add feature to clear ml downloads

apps/weblibre/lib/features/settings/presentation/screens/advanced_settings.dart

@@ -24,6 +24,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_hooks/flutter_hooks.dart';
 import 'package:flutter_material_design_icons/flutter_material_design_icons.dart';
+import 'package:flutter_mozilla_components/flutter_mozilla_components.dart';
 import 'package:google_fonts/google_fonts.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 import 'package:weblibre/core/providers/app_state.dart';
@@ -85,6 +86,12 @@ const List<SettingsSectionDefinition> advancedSettingsSections = [
         keywords: ['favicons', 'cache'],
         child: _IconCacheTile(),
       ),
+      SettingsEntryDefinition(
+        title: 'ML Downloads',
+        subtitle: 'Downloaded AI models and runtime files',
+        keywords: ['ai', 'ml', 'models', 'onnx', 'cache'],
+        child: _MlCacheTile(),
+      ),
       SettingsEntryDefinition(
         title: 'Error Logs',
         subtitle: 'View and copy logs for issue reporting',
@@ -294,6 +301,92 @@ class _IconCacheTile extends HookConsumerWidget {
   }
 }
 
+class _MlCacheTile extends HookWidget {
+  const _MlCacheTile();
+
+  Future<bool> _confirmClear(BuildContext context) async {
+    final result = await showDialog<bool>(
+      context: context,
+      builder: (context) => AlertDialog(
+        title: const Text('Clear ML downloads?'),
+        content: const Text(
+          'This clears downloaded AI models and ONNX runtime files for this profile. '
+          'They will be downloaded again when needed. Restart WebLibre before retrying ML features.',
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.of(context).pop(false),
+            child: const Text('Cancel'),
+          ),
+          FilledButton(
+            onPressed: () => Navigator.of(context).pop(true),
+            child: const Text('Clear'),
+          ),
+        ],
+      ),
+    );
+
+    return result ?? false;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final isClearing = useState(false);
+
+    return CustomListTile(
+      title: 'ML Downloads',
+      subtitle: 'Downloaded AI models and runtime files',
+      prefix: Padding(
+        padding: const EdgeInsets.only(right: 16.0),
+        child: Icon(
+          Icons.memory,
+          size: 24,
+          color: Theme.of(context).colorScheme.onSurfaceVariant,
+        ),
+      ),
+      suffix: FilledButton.icon(
+        onPressed: isClearing.value
+            ? null
+            : () async {
+                if (!await _confirmClear(context)) {
+                  return;
+                }
+
+                isClearing.value = true;
+                try {
+                  await GeckoMlService().clearMlCache();
+
+                  if (context.mounted) {
+                    showInfoMessage(
+                      context,
+                      'ML downloads cleared. Restart WebLibre before retrying.',
+                    );
+                  }
+                } catch (e) {
+                  if (context.mounted) {
+                    showErrorMessage(
+                      context,
+                      'Failed to clear ML downloads: $e',
+                    );
+                  }
+                } finally {
+                  if (context.mounted) {
+                    isClearing.value = false;
+                  }
+                }
+              },
+        icon: isClearing.value
+            ? const SizedBox.square(
+                dimension: 18,
+                child: CircularProgressIndicator(strokeWidth: 2),
+              )
+            : const Icon(Icons.delete),
+        label: Text(isClearing.value ? 'Clearing' : 'Clear'),
+      ),
+    );
+  }
+}
+
 class _ErrorLogsTile extends StatelessWidget {
   const _ErrorLogsTile();
 

packages/flutter_mozilla_components/android/src/main/assets/extensions/ml_engine/api/ml.js

@@ -6,8 +6,11 @@
 
 const {
     createEngine,
+    EngineProcess,
     FEATURES,
 } = ChromeUtils.importESModule("chrome://global/content/ml/EngineProcess.sys.mjs");
+const { ModelHub } = ChromeUtils.importESModule("chrome://global/content/ml/ModelHub.sys.mjs");
+const { OPFS } = ChromeUtils.importESModule("chrome://global/content/ml/OPFS.sys.mjs");
 
 const ML_TASK_FEATURE_EXTRACTION = "feature-extraction";
 const ML_TASK_TEXT2TEXT = "text2text-generation";
@@ -154,7 +157,7 @@ async function createMlEngine(engineConfig, progressCallback) {
         numThreads,
     };
 
-        return await createEngine(initData, progressCallback);
+    return await createEngine(initData, progressCallback);
 }
 
 this.ml = class extends ExtensionAPI {
@@ -234,6 +237,16 @@ this.ml = class extends ExtensionAPI {
                         const generated = cutAtDuplicateWords((res[0]["generated_text"] || "").trim());
 
                         return generated;
+                    },
+                    async clearCache() {
+                        self.embeddingEngine = null;
+                        self.topicEngine = null;
+
+                        await EngineProcess.destroyMLEngine();
+                        await new ModelHub().purgeDatabase();
+                        await OPFS.remove("mlRuntimeFiles", { recursive: true });
+
+                        return true;
                     }
                 }
             }

packages/flutter_mozilla_components/android/src/main/assets/extensions/ml_engine/background.js

@@ -56,6 +56,12 @@ port.onMessage.addListener(async (message) => {
                 sendJsonResultForRequest(requestId)(result);
                 break;
             }
+            case "clearMlCache": {
+                const result = await browser.experiments.ml.clearCache();
+
+                sendJsonResultForRequest(requestId)(result);
+                break;
+            }
             default:
                 throw new Error(`Unsupported ML action: ${message["action"]}`);
         }

packages/flutter_mozilla_components/android/src/main/assets/extensions/ml_engine/schema.json

@@ -85,7 +85,14 @@
                         "description": "Array of document titles/content"
                     }
                 ]
+            },
+            {
+                "name": "clearCache",
+                "type": "function",
+                "description": "Clear downloaded ML models and runtime files",
+                "async": true,
+                "parameters": []
             }
         ]
     }
-]
+]

packages/flutter_mozilla_components/android/src/main/kotlin/eu/weblibre/flutter_mozilla_components/api/GeckoMlApiImpl.kt

@@ -131,4 +131,16 @@ class GeckoMlApiImpl(
         })
     }
 
-}
+    override fun clearMlCache(callback: (Result<Unit>) -> Unit) {
+        MLEngineFeature.scheduleRequest("clearMlCache", JSONObject(), object : ResultConsumer<JSONObject> {
+            override fun success(result: JSONObject) {
+                callback(Result.success(Unit))
+            }
+
+            override fun error(errorCode: String, errorMessage: String?, errorDetails: Any?) {
+                callback(Result.failure(Exception("$errorCode $errorMessage $errorDetails")))
+            }
+        })
+    }
+
+}

packages/flutter_mozilla_components/android/src/main/kotlin/eu/weblibre/flutter_mozilla_components/pigeons/Gecko.g.kt

@@ -8315,6 +8315,7 @@ interface GeckoPrefApi {
 interface GeckoMlApi {
   fun predictDocumentTopic(documents: List<String>, callback: (Result<String>) -> Unit)
   fun generateDocumentEmbeddings(documents: List<String>, callback: (Result<List<Any?>>) -> Unit)
+  fun clearMlCache(callback: (Result<Unit>) -> Unit)
 
   companion object {
     /** The codec used by GeckoMlApi. */
@@ -8365,6 +8366,23 @@ interface GeckoMlApi {
           channel.setMessageHandler(null)
         }
       }
+      run {
+        val channel = BasicMessageChannel<Any?>(binaryMessenger, "dev.flutter.pigeon.flutter_mozilla_components.GeckoMlApi.clearMlCache$separatedMessageChannelSuffix", codec)
+        if (api != null) {
+          channel.setMessageHandler { _, reply ->
+            api.clearMlCache{ result: Result<Unit> ->
+              val error = result.exceptionOrNull()
+              if (error != null) {
+                reply.reply(GeckoPigeonUtils.wrapError(error))
+              } else {
+                reply.reply(GeckoPigeonUtils.wrapResult(null))
+              }
+            }
+          }
+        } else {
+          channel.setMessageHandler(null)
+        }
+      }
     }
   }
 }

packages/flutter_mozilla_components/lib/src/domain/services/gecko_ml.dart

@@ -28,4 +28,8 @@ class GeckoMlService {
         .map((values) => (values! as List).cast<double>())
         .toList();
   }
+
+  Future<void> clearMlCache() {
+    return _apiInstance.clearMlCache();
+  }
 }

packages/flutter_mozilla_components/lib/src/pigeons/gecko.g.dart

@@ -8621,6 +8621,24 @@ class GeckoMlApi {
     );
     return pigeonVar_replyValue! as List<Object?>;
   }
+
+  Future<void> clearMlCache() async {
+    final pigeonVar_channelName =
+        'dev.flutter.pigeon.flutter_mozilla_components.GeckoMlApi.clearMlCache$pigeonVar_messageChannelSuffix';
+    final pigeonVar_channel = BasicMessageChannel<Object?>(
+      pigeonVar_channelName,
+      pigeonChannelCodec,
+      binaryMessenger: pigeonVar_binaryMessenger,
+    );
+    final Future<Object?> pigeonVar_sendFuture = pigeonVar_channel.send(null);
+    final pigeonVar_replyList = await pigeonVar_sendFuture as List<Object?>?;
+
+    _extractReplyValueOrThrow(
+      pigeonVar_replyList,
+      pigeonVar_channelName,
+      isNullValid: true,
+    );
+  }
 }
 
 class GeckoBrowserExtensionApi {

packages/flutter_mozilla_components/pigeons/gecko.dart

@@ -1848,6 +1848,8 @@ abstract class GeckoMlApi {
   String predictDocumentTopic(List<String> documents);
   @async
   List generateDocumentEmbeddings(List<String> documents);
+  @async
+  void clearMlCache();
 }
 
 @HostApi()