64 lines
1.9 KiB
Dart
64 lines
1.9 KiB
Dart
import 'dart:io';
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import 'package:path_provider/path_provider.dart';
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import 'package:path/path.dart' as p;
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class ModelDownloadService {
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static const modelFileName = 'gemma-2b-it-gpu-int4.bin';
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static const modelSizeBytes = 1183285248; // ~1.1 GB
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// Gemma 2B IT CPU int4 — MediaPipe LLM Inference model
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static const _downloadUrl =
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'https://storage.googleapis.com/mediapipe-models/llm_inference/'
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'gemma-2b-it-cpu-int4/float32/1/gemma-2b-it-cpu-int4.bin';
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Future<String> get modelPath async {
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final dir = await getApplicationSupportDirectory();
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return p.join(dir.path, modelFileName);
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}
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Future<bool> isModelPresent() async {
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final path = await modelPath;
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final file = File(path);
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if (!file.existsSync()) return false;
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// Verify the file isn't a partial download (allow small variance)
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final size = await file.length();
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return size > modelSizeBytes * 0.99;
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}
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/// Streams download progress as a value from 0.0 to 1.0.
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Stream<double> download() async* {
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final path = await modelPath;
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final file = File(path);
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final client = HttpClient();
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try {
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final request = await client.getUrl(Uri.parse(_downloadUrl));
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final response = await request.close();
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if (response.statusCode != 200) {
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throw Exception('Download failed: HTTP ${response.statusCode}');
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}
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final totalBytes =
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response.contentLength > 0 ? response.contentLength : modelSizeBytes;
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int receivedBytes = 0;
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final sink = file.openWrite();
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try {
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await for (final chunk in response) {
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sink.add(chunk);
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receivedBytes += chunk.length;
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yield (receivedBytes / totalBytes).clamp(0.0, 1.0);
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}
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} finally {
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await sink.close();
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}
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} catch (_) {
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if (await file.exists()) await file.delete();
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rethrow;
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} finally {
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client.close();
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}
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}
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}
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