W400)
+    val exprMin = TextStyle(fontSize = 36.sp, lineHeight = 44.sp, fontWeight = FontWeight.W400)
+    val historyExpr = TextStyle(fontSize = 18.sp, lineHeight = 24.sp, fontWeight = FontWeight.W400)
+    val historyResult = TextStyle(fontSize = 28.sp, lineHeight = 34.sp, fontWeight = FontWeight.W400)
+}
+
+object WSpace {
+    val s0 = 0.dp
+    val s4 = 4.dp
+    val s8 = 8.dp
+    val s12 = 12.dp
+    val s16 = 16.dp
+    val s24 = 24.dp
+    val s32 = 32.dp
+}
+
+object WRadius {
+    val display = 32.dp
+    val key = 999.dp
+    val keyPressed = 24.dp
+    val menu = 24.dp
+    val pill = 999.dp
+}

rechner/app/src/main/res/drawable/ic_launcher_background.xml

@@ -0,0 +1 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android" android:width="108dp" android:height="108dp" android:viewportWidth="108" android:viewportHeight="108"><path android:fillColor="#FF1E3A5F" android:pathData="M0,0h108v108h-108z"/></vector>

rechner/app/src/main/res/drawable/ic_launcher_foreground.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android" android:width="108dp" android:height="108dp" android:viewportWidth="108" android:viewportHeight="108">
+    <path android:fillColor="#FFD6E3FF" android:pathData="M37,30h8a7,7 0 0 1 7,7v8a7,7 0 0 1 -7,7h-8a7,7 0 0 1 -7,-7v-8a7,7 0 0 1 7,-7z"/>
+    <path android:fillColor="#FFD6E3FF" android:pathData="M63,30h8a7,7 0 0 1 7,7v8a7,7 0 0 1 -7,7h-8a7,7 0 0 1 -7,-7v-8a7,7 0 0 1 7,-7z"/>
+    <path android:fillColor="#FFD6E3FF" android:pathData="M37,56h8a7,7 0 0 1 7,7v8a7,7 0 0 1 -7,7h-8a7,7 0 0 1 -7,-7v-8a7,7 0 0 1 7,-7z"/>
+    <path android:fillColor="#FFFFB86B" android:pathData="M63,56h8a7,7 0 0 1 7,7v8a7,7 0 0 1 -7,7h-8a7,7 0 0 1 -7,-7v-8a7,7 0 0 1 7,-7z"/>
+    <path android:strokeColor="#FF1E3A5F" android:strokeWidth="2.6" android:strokeLineCap="round" android:pathData="M36,41h10M41,36v10"/>
+    <path android:strokeColor="#FF1E3A5F" android:strokeWidth="2.6" android:strokeLineCap="round" android:pathData="M62,41h10"/>
+    <path android:strokeColor="#FF1E3A5F" android:strokeWidth="2.6" android:strokeLineCap="round" android:pathData="M37.5,63.5l7,7M44.5,63.5l-7,7"/>
+    <path android:strokeColor="#FF5A2E00" android:strokeWidth="2.6" android:strokeLineCap="round" android:pathData="M62,64h10M62,70h10"/>
+</vector>

rechner/app/src/main/res/drawable/ic_launcher_monochrome.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android" android:width="108dp" android:height="108dp" android:viewportWidth="108" android:viewportHeight="108">
+    <path android:fillColor="#FF000000" android:pathData="M37,30h8a7,7 0 0 1 7,7v8a7,7 0 0 1 -7,7h-8a7,7 0 0 1 -7,-7v-8a7,7 0 0 1 7,-7z"/>
+    <path android:fillColor="#FF000000" android:pathData="M63,30h8a7,7 0 0 1 7,7v8a7,7 0 0 1 -7,7h-8a7,7 0 0 1 -7,-7v-8a7,7 0 0 1 7,-7z"/>
+    <path android:fillColor="#FF000000" android:pathData="M37,56h8a7,7 0 0 1 7,7v8a7,7 0 0 1 -7,7h-8a7,7 0 0 1 -7,-7v-8a7,7 0 0 1 7,-7z"/>
+    <path android:fillColor="#FF000000" android:pathData="M63,56h8a7,7 0 0 1 7,7v8a7,7 0 0 1 -7,7h-8a7,7 0 0 1 -7,-7v-8a7,7 0 0 1 7,-7z"/>
+    <path android:strokeColor="#FFFFFFFF" android:strokeWidth="2.6" android:strokeLineCap="round" android:pathData="M36,41h10M41,36v10"/>
+    <path android:strokeColor="#FFFFFFFF" android:strokeWidth="2.6" android:strokeLineCap="round" android:pathData="M62,41h10"/>
+    <path android:strokeColor="#FFFFFFFF" android:strokeWidth="2.6" android:strokeLineCap="round" android:pathData="M37.5,63.5l7,7M44.5,63.5l-7,7"/>
+    <path android:strokeColor="#FFFFFFFF" android:strokeWidth="2.6" android:strokeLineCap="round" android:pathData="M62,64h10M62,70h10"/>
+</vector>

rechner/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background"/>
+    <foreground android:drawable="@drawable/ic_launcher_foreground"/>
+    <monochrome android:drawable="@drawable/ic_launcher_monochrome"/>
+</adaptive-icon>

rechner/app/src/main/res/values/strings.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="history">Verlauf</string>
+    <string name="more">Weitere Optionen</string>
+    <string name="more_functions">Weitere Funktionen</string>
+    <string name="clear_history">Verlauf löschen</string>
+    <string name="no_history">Noch keine Rechnungen</string>
+    <string name="current_expression">Aktuelle Eingabe</string>
+    <string name="today">Heute</string>
+    <string name="yesterday">Gestern</string>
+    <string name="copy">Kopieren</string>
+    <string name="paste">Einfügen</string>
+    <string name="theme">Design</string>
+    <string name="theme_system">System</string>
+    <string name="theme_light">Hell</string>
+    <string name="theme_dark">Dunkel</string>
+    <string name="err_div_zero">Division durch null geht nicht</string>
+    <string name="err_domain">Nicht definiert</string>
+    <string name="err_too_big">Zahl zu groß</string>
+    <string name="err_syntax">Ungültige Eingabe</string>
+</resources>

rechner/app/src/test/java/app/rechner/EngineTest.kt

@@ -0,0 +1,52 @@
+package app.rechner
+
+import app.rechner.engine.Angle
+import app.rechner.engine.Engine
+import app.rechner.engine.ErrorKind
+import app.rechner.engine.NumberFormat
+import app.rechner.engine.Outcome
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class EngineTest {
+    private val e = Engine(',')
+    private val f = NumberFormat(',', '.')
+    private fun calc(s: String, angle: Angle = Angle.DEG): String = when (val r = e.evaluate(s, angle)) {
+        is Outcome.Value -> f.format(r.value)
+        is Outcome.Error -> r.kind.name
+        Outcome.Empty -> ""
+    }
+
+    @Test fun basics() {
+        assertEquals("46", calc("12+34"))
+        assertEquals("14", calc("2+3×4"))
+        assertEquals("20", calc("(2+3)×4"))
+        assertEquals("−625", calc("−5×125"))
+        assertEquals("2,5", calc("5÷2"))
+        assertEquals("118", calc("69+49"))
+    }
+    @Test fun exactDecimals() { assertEquals("0,3", calc("0,1+0,2")); assertEquals("1", calc("1÷3×3")) }
+    @Test fun grouping() { assertEquals("7.720", calc("7.775−55")); assertEquals("2.025", calc("2.024+1")) }
+    @Test fun percent() {
+        assertEquals("55", calc("50+10%")); assertEquals("45", calc("50−10%"))
+        assertEquals("5", calc("50×10%")); assertEquals("0,1", calc("10%"))
+    }
+    @Test fun powersAndRoots() {
+        assertEquals("−4", calc("−2^2")); assertEquals("512", calc("2^3^2")); assertEquals("3", calc("√9"))
+        assertEquals("0,5", calc("2^−1")); assertEquals("1,41421356237", calc("√2"))
+    }
+    @Test fun implicitMultiplication() { assertEquals("6,28318530718", calc("2π")); assertEquals("12", calc("3(4)")); assertEquals("6", calc("2√9")) }
+    @Test fun trig() {
+        assertEquals("0,5", calc("sin(30)")); assertEquals("−1", calc("cos(180)")); assertEquals("1", calc("tan(45)"))
+        assertEquals("−1", calc("cos(π)", Angle.RAD)); assertEquals("30", calc("sin⁻¹(0,5)"))
+        assertEquals("DOMAIN", calc("tan(90)"))
+    }
+    @Test fun logs() { assertEquals("2", calc("log(100)")); assertEquals("1", calc("ln(e)")); assertEquals("DOMAIN", calc("ln(0)")) }
+    @Test fun factorial() { assertEquals("120", calc("5!")); assertEquals("9,33262154E157", calc("100!")); assertEquals("DOMAIN", calc("2,5!")) }
+    @Test fun errors() { assertEquals("DIV_ZERO", calc("1÷0")); assertEquals("DOMAIN", calc("√(−1)")) }
+    @Test fun lenientInput() {
+        assertEquals("5", calc("(2+3")); assertEquals("5", calc("5+")); assertEquals("", calc("")); assertEquals("", calc("×"))
+        assertEquals("7", calc("sin(30)+6,5"))
+    }
+    @Test fun smallNumbers() { assertEquals("1E−7", calc("1÷10000000")) }
+}

rechner/app/src/test/java/app/rechner/ScreenshotTest.kt

@@ -0,0 +1,47 @@
+package app.rechner
+
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.test.junit4.createComposeRule
+import androidx.compose.ui.test.onRoot
+import app.rechner.data.HistoryEntry
+import app.rechner.data.Prefs
+import app.rechner.data.ThemeMode
+import app.rechner.engine.Angle
+import app.rechner.ui.CalcState
+import app.rechner.ui.CalculatorContent
+import app.rechner.ui.theme.CalcTheme
+import com.github.takahirom.roborazzi.captureRoboImage
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+import org.robolectric.annotation.GraphicsMode
+
+@RunWith(RobolectricTestRunner::class)
+@GraphicsMode(GraphicsMode.Mode.NATIVE)
+@Config(sdk = [35], qualifiers = "de-rDE-w412dp-h915dp-xxhdpi", application = android.app.Application::class)
+class ScreenshotTest {
+    @get:Rule val compose = createComposeRule()
+    private val now = System.currentTimeMillis()
+    private val history = listOf(
+        HistoryEntry(1, "69+49", "118", now - 86_400_000), HistoryEntry(2, "16×0,5", "8", now - 4_000_000),
+        HistoryEntry(3, "−5×125", "−625", now - 3_000_000), HistoryEntry(4, "2.024+1", "2.025", now - 60_000),
+    )
+
+    private fun shot(name: String, dark: Boolean, state: CalcState, history: Boolean = false, sci: Boolean = false, prefs: Prefs = Prefs()) {
+        compose.setContent {
+            CalcTheme(if (dark) ThemeMode.DARK else ThemeMode.LIGHT, dynamic = false) {
+                CalculatorContent(state, this.history, prefs, ',', {}, {}, {}, {}, {}, {}, {}, {}, { "" }, initialHistoryOpen = history, initialScientific = sci)
+            }
+        }
+        compose.onRoot().captureRoboImage("../../replica/rechner/clone-screens/$name.png")
+    }
+
+    @Test fun s01_empty_dark() = shot("S01-empty-dark", true, CalcState())
+    @Test fun s01_typing_light() = shot("S01-typing-light", false, CalcState("7.775−55", "7.720"))
+    @Test fun s01_result_dark() = shot("S01-result-dark", true, CalcState("118", showingResult = true))
+    @Test fun s01_error() = shot("S01-error-light", false, CalcState("1÷0", error = app.rechner.engine.ErrorKind.DIV_ZERO))
+    @Test fun s02_scientific_dark() = shot("S02-scientific-dark", true, CalcState("cos(π)", "−1"), sci = true, prefs = Prefs(angle = Angle.RAD))
+    @Test fun s03_history_dark() = shot("S03-history-dark", true, CalcState("cos(π)", "−1"), history = true)
+}

rechner/build.gradle.kts

@@ -0,0 +1,7 @@
+plugins {
+    id("com.android.application") version "8.13.0" apply false
+    id("org.jetbrains.kotlin.android") version "2.2.20" apply false
+    id("org.jetbrains.kotlin.plugin.compose") version "2.2.20" apply false
+    id("com.google.devtools.ksp") version "2.2.20-2.0.3" apply false
+    id("io.github.takahirom.roborazzi") version "1.46.1" apply false
+}

rechner/gradle.properties

@@ -0,0 +1,4 @@
+org.gradle.jvmargs=-Xmx4g -Dfile.encoding=UTF-8
+android.useAndroidX=true
+kotlin.code.style=official
+android.nonTransitiveRClass=true

rechner/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.14.3-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

rechner/gradlew

@@ -0,0 +1,251 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH="\\\"\\\""
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

rechner/gradlew.bat

@@ -0,0 +1,94 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

rechner/settings.gradle.kts

@@ -0,0 +1,16 @@
+pluginManagement {
+    repositories {
+        google()
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+rootProject.name = "Rechner"
+include(":app")

replica/rechner/architecture.md

@@ -0,0 +1,43 @@
+# Architecture: Rechner (Android, ohne Google)
+
+Same conventions as `wetter/` and `uhr/`: one native app, no server, **no network permission**.
+
+## Stack
+
+| Schicht | Wahl | warum |
+| --- | --- | --- |
+| UI | Kotlin + Compose, Material 3 Expressive, dynamic colour | same look and pipeline as the other apps |
+| Rechenkern | own recursive-descent parser → AST → evaluator on `BigDecimal` (MathContext 50 digits), integers stay exact `BigInteger` | no floating-point surprises (0.1+0.2 = 0.3), 100! exact; pure Kotlin, unit-tested on the JVM |
+| Funktionen | sin/cos/tan/ln/log/eˣ/√/^ via `Math` on doubles only where unavoidable, results rounded to 15 significant digits, exact values snapped (sin 30° = 0.5, cos π = −1) | readable answers without fake precision |
+| Persistenz | Room (history) + DataStore (memory, angle unit, current expression) | – |
+| Build/Verteilung | minSdk 29, `scripts/release.sh rechner` (Obtainium) | – |
+
+## Schema
+
+`schema.sql`: 1 table `history`. Single user, app-private storage.
+
+## Interne API
+
+| Aufruf | macht | Flow |
+| --- | --- | --- |
+| `Engine.evaluate(expr, angle)` | parse + evaluate, tolerant of unfinished input (auto-closes parentheses, ignores a trailing operator) | F01, F02 |
+| `Editor.input(key)` | cursor-aware editing: digits, operators (replace a trailing operator), smart parentheses, %, functions insert `sin(`, backspace removes whole tokens | F01, F02 |
+| `Calc.equals()` | evaluate, store history row, result becomes the expression | F01 |
+| `History.observe()/clear()` | grouped by local day | F03 |
+| `Memory.store(value)/recall()` | DataStore | F05 |
+| `Clipboard.copy/paste` | system clipboard; paste is sanitised to calculator tokens | F04 |
+
+## Was beißt
+
+- **Precision:** division keeps 50 digits internally; display rounds to fit and strips trailing zeros; repeating decimals shown truncated with an ellipsis rather than rounded up wrongly.
+- **Percent:** `50+10%` = 55 (percent of the left operand for + and −), `50×10%` = 5; standalone `10%` = 0.1.
+- **Locale:** German uses comma decimal and dot grouping; the parser accepts the locale separator only.
+- **Big results:** 100! has 158 digits; display shows them scientifically (1,5E157) and the full value on scroll.
+- **Domain errors:** √(−1), ln 0, tan 90°, 0÷0, factorial of non-integers → error text, never a crash.
+
+## Build-Reihenfolge
+
+1. Vertical slice (S01): engine + keypad + live result + equals; engine unit tests.
+2. Must: scientific row and panel (S02), Deg/Rad, Inv, errors, auto-shrinking display, history (S03), copy/paste (S04), expressive keys, dynamic colour.
+3. Should: memory, implicit multiplication, pull-down history, haptics, big numbers, locale separators, clear history.
+4. Could: landscape layout with all functions.

replica/rechner/build-log.md

@@ -0,0 +1,13 @@
+# Build log: Rechner
+
+App in `rechner/`. Engine unit tests: 12 suites of cases (exact decimals, percent rules, powers, implicit multiplication, trig incl. exact angles, logs, factorial, errors, lenient input). Screenshots via Roborazzi → `replica/rechner/clone-screens/`.
+
+| ID | date | status | missing | notes |
+| --- | --- | --- | --- | --- |
+| S01 Calculator | 2026-10-17 | done | – | verified on device: 12+34 live preview 46, = makes 46 the expression; display grows to meet the keypad |
+| S02 Scientific | 2026-10-17 | done | – | verified on device: Rad, cos(π) → −1 |
+| S03 History | 2026-10-17 | done | – | verified on device: pull down shows "Heute" group and the current expression |
+| S04 Context menu | 2026-10-17 | done | cut | copy, paste, MS, MR |
+| S05 Settings | 2026-10-17 | done | – | theme and clear history in the overflow menu |
+
+Not done: landscape layout; scrolling through all digits of very long results.

replica/rechner/design/Tokens.kt

@@ -0,0 +1,75 @@
+// Generated from tokens.json by gen_theme.py. Do not edit by hand.
+package app.rechner.ui.theme
+
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+
+object WColor {
+    val bg = Color(0xFFF9F9FF)
+    val display = Color(0xFFE1E5EE)
+    val sheet = Color(0xFFE8EBF2)
+    val text = Color(0xFF191C20)
+    val textMuted = Color(0xFF43474E)
+    val result = Color(0xFF5A5F68)
+    val keyDigit = Color(0xFFEEF0F5)
+    val onKeyDigit = Color(0xFF191C20)
+    val keyOp = Color(0xFFD6E3F5)
+    val onKeyOp = Color(0xFF0E1D2E)
+    val keyAc = Color(0xFFEAD9FF)
+    val onKeyAc = Color(0xFF25113D)
+    val keyEq = Color(0xFFCDE3FB)
+    val onKeyEq = Color(0xFF06233D)
+    val keyFn = Color(0xFFDDE3EC)
+    val onKeyFn = Color(0xFF191C20)
+    val error = Color(0xFFBA1A1A)
+    val darkBg = Color(0xFF0B1414)
+    val darkDisplay = Color(0xFF283535)
+    val darkSheet = Color(0xFF1E2A2A)
+    val darkText = Color(0xFFE0E6E6)
+    val darkTextMuted = Color(0xFFBEC8C8)
+    val darkResult = Color(0xFF9FB0B0)
+    val darkKeyDigit = Color(0xFF172121)
+    val darkOnKeyDigit = Color(0xFFDDE4E4)
+    val darkKeyOp = Color(0xFFA3D1D3)
+    val darkOnKeyOp = Color(0xFF002F31)
+    val darkKeyAc = Color(0xFF8FD5E8)
+    val darkOnKeyAc = Color(0xFF00303B)
+    val darkKeyEq = Color(0xFF00E0CC)
+    val darkOnKeyEq = Color(0xFF00332E)
+    val darkKeyFn = Color(0xFF253232)
+    val darkOnKeyFn = Color(0xFFDDE4E4)
+    val darkError = Color(0xFFFFB4AB)
+}
+
+object WType {
+    val label = TextStyle(fontSize = 14.sp, lineHeight = 20.sp, fontWeight = FontWeight.W500)
+    val body = TextStyle(fontSize = 16.sp, lineHeight = 24.sp, fontWeight = FontWeight.W400)
+    val fn = TextStyle(fontSize = 22.sp, lineHeight = 28.sp, fontWeight = FontWeight.W400)
+    val key = TextStyle(fontSize = 34.sp, lineHeight = 40.sp, fontWeight = FontWeight.W400)
+    val result = TextStyle(fontSize = 36.sp, lineHeight = 44.sp, fontWeight = FontWeight.W400)
+    val expr = TextStyle(fontSize = 72.sp, lineHeight = 80.sp, fontWeight = FontWeight.W400)
+    val exprMin = TextStyle(fontSize = 36.sp, lineHeight = 44.sp, fontWeight = FontWeight.W400)
+    val historyExpr = TextStyle(fontSize = 18.sp, lineHeight = 24.sp, fontWeight = FontWeight.W400)
+    val historyResult = TextStyle(fontSize = 28.sp, lineHeight = 34.sp, fontWeight = FontWeight.W400)
+}
+
+object WSpace {
+    val s0 = 0.dp
+    val s4 = 4.dp
+    val s8 = 8.dp
+    val s12 = 12.dp
+    val s16 = 16.dp
+    val s24 = 24.dp
+    val s32 = 32.dp
+}
+
+object WRadius {
+    val display = 32.dp
+    val key = 999.dp
+    val keyPressed = 24.dp
+    val menu = 24.dp
+    val pill = 999.dp
+}

replica/rechner/design/components.md

@@ -0,0 +1,26 @@
+# Komponenten: Rechner
+
+```
+Display (S01)
+  expression  right aligned, expr 72sp shrinking to expr-min as it grows, then scrolls horizontally; cursor; selectable (long press → S04)
+  result      live preview below (result 36sp, muted); on "=" it animates up into the expression
+  states      empty (blinking cursor), typing, final, error (error colour, message), overflow (scroll)
+  tokens      display bg, radius display at the bottom corners, drag handle 32×4 at the bottom edge
+
+FunctionRow (S01) / ScientificPanel (S02)
+  collapsed   √ π ^ ! as text keys + chevron button (circle)
+  expanded    tonal pills: √ π ^ ! / Deg|Rad sin cos tan / Inv e ln log; Inv toggles labels (sin⁻¹ cos⁻¹ tan⁻¹ / eˣ 10ˣ x²)
+  motion      expand with the keypad sliding down (sheet spring)
+
+Key
+  variants    digit, op (÷ × − +, ( ), %), ac, eq, fn
+  shape       circle at rest → squircle (key-pressed radius) while pressed, spring back; haptic KEYBOARD_TAP
+  a11y        content descriptions in words ("geteilt durch", "Klammer", "Wurzel"), backspace long-press = clear
+
+HistorySheet (S03)
+  pull the display down (or ⏱ button) to reveal; groups by day ("Heute", "Gestern", date); row = expression muted + result large, right aligned;
+  tap inserts the result; "Aktuelle Eingabe" label above the live expression; empty state text; clear in the overflow menu
+
+ContextMenu (S04)
+  floating pill: Ausschneiden, Kopieren, Einfügen, MS, MR (when memory set)
+```

replica/rechner/design/gen_theme.py

@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+"""tokens.json -> Tokens.kt (Compose). Re-run after every token change."""
+import json, re, sys, pathlib
+src = pathlib.Path(sys.argv[1] if len(sys.argv) > 1 else "tokens.json")
+out = pathlib.Path(sys.argv[2] if len(sys.argv) > 2 else src.with_name("Tokens.kt"))
+t = json.loads(src.read_text())
+camel = lambda s: re.sub(r"-(\w)", lambda m: m.group(1).upper(), s)
+L = ["// Generated from tokens.json by gen_theme.py. Do not edit by hand.",
+     "package app.rechner.ui.theme", "",
+     "import androidx.compose.ui.graphics.Color",
+     "import androidx.compose.ui.text.TextStyle",
+     "import androidx.compose.ui.text.font.FontWeight",
+     "import androidx.compose.ui.unit.dp",
+     "import androidx.compose.ui.unit.sp", "",
+     "object WColor {"]
+L += [f"    val {camel(k)} = Color(0xFF{v.lstrip('#').upper()})" for k, v in t["color"].items()]
+L += ["}", "", "object WType {"]
+for k, v in t["type"].items():
+    L.append(f"    val {camel(k)} = TextStyle(fontSize = {v['size']}.sp, lineHeight = {v['line']}.sp, fontWeight = FontWeight.W{v['weight']})")
+L += ["}", "", "object WSpace {"]
+L += [f"    val s{v} = {v}.dp" for v in t["space"]]
+L += ["}", "", "object WRadius {"]
+L += [f"    val {camel(k)} = {v}.dp" for k, v in t["radius"].items()]
+L += ["}", ""]
+out.write_text("\n".join(L))
+print("wrote", out)

replica/rechner/design/tokens.json

@@ -0,0 +1,43 @@
+{
+  "_about": "Rechner tokens from replica/rechner/screens/ref-01..07 (light, dark, Material You). Fallback palette; on Android 12+ dynamic colour drives the key roles. Check: python3 ~/.claude/skills/replica-design/contrast.py replica/rechner/design/tokens.json",
+  "color": {
+    "bg": "#f9f9ff", "display": "#e1e5ee", "sheet": "#e8ebf2",
+    "text": "#191c20", "text-muted": "#43474e", "result": "#5a5f68",
+    "key-digit": "#eef0f5", "on-key-digit": "#191c20",
+    "key-op": "#d6e3f5", "on-key-op": "#0e1d2e",
+    "key-ac": "#ead9ff", "on-key-ac": "#25113d",
+    "key-eq": "#cde3fb", "on-key-eq": "#06233d",
+    "key-fn": "#dde3ec", "on-key-fn": "#191c20",
+    "error": "#ba1a1a",
+    "dark-bg": "#0b1414", "dark-display": "#283535", "dark-sheet": "#1e2a2a",
+    "dark-text": "#e0e6e6", "dark-text-muted": "#bec8c8", "dark-result": "#9fb0b0",
+    "dark-key-digit": "#172121", "dark-on-key-digit": "#dde4e4",
+    "dark-key-op": "#a3d1d3", "dark-on-key-op": "#002f31",
+    "dark-key-ac": "#8fd5e8", "dark-on-key-ac": "#00303b",
+    "dark-key-eq": "#00e0cc", "dark-on-key-eq": "#00332e",
+    "dark-key-fn": "#253232", "dark-on-key-fn": "#dde4e4",
+    "dark-error": "#ffb4ab"
+  },
+  "pairs": [
+    ["text","display"],["text-muted","display"],["result","display"],["text","sheet"],["text-muted","sheet"],["text","bg"],
+    ["on-key-digit","key-digit"],["on-key-op","key-op"],["on-key-ac","key-ac"],["on-key-eq","key-eq"],["on-key-fn","key-fn"],["error","display"],
+    ["dark-text","dark-display"],["dark-text-muted","dark-display"],["dark-result","dark-display"],["dark-text","dark-sheet"],["dark-text-muted","dark-sheet"],["dark-text","dark-bg"],
+    ["dark-on-key-digit","dark-key-digit"],["dark-on-key-op","dark-key-op"],["dark-on-key-ac","dark-key-ac"],["dark-on-key-eq","dark-key-eq"],["dark-on-key-fn","dark-key-fn"],["dark-error","dark-display"]
+  ],
+  "font": {"sans": "Roboto Flex (OFL)", "display": "Roboto Flex, weight 400, tabular figures for expression and result"},
+  "type": {
+    "label": {"size": 14, "line": 20, "weight": 500},
+    "body": {"size": 16, "line": 24, "weight": 400},
+    "fn": {"size": 22, "line": 28, "weight": 400},
+    "key": {"size": 34, "line": 40, "weight": 400},
+    "result": {"size": 36, "line": 44, "weight": 400},
+    "expr": {"size": 72, "line": 80, "weight": 400},
+    "expr-min": {"size": 36, "line": 44, "weight": 400},
+    "history-expr": {"size": 18, "line": 24, "weight": 400},
+    "history-result": {"size": 28, "line": 34, "weight": 400}
+  },
+  "space": [0, 4, 8, 12, 16, 24, 32],
+  "radius": {"display": 32, "key": 999, "key-pressed": 24, "menu": 24, "pill": 999},
+  "layout": {"key-gap": 12, "gutter": 16, "keypad-cols": 4, "display-min-height": "35%"},
+  "motion": {"key-press": "spring dampingRatio 0.6 stiffness 800 (circle -> squircle)", "sheet": "spring 0.9 / 400"}
+}

replica/rechner/features.csv

@@ -0,0 +1,29 @@
+feature,area,priority,original,clone,notes
+Basic arithmetic + − × ÷,core,must,yes,yes,
+Live result preview while typing,core,must,yes,yes,
+Equals makes the result the new expression,core,must,yes,yes,
+Parentheses smart toggle key,core,must,yes,yes,
+Percent,core,must,yes,yes,
+Backspace and long-press to clear,core,must,yes,yes,
+AC clears,core,must,yes,yes,
+Exact arithmetic (no floating point errors),core,must,yes,yes,BigDecimal/rational
+Errors shown (division by zero domain errors),core,must,yes,yes,
+Auto-shrinking display for long input,display,must,yes,yes,
+Scientific row √ π ^ !,science,must,yes,yes,
+Expanded panel sin cos tan ln log e,science,must,yes,yes,
+Deg/Rad switch,science,must,yes,yes,
+Inv swaps to inverse functions,science,must,yes,yes,
+Implicit multiplication (2π 3(4)),core,should,yes,yes,
+History grouped by day,history,must,yes,yes,
+Tap a history entry to reuse,history,must,yes,yes,
+Clear history,history,should,yes,yes,
+Pull down the display to open history,history,should,yes,yes,
+Copy result / paste into expression,clipboard,must,yes,yes,
+Memory store and recall (MS MR),clipboard,should,yes,yes,
+Big numbers like 100! with scrolling,core,should,yes,partial,"exact, shown scientific (9,33E157); full digits not scrollable yet"
+Locale decimal separator,display,should,yes,yes,comma in German
+Expressive keys with press morph,design,must,yes,yes,
+Dynamic colour (wallpaper) and dark mode,design,must,yes,yes,
+Haptic key feedback,design,should,yes,yes,
+Tablet / landscape layout with all functions,layout,could,yes,no,
+Feedback and help,other,could,yes,skip,Google service

replica/rechner/recon.md

@@ -0,0 +1,78 @@
+# Recon map: Google Calculator / Pixel Calculator (Android)
+
+Scope: the whole app: keypad, scientific functions, live result, history, memory, copy/paste, settings
+For: personal use, a calculator without Google services (project NoGooleApps)
+Date: 2026-10-17
+
+## Sources
+
+| # | source | URL | notes |
+| --- | --- | --- | --- |
+| 1 | app store listing | https://play.google.com/store/apps/details?id=com.google.android.calculator | page did not load via fetch; listing images supplied by the user (ref-01..03) |
+| 2 | screenshots | replica/rechner/screens/ref-01..07.png | supplied by user: history with "Current expression" sheet and MS/Copy menu (ref-01, -02, -06), scientific panel open (ref-03), launcher icon (ref-04), selection with Cut/Copy/MS (ref-05), empty dark state with Material You colours (ref-07). Reference only, never shipped |
+| 3 | general knowledge of the app as a user | – | precise arithmetic (no 0.1+0.2 errors), very long results scroll, Deg/Rad, Inv swaps functions |
+
+## Core loop
+
+Type a calculation and see the result update live, then tap = to make it the new start value.
+
+## Screens
+
+| ID | screen | how to reach | purpose | key components | states seen |
+| --- | --- | --- | --- | --- | --- |
+| S01 | Calculator | launch | type and evaluate | display (expression + live result, right aligned, auto-shrinking font), scientific row (√ π ^ !) with expand chevron, keypad 4×5 (AC, ( ), %, ÷ / 7-9 × / 4-6 − / 1-3 + / 0 . ⌫ =), history button, overflow | empty (cursor), typing, live result, result after =, error ("Kann nicht durch 0 teilen"), too long (scrolls) (ref-05..07) |
+| S02 | Scientific panel | chevron or swipe up on the row | more functions | extra rows: Deg/Rad, sin cos tan, Inv, e ln log, (with Inv: sin⁻¹ cos⁻¹ tan⁻¹, eˣ, 10ˣ, x²) | collapsed, expanded (ref-03) |
+| S03 | History | pull the display down / history button | past calculations | list grouped by day ("Heute"), each expression + result, "Current expression" at the bottom of the sheet, tap to reuse, clear history | empty, filled (ref-01, -02, -06) |
+| S04 | Context menu | long press on display or a history result | reuse values | Cut, Copy, Paste, MS (memory store), MR when memory set | (ref-01, -05) |
+| S05 | Settings / overflow | ⋮ | options | history clear, choose theme, about, (original: send feedback) | |
+
+## Flows
+
+```
+F01 Quick sum
+    S01: 1 2 + 3 4 → live result 46 → =
+    happy path taps: 6
+F02 Scientific
+    S01 → expand → sin ( Deg … ) → =
+F03 Reuse an old result
+    S01 pull down → S03 → tap a result → it is inserted at the cursor
+F04 Copy the result
+    S01 long press → S04 Copy
+F05 Store a value and recall it
+    long press → MS … later long press → MR
+    edge: memory survives app restart
+edge cases everywhere: division by zero, unbalanced parentheses (auto close), 0.1+0.2 exact, 100! (big), %, implicit multiplication "2π", leading minus, very long input
+```
+
+## Components
+
+| component | variants | states | used on |
+| --- | --- | --- | --- |
+| Key | digit (surface), operator (secondary container), AC (tertiary), equals (primary, fully round), function (text only in the collapsed row / tonal pills when expanded) | default, pressed (shape squishes to a squircle), disabled | S01, S02 |
+| Display | expression (large, shrinks with length), result preview (smaller, accent colour), cursor | empty, typing, final, error | S01 |
+| Sheet | history over display with drag handle | collapsed, expanded | S03 |
+| History row | expression muted, result bold | pressed | S03 |
+| Context menu | floating pill menu | | S04 |
+| Chevron | expand/collapse | | S02 |
+
+## Inferred data model
+
+```
+HistoryEntry  id, expression (text), result (text), created_at
+              evidence: S03 "Today" grouping  confidence: high
+Memory        value (exact number as text)   confidence: high (MS/MR)
+Settings      angle_unit (deg|rad), theme      confidence: high
+```
+
+## Feature matrix
+
+See `features.csv`.
+
+## Out of scope
+
+- Google's feedback/help integration.
+- Google's own number fonts and icons: Roboto Flex and own icon.
+
+## Size
+
+Screens 5, flows 5, entities 3. Hard parts: (1) exact arithmetic with big numbers and correct rounding/display of irrational results, (2) a parser that tolerates partial input for the live result (implicit multiplication, auto-closing parentheses, percent rules), (3) the expressive keypad (shape morph on press, auto-sizing display). Size: S–M.

replica/rechner/schema.sql

@@ -0,0 +1,9 @@
+-- Local SQLite (Room). No network, no accounts.
+CREATE TABLE history (
+  id          INTEGER PRIMARY KEY AUTOINCREMENT,
+  expression  TEXT    NOT NULL CHECK (length(expression) > 0),
+  result      TEXT    NOT NULL,
+  created_at  INTEGER NOT NULL            -- epoch ms UTC; grouped by local day in the UI
+);
+CREATE INDEX history_created ON history(created_at);
+-- Memory value, angle unit, theme and the current (unfinished) expression live in DataStore.

replica/uhr/build-log.md

@@ -11,11 +11,11 @@ Device checks on a Pixel 10 Pro XL (Android 16) via a debug-only activity that s
 | S03 Time picker | 2026-10-17 | done | – | – |
 | S04 Sound picker | 2026-10-17 | done | – | own file not device-tested |
 | S05 Pause alarm | 2026-10-17 | done | – | – |
-| S06 Clock | 2026-10-17 | done | reorder cities | city names offline via ICU exemplar cities |
+| S06 Clock | 2026-10-17 | done | – | city names offline via ICU exemplar cities |
 | S07 Add city | 2026-10-17 | done | – | – |
-| S08 Timer | 2026-10-17 | done | label edit UI | verified on device: 5 s timer rang in the background, stopped from the notification |
+| S08 Timer | 2026-10-17 | done | – | verified on device: 5 s timer rang in the background, stopped from the notification |
 | S09 Stopwatch | 2026-10-17 | done | – | – |
-| S10 Bedtime | 2026-10-17 | partial | sunrise alarm, sleep sounds | – |
+| S10 Bedtime | 2026-10-17 | done | sunrise full-screen not confirmed on device | sleep sounds generated in-house; the sunrise needs the full-screen-intent permission, which Android 14+ does not grant sideloaded apps by default (the app asks) |
 | S11 Ringing | 2026-10-17 | done | – | – |
 | S12 Timer ringing | 2026-10-17 | done | – | shares the ringing screen |
 | S13 Settings | 2026-10-17 | done | timer sound picker, home time zone | – |

replica/uhr/design/Tokens.kt

@@ -65,6 +65,10 @@ object WColor {
     val timerProgress = Color(0xFF7EC4A8)
     val nightText = Color(0xFFC4433A)
     val nightBg = Color(0xFF000000)
+    val sunriseNight = Color(0xFF0D0710)
+    val sunriseEmber = Color(0xFF5A1A10)
+    val sunriseDay = Color(0xFFFFD9A0)
+    val sunriseSun = Color(0xFFFFF3D6)
 }
 
 object WType {

replica/uhr/design/tokens.json

@@ -1,45 +1,230 @@
 {
   "_about": "Uhr tokens. Roles read by eye from replica/uhr/screens/ref-01..07 (Pixel Clock, dark first). Own values, no brand colour copied; on Android 12+ dynamic colour (wallpaper) replaces the accent roles. Check: python3 ~/.claude/skills/replica-design/contrast.py replica/uhr/design/tokens.json",
   "color": {
-    "bg": "#f8f9ff", "surface": "#ffffff", "card": "#eef0f6", "card-high": "#e2e5ec",
-    "border": "#c3c6cf", "border-input": "#73777f",
-    "text": "#191c20", "text-muted": "#43474e", "text-off": "#5c6068",
-    "accent": "#2f5ea8", "on-accent": "#ffffff",
-    "accent-container": "#d6e3ff", "on-accent-container": "#001b3e",
-    "fab": "#a8c7fa", "on-fab": "#0b2a55",
-    "chip-on": "#2f5ea8", "on-chip-on": "#ffffff",
-    "secondary-pill": "#dfe2eb", "on-secondary-pill": "#191c20",
-    "stop": "#ffd8e4", "on-stop": "#4a1426",
+    "bg": "#f8f9ff",
+    "surface": "#ffffff",
+    "card": "#eef0f6",
+    "card-high": "#e2e5ec",
+    "border": "#c3c6cf",
+    "border-input": "#73777f",
+    "text": "#191c20",
+    "text-muted": "#43474e",
+    "text-off": "#5c6068",
+    "accent": "#2f5ea8",
+    "on-accent": "#ffffff",
+    "accent-container": "#d6e3ff",
+    "on-accent-container": "#001b3e",
+    "fab": "#a8c7fa",
+    "on-fab": "#0b2a55",
+    "chip-on": "#2f5ea8",
+    "on-chip-on": "#ffffff",
+    "secondary-pill": "#dfe2eb",
+    "on-secondary-pill": "#191c20",
+    "stop": "#ffd8e4",
+    "on-stop": "#4a1426",
     "danger": "#ba1a1a",
-    "nav": "#eceef4", "nav-indicator": "#d6e3ff",
-
-    "dark-bg": "#111318", "dark-surface": "#111318", "dark-card": "#1d2024", "dark-card-high": "#272a2f",
-    "dark-border": "#43474e", "dark-border-input": "#8d9199",
-    "dark-text": "#e2e2e9", "dark-text-muted": "#c3c6cf", "dark-text-off": "#9a9ea6",
-    "dark-accent": "#a8c7fa", "dark-on-accent": "#062e6f",
-    "dark-accent-container": "#244a80", "dark-on-accent-container": "#d6e3ff",
-    "dark-fab": "#a8c7fa", "dark-on-fab": "#062e6f",
-    "dark-chip-on": "#a8c7fa", "dark-on-chip-on": "#062e6f",
-    "dark-secondary-pill": "#3a3d43", "dark-on-secondary-pill": "#e2e2e9",
-    "dark-stop": "#f2b8c9", "dark-on-stop": "#4a1426",
+    "nav": "#eceef4",
+    "nav-indicator": "#d6e3ff",
+    "dark-bg": "#111318",
+    "dark-surface": "#111318",
+    "dark-card": "#1d2024",
+    "dark-card-high": "#272a2f",
+    "dark-border": "#43474e",
+    "dark-border-input": "#8d9199",
+    "dark-text": "#e2e2e9",
+    "dark-text-muted": "#c3c6cf",
+    "dark-text-off": "#9a9ea6",
+    "dark-accent": "#a8c7fa",
+    "dark-on-accent": "#062e6f",
+    "dark-accent-container": "#244a80",
+    "dark-on-accent-container": "#d6e3ff",
+    "dark-fab": "#a8c7fa",
+    "dark-on-fab": "#062e6f",
+    "dark-chip-on": "#a8c7fa",
+    "dark-on-chip-on": "#062e6f",
+    "dark-secondary-pill": "#3a3d43",
+    "dark-on-secondary-pill": "#e2e2e9",
+    "dark-stop": "#f2b8c9",
+    "dark-on-stop": "#4a1426",
     "dark-danger": "#ffb4ab",
-    "dark-nav": "#1d2024", "dark-nav-indicator": "#3a3f47",
-
-    "ring-bg": "#1e5a52", "ring-on": "#b4f1e6", "ring-track": "#2b6e65", "ring-thumb": "#3f9a7f", "on-ring-thumb": "#ffffff",
-    "timer-track": "#3a3d43", "timer-progress": "#7ec4a8",
-    "night-text": "#c4433a", "night-bg": "#000000"
+    "dark-nav": "#1d2024",
+    "dark-nav-indicator": "#3a3f47",
+    "ring-bg": "#1e5a52",
+    "ring-on": "#b4f1e6",
+    "ring-track": "#2b6e65",
+    "ring-thumb": "#3f9a7f",
+    "on-ring-thumb": "#ffffff",
+    "timer-track": "#3a3d43",
+    "timer-progress": "#7ec4a8",
+    "night-text": "#c4433a",
+    "night-bg": "#000000",
+    "sunrise-night": "#0d0710",
+    "sunrise-ember": "#5a1a10",
+    "sunrise-day": "#ffd9a0",
+    "sunrise-sun": "#fff3d6"
   },
   "pairs": [
-    ["text","bg"],["text","card"],["text","card-high"],["text-muted","bg"],["text-muted","card"],["text-off","card"],
-    ["on-accent","accent"],["on-accent-container","accent-container"],["on-fab","fab"],["on-chip-on","chip-on"],
-    ["on-secondary-pill","secondary-pill"],["on-stop","stop"],["accent","card"],["danger","card"],["text","nav"],["text","nav-indicator"],
-    ["border-input","surface","ui"],
-    ["dark-text","dark-bg"],["dark-text","dark-card"],["dark-text","dark-card-high"],["dark-text-muted","dark-bg"],["dark-text-muted","dark-card"],["dark-text-off","dark-card"],
-    ["dark-on-accent","dark-accent"],["dark-on-accent-container","dark-accent-container"],["dark-on-fab","dark-fab"],["dark-on-chip-on","dark-chip-on"],
-    ["dark-on-secondary-pill","dark-secondary-pill"],["dark-on-stop","dark-stop"],["dark-accent","dark-card"],["dark-danger","dark-card"],
-    ["dark-text","dark-nav"],["dark-text","dark-nav-indicator"],["dark-border-input","dark-card","ui"],
-    ["ring-on","ring-bg"],["ring-on","ring-track"],["on-ring-thumb","ring-thumb","large"],
-    ["timer-progress","dark-card","ui"],["night-text","night-bg","large"]
+    [
+      "text",
+      "bg"
+    ],
+    [
+      "text",
+      "card"
+    ],
+    [
+      "text",
+      "card-high"
+    ],
+    [
+      "text-muted",
+      "bg"
+    ],
+    [
+      "text-muted",
+      "card"
+    ],
+    [
+      "text-off",
+      "card"
+    ],
+    [
+      "on-accent",
+      "accent"
+    ],
+    [
+      "on-accent-container",
+      "accent-container"
+    ],
+    [
+      "on-fab",
+      "fab"
+    ],
+    [
+      "on-chip-on",
+      "chip-on"
+    ],
+    [
+      "on-secondary-pill",
+      "secondary-pill"
+    ],
+    [
+      "on-stop",
+      "stop"
+    ],
+    [
+      "accent",
+      "card"
+    ],
+    [
+      "danger",
+      "card"
+    ],
+    [
+      "text",
+      "nav"
+    ],
+    [
+      "text",
+      "nav-indicator"
+    ],
+    [
+      "border-input",
+      "surface",
+      "ui"
+    ],
+    [
+      "dark-text",
+      "dark-bg"
+    ],
+    [
+      "dark-text",
+      "dark-card"
+    ],
+    [
+      "dark-text",
+      "dark-card-high"
+    ],
+    [
+      "dark-text-muted",
+      "dark-bg"
+    ],
+    [
+      "dark-text-muted",
+      "dark-card"
+    ],
+    [
+      "dark-text-off",
+      "dark-card"
+    ],
+    [
+      "dark-on-accent",
+      "dark-accent"
+    ],
+    [
+      "dark-on-accent-container",
+      "dark-accent-container"
+    ],
+    [
+      "dark-on-fab",
+      "dark-fab"
+    ],
+    [
+      "dark-on-chip-on",
+      "dark-chip-on"
+    ],
+    [
+      "dark-on-secondary-pill",
+      "dark-secondary-pill"
+    ],
+    [
+      "dark-on-stop",
+      "dark-stop"
+    ],
+    [
+      "dark-accent",
+      "dark-card"
+    ],
+    [
+      "dark-danger",
+      "dark-card"
+    ],
+    [
+      "dark-text",
+      "dark-nav"
+    ],
+    [
+      "dark-text",
+      "dark-nav-indicator"
+    ],
+    [
+      "dark-border-input",
+      "dark-card",
+      "ui"
+    ],
+    [
+      "ring-on",
+      "ring-bg"
+    ],
+    [
+      "ring-on",
+      "ring-track"
+    ],
+    [
+      "on-ring-thumb",
+      "ring-thumb",
+      "large"
+    ],
+    [
+      "timer-progress",
+      "dark-card",
+      "ui"
+    ],
+    [
+      "night-text",
+      "night-bg",
+      "large"
+    ]
   ],
   "font": {
     "sans": "Roboto Flex (OFL), system fallback",
@@ -48,21 +233,88 @@
     "mono": "tabular figures (fontFeatureSettings tnum) instead of a mono font for the stopwatch"
   },
   "type": {
-    "label-sm": {"size": 12, "line": 16, "weight": 500},
-    "label": {"size": 14, "line": 20, "weight": 500},
-    "body-sm": {"size": 14, "line": 20, "weight": 400},
-    "body": {"size": 16, "line": 24, "weight": 400},
-    "title": {"size": 22, "line": 28, "weight": 400},
-    "headline": {"size": 28, "line": 36, "weight": 400},
-    "alarm-time": {"size": 56, "line": 60, "weight": 600},
-    "alarm-ampm": {"size": 20, "line": 24, "weight": 600},
-    "timer-time": {"size": 44, "line": 48, "weight": 400},
-    "clock-big": {"size": 88, "line": 92, "weight": 400},
-    "stopwatch": {"size": 72, "line": 76, "weight": 500},
-    "ringing": {"size": 104, "line": 108, "weight": 400}
+    "label-sm": {
+      "size": 12,
+      "line": 16,
+      "weight": 500
+    },
+    "label": {
+      "size": 14,
+      "line": 20,
+      "weight": 500
+    },
+    "body-sm": {
+      "size": 14,
+      "line": 20,
+      "weight": 400
+    },
+    "body": {
+      "size": 16,
+      "line": 24,
+      "weight": 400
+    },
+    "title": {
+      "size": 22,
+      "line": 28,
+      "weight": 400
+    },
+    "headline": {
+      "size": 28,
+      "line": 36,
+      "weight": 400
+    },
+    "alarm-time": {
+      "size": 56,
+      "line": 60,
+      "weight": 600
+    },
+    "alarm-ampm": {
+      "size": 20,
+      "line": 24,
+      "weight": 600
+    },
+    "timer-time": {
+      "size": 44,
+      "line": 48,
+      "weight": 400
+    },
+    "clock-big": {
+      "size": 88,
+      "line": 92,
+      "weight": 400
+    },
+    "stopwatch": {
+      "size": 72,
+      "line": 76,
+      "weight": 500
+    },
+    "ringing": {
+      "size": 104,
+      "line": 108,
+      "weight": 400
+    }
+  },
+  "space": [
+    0,
+    2,
+    4,
+    8,
+    12,
+    16,
+    20,
+    24,
+    32,
+    48
+  ],
+  "radius": {
+    "xs": 8,
+    "sm": 12,
+    "md": 16,
+    "lg": 24,
+    "card": 28,
+    "pill": 999,
+    "nav-indicator": 16
   },
-  "space": [0, 2, 4, 8, 12, 16, 20, 24, 32, 48],
-  "radius": {"xs": 8, "sm": 12, "md": 16, "lg": 24, "card": 28, "pill": 999, "nav-indicator": 16},
   "shape": {
     "fab": "circle 96dp (large, centred above the nav bar)",
     "stopwatch-primary": "pill 72dp tall, full width",
@@ -72,7 +324,14 @@
   "motion": {
     "card-expand": "spring dampingRatio 0.85 stiffness 380",
     "slide-act": "spring back dampingRatio 0.7",
-    "fast": "120ms", "base": "250ms"
+    "fast": "120ms",
+    "base": "250ms"
   },
-  "layout": {"gutter": 16, "card-gap": 8, "nav-height": 80, "fab-bottom": 16, "card-padding": 20}
-}
+  "layout": {
+    "gutter": 16,
+    "card-gap": 8,
+    "nav-height": 80,
+    "fab-bottom": 16,
+    "card-padding": 20
+  }
+}

replica/uhr/features.csv

@@ -24,14 +24,14 @@ Missed alarm notification,notifications,should,yes,yes,
 Snoozed notification with dismiss,notifications,must,yes,yes,
 World clock: local time and date,clock,must,yes,yes,
 World clock: add city via search,clock,must,yes,yes,
-World clock: reorder and swipe to delete,clock,should,yes,partial,swipe to delete only
+World clock: reorder and swipe to delete,clock,should,yes,yes,"long-press drag; verified on device, order persists"
 Analog or digital clock style,clock,should,yes,yes,
 Show seconds,clock,could,yes,yes,
 Automatic home clock when travelling,clock,could,yes,no,
 Timer keypad h m s,timer,must,yes,yes,
 Run several timers at once,timer,must,yes,yes,
 Timer ring progress +1:00 pause reset delete,timer,must,yes,yes,
-Timer labels,timer,could,yes,partial,stored and shown; no UI to edit yet
+Timer labels,timer,could,yes,yes,tap the title to rename
 Timer runs in background with notification,timer,must,yes,yes,
 Timer ringing screen,timer,must,yes,yes,
 Timer sound and vibrate settings,settings,should,yes,partial,vibrate setting only; sound uses default
@@ -40,8 +40,8 @@ Stopwatch laps,stopwatch,must,yes,yes,
 Stopwatch running notification,stopwatch,should,yes,yes,
 Bedtime schedule with wake-up alarm,bedtime,should,yes,yes,
 Bedtime reminder notification,bedtime,should,yes,yes,
-Sunrise alarm (brightening screen),bedtime,could,yes,no,
-Sleep sounds with timer,bedtime,could,yes,no,own CC0 sounds
+Sunrise alarm (brightening screen),bedtime,could,yes,partial,scheduled 15 min before the bedtime wake alarm via full-screen notification; full-screen launch not confirmed on device (no keyguard during test)
+Sleep sounds with timer,bedtime,could,yes,yes,"own generated sounds (rain, waves, brown noise), sleep timer with 20 s fade-out; verified playing on device"
 Screensaver / bedside clock with night mode,display,could,yes,no,DreamService
 Digital clock widget,widgets,must,yes,yes,
 Analog clock widget,widgets,should,yes,yes,

uhr/app/build.gradle.kts

@@ -16,8 +16,8 @@ android {
         applicationId = "app.uhr"
         minSdk = 29
         targetSdk = 36
-        versionCode = 2
-        versionName = "0.1.1"
+        versionCode = 4
+        versionName = "0.2.0"
     }
 
     // Release key lives outside the repo; without it, release builds fall back to the debug key (local only).

uhr/app/src/debug/java/app/uhr/DebugAlarmActivity.kt

@@ -13,6 +13,15 @@ class DebugAlarmActivity : Activity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         Graph.init(this)
+        if (intent.getBooleanExtra("sunrise", false)) {
+            // through the real path: AlarmManager -> receiver -> full-screen notification, 20 s from now
+            Graph.repo.scheduler.scheduleSunrise(System.currentTimeMillis() + app.uhr.alarm.SunriseActivity.DURATION_MS + 20_000L)
+            finish(); return
+        }
+        if (intent.getBooleanExtra("cities", false)) {
+            runBlocking { app.uhr.data.Zones.search("").let { } ; listOf("Tokyo", "New_York", "London").forEach { c -> app.uhr.data.Zones.search(c.replace('_', ' ')).firstOrNull()?.let { Graph.repo.addCity(it) } } }
+            finish(); return
+        }
         val timerS = intent.getIntExtra("timer_seconds", 0)
         if (timerS > 0) {
             val id = runBlocking { Graph.repo.startTimer(timerS * 1000L, "Testtimer") }

uhr/app/src/main/AndroidManifest.xml

@@ -37,6 +37,9 @@
             android:turnScreenOn="true"
             android:taskAffinity="" />
 
+        <activity android:name=".alarm.SunriseActivity" android:exported="false" android:excludeFromRecents="true"
+            android:launchMode="singleInstance" android:showWhenLocked="true" android:turnScreenOn="true" android:taskAffinity="" />
+        <service android:name=".alarm.SleepSoundService" android:exported="false" android:foregroundServiceType="mediaPlayback" />
         <service android:name=".alarm.RingingService" android:exported="false" android:foregroundServiceType="mediaPlayback" />
 
         <receiver android:name=".alarm.AlarmReceiver" android:exported="false" android:directBootAware="false">

uhr/app/src/main/java/app/uhr/MainActivity.kt

@@ -164,6 +164,7 @@ private fun ClockApp(settings: Settings, requestedTab: Int) {
             override fun reset(id: Long) { scope.launch { repo.resetTimer(id) } }
             override fun delete(id: Long) { scope.launch { repo.deleteTimer(id) } }
             override fun stopRinging() { RingingService.stop(context) }
+            override fun rename(id: Long, label: String) { scope.launch { repo.setTimerLabel(id, label) } }
         }
     }
 
@@ -209,7 +210,7 @@ private fun ClockApp(settings: Settings, requestedTab: Int) {
     ) { pad ->
         when (tab) {
             0 -> AlarmScreen(alarms, settings, alarmActions, snackbar, pad)
-            1 -> ClockScreen(settings, cities, next, pad, onDeleteCity = { c -> scope.launch { repo.deleteCity(c.id) } })
+            1 -> ClockScreen(settings, cities, next, pad, onDeleteCity = { c -> scope.launch { repo.deleteCity(c.id) } }, onReorder = { ids -> scope.launch { repo.reorderCities(ids) } })
             2 -> {
                 if (keypad && timers.isNotEmpty()) BackHandler { keypad = false; digits = "" }
                 TimerScreen(timers, keypad, digits, { digits = it }, timerActions, pad)

uhr/app/src/main/java/app/uhr/alarm/AlarmReceiver.kt

@@ -31,12 +31,13 @@ class AlarmReceiver : BroadcastReceiver() {
         val repo = Graph.repo
         when (action) {
             Intent.ACTION_BOOT_COMPLETED, Intent.ACTION_LOCKED_BOOT_COMPLETED, Intent.ACTION_TIME_CHANGED, "android.intent.action.TIME_SET",
-            Intent.ACTION_TIMEZONE_CHANGED, Intent.ACTION_MY_PACKAGE_REPLACED -> repo.scheduler.rescheduleAll()
+            Intent.ACTION_TIMEZONE_CHANGED, Intent.ACTION_MY_PACKAGE_REPLACED -> { repo.scheduler.rescheduleAll(); repo.scheduleBedtime() }
             ACTION_UPCOMING -> repo.alarm(id)?.let { a -> repo.instance(id)?.let { Notifications.upcoming(context, a, it.fireAt) } }
             ACTION_DISMISS_NEXT -> repo.dismissNext(id)
             ACTION_SNOOZE_DISMISS -> repo.finishAlarm(id)
             ACTION_TIMER_PAUSE -> repo.pauseTimer(id)
             ACTION_TIMER_ADD_MINUTE -> repo.addMinute(id)
+            ACTION_SUNRISE -> Notifications.sunrise(context, id)
             ACTION_BEDTIME -> { Notifications.bedtime(context); repo.scheduleBedtime() }
         }
     }
@@ -51,6 +52,7 @@ class AlarmReceiver : BroadcastReceiver() {
         const val ACTION_TIMER_PAUSE = "app.uhr.TIMER_PAUSE"
         const val ACTION_TIMER_ADD_MINUTE = "app.uhr.TIMER_ADD_MINUTE"
         const val ACTION_BEDTIME = "app.uhr.BEDTIME"
+        const val ACTION_SUNRISE = "app.uhr.SUNRISE"
         private val scope = CoroutineScope(SupervisorJob() + Dispatchers.Default)
     }
 }

uhr/app/src/main/java/app/uhr/alarm/Notifications.kt

@@ -32,6 +32,8 @@ object Notifications {
     const val ID_STOPWATCH = 2
     const val ID_RINGING = 3
     const val ID_BEDTIME = 4
+    const val ID_SLEEP = 5
+    const val ID_SUNRISE = 6
     private const val ALARM_BASE = 1000
 
     fun createChannels(context: Context) {
@@ -147,6 +149,26 @@ object Notifications {
         )
     }
 
+    /** Full-screen intent is the only way to bring the sunrise screen up from the background. */
+    fun sunrise(context: Context, fireAt: Long) {
+        if (!allowed(context)) return
+        val full = PendingIntent.getActivity(
+            context, 7, Intent(context, SunriseActivity::class.java).putExtra(SunriseActivity.EXTRA_FIRE_AT, fireAt)
+                .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_NO_USER_ACTION),
+            PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT,
+        )
+        // an update of an existing notification does not fire its full-screen intent again
+        nm(context).cancel(ID_SUNRISE)
+        nm(context).notify(
+            ID_SUNRISE,
+            NotificationCompat.Builder(context, CH_RINGING).setSmallIcon(R.drawable.ic_stat_alarm)
+                .setContentTitle(context.getString(R.string.sunrise_running)).setSilent(true)
+                .setCategory(NotificationCompat.CATEGORY_ALARM).setPriority(NotificationCompat.PRIORITY_MAX)
+                .setFullScreenIntent(full, true).setContentIntent(full).setTimeoutAfter(SunriseActivity.DURATION_MS + 60_000)
+                .setVisibility(NotificationCompat.VISIBILITY_PUBLIC).build(),
+        )
+    }
+
     fun ringing(context: Context, title: String, text: String, fullScreen: PendingIntent, stop: PendingIntent, snooze: PendingIntent?): Notification =
         NotificationCompat.Builder(context, CH_RINGING).setSmallIcon(R.drawable.ic_stat_alarm)
             .setContentTitle(title).setContentText(text)

uhr/app/src/main/java/app/uhr/alarm/Scheduler.kt

@@ -71,6 +71,20 @@ class Scheduler(private val context: Context, private val dao: ClockDao) {
     fun scheduleBedtimeReminder(at: Long) =
         am.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, at, broadcast(AlarmReceiver.ACTION_BEDTIME, 0, REQ_BEDTIME))
 
+    fun scheduleSunrise(fireAt: Long) {
+        val at = fireAt - SunriseActivity.DURATION_MS
+        if (at > System.currentTimeMillis()) am.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, at, sunriseIntent(fireAt))
+    }
+
+    fun cancelSunrise() = am.cancel(sunriseIntent(0))
+
+    /** One sunrise at a time (fixed request code); the wake-up time travels as an extra. */
+    private fun sunriseIntent(fireAt: Long) = PendingIntent.getBroadcast(
+        context, REQ_SUNRISE,
+        Intent(context, AlarmReceiver::class.java).setAction(AlarmReceiver.ACTION_SUNRISE).putExtra(AlarmReceiver.EXTRA_ID, fireAt),
+        PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT,
+    )
+
     fun cancelBedtimeReminder() = am.cancel(broadcast(AlarmReceiver.ACTION_BEDTIME, 0, REQ_BEDTIME))
 
     private fun ringIntent(id: Long) = broadcast(AlarmReceiver.ACTION_RING, id, REQ_RING)
@@ -89,5 +103,6 @@ class Scheduler(private val context: Context, private val dao: ClockDao) {
         private const val REQ_UPCOMING = 1_000_000
         private const val REQ_TIMER = 2_000_000
         private const val REQ_BEDTIME = 3_000_000
+        private const val REQ_SUNRISE = 4_000_000
     }
 }

uhr/app/src/main/java/app/uhr/alarm/SleepSoundService.kt

@@ -0,0 +1,109 @@
+package app.uhr.alarm
+
+import android.app.PendingIntent
+import android.app.Service
+import android.content.Context
+import android.content.Intent
+import android.content.pm.ServiceInfo
+import android.media.AudioAttributes
+import android.media.MediaPlayer
+import android.net.Uri
+import android.os.IBinder
+import androidx.core.app.NotificationCompat
+import androidx.core.app.ServiceCompat
+import app.uhr.MainActivity
+import app.uhr.R
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.launch
+
+enum class SleepSound(val res: Int, val title: Int) {
+    RAIN(R.raw.sleep_rain, R.string.sound_rain),
+    WAVES(R.raw.sleep_waves, R.string.sound_waves),
+    BROWN(R.raw.sleep_brown, R.string.sound_brown),
+}
+
+data class SleepPlayback(val sound: SleepSound, val endsAt: Long)
+
+/** Plays a looping sleep sound on the media stream and fades it out at the end of the sleep timer. */
+class SleepSoundService : Service() {
+    private val scope = CoroutineScope(SupervisorJob() + Dispatchers.Main)
+    private var player: MediaPlayer? = null
+    private var job: Job? = null
+
+    override fun onBind(intent: Intent?): IBinder? = null
+
+    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
+        if (intent?.action == ACTION_STOP) { stop(); return START_NOT_STICKY }
+        val sound = SleepSound.entries.getOrNull(intent?.getIntExtra(EXTRA_SOUND, 0) ?: 0) ?: SleepSound.RAIN
+        val minutes = intent?.getIntExtra(EXTRA_MINUTES, 30) ?: 30
+        val endsAt = System.currentTimeMillis() + minutes * 60_000L
+        ServiceCompat.startForeground(this, Notifications.ID_SLEEP, notification(sound, endsAt), ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PLAYBACK)
+        player?.release()
+        player = MediaPlayer().apply {
+            setAudioAttributes(AudioAttributes.Builder().setUsage(AudioAttributes.USAGE_MEDIA).setContentType(AudioAttributes.CONTENT_TYPE_MUSIC).build())
+            setDataSource(this@SleepSoundService, Uri.parse("android.resource://$packageName/${sound.res}"))
+            isLooping = true
+            prepare()
+            setVolume(0f, 0f)
+            start()
+        }
+        state.value = SleepPlayback(sound, endsAt)
+        job?.cancel()
+        job = scope.launch {
+            fade(0f, 1f, 3_000)
+            delay((endsAt - System.currentTimeMillis() - FADE_OUT_MS).coerceAtLeast(0))
+            fade(1f, 0f, FADE_OUT_MS)
+            stop()
+        }
+        return START_NOT_STICKY
+    }
+
+    private suspend fun fade(from: Float, to: Float, ms: Long) {
+        val steps = (ms / 100).toInt().coerceAtLeast(1)
+        for (i in 1..steps) {
+            val v = from + (to - from) * i / steps
+            runCatching { player?.setVolume(v, v) }
+            delay(100)
+        }
+    }
+
+    private fun notification(sound: SleepSound, endsAt: Long) =
+        NotificationCompat.Builder(this, Notifications.CH_RUNNING).setSmallIcon(R.drawable.ic_stat_bedtime)
+            .setContentTitle(getString(sound.title)).setContentText(getString(R.string.sleep_sound_running))
+            .setUsesChronometer(true).setChronometerCountDown(true).setWhen(endsAt).setShowWhen(true)
+            .setOngoing(true).setSilent(true)
+            .setContentIntent(PendingIntent.getActivity(this, 5, Intent(this, MainActivity::class.java).putExtra(MainActivity.EXTRA_TAB, 4), PendingIntent.FLAG_IMMUTABLE))
+            .addAction(0, getString(R.string.stop), PendingIntent.getService(this, 6, Intent(this, SleepSoundService::class.java).setAction(ACTION_STOP), PendingIntent.FLAG_IMMUTABLE))
+            .build()
+
+    private fun stop() {
+        job?.cancel()
+        player?.runCatching { stop(); release() }; player = null
+        state.value = null
+        ServiceCompat.stopForeground(this, ServiceCompat.STOP_FOREGROUND_REMOVE)
+        stopSelf()
+    }
+
+    override fun onDestroy() { player?.release(); state.value = null; scope.cancel(); super.onDestroy() }
+
+    companion object {
+        private const val ACTION_STOP = "stop"
+        private const val EXTRA_SOUND = "sound"
+        private const val EXTRA_MINUTES = "minutes"
+        private const val FADE_OUT_MS = 20_000L
+        private val state = MutableStateFlow<SleepPlayback?>(null)
+        val playing: StateFlow<SleepPlayback?> get() = state
+
+        fun start(context: Context, sound: SleepSound, minutes: Int) = context.startForegroundService(
+            Intent(context, SleepSoundService::class.java).putExtra(EXTRA_SOUND, sound.ordinal).putExtra(EXTRA_MINUTES, minutes),
+        )
+        fun stop(context: Context) = context.startService(Intent(context, SleepSoundService::class.java).setAction(ACTION_STOP))
+    }
+}

uhr/app/src/main/java/app/uhr/alarm/SunriseActivity.kt

@@ -0,0 +1,62 @@
+package app.uhr.alarm
+
+import android.os.Bundle
+import android.view.WindowManager
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.compose.foundation.Canvas
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableFloatStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.graphics.Brush
+import androidx.compose.ui.graphics.lerp
+import app.uhr.ui.theme.WColor
+import kotlinx.coroutines.delay
+
+/**
+ * Sunrise alarm: in the last minutes before the wake-up alarm the screen turns on over the lock screen
+ * and brightens slowly from a dim red glow to warm daylight. Tap to dismiss; the alarm still rings.
+ */
+class SunriseActivity : ComponentActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setShowWhenLocked(true)
+        setTurnScreenOn(true)
+        window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
+        val endsAt = intent.getLongExtra(EXTRA_FIRE_AT, System.currentTimeMillis() + DURATION_MS)
+        val startedAt = endsAt - DURATION_MS
+        setContent {
+            val progress = remember { mutableFloatStateOf(0f) }
+            val ringing by RingingService.ringing.collectAsState()
+            LaunchedEffect(Unit) {
+                while (true) {
+                    val p = ((System.currentTimeMillis() - startedAt).toFloat() / DURATION_MS).coerceIn(0f, 1f)
+                    progress.floatValue = p
+                    // the window brightness follows the colour, from almost off to full
+                    window.attributes = window.attributes.apply { screenBrightness = 0.01f + 0.99f * p * p }
+                    delay(500)
+                }
+            }
+            // the ringing screen takes over when the alarm starts
+            LaunchedEffect(ringing) { if (ringing != null) finish() }
+            val p = progress.floatValue
+            Canvas(Modifier.fillMaxSize().clickable { finish() }) {
+                val top = lerp(WColor.sunriseNight, WColor.sunriseDay, p)
+                val glow = lerp(WColor.sunriseEmber, WColor.sunriseSun, p)
+                drawRect(Brush.verticalGradient(listOf(top, glow)))
+                drawCircle(Brush.radialGradient(listOf(glow.copy(alpha = .9f), glow.copy(alpha = 0f)), Offset(size.width / 2, size.height), size.width * (0.4f + p)), size.width * (0.4f + p), Offset(size.width / 2, size.height))
+            }
+        }
+    }
+
+    companion object {
+        const val EXTRA_FIRE_AT = "fire_at"
+        const val DURATION_MS = 15 * 60_000L
+    }
+}

uhr/app/src/main/java/app/uhr/data/ClockRepo.kt

@@ -28,10 +28,11 @@ class ClockRepo(private val context: Context, private val dao: ClockDao, val pre
     suspend fun save(alarm: Alarm): Long = lock.withLock {
         val stamped = alarm.copy(updatedAt = System.currentTimeMillis())
         val id = if (alarm.id == 0L) dao.insert(stamped) else stamped.id.also { dao.update(stamped) }
-        dao.alarm(id)?.let { scheduler.reschedule(it) }
+        val saved = dao.alarm(id)
+        saved?.let { scheduler.reschedule(it) }
         updateClockWidgets(context)
         id
-    }
+    }.also { id -> if (dao.alarm(id)?.isBedtimeWake == true) scheduleBedtime() }
 
     suspend fun delete(alarm: Alarm) = lock.withLock {
         scheduler.cancel(alarm.id)
@@ -182,8 +183,15 @@ class ClockRepo(private val context: Context, private val dao: ClockDao, val pre
         scheduleBedtime()
     }
 
+    suspend fun bedtimeAlarmFireAt(): Long? {
+        val a = dao.bedtimeAlarm()?.takeIf { it.enabled } ?: return null
+        return dao.instance(a.id)?.takeIf { it.state == InstanceState.SCHEDULED }?.fireAt
+    }
+
     suspend fun scheduleBedtime() {
         val b = prefs.bedtime.first()
+        scheduler.cancelSunrise()
+        if (b.enabled && b.sunrise) bedtimeAlarmFireAt()?.let { scheduler.scheduleSunrise(it) }
         scheduler.cancelBedtimeReminder()
         if (!b.enabled || b.reminderMin < 0) return
         val reminder = Alarm(hour = b.bedHour, minute = b.bedMinute, days = b.days)

uhr/app/src/main/java/app/uhr/data/Prefs.kt

@@ -55,6 +55,7 @@ data class Bedtime(
     val wakeMinute: Int = 0,
     val days: Int = Alarm.WEEKDAYS,
     val reminderMin: Int = 15,
+    val sunrise: Boolean = false,
 )
 
 private val Context.store by preferencesDataStore("clock")
@@ -85,6 +86,7 @@ class Prefs(private val context: Context) {
         val wakeM = intPreferencesKey("wake_m")
         val bedDays = intPreferencesKey("bed_days")
         val bedReminder = intPreferencesKey("bed_reminder")
+        val sunrise = booleanPreferencesKey("sunrise")
     }
 
     private fun Preferences.settings(): Settings {
@@ -142,14 +144,14 @@ class Prefs(private val context: Context) {
         Bedtime(
             enabled = p[K.bedOn] ?: d.enabled, bedHour = p[K.bedH] ?: d.bedHour, bedMinute = p[K.bedM] ?: d.bedMinute,
             wakeHour = p[K.wakeH] ?: d.wakeHour, wakeMinute = p[K.wakeM] ?: d.wakeMinute,
-            days = p[K.bedDays] ?: d.days, reminderMin = p[K.bedReminder] ?: d.reminderMin,
+            days = p[K.bedDays] ?: d.days, reminderMin = p[K.bedReminder] ?: d.reminderMin, sunrise = p[K.sunrise] ?: d.sunrise,
         )
     }
 
     suspend fun setBedtime(b: Bedtime) {
         context.store.edit { p ->
             p[K.bedOn] = b.enabled; p[K.bedH] = b.bedHour; p[K.bedM] = b.bedMinute; p[K.wakeH] = b.wakeHour
-            p[K.wakeM] = b.wakeMinute; p[K.bedDays] = b.days; p[K.bedReminder] = b.reminderMin
+            p[K.wakeM] = b.wakeMinute; p[K.bedDays] = b.days; p[K.bedReminder] = b.reminderMin; p[K.sunrise] = b.sunrise
         }
     }
 }

uhr/app/src/main/java/app/uhr/ui/screens/AlarmScreen.kt

@@ -8,6 +8,9 @@ import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.animateContentSize
 import androidx.compose.animation.core.spring
+import androidx.compose.animation.core.tween
+import androidx.compose.animation.core.VisibilityThreshold
+import androidx.compose.ui.graphics.graphicsLayer
 import androidx.compose.foundation.background
 import androidx.compose.foundation.border
 import androidx.compose.foundation.clickable
@@ -36,6 +39,7 @@ import androidx.compose.material.icons.outlined.NotificationsActive
 import androidx.compose.material.icons.outlined.PauseCircle
 import androidx.compose.material.icons.outlined.Vibration
 import androidx.compose.material.icons.rounded.Check
+import androidx.compose.material.icons.rounded.GraphicEq
 import androidx.compose.material.icons.rounded.ExpandLess
 import androidx.compose.material.icons.rounded.ExpandMore
 import androidx.compose.material3.AlertDialog
@@ -93,6 +97,12 @@ import java.time.LocalDate
 import java.time.ZoneId
 import java.time.ZoneOffset
 
+/** One spring for everything that moves when a card opens, so size, content and neighbours stay in step. */
+private val expandSpring = spring<Float>(dampingRatio = 0.9f, stiffness = 500f)
+private fun androidx.compose.animation.core.SpringSpec<Float>.toIntOffset() =
+    spring(dampingRatio, stiffness, androidx.compose.ui.unit.IntOffset.VisibilityThreshold)
+private val expandSpringSize = spring(0.9f, 500f, androidx.compose.ui.unit.IntSize.VisibilityThreshold)
+
 /** Actions the alarm screen needs; MainActivity passes the repository, tests pass fakes. */
 interface AlarmActions {
     fun save(alarm: Alarm)
@@ -131,12 +141,12 @@ fun AlarmScreen(
     ) {
         if (bedtime.isNotEmpty()) item(key = "h-bed") { SectionHeader(stringResource(R.string.wake_up)) }
         items(bedtime, key = { it.alarm.id }) { a ->
-            AlarmCard(a, settings, expanded == a.alarm.id, { expanded = if (expanded == a.alarm.id) null else a.alarm.id }, actions, onDelete = null)
+            AlarmCard(Modifier.animateItem(placementSpec = expandSpring.toIntOffset()), a, settings, expanded == a.alarm.id, { expanded = if (expanded == a.alarm.id) null else a.alarm.id }, actions, onDelete = null)
         }
         if (bedtime.isNotEmpty() && others.isNotEmpty()) item(key = "h-other") { SectionHeader(stringResource(R.string.other_alarms)) }
         items(others, key = { it.alarm.id }) { a ->
             AlarmCard(
-                a, settings, expanded == a.alarm.id, { expanded = if (expanded == a.alarm.id) null else a.alarm.id }, actions,
+                Modifier.animateItem(placementSpec = expandSpring.toIntOffset()), a, settings, expanded == a.alarm.id, { expanded = if (expanded == a.alarm.id) null else a.alarm.id }, actions,
                 onDelete = {
                     actions.delete(a.alarm)
                     expanded = null
@@ -157,6 +167,7 @@ private fun SectionHeader(text: String) =
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 private fun AlarmCard(
+    modifier: Modifier,
     item: AlarmWithInstance,
     settings: Settings,
     expanded: Boolean,
@@ -181,21 +192,23 @@ private fun AlarmCard(
         else -> ""
     }
     Column(
-        Modifier.fillMaxWidth().clip(RoundedCornerShape(WRadius.card)).background(scheme.surfaceContainerLow)
-            .clickable(onClick = onToggleExpand).padding(WSpace.s20).animateContentSize(spring(dampingRatio = .85f, stiffness = 380f))
+        modifier.fillMaxWidth().clip(RoundedCornerShape(WRadius.card)).background(scheme.surfaceContainerLow)
+            .clickable(onClick = onToggleExpand).padding(WSpace.s20)
             .semantics(mergeDescendants = !expanded) {
                 contentDescription = listOf(a.label, Fmt.time(a.hour, a.minute), status).filter { it.isNotBlank() }.joinToString(", ")
                 stateDescription = res.getString(if (a.enabled) R.string.on else R.string.off)
             },
     ) {
-        Row(verticalAlignment = Alignment.CenterVertically) {
-            if (expanded) {
-                LabelField(a.label) { actions.save(a.copy(label = it)) }
-            } else {
-                Text(a.label, style = WType.label, color = scheme.onSurfaceVariant, modifier = Modifier.weight(1f))
+        val rotation by androidx.compose.animation.core.animateFloatAsState(if (expanded) 180f else 0f, expandSpring, label = "chevron")
+        Row(Modifier.height(48.dp), verticalAlignment = Alignment.CenterVertically) {
+            androidx.compose.animation.Crossfade(expanded, Modifier.weight(1f), animationSpec = tween(180), label = "label") { open ->
+                Row(Modifier.fillMaxWidth().height(48.dp), verticalAlignment = Alignment.CenterVertically) {
+                    if (open) LabelField(a.label) { actions.save(a.copy(label = it)) }
+                    else Text(a.label, style = WType.label, color = scheme.onSurfaceVariant, modifier = Modifier.weight(1f))
+                }
             }
             Box(Modifier.size(28.dp).clip(CircleShape).background(scheme.surfaceContainerHigh), contentAlignment = Alignment.Center) {
-                Icon(if (expanded) Icons.Rounded.ExpandLess else Icons.Rounded.ExpandMore, null, Modifier.size(20.dp), tint = scheme.onSurface)
+                Icon(Icons.Rounded.ExpandMore, null, Modifier.size(20.dp).graphicsLayer { rotationZ = rotation }, tint = scheme.onSurface)
             }
         }
         Spacer(Modifier.height(WSpace.s8))
@@ -208,7 +221,11 @@ private fun AlarmCard(
             Text(status, style = WType.bodySm, color = scheme.onSurface, modifier = Modifier.weight(1f))
             Switch(a.enabled, onCheckedChange = { actions.save(a.copy(enabled = it, skipUntil = null)) })
         }
-        AnimatedVisibility(expanded) {
+        AnimatedVisibility(
+            expanded,
+            enter = androidx.compose.animation.expandVertically(expandSpringSize, expandFrom = Alignment.Top) + androidx.compose.animation.fadeIn(tween(220, delayMillis = 60)),
+            exit = androidx.compose.animation.shrinkVertically(expandSpringSize, shrinkTowards = Alignment.Top) + androidx.compose.animation.fadeOut(tween(120)),
+        ) {
             Column {
                 Spacer(Modifier.height(WSpace.s12))
                 DayChips(a, settings.weekStart) { actions.save(it) }
@@ -247,17 +264,23 @@ private fun AlarmCard(
 @Composable
 private fun androidx.compose.foundation.layout.RowScope.LabelField(value: String, onDone: (String) -> Unit) {
     var text by remember(value) { mutableStateOf(value) }
-    TextField(
+    androidx.compose.foundation.text.BasicTextField(
         text, { text = it }, Modifier.weight(1f),
-        placeholder = { Text(stringResource(R.string.add_label)) },
-        leadingIcon = { Icon(Icons.Outlined.Label, null) },
-        singleLine = true, textStyle = WType.body,
+        textStyle = WType.body.copy(color = MaterialTheme.colorScheme.onSurface),
+        cursorBrush = androidx.compose.ui.graphics.SolidColor(MaterialTheme.colorScheme.primary),
+        singleLine = true,
         keyboardOptions = KeyboardOptions(imeAction = ImeAction.Done),
         keyboardActions = androidx.compose.foundation.text.KeyboardActions(onDone = { onDone(text.trim()) }),
-        colors = TextFieldDefaults.colors(
-            focusedContainerColor = androidx.compose.ui.graphics.Color.Transparent, unfocusedContainerColor = androidx.compose.ui.graphics.Color.Transparent,
-            unfocusedIndicatorColor = androidx.compose.ui.graphics.Color.Transparent,
-        ),
+        decorationBox = { inner ->
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                Icon(Icons.Outlined.Label, null, Modifier.size(20.dp), tint = MaterialTheme.colorScheme.onSurfaceVariant)
+                Spacer(Modifier.width(WSpace.s12))
+                Box {
+                    if (text.isEmpty()) Text(stringResource(R.string.add_label), style = WType.body, color = MaterialTheme.colorScheme.onSurfaceVariant)
+                    inner()
+                }
+            }
+        },
     )
     androidx.compose.runtime.DisposableEffect(Unit) { onDispose { if (text.trim() != value) onDone(text.trim()) } }
 }
@@ -366,12 +389,14 @@ fun SoundDialog(current: String?, onDismiss: () -> Unit, onPick: (String?) -> Un
         }
         list
     }
-    var preview by remember { mutableStateOf<android.media.Ringtone?>(null) }
-    androidx.compose.runtime.DisposableEffect(Unit) { onDispose { preview?.stop() } }
+    // demo on the alarm stream, like the real ring: audible in silent mode and Do Not Disturb
+    val preview = remember { SoundPreview(context) }
+    var playing by remember { mutableStateOf<String?>("none") }
+    androidx.compose.runtime.DisposableEffect(Unit) { onDispose { preview.stop() } }
     fun play(uri: String?) {
-        preview?.stop()
-        val u = when (uri) { null -> Uri.parse("android.resource://${context.packageName}/${R.raw.alarm_default}"); Alarm.SILENT -> null; else -> Uri.parse(uri) }
-        preview = u?.let { RingtoneManager.getRingtone(context, it) }?.also { it.play() }
+        if (playing == uri && preview.isPlaying) { preview.stop(); playing = "none"; return }
+        playing = uri
+        preview.play(uri)
     }
     val file = rememberLauncherForActivityResult(ActivityResultContracts.OpenDocument()) { uri ->
         if (uri != null) {
@@ -394,12 +419,49 @@ fun SoundDialog(current: String?, onDismiss: () -> Unit, onPick: (String?) -> Un
                     ) {
                         RadioButton(selected == uri, onClick = null)
                         Spacer(Modifier.width(WSpace.s12))
-                        Text(name, style = WType.body)
+                        Text(name, style = WType.body, modifier = Modifier.weight(1f))
+                        if (playing == uri && uri != Alarm.SILENT) Icon(Icons.Rounded.GraphicEq, stringResource(R.string.playing), tint = MaterialTheme.colorScheme.primary)
                     }
                 }
             }
         },
-        confirmButton = { TextButton(onClick = { onPick(selected) }) { Text(stringResource(android.R.string.ok)) } },
-        dismissButton = { TextButton(onClick = onDismiss) { Text(stringResource(android.R.string.cancel)) } },
+        confirmButton = { TextButton(onClick = { preview.stop(); onPick(selected) }) { Text(stringResource(android.R.string.ok)) } },
+        dismissButton = { TextButton(onClick = { preview.stop(); onDismiss() }) { Text(stringResource(android.R.string.cancel)) } },
     )
 }
+
+/** Plays a sound for a few seconds on the alarm stream at the user's alarm volume, then fades out. */
+class SoundPreview(private val context: android.content.Context) {
+    private var player: android.media.MediaPlayer? = null
+    private val handler = android.os.Handler(android.os.Looper.getMainLooper())
+    val isPlaying: Boolean get() = runCatching { player?.isPlaying == true }.getOrDefault(false)
+
+    fun play(uri: String?) {
+        stop()
+        val u = when (uri) {
+            Alarm.SILENT -> return
+            null -> Uri.parse("android.resource://${context.packageName}/${R.raw.alarm_default}")
+            else -> Uri.parse(uri)
+        }
+        player = runCatching {
+            android.media.MediaPlayer().apply {
+                setAudioAttributes(android.media.AudioAttributes.Builder().setUsage(android.media.AudioAttributes.USAGE_ALARM)
+                    .setContentType(android.media.AudioAttributes.CONTENT_TYPE_SONIFICATION).build())
+                setDataSource(context, u)
+                isLooping = true
+                prepare()
+                start()
+            }
+        }.getOrNull()
+        // a demo, not an alarm: stop after a few seconds
+        handler.postDelayed({ stop() }, DEMO_MS)
+    }
+
+    fun stop() {
+        handler.removeCallbacksAndMessages(null)
+        player?.runCatching { stop(); release() }
+        player = null
+    }
+
+    private companion object { const val DEMO_MS = 8_000L }
+}

uhr/app/src/main/java/app/uhr/ui/screens/BedtimeScreen.kt

@@ -22,6 +22,14 @@ import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.outlined.Bedtime
 import androidx.compose.material.icons.outlined.NotificationsActive
 import androidx.compose.material.icons.outlined.WbSunny
+import androidx.compose.material.icons.outlined.WbTwilight
+import androidx.compose.material.icons.outlined.Waves
+import androidx.compose.material.icons.rounded.Stop
+import androidx.compose.material.icons.rounded.PlayArrow
+import androidx.compose.runtime.collectAsState
+import androidx.compose.ui.platform.LocalContext
+import app.uhr.alarm.SleepSound
+import app.uhr.alarm.SleepSoundService
 import androidx.compose.material3.Button
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
@@ -102,7 +110,9 @@ fun BedtimeScreen(b: Bedtime, settings: Settings, onSave: (Bedtime) -> Unit, con
                     { m -> if (m < 0) stringResource(R.string.off) else if (m == 0) stringResource(R.string.at_bedtime) else stringResource(R.string.minutes_before, m) },
                     { m -> onSave(b.copy(reminderMin = m)) }, Icons.Outlined.NotificationsActive)
             }
+            item { SettingsSwitch(it, stringResource(R.string.sunrise_alarm), b.sunrise, { v -> onSave(b.copy(sunrise = v)) }, stringResource(R.string.sunrise_alarm_sub), Icons.Outlined.WbTwilight) }
         }
+        SleepSounds()
         Spacer(Modifier.height(120.dp))
     }
     if (pickBed) TimeDialog(b.bedHour, b.bedMinute, { pickBed = false }) { h, m -> pickBed = false; onSave(b.copy(bedHour = h, bedMinute = m)) }
@@ -122,3 +132,29 @@ private fun TimeTile(icon: androidx.compose.ui.graphics.vector.ImageVector, labe
         Text(time, style = tabular(WType.timerTime))
     }
 }
+
+/** Own looping sounds with a sleep timer; they fade out at the end. */
+@Composable
+private fun SleepSounds() {
+    val context = LocalContext.current
+    val playing by SleepSoundService.playing.collectAsState()
+    var sound by remember { mutableStateOf(playing?.sound ?: SleepSound.RAIN) }
+    var minutes by remember { mutableStateOf(30) }
+    SettingsGroup(stringResource(R.string.sleep_sounds)) {
+        item {
+            SettingsChoice(it, stringResource(R.string.sleep_sound), SleepSound.entries, sound, { s -> stringResource(s.title) }, { s -> sound = s }, Icons.Outlined.Waves)
+        }
+        item {
+            SettingsChoice(it, stringResource(R.string.sleep_timer), listOf(15, 30, 45, 60, 90), minutes, { m -> stringResource(R.string.n_minutes, m) }, { m -> minutes = m }, Icons.Outlined.Bedtime)
+        }
+        item {
+            val on = playing != null
+            app.uhr.ui.components.SettingsItem(
+                it, stringResource(if (on) R.string.stop else R.string.sleep_play),
+                if (on) stringResource(R.string.sleep_ends, app.uhr.ui.components.Fmt.clock(playing!!.endsAt)) else null,
+                if (on) Icons.Rounded.Stop else Icons.Rounded.PlayArrow,
+                onClick = { if (on) SleepSoundService.stop(context) else SleepSoundService.start(context, sound, minutes) },
+            )
+        }
+    }
+}

uhr/app/src/main/java/app/uhr/ui/screens/ClockScreen.kt

@@ -40,6 +40,10 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
+import androidx.compose.foundation.gestures.detectDragGesturesAfterLongPress
+import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.zIndex
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.dp
@@ -69,6 +73,7 @@ fun ClockScreen(
     contentPadding: PaddingValues,
     onDeleteCity: (City) -> Unit,
     nowOverride: Long? = null,
+    onReorder: (List<Long>) -> Unit = {},
 ) {
     val tick = remember { mutableLongStateOf(nowOverride ?: System.currentTimeMillis()) }
     if (nowOverride == null) LaunchedEffect(settings.showSeconds) {
@@ -77,6 +82,11 @@ fun ClockScreen(
     val now = tick.longValue
     val res = LocalContext.current.resources
     val scheme = MaterialTheme.colorScheme
+    val view = androidx.compose.ui.platform.LocalView.current
+    val density = androidx.compose.ui.platform.LocalDensity.current
+    var order by remember(cities) { mutableStateOf(cities) }
+    var draggedId by remember { mutableStateOf<Long?>(null) }
+    var dragOffset by remember { androidx.compose.runtime.mutableFloatStateOf(0f) }
     LazyColumn(
         Modifier.fillMaxSize(),
         contentPadding = PaddingValues(start = WSpace.s16, end = WSpace.s16, top = contentPadding.calculateTopPadding(), bottom = contentPadding.calculateBottomPadding() + 120.dp),
@@ -101,7 +111,33 @@ fun ClockScreen(
                 }
             }
         }
-        items(cities, key = { it.id }) { city -> CityRow(city, now, settings) { onDeleteCity(city) } }
+        items(order, key = { it.id }) { city ->
+            val dragging = draggedId == city.id
+            Box(
+                Modifier.zIndex(if (dragging) 1f else 0f)
+                    .graphicsLayer { translationY = if (dragging) dragOffset else 0f; scaleX = if (dragging) 1.03f else 1f; scaleY = scaleX; shadowElevation = if (dragging) 12f else 0f }
+                    .then(if (dragging) Modifier else Modifier.animateItem())
+                    .pointerInput(city.id) {
+                        detectDragGesturesAfterLongPress(
+                            onDragStart = { draggedId = city.id; dragOffset = 0f; view.performHapticFeedback(android.view.HapticFeedbackConstants.LONG_PRESS) },
+                            onDragEnd = { draggedId = null; dragOffset = 0f; onReorder(order.map { it.id }) },
+                            onDragCancel = { draggedId = null; dragOffset = 0f; order = cities },
+                        ) { change, drag ->
+                            change.consume()
+                            dragOffset += drag.y
+                            // swap with the neighbour once the card has moved past half of it
+                            val step = size.height + with(density) { WSpace.s8.toPx() }
+                            val i = order.indexOfFirst { it.id == city.id }
+                            val target = (i + (dragOffset / step).toInt()).coerceIn(0, order.lastIndex)
+                            if (target != i) {
+                                order = order.toMutableList().apply { add(target, removeAt(i)) }
+                                dragOffset -= (target - i) * step
+                                view.performHapticFeedback(android.view.HapticFeedbackConstants.SEGMENT_TICK)
+                            }
+                        }
+                    },
+            ) { CityRow(city, now, settings) { onDeleteCity(city) } }
+        }
     }
 }
 

uhr/app/src/main/java/app/uhr/ui/screens/SettingsScreen.kt

@@ -11,6 +11,7 @@ import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.rounded.ArrowBack
 import androidx.compose.material.icons.outlined.AccessTime
+import androidx.compose.material.icons.outlined.BatteryChargingFull
 import androidx.compose.material.icons.outlined.CalendarMonth
 import androidx.compose.material.icons.outlined.DarkMode
 import androidx.compose.material.icons.outlined.Snooze
@@ -84,6 +85,9 @@ fun SettingsScreen(s: Settings, onChange: ((Settings) -> Settings) -> Unit, onBa
                     SettingsChoice(it, stringResource(R.string.theme), ThemeMode.entries, s.theme, { v -> stringResource(labels.getValue(v)) }, { v -> onChange { x -> x.copy(theme = v) } }, Icons.Outlined.DarkMode)
                 }
             }
+            SettingsGroup(stringResource(R.string.charging)) {
+                item { app.uhr.ui.components.SettingsItem(it, stringResource(R.string.adaptive_charging), stringResource(R.string.adaptive_charging_text), Icons.Outlined.BatteryChargingFull) }
+            }
             Spacer(Modifier.height(32.dp()))
         }
     }

uhr/app/src/main/java/app/uhr/ui/screens/TimerScreen.kt

@@ -39,6 +39,7 @@ import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.setValue
 import androidx.compose.runtime.mutableLongStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
@@ -72,6 +73,7 @@ interface TimerActions {
     fun reset(id: Long)
     fun delete(id: Long)
     fun stopRinging()
+    fun rename(id: Long, label: String) {}
 }
 
 /** S08: keypad when there is no timer (or after "+"), cards for running ones. */
@@ -109,7 +111,9 @@ private fun TimerCard(t: Timer, now: Long, actions: TimerActions) {
     val label = t.label.ifBlank { stringResource(R.string.timer_of, Fmt.duration(t.durationMs)) }
     Column(Modifier.fillMaxWidth().clip(RoundedCornerShape(WRadius.card)).background(scheme.surfaceContainerLow).padding(WSpace.s20)) {
         Row(verticalAlignment = Alignment.CenterVertically) {
-            Text(label, style = WType.title, modifier = Modifier.weight(1f))
+            var renaming by remember { androidx.compose.runtime.mutableStateOf(false) }
+            Text(label, style = WType.title, modifier = Modifier.weight(1f).clip(RoundedCornerShape(WRadius.xs)).clickable { renaming = true })
+            if (renaming) RenameDialog(t.label, { renaming = false }) { renaming = false; actions.rename(t.id, it) }
             IconButton(onClick = { actions.delete(t.id) }) { Icon(Icons.Rounded.Close, stringResource(R.string.delete)) }
         }
         Row(verticalAlignment = Alignment.CenterVertically) {
@@ -205,3 +209,18 @@ private fun Keypad(digits: String, onDigits: (String) -> Unit, modifier: Modifie
         }
     }
 }
+
+@Composable
+private fun RenameDialog(current: String, onDismiss: () -> Unit, onSave: (String) -> Unit) {
+    var text by remember { androidx.compose.runtime.mutableStateOf(current) }
+    androidx.compose.material3.AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text(stringResource(R.string.rename_timer)) },
+        text = {
+            androidx.compose.material3.OutlinedTextField(text, { text = it.take(40) }, singleLine = true,
+                placeholder = { Text(stringResource(R.string.add_label)) }, modifier = Modifier.fillMaxWidth())
+        },
+        confirmButton = { androidx.compose.material3.TextButton(onClick = { onSave(text.trim()) }) { Text(stringResource(android.R.string.ok)) } },
+        dismissButton = { androidx.compose.material3.TextButton(onClick = onDismiss) { Text(stringResource(android.R.string.cancel)) } },
+    )
+}

uhr/app/src/main/java/app/uhr/ui/theme/Tokens.kt

@@ -65,6 +65,10 @@ object WColor {
     val timerProgress = Color(0xFF7EC4A8)
     val nightText = Color(0xFFC4433A)
     val nightBg = Color(0xFF000000)
+    val sunriseNight = Color(0xFF0D0710)
+    val sunriseEmber = Color(0xFF5A1A10)
+    val sunriseDay = Color(0xFFFFD9A0)
+    val sunriseSun = Color(0xFFFFF3D6)
 }
 
 object WType {

uhr/app/src/main/res/values/strings.xml

@@ -46,6 +46,7 @@
     <string name="alarm_sound">Weckton</string>
     <string name="sound_default">Standard (Morgenklang)</string>
     <string name="sound_silent">Ohne Ton</string>
+    <string name="playing">Wird abgespielt</string>
     <string name="add_own_sound">+ Eigene Audiodatei wählen</string>
     <string name="pick_time">Uhrzeit wählen</string>
     <string name="use_dial">Zifferblatt</string>
@@ -86,6 +87,19 @@
     <string name="at_bedtime">Zur Schlafenszeit</string>
     <string name="minutes_before">%1$d Min. vorher</string>
 
+    <string name="sunrise_alarm">Sonnenaufgang</string>
+    <string name="sunrise_alarm_sub">15 Min. vor dem Aufwachen wird der Bildschirm langsam heller</string>
+    <string name="sunrise_running">Sonnenaufgang läuft</string>
+    <string name="sleep_sounds">Einschlafgeräusche</string>
+    <string name="sleep_sound">Geräusch</string>
+    <string name="sleep_timer">Ausschalten nach</string>
+    <string name="sleep_play">Abspielen</string>
+    <string name="sleep_ends">Endet um %1$s, wird leiser</string>
+    <string name="sleep_sound_running">Läuft, blendet am Ende aus</string>
+    <string name="sound_rain">Regen</string>
+    <string name="sound_waves">Meeresrauschen</string>
+    <string name="sound_brown">Tiefes Rauschen</string>
+    <string name="rename_timer">Timer benennen</string>
     <string name="silence_after">Automatisch stumm nach</string>
     <string name="snooze_length">Schlummerdauer</string>
     <string name="alarm_volume">Lautstärke</string>
@@ -103,6 +117,9 @@
     <string name="theme_system">System</string>
     <string name="theme_light">Hell</string>
     <string name="theme_dark">Dunkel</string>
+    <string name="charging">Laden</string>
+    <string name="adaptive_charging">Adaptives Laden</string>
+    <string name="adaptive_charging_text">Diese App meldet jeden Wecker als „nächsten Wecker“ an das System. Ladefunktionen wie das adaptive Laden auf Pixel-Geräten richten sich danach und laden bis zum Klingeln langsam auf 100 %. Die Ladegeschwindigkeit selbst kann nur das System steuern, keine App. Auf GrapheneOS gibt es stattdessen die Ladebegrenzung auf 80 % in den Akku-Einstellungen.</string>
     <string name="n_minutes">%1$d Minuten</string>
     <string name="n_seconds">%1$d Sekunden</string>