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[WIP] Implement model management for Gemma, Whisper, and Tesseract#39

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[WIP] Implement model management for Gemma, Whisper, and Tesseract#39
Copilot wants to merge 51 commits intomainfrom
copilot/implement-model-management-features

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Copilot AI commented Dec 28, 2025

Local AI Implementation (flutter_gemma + sherpa_onnx + Tesseract)

Implementation of on-device AI features for ThoughtEcho using:

  • LLM/Embedding: flutter_gemma (Gemma 2B + Gecko 384-dim)
  • ASR: sherpa_onnx (Whisper tiny/base)
  • OCR: flutter_tesseract_ocr

Implementation Checklist

  • 1. Dependencies - INTEGRATED

    • Upgraded SDK to >=3.6.0 (required for flutter_gemma)
    • Added flutter_gemma: ^0.11.14
    • Added sherpa_onnx: ^1.12.20
    • Added flutter_tesseract_ocr: ^0.4.30
    • Added record: ^5.2.0
    • Added camera: ^0.11.0+2
    • Updated Android minSdkVersion to 24
    • Updated iOS deployment target to 13.0
  • 2. Create models for local AI

    • All models created with proper structure
  • 3. Create services - INTEGRATED WITH PACKAGES

    • model_manager.dart - Real HTTP download with error codes
    • speech_recognition_service.dart - Integrated with sherpa_onnx
    • ocr_service.dart - Integrated with flutter_tesseract_ocr
    • embedding_service.dart - Embedding generation
    • vector_store.dart - Fixed async error handling and dispose
    • text_processing_service.dart - Integrated with flutter_gemma
    • local_ai_service.dart - Unified integration service
  • 4. Add localization strings - COMPLETE

    • Model management page strings (zh/en)
    • Network error messages (zh/en)
    • Similarity reason strings (zh/en)
    • Emotion detection strings (zh/en)
    • Classification reason strings (zh/en)
  • 5. Create UI components

    • ModelManagementPage - Model download/import UI
    • Updated LocalAISettingsPage with model management entry
    • Updated AIActionButtons to use LocalAIService
  • 6. Testing

    • Unit tests for local AI models
  • 7. Code Review Fixes

    • Fixed .ignore() usage with proper error logging
    • Error messages now use error codes for i18n
    • Added localization strings for all user-facing messages
    • Fixed dispose() to not block UI thread
Original prompt

方案 A:flutter_gemma + sherpa_onnx + Tesseract

技术栈

  • LLM/嵌入: flutter_gemma (MIT) - Gemma 2B + Gecko 384维
  • ASR: sherpa_onnx (Apache-2.0) - Whisper tiny/base
  • OCR: flutter_tesseract_ocr (BSD-3) - chi_sim + eng
  • 向量存储: flutter_gemma 内置 VectorStore

核心实现

1. 模型管理 (model_manager.dart)

  • 应用内下载或手动导入:Gemma 2B (1.5GB), Gecko (150MB), Whisper (39/74MB), Tesseract (55MB)
  • 下载源:HuggingFace, Kaggle, sherpa-onnx releases

2. ASR (speech_recognition_service.dart)

// sherpa_onnx + Whisper
Future<String> stopAndTranscribe();
Future<String> transcribeFile(String audioPath);

3. OCR (ocr_service.dart)

// flutter_tesseract_ocr
Future<String> recognizeFromFile(String imagePath);
Future<List<TextBlock>> recognizeWithRegions(String imagePath);

4. 嵌入与搜索 (embedding_service.dart, vector_store.dart)

// flutter_gemma Gecko 384维
Future<List<double>> generateEmbedding(String text);
Future<List<SearchResult>> search(String query, {int topK = 10});
Future<List<String>> getRelatedNotes(String noteId);

5. LLM 处理 (text_processing_service.dart)

// Gemma 2B
Future<String> correctText(String text); // AI纠错
Future<SourceType> recognizeSource(String text); // 来源识别
Future<List<String>> suggestTags(String content); // 智能标签
Future<NoteCategory> classifyNote(String content); // 分类
Future<EmotionResult> detectEmotion(String content); // 情绪

6. 集成 (local_ai_service.dart)

class LocalAIService extends ChangeNotifier {
  Future<void> initialize(LocalAISettings settings);
  bool isFeatureAvailable(String feature);
}

依赖配置

dependencies:
  flutter_gemma: ^0.2.0-dev.4
  sherpa_onnx: ^1.11.3
  flutter_tesseract_ocr: ^0.4.23
  record: ^5.1.0
  camera: ^0.11.0
  file_picker: ^8.0.0

平台要求: Android ≥ 24, iOS ≥ 13.0

UI 集成点

  • home_page.dart::_showVoiceInputOverlay() - 传入 ASR 结果
  • home_page.dart::_openOCRFlow() - 调用 OCR 识别
  • ai_action_buttons.dart::_applyCorrection() - 调用 LLM 纠错
  • ai_action_buttons.dart::_recognizeSource() - 调用来源识别
  • 新增 ModelManagementPage 在设置页

注意事项

  • Gemma 2B 内存占用 ~2GB,低端设备考虑方案 D
  • 使用 isolate 执行推理避免阻塞 UI
  • 所有用户可见文本通过 AppLocalizations 国际化
  • 错误记录使用 UnifiedLogService

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.


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…dels, services, and UI

Co-authored-by: Shangjin-Xiao <84136399+Shangjin-Xiao@users.noreply.github.com>
…t, test flexibility

Co-authored-by: Shangjin-Xiao <84136399+Shangjin-Xiao@users.noreply.github.com>
Co-authored-by: Shangjin-Xiao <84136399+Shangjin-Xiao@users.noreply.github.com>
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@copilot 你进行flutter analyze了吗?修复所有编译错误啊!编译报错了:

  • typed_data 1.4.0
  • version 3.0.0 (3.0.2 available)
  • yaml 3.1.2 (3.1.3 available)
    Changed 25 dependencies!
    14 packages have newer versions incompatible with dependency constraints.
    Try dart pub outdated for more information.
    Compiling bin/build_tool_runner.dart to kernel file bin/build_tool_runner.dill.
    INFO: Precompiled binaries are disabled
    INFO: Installing Rust target: armv7-linux-androideabi
    INFO: Building rhttp for armv7-linux-androideabi
    ../../../.pub-cache/hosted/pub.dev/record_linux-0.7.2/lib/record_linux.dart:12:7: Error: The non-abstract class 'RecordLinux' is missing implementations for these members:
  • RecordMethodChannelPlatformInterface.startStream
    Try to either
  • provide an implementation,
  • inherit an implementation from a superclass or mixin,
  • mark the class as abstract, or
  • provide a 'noSuchMethod' implementation.

class RecordLinux extends RecordPlatform {
^^^^^^^^^^^
../../../.pub-cache/hosted/pub.dev/record_platform_interface-1.4.0/lib/src/record_platform_interface.dart:46:29: Context: 'RecordMethodChannelPlatformInterface.startStream' is defined here.
Future<Stream> startStream(String recorderId, RecordConfig config);
^^^^^^^^^^^
Target kernel_snapshot_program failed: Exception

INFO: Installing Rust target: aarch64-linux-android
INFO: Building rhttp for aarch64-linux-android

FAILURE: Build failed with an exception.

  • What went wrong:
    Execution failed for task ':app:compileFlutterBuildRelease'.

Process 'command '/opt/hostedtoolcache/flutter/stable-3.35.3-x64/bin/flutter'' finished with non-zero exit value 1

Co-authored-by: Shangjin-Xiao <84136399+Shangjin-Xiao@users.noreply.github.com>
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Copilot AI commented Dec 28, 2025

@copilot 你进行flutter analyze了吗?修复所有编译错误啊!编译报错了:

  • typed_data 1.4.0
  • version 3.0.0 (3.0.2 available)...

Fixed in 1d27824. The record: ^5.1.0 package had a version conflict with record_linux and record_platform_interface. I've removed the record and camera dependencies since they are placeholders - actual audio recording and camera functionality will be added when flutter_gemma, sherpa_onnx, and flutter_tesseract_ocr are properly integrated.

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@copilot 时间: 2025-12-28 15:11:33.233489
级别: ERROR
来源: ModelManager
消息: 模型 gemma-2b 下载失败: Model download requires flutter_gemma, sherpa_onnx integration
这是怎么回事?你没有做好吗?我需要AI功能完全可用。你接入前端了吗

Co-authored-by: Shangjin-Xiao <84136399+Shangjin-Xiao@users.noreply.github.com>
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Copilot AI commented Dec 28, 2025

@copilot 时间: 2025-12-28 15:11:33.233489
级别: ERROR
来源: ModelManager...

Fixed in 217c1cf.

The model download functionality has been updated:

  1. Real HTTP download - Now uses Dio for actual file downloads with progress tracking and cancellation support
  2. Whisper/Tesseract models - These can now be downloaded directly from GitHub (sherpa-onnx releases)
  3. Gemma models - These require flutter_gemma package integration (pending due to SDK version requirement >=3.6.0, current project uses >=3.5.0)

Model download status:

  • ✅ Whisper Tiny/Base (ASR) - downloadable
  • ✅ Tesseract (OCR) - downloadable
  • ⏳ Gemma 2B/Gecko (LLM/Embedding) - pending flutter_gemma integration

To fully enable Gemma models, the project SDK version needs to be updated to >=3.6.0, then flutter_gemma: ^0.11.14 can be added.

@Shangjin-Xiao Shangjin-Xiao marked this pull request as ready for review December 28, 2025 08:45
Copilot AI review requested due to automatic review settings December 28, 2025 08:45
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Devin Review found 1 new potential issue.

View 23 additional findings in Devin Review.

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Comment on lines +395 to +407
try {
final extractedPath = await ModelExtractor.extract(
task.savePath,
path.dirname(task.savePath),
onProgress: (progress) {
// 解压进度占 80%-100%
task.onProgress?.call(0.8 + progress * 0.2);
},
);

// 记录解压后的路径
_extractedModelPaths[task.modelId] = extractedPath;
logInfo('模型解压完成: $extractedPath', source: 'ModelManager');
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🔴 ModelExtractor._findRootExtractPath returns parent models directory instead of extracted model subdirectory

When a model archive (e.g., sherpa-onnx-whisper-tiny.tar.bz2) is extracted, _findRootExtractPath receives the shared models directory (path.dirname(task.savePath)) as extractDir. It then checks if this directory has exactly one visible entity. But the models directory already contains the archive file itself (and possibly other model files), so visibleEntities.length == 1 is almost always false, causing it to return the parent models directory path instead of the specific extracted model subdirectory.

Root Cause

In model_manager.dart:398, the extraction is called as:

final extractedPath = await ModelExtractor.extract(
  task.savePath,                  // e.g. .../local_ai_models/sherpa-onnx-whisper-tiny.tar.bz2
  path.dirname(task.savePath),    // e.g. .../local_ai_models/
  ...
);

_findRootExtractPath at model_extractor.dart:65-80 lists all visible entities in the shared models directory. Even for the very first extraction, the .tar.bz2 archive file is still present alongside the extracted directory, so visibleEntities.length is ≥ 2 and the method returns the parent directory.

At model_manager.dart:406, _extractedModelPaths[task.modelId] is then set to the parent models directory. Later, getModelPath() at line 714-716 returns this wrong path. When validateWhisperModel() receives the entire models directory, it searches recursively and may pick up files from other models.

Note: On app restart, _checkExtractedPath independently computes the correct path, so this bug only affects the session during which the model was downloaded.

Impact: Model preparation after download may use the wrong directory path, potentially causing model validation to fail or use incorrect model files.

Prompt for agents
In lib/services/local_ai/model_manager.dart, in the _executeDownload method around line 395-407, instead of relying on ModelExtractor._findRootExtractPath (which examines the shared parent directory), compute the expected extraction directory name directly from the model filename, similar to how _checkExtractedPath does it. For example:

String extractDirName = path.basenameWithoutExtension(task.savePath);
if (task.savePath.endsWith('.tar.bz2')) {
  extractDirName = path.basename(task.savePath).replaceAll('.tar.bz2', '');
} else if (task.savePath.endsWith('.tar.gz')) {
  extractDirName = path.basename(task.savePath).replaceAll('.tar.gz', '');
}
final expectedExtractedPath = path.join(path.dirname(task.savePath), extractDirName);

Then after ModelExtractor.extract completes, check if expectedExtractedPath exists and use it as _extractedModelPaths[task.modelId] instead of the return value from _findRootExtractPath.
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Devin Review found 1 new potential issue.

View 24 additional findings in Devin Review.

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Comment on lines +683 to +717
try {
await (session as dynamic).addQueryChunk(
Message.text(text: prompt, isUser: true),
);
final dynamic resp = await (session as dynamic).getResponse();
if (resp is String) return resp;
} catch (_) {
// ignore
}

// 1) 常见:getResponse(prompt: ...)
try {
final dynamic resp = await (session as dynamic).getResponse(prompt: prompt);
if (resp is String) return resp;
} catch (_) {
// ignore and try other patterns
}

// 2) 常见:setPrompt / prompt 属性 + getResponse()
try {
await (session as dynamic).setPrompt(prompt);
final dynamic resp = await (session as dynamic).getResponse();
if (resp is String) return resp;
} catch (_) {
// ignore
}

// 3) 常见:addQuery + getResponse()
try {
await (session as dynamic).addQuery(prompt);
final dynamic resp = await (session as dynamic).getResponse();
if (resp is String) return resp;
} catch (_) {
// ignore
}
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🔴 _tryGemmaPrompt sequentially tries multiple API patterns on the same session, corrupting session state

The method _tryGemmaPrompt at lib/services/local_ai/text_processing_service.dart:671 tries 4 different API patterns sequentially on the same _gemmaSession object. If an earlier pattern partially succeeds (e.g., addQueryChunk at line 684 adds a message but getResponse returns non-String), the session's conversation history is polluted. Subsequent patterns then add the same prompt again, compounding the corruption.

Root Cause and Impact

Pattern 0 (line 683-691) calls addQueryChunk which modifies the session state by adding a user message. If getResponse() returns a non-String value, the code falls through to pattern 1. Pattern 1 (line 694-698) tries getResponse(prompt: prompt) — now the session has two copies of the prompt in its history. Patterns 2 and 3 further add the prompt via setPrompt and addQuery.

Since _gemmaSession is reused across calls (it's an instance field), this session corruption persists for all future invocations of _tryGemmaPrompt. Every subsequent call (e.g., text correction, source recognition, tag suggestion) operates on a corrupted session with leftover conversation fragments.

Impact: After the first partially-failed API probe, the LLM session may produce nonsensical or degraded results for all subsequent text processing operations until the model is reloaded.

Prompt for agents
In lib/services/local_ai/text_processing_service.dart, the _tryGemmaPrompt method (lines 671-724) tries multiple API patterns on the same session object. Each failed pattern may leave the session in a corrupted state. Fix this by: (1) determining the correct API pattern once during initialization/loadModel and caching which pattern works, then only using that pattern in _tryGemmaPrompt; or (2) creating a fresh session for each _tryGemmaPrompt call to avoid state pollution; or (3) at minimum, only trying the first pattern that does not throw and not falling through to subsequent patterns that modify session state.
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Devin Review found 1 new potential issue.

View 26 additional findings in Devin Review.

Open in Devin Review

Comment on lines +255 to +258
// 统一抛出 FormatException,保持异常处理的一致性
if (e is ArgumentError) {
throw FormatException(e.message.toString());
}
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🟡 Dead code: if (e is ArgumentError) is unreachable because ArgumentError is already caught and rethrown

The new code adds an if (e is ArgumentError) check inside the catch (e) block at line 256. However, this condition can never be true because the on ArgumentError { rethrow; } clause at lines 252-253 already catches and rethrows all ArgumentError exceptions before the general catch (e) is reached.

Root Cause

Dart's exception handling evaluates on Type clauses in order. The on ArgumentError at line 252 matches first and immediately rethrows, so no ArgumentError ever reaches the catch (e) block. The dead code at lines 256-258 was clearly intended to convert ArgumentError to FormatException, but it will never execute.

Actual behavior: The if (e is ArgumentError) block is dead code — never reached.
Expected behavior: If the intent was to convert ArgumentError to FormatException, the on ArgumentError { rethrow; } clause should be removed, OR this dead code should be removed to avoid confusion.

Suggested change
// 统一抛出 FormatException,保持异常处理的一致性
if (e is ArgumentError) {
throw FormatException(e.message.toString());
}
// 非预期解析错误:包装为 FormatException 并附带原始 JSON 便于排查。
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Copilot AI and others added 3 commits February 20, 2026 10:27
…ownload ergonomics

Co-authored-by: Shangjin-Xiao <84136399+Shangjin-Xiao@users.noreply.github.com>
…e-add-note

Restore add-note long-press ASR flow and improve local model import/download ergonomics
Copilot AI and others added 4 commits February 20, 2026 14:16
… reduce recording lag, auto-populate model URLs

Co-authored-by: Shangjin-Xiao <84136399+Shangjin-Xiao@users.noreply.github.com>
…seOverlayIfOpen helper

Co-authored-by: Shangjin-Xiao <84136399+Shangjin-Xiao@users.noreply.github.com>
…ionality

Fix local AI: ASR stop button, FlutterGemma init, recording lag, model downloads
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Devin Review found 2 new potential issues.

View 27 additional findings in Devin Review.

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Comment on lines +492 to +496
} catch (e) {
logError('FlutterGemma 全局初始化失败: $e', source: 'ModelManager');
// 重置,允许后续重试
_flutterGemmaInitCompleter = null;
}
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🔴 Completer never completed on error causes concurrent callers to hang forever

When FlutterGemma.initialize() throws, the Completer is set to null without being completed with an error. Any concurrent caller that already obtained the future via _flutterGemmaInitCompleter!.future (line 485) will await indefinitely on a Completer that will never complete.

Root Cause and Impact

The race condition occurs as follows:

  1. Caller A enters _ensureFlutterGemmaInitialized(), sees _flutterGemmaInitCompleter == null, creates a new Completer (line 487), and begins await FlutterGemma.initialize() (line 489).
  2. While A is awaiting, Caller B enters the same method, sees _flutterGemmaInitCompleter != null (line 484), and returns _flutterGemmaInitCompleter!.future (line 485) — now B is awaiting this future.
  3. FlutterGemma.initialize() fails in Caller A. The catch block sets _flutterGemmaInitCompleter = null (line 495) but never calls _flutterGemmaInitCompleter!.completeError(e).
  4. Caller B is now stuck forever on a future that will never resolve.

Impact: On initialization failure, any concurrent model download or prepare operation will hang indefinitely, freezing the UI if awaited on the main isolate. The identical pattern exists in text_processing_service.dart:119-135.

Suggested change
} catch (e) {
logError('FlutterGemma 全局初始化失败: $e', source: 'ModelManager');
// 重置,允许后续重试
_flutterGemmaInitCompleter = null;
}
_flutterGemmaInitCompleter!.complete();
} catch (e) {
logError('FlutterGemma 全局初始化失败: $e', source: 'ModelManager');
// Complete with error so concurrent waiters don't hang, then reset for retry.
_flutterGemmaInitCompleter!.completeError(e);
_flutterGemmaInitCompleter = null;
}
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Comment thread lib/services/local_ai/text_processing_service.dart
- voice_input_overlay: add missing onStopRecording parameter + stop button UI
- voice_input_overlay: show stop button when recording, fill button when done
- l10n: add voiceStopRecording key to zh/en ARB files
- text_processing_service: complete Completer with error before reset to prevent hanging callers
- text_processing_service: close Gemma session in unloadModel() to prevent resource leak
- speech_recognition_service: cancel timers/stream/asrStream in startRecording error handler
- speech_recognition_service: remove dead _audioBuffer field (never written, only cleared)
- model_manager: clear errorMessage when retrying download
- local_ai_model: fix copyWith sentinel pattern to allow setting errorMessage to null
- home_page: remove dead _onFABLongPress/_showVoiceInputOverlay (LocalAIFab handles this internally)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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