# Architecture: Telefon (Android, ohne Google)

Same conventions as the other apps. **No network permission.** The app owns almost no data: it reads the system call log and contacts.

## Stack

| Schicht | Wahl | warum |
| --- | --- | --- |
| UI | Kotlin + Compose, M3 Expressive, dynamic colour | same as the others |
| Telefonie | `RoleManager.ROLE_DIALER` + own `InCallService` (BIND_INCALL_SERVICE, IN_CALL_SERVICE_UI) | the only official way to show the call UI and control calls |
| Anrufen | `TelecomManager.placeCall` | uses the default SIM/phone account, works for emergency numbers through the system |
| Daten | `CallLog.Calls` and `ContactsContract` via ContentResolver, observed with ContentObserver → Flow | no copy of personal data in our database |
| Eigene Daten | DataStore (quick replies, theme) | – |
| Audio | `InCallService.setMuted / setAudioRoute`, `CallEndpoint` on API 34+ | speaker, earpiece, Bluetooth |
| Näherungssensor | `PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK` while the earpiece is active | screen off at the ear |

## Permissions

READ_CALL_LOG, WRITE_CALL_LOG (delete entries), READ_CONTACTS, CALL_PHONE, READ_PHONE_STATE, MANAGE_OWN_CALLS no, USE_FULL_SCREEN_INTENT, POST_NOTIFICATIONS, WAKE_LOCK, SEND_SMS no (quick replies hand off to the SMS app with `smsto:`).
The dialer role grants most of these automatically once the user accepts it.

## Data

No schema. Own state in DataStore only. Access: single user; the system enforces the permissions.

## Interne API

| Aufruf | macht | Flow |
| --- | --- | --- |
| `CallLogRepo.observe(filter)` | query CallLog, join contact name/photo by number (PhoneLookup), group by day | F01 |
| `ContactsRepo.favorites()` / `search(q)` / `t9(digits)` | starred contacts; name/number search; T9 digit match on names and numbers | F02, F03, F06 |
| `Dialer.call(number)` | `placeCall(tel:)` | F01–F03 |
| `CallManager` (in `InCallService`) | StateFlow of calls; answer, reject (with SMS), hold, unhold, mute, route, DTMF, disconnect | F04, F05, F07 |
| `Role.request()` | role request intent | F08 |

## Was beißt

- **Wrong default dialer state**: without the role, calls still work through the system dialer; the app shows a banner instead of failing.
- **Lock screen**: incoming UI via full-screen-intent notification; `showWhenLocked` + `turnScreenOn` on the activity.
- **Ringtone**: the system rings for the default dialer? No: the InCallService app must play the ringtone itself only when `Call.Details` say so; on modern Android the platform `Ringer` plays it for the default dialer. We do not play our own.
- **Process death mid-call**: the InCallService is bound by the system as long as calls exist; UI state is rebuilt from `calls`.
- **Emergency numbers**: always via `placeCall`, never blocked by our UI.
- **Privacy**: no network, no analytics; call log stays in the system.

## Build-Reihenfolge

1. Slice: role request, InCallService, incoming + in-call screens, place a call from the keypad.
2. Must: call log with grouping and call back, favourites, search, notifications, mute/speaker/DTMF, proximity.
3. Should: filters, T9, hold, call waiting, quick reply SMS, details screen, voicemail, Bluetooth.