Files
meshcore-open/lib/services/translation_service.dart
T
2026-05-01 01:50:06 +03:00

697 lines
21 KiB
Dart

import 'dart:async';
import 'package:flutter/foundation.dart';
import 'package:http/http.dart' as http;
import 'package:llamadart/llamadart.dart';
import '../models/app_settings.dart';
import '../models/translation_support.dart';
import '../helpers/gif_helper.dart';
import '../utils/app_logger.dart';
import 'app_settings_service.dart';
import 'translation_file_store.dart';
class TranslationResult {
final String translatedText;
final String targetLanguageCode;
final String? detectedLanguageCode;
final String? modelId;
final MessageTranslationStatus status;
const TranslationResult({
required this.translatedText,
required this.targetLanguageCode,
required this.status,
this.detectedLanguageCode,
this.modelId,
});
}
class TranslationDownloadCancelled implements Exception {
const TranslationDownloadCancelled();
@override
String toString() => 'Download canceled.';
}
class TranslationService extends ChangeNotifier {
final AppSettingsService _appSettingsService;
final TranslationFileStore _fileStore;
TranslationService(
this._appSettingsService, {
TranslationFileStore? fileStore,
}) : _fileStore = fileStore ?? TranslationFileStore();
bool _isBusy = false;
bool _isDownloading = false;
bool _cancelDownloadRequested = false;
String? _lastError;
Future<void> _queue = Future<void>.value();
LlamaEngine? _engine;
String? _loadedModelPath;
String? _failedModelPath;
int _downloadedBytes = 0;
int? _downloadTotalBytes;
String? _downloadFileName;
bool get isBusy => _isBusy;
bool get isDownloading => _isDownloading;
String? get lastError => _lastError;
int get downloadedBytes => _downloadedBytes;
int? get downloadTotalBytes => _downloadTotalBytes;
String? get downloadFileName => _downloadFileName;
double? get downloadProgress {
final total = _downloadTotalBytes;
if (!_isDownloading || total == null || total <= 0) {
return null;
}
return (_downloadedBytes / total).clamp(0.0, 1.0);
}
AppSettings get _settings => _appSettingsService.settings;
String? resolvedTargetLanguageCode(String? fallbackLanguageCode) {
return _settings.translationTargetLanguageCode ??
_settings.languageOverride ??
fallbackLanguageCode;
}
String? resolvedIncomingLanguageCode(String? fallbackLanguageCode) {
return _settings.translationTargetLanguageCode ??
_settings.languageOverride ??
fallbackLanguageCode ??
'en';
}
bool shouldTranslateIncoming({
required String text,
required bool isCli,
required bool isOutgoing,
}) {
if (!_settings.translationEnabled || isCli || isOutgoing) {
return false;
}
return _isPlainTextEligible(text);
}
bool shouldTranslateOutgoing({
required String text,
required String? targetLanguageCode,
}) {
return _settings.composerTranslationEnabled &&
targetLanguageCode != null &&
targetLanguageCode.isNotEmpty &&
_isPlainTextEligible(text);
}
List<TranslationModelRecord> get availableModels =>
_settings.translationDownloadedModels;
TranslationModelRecord? get selectedModel {
final selectedId = _settings.translationSelectedModelId;
if (selectedId == null) {
return availableModels.isNotEmpty ? availableModels.first : null;
}
for (final model in availableModels) {
if (model.id == selectedId) {
return model;
}
}
return availableModels.isNotEmpty ? availableModels.first : null;
}
Future<void> refreshDownloadedModels() async {
if (_isDownloading) return;
final scanned = await _fileStore.scanDownloadedModels();
if (scanned.isEmpty) {
return;
}
final existingByPath = {
for (final model in _settings.translationDownloadedModels)
model.localPath: model,
};
final merged = scanned.map((model) {
final existing = existingByPath[model.localPath];
if (existing == null) {
return model;
}
return TranslationModelRecord(
id: existing.id,
name: existing.name,
sourceUrl: existing.sourceUrl,
localPath: existing.localPath,
downloadedAt: existing.downloadedAt,
fileSizeBytes: model.fileSizeBytes,
);
}).toList();
await _appSettingsService.setTranslationDownloadedModels(merged);
_failedModelPath = null;
if (_settings.translationSelectedModelId == null && merged.isNotEmpty) {
await _appSettingsService.setTranslationSelectedModelId(merged.first.id);
}
}
static const int _parallelChunks = 8;
static const int _parallelMinBytes = 10 * 1024 * 1024; // 10 MB
Future<TranslationModelRecord> downloadModel({
required String sourceUrl,
String? fileName,
String? id,
}) async {
final uri = Uri.tryParse(sourceUrl);
if (uri == null || !uri.hasScheme) {
throw ArgumentError('Invalid model URL.');
}
return _runExclusive(() async {
_setBusy(true);
_setDownloading(true);
_lastError = null;
try {
final resolvedFileName =
fileName ??
_sanitizeFileName(
uri.pathSegments.isNotEmpty
? uri.pathSegments.last
: 'translation-model.gguf',
);
_downloadFileName = resolvedFileName;
_downloadedBytes = 0;
_cancelDownloadRequested = false;
// HEAD request to check size and range support.
final headClient = http.Client();
int? totalSize;
bool supportsRange = false;
try {
final headResponse = await headClient.send(http.Request('HEAD', uri));
totalSize = headResponse.contentLength;
supportsRange =
headResponse.headers['accept-ranges']?.contains('bytes') == true;
await headResponse.stream.drain<void>();
} finally {
headClient.close();
}
_downloadTotalBytes = totalSize;
notifyListeners();
DownloadedModelFile downloaded;
if (supportsRange &&
totalSize != null &&
totalSize > _parallelMinBytes) {
downloaded = await _downloadParallel(
uri: uri,
fileName: resolvedFileName,
totalSize: totalSize,
);
} else {
downloaded = await _downloadSingle(
uri: uri,
fileName: resolvedFileName,
);
}
final record = TranslationModelRecord(
id: id ?? resolvedFileName,
name: resolvedFileName,
sourceUrl: sourceUrl,
localPath: downloaded.localPath,
downloadedAt: DateTime.now(),
fileSizeBytes: downloaded.fileSizeBytes,
);
final updated = [
for (final existing in _settings.translationDownloadedModels)
if (existing.id != record.id) existing,
record,
];
await _appSettingsService.setTranslationDownloadedModels(updated);
await _appSettingsService.setTranslationSelectedModelId(record.id);
await _appSettingsService.setTranslationModelSourceUrl(sourceUrl);
_failedModelPath = null;
return record;
} finally {
_setDownloading(false);
}
});
}
Future<DownloadedModelFile> _downloadSingle({
required Uri uri,
required String fileName,
}) async {
final client = http.Client();
try {
final response = await client.send(http.Request('GET', uri));
if (response.statusCode < 200 || response.statusCode >= 300) {
throw StateError('Model download failed: HTTP ${response.statusCode}');
}
_downloadTotalBytes ??= response.contentLength;
notifyListeners();
final trackedStream = _trackDownloadProgress(response.stream);
return await _fileStore.writeModelBytes(
fileName: fileName,
chunks: trackedStream,
);
} finally {
client.close();
}
}
Future<DownloadedModelFile> _downloadParallel({
required Uri uri,
required String fileName,
required int totalSize,
}) async {
final chunkSize = (totalSize / _parallelChunks).ceil();
final chunkPaths = <String>[];
final clients = <http.Client>[];
var combineReached = false;
try {
final futures = <Future<void>>[];
for (var i = 0; i < _parallelChunks; i++) {
final start = i * chunkSize;
final end = (start + chunkSize - 1).clamp(0, totalSize - 1);
if (start >= totalSize) break;
final chunkPath = await _fileStore.chunkFilePath(fileName, i);
chunkPaths.add(chunkPath);
final client = http.Client();
clients.add(client);
futures.add(
_downloadRange(
client: client,
uri: uri,
chunkPath: chunkPath,
start: start,
end: end,
),
);
}
await Future.wait(futures);
if (_cancelDownloadRequested) {
throw const TranslationDownloadCancelled();
}
_downloadFileName = 'Merging chunks...';
notifyListeners();
combineReached = true;
return await _fileStore.combineChunks(
fileName: fileName,
chunkPaths: chunkPaths,
);
} finally {
for (final client in clients) {
client.close();
}
if (!combineReached) {
for (final chunkPath in chunkPaths) {
await _fileStore.deleteFile(chunkPath);
}
}
}
}
Future<void> _downloadRange({
required http.Client client,
required Uri uri,
required String chunkPath,
required int start,
required int end,
}) async {
final request = http.Request('GET', uri);
request.headers['Range'] = 'bytes=$start-$end';
final response = await client.send(request);
if (response.statusCode != 206) {
await response.stream.drain<void>();
throw StateError(
'Range download failed: HTTP ${response.statusCode}'
'${response.statusCode == 200 ? ' (server ignored Range header)' : ''}',
);
}
final trackedStream = _trackDownloadProgress(response.stream);
await _fileStore.writeModelBytes(
fileName: chunkPath.split(RegExp(r'[/\\]')).last,
chunks: trackedStream,
);
}
void cancelDownload() {
if (!_isDownloading) {
return;
}
_cancelDownloadRequested = true;
_lastError = 'Download stopped.';
notifyListeners();
}
Future<void> removeModel(TranslationModelRecord model) async {
await _runExclusive(() async {
_setBusy(true);
_lastError = null;
await _fileStore.deleteModel(model);
final updated = _settings.translationDownloadedModels
.where((entry) => entry.id != model.id)
.toList();
await _appSettingsService.setTranslationDownloadedModels(updated);
if (_settings.translationSelectedModelId == model.id) {
await _appSettingsService.setTranslationSelectedModelId(
updated.isNotEmpty ? updated.first.id : null,
);
}
});
}
Future<TranslationResult?> translateIncomingText({
required String text,
required String? targetLanguageCode,
}) async {
if (targetLanguageCode == null || !_isPlainTextEligible(text)) {
return null;
}
final detectedLanguageCode = await detectLanguage(text);
if (detectedLanguageCode != null &&
detectedLanguageCode == targetLanguageCode) {
return const TranslationResult(
translatedText: '',
targetLanguageCode: '',
status: MessageTranslationStatus.skipped,
);
}
final translatedText = await _translateText(
text: text,
targetLanguageCode: targetLanguageCode,
sourceLanguageCode: detectedLanguageCode,
);
if (translatedText == null || translatedText.trim().isEmpty) {
return null;
}
// If translation is nearly identical, text was already in target language.
if (translatedText.trim().toLowerCase() == text.trim().toLowerCase()) {
return const TranslationResult(
translatedText: '',
targetLanguageCode: '',
status: MessageTranslationStatus.skipped,
);
}
return TranslationResult(
translatedText: translatedText.trim(),
targetLanguageCode: targetLanguageCode,
detectedLanguageCode: detectedLanguageCode,
modelId: selectedModel?.id,
status: MessageTranslationStatus.completed,
);
}
Future<TranslationResult?> translateOutgoingText({
required String text,
required String? targetLanguageCode,
}) async {
if (targetLanguageCode == null || !_isPlainTextEligible(text)) {
return null;
}
final detectedLanguageCode = await detectLanguage(text);
if (detectedLanguageCode != null &&
detectedLanguageCode == targetLanguageCode) {
return const TranslationResult(
translatedText: '',
targetLanguageCode: '',
status: MessageTranslationStatus.skipped,
);
}
final translatedText = await _translateText(
text: text,
targetLanguageCode: targetLanguageCode,
sourceLanguageCode: detectedLanguageCode,
);
if (translatedText == null || translatedText.trim().isEmpty) {
return null;
}
return TranslationResult(
translatedText: translatedText.trim(),
targetLanguageCode: targetLanguageCode,
detectedLanguageCode: detectedLanguageCode,
modelId: selectedModel?.id,
status: MessageTranslationStatus.completed,
);
}
Future<String?> detectLanguage(String text) async {
return _heuristicLanguageCode(text);
}
Future<String?> _translateText({
required String text,
required String targetLanguageCode,
String? sourceLanguageCode,
}) async {
if (!_hasUsableModel) {
return null;
}
final model = selectedModel;
if (model == null || model.localPath.isEmpty) {
return null;
}
final targetLabel = _languageLabel(targetLanguageCode);
final instruction = targetLanguageCode == 'zh'
? '将以下文本翻译为中文,注意只需要输出翻译后的结果,不要额外解释:\n\n$text'
: 'Translate the following segment into $targetLabel, without additional explanation.\n\n$text';
try {
return await _runExclusive(() async {
final engine = await _ensureContext(model.localPath);
if (engine == null) {
return null;
}
final messages = [
LlamaChatMessage.fromText(
role: LlamaChatRole.user,
text: instruction,
),
];
final output = StringBuffer();
await for (final chunk in engine.create(
messages,
params: const GenerationParams(
maxTokens: 256,
temp: 0.7,
topK: 20,
topP: 0.6,
penalty: 1.05,
reusePromptPrefix: false,
),
enableThinking: false,
sourceLangCode: sourceLanguageCode,
targetLangCode: targetLanguageCode,
)) {
final content = chunk.choices.firstOrNull?.delta.content;
if (content != null) {
output.write(content);
}
if (output.length >= text.length * 4 + 100) {
break;
}
}
return _sanitizeOutput(output.toString());
});
} catch (error) {
_lastError = error.toString();
appLogger.warn('Translation request failed: $error');
notifyListeners();
return null;
}
}
bool get _hasUsableModel {
final model = selectedModel;
return !kIsWeb && model != null && model.localPath.isNotEmpty;
}
bool _isPlainTextEligible(String text) {
final trimmed = text.trim();
if (trimmed.isEmpty) {
return false;
}
if (GifHelper.parseGif(trimmed) != null) {
return false;
}
return !(trimmed.startsWith('m:') ||
trimmed.startsWith('V1|') ||
trimmed.startsWith('r:'));
}
String? _heuristicLanguageCode(String text) {
final trimmed = text.trim();
if (trimmed.isEmpty) {
return null;
}
if (RegExp(r'[ぁ-んァ-ン]').hasMatch(text)) {
return 'ja';
}
if (RegExp(r'[가-힣]').hasMatch(text)) {
return 'ko';
}
if (RegExp(r'[\u4e00-\u9fff]').hasMatch(text)) {
return 'zh';
}
final lower = trimmed.toLowerCase();
final patterns = <String, String>{
'uk': r'\b(привіт|дякую|будь|ласка|як|де|не|так|це|є|най|ще|може|для)\b',
'ru': r'\b(что|это|как|не|да|нет|он|она|они|быть|есть|для|сегодня|если|уже|может)\b',
'bg': r'\b(ще|няма|благодаря|моля|това|какво|тук|ние|вие|не|със|за)\b',
'de': r'\b(der|die|das|und|ist|nicht|ein|eine|ich|für|mit|auf|zu|auch|als|an|im|am|es|dem|den|sich|von)\b',
'en': r'\b(the|and|is|you|for|with|from|not|that|this|have|be|are|was|were|but|can|will|your|what|when|how|they)\b',
'es': r'\b(el|la|los|las|es|que|de|en|con|por|para|no|un|una|se|como|su|al|del|está)\b',
'fr': r'\b(le|la|les|un|une|et|est|que|qui|pour|dans|pas|avec|sur|ne|vous|il|elle|des|ce|cette|je|tu|nous|vous)\b',
'it': r'\b(il|la|lo|un|una|che|di|da|in|per|con|non|si|mi|ti|noi|voi|lui|lei)\b',
'pt': r'\b(os|as|que|de|do|da|em|para|com|por|não|uma|um|se|você|também)\b',
'nl': r'\b(de|het|een|en|is|niet|dat|wat|je|ik|op|aan|voor|met|als|nog|zijn)\b',
'sv': r'\b(och|är|det|att|som|en|på|inte|har|var|men|du|jag|vi|ni|den|detta)\b',
'pl': r'\b(na|się|nie|jest|to|że|do|od|dla|czy|tak|ale|ma|jak|on|ona|my)\b',
'sk': r'\b(je|na|so|že|do|od|za|si|to|ten|tá|tí|ako|má|nie|som|sa)\b',
'sl': r'\b(in|je|na|se|da|za|od|ne|to|ta|so|kako|bo|sem|si)\b',
'hu': r'\b(az|és|nem|van|volt|hogy|mit|mire|ki|mi|ez|azért|is|de|ha|te|ő|mi|itt)\b',
};
final scores = <String, int>{};
for (final entry in patterns.entries) {
scores[entry.key] = RegExp(entry.value, caseSensitive: false)
.allMatches(lower)
.length;
}
final sorted = scores.entries.toList()
..sort((a, b) => b.value.compareTo(a.value));
if (sorted.isEmpty || sorted.first.value == 0) {
return null;
}
if (sorted.length > 1 && sorted.first.value == sorted[1].value) {
return null;
}
return sorted.first.key;
}
String _languageLabel(String code) {
for (final option in supportedTranslationLanguages) {
if (option.code == code) {
return option.label;
}
}
return code.toUpperCase();
}
String _sanitizeOutput(String raw) {
var result = raw.trim();
result = result.replaceAll(RegExp(r'\*\*'), '');
result = result.replaceAll(RegExp(r'<[^>]+>'), '');
return result.trim();
}
String _sanitizeFileName(String fileName) {
final cleaned = fileName.replaceAll(RegExp(r'[^A-Za-z0-9._-]'), '_');
return cleaned.isEmpty ? 'translation-model.gguf' : cleaned;
}
Future<LlamaEngine?> _ensureContext(String modelPath) async {
if (_engine != null && _loadedModelPath == modelPath) {
return _engine;
}
if (modelPath == _failedModelPath) {
return null;
}
if (_engine != null) {
await _engine!.dispose();
_engine = null;
_loadedModelPath = null;
}
final engine = LlamaEngine(LlamaBackend());
try {
await engine.loadModel(
modelPath,
modelParams: const ModelParams(
gpuLayers: 0,
preferredBackend: GpuBackend.cpu,
),
);
_engine = engine;
_loadedModelPath = modelPath;
_failedModelPath = null;
return _engine;
} catch (_) {
await engine.dispose();
_failedModelPath = modelPath;
rethrow;
}
}
Future<void> releaseModel() async {
await _runExclusive(() async {
final engine = _engine;
if (engine == null) {
_loadedModelPath = null;
return;
}
_engine = null;
_loadedModelPath = null;
await engine.dispose();
});
}
Future<T> _runExclusive<T>(Future<T> Function() action) {
final completer = Completer<T>();
_setBusy(true);
_queue = _queue.then((_) async {
try {
completer.complete(await action());
} catch (error, stackTrace) {
completer.completeError(error, stackTrace);
} finally {
_setBusy(false);
}
});
return completer.future;
}
Stream<List<int>> _trackDownloadProgress(Stream<List<int>> source) async* {
await for (final chunk in source) {
if (_cancelDownloadRequested) {
throw const TranslationDownloadCancelled();
}
_downloadedBytes += chunk.length;
notifyListeners();
yield chunk;
}
}
void _setBusy(bool value) {
if (_isBusy == value) {
return;
}
_isBusy = value;
notifyListeners();
}
void _setDownloading(bool value) {
_isDownloading = value;
if (!value) {
_cancelDownloadRequested = false;
_downloadedBytes = 0;
_downloadTotalBytes = null;
_downloadFileName = null;
}
notifyListeners();
}
@override
void dispose() {
final engine = _engine;
_engine = null;
_loadedModelPath = null;
if (engine != null) {
unawaited(engine.dispose());
}
super.dispose();
}
}