gistfile1.txt

import 'dart:async';
import 'dart:io';

import 'package:background_downloader/background_downloader.dart';
import 'package:dio/dio.dart';
import 'package:dio/io.dart';
import 'package:easy_debounce/easy_throttle.dart';
import 'package:hooks_riverpod/hooks_riverpod.dart';
import 'package:loggy/loggy.dart';
import 'package:path/path.dart' as p;

import 'package:telosnex/extensions/is_web.dart';
import 'package:telosnex/misc/hugging_face.dart';
import 'package:telosnex/models/ai_model_view_model.dart';
import 'package:telosnex/models/ai_model_view_model_web.dart';
import 'package:telosnex/models/download_state.dart';
import 'package:telosnex/persistence/path_providers.dart';
import 'package:telosnex/providers/ai_model_download.dart';
import 'package:telosnex/widgets/patrol_keys.dart';

extension Download on AiModelViewModel {
  Future<void> download(ProviderContainer ref, String filename) async {
    @pragma('vm:awaiter-link')
    final completer = Completer<void>();

    final url = getHuggingFaceUrl(
      repoId: repoId,
      filename: filename,
      revision: 'main',
    );
    final path = p.join(
      isWeb ? '' : PathProvider.documentsDirectory,
      'models',
      filename,
    );
    final startTime = DateTime.now();
    final dlManager = ref.read(aiModelDownloadProvider.notifier);
    if (P.isTesting && !P.isIntegrationTesting) {
      // Fake the download for testing.
      // The below code can't work in unit tests.
      // - web requires web APis for storage
      // - native uses background_downloader package and doesn't support
      //   running async.
      final newState = DownloadState(
        currentProgress: 500,
        totalSize: 1000,
        startTime: startTime,
      );
      @pragma('vm:awaiter-link')
      final updateCompleter = Completer<void>();
      // ignore: avoid_print
      print(
        '[AiModelViewModel._download] waiting 1 second for fake downloading model update for $path',
      );

      EasyThrottle.throttle(filename, const Duration(seconds: 1), () {
        dlManager.update(this, newState);
        updateCompleter.complete();
      });
      await updateCompleter.future;
      // ignore: avoid_print
      print(
        '[AiModelViewModel._download] waiting 3 seconds for fake downloading model complete for $path',
      );
      await Future.delayed(const Duration(seconds: 3));
      final file = File(path);
      file.createSync(recursive: true);
      file.writeAsBytesSync(List.generate(1000, (index) => index));
      EasyThrottle.cancel(filename);
      dlManager.update(
        this,
        DownloadState(
          currentProgress: 1,
          totalSize: 1,
          startTime: startTime,
        ),
      );
      ref.invalidate(modelFileExistsProvider(path));
      logInfo('[AiModelViewModel._download] fake downloaded model: $path');

      completer.complete();
      return;
    }

    if (isWeb) {
      logInfo('[AiModelViewModel._download] isWeb, downloading model: $url');
      doWebDownload(ref, completer);
    } else if (Platform.isWindows) {
      logInfo(
          '[AiModelViewModel._download] isWindows, downloading model: $url');

      // Needed to work around strange error with SSL cert x huggingface seen on
      // Framework laptop running Windows 11. Background downloader _may_ also
      // work if we can figure out how to override bad cert when host is HF.
      try {
        final file = File(path);
        if (file.existsSync()) {
          logInfo(
            '[AiModelViewModel._download] model already exists @ $path. Invalidating provider.',
          );
          ref.invalidate(modelFileExistsProvider(path));
          return;
        }
        // Note: Can't use Sentry dio here, it breaks the logging that lets us
        // know ex. it was a bad cert.
        final dio = Dio();
        // Avoid Error: HandshakeException: Handshake error in client (OS Error:
        //       	CERTIFICATE_VERIFY_FAILED: unable to get local issuer certificate(../../flutter/third_party/boringssl/src/ssl/handshake.cc:393)))
        (dio.httpClientAdapter as IOHttpClientAdapter).createHttpClient = () =>
            HttpClient()
              ..badCertificateCallback =
                  (X509Certificate cert, String host, int port) {
                // huggingface.co was added initially, sometime Q2-Q3 2024
                // cdn-lfs.hf.co added 23-10-2024
                if (host.endsWith('huggingface.co') || host.endsWith('hf.co')) {
                  return true;
                }
                logError(
                  '[AiModelViewModel._download] Bad certificate for $host:$port. Cert: $cert',
                );
                return false;
              };
        unawaited(dio.download(
          url,
          path,
          onReceiveProgress: (count, total) {
            final newState = DownloadState(
              currentProgress: count,
              totalSize: total,
              startTime: startTime,
            );
            EasyThrottle.throttle(
              this.filename,
              const Duration(seconds: 1),
              () {
                dlManager.update(this, newState);
              },
            );
            if (count == total) {
              EasyThrottle.cancel(filename);
              dlManager.update(this, newState);
            }
          },
        ).then((value) {
          ref.invalidate(modelFileExistsProvider(path));
          logInfo('[AiModelViewModel._download] downloaded model: $path');
          completer.complete();
        }).onError((error, stackTrace) {
          logError(
            '[AiModelViewModel._download] Error downloading model: $error',
            error,
            stackTrace,
          );
          completer.complete();
        }));
      } catch (e, s) {
        logError('Failed to download model: $filename. URL: $url', e, s);
        completer.completeError(
          'Failed to download model: $filename. URL: $url',
          s,
        );
      }
    } else {
      logInfo(
          '[AiModelViewModel._download] using DownloadTask to download66 model: $url');

      final file = File(path);
      if (file.existsSync()) {
        logInfo(
          '[AiModelViewModel._download] model already exists @ $path. Invalidating provider.',
        );
        ref.invalidate(modelFileExistsProvider(path));
        return;
      }
      // define the task
      final task = DownloadTask(
        url: url,
        directory: p.dirname(path), // must be a directory path (no filename
        filename: p.basename(path),
        baseDirectory: BaseDirectory.root,
        updates: Updates.statusAndProgress,
        allowPause:
            true, // ensures Android can progress on DLs past 8-10 minutes. See https://github.com/781flyingdutchman/background_downloader/issues/13
      );

      // enqueue the download
      var size = await task.expectedFileSize();
      if (size < 0) {
        completer.completeError(
          'Invalid file size for $filename: $size. Most likely, the model download link is invalid. URL: $url',
          StackTrace.current,
        );
        return completer.future;
      }
      // An `await` here causes method to never return. Observed on Windows when
      // it thinks (erroneously) that the URL does not exist, then calls status
      // callback with failed, which then attempted to call completer.completeError.
      // The caller never received the error.
      unawaited(FileDownloader().download(
        task,
        onProgress: (progress) {
          if (size <= 0) {
            loggy.debug('Progress: $progress but no size. URL: $url');
            return;
          }
          final count = (progress * size).clamp(0.0, size.toDouble()).floor();
          final newState = DownloadState(
            currentProgress: count,
            totalSize: size,
            startTime: startTime,
          );
          EasyThrottle.throttle(filename, const Duration(seconds: 1), () {
            dlManager.update(this, newState);
          });
        },
        onStatus: (update) {
          logInfo('[AiModelViewModel._download] status update: $update');
          switch (update) {
            case TaskStatus.enqueued:
            case TaskStatus.running:
            case TaskStatus.canceled:
            case TaskStatus.waitingToRetry:
            case TaskStatus.paused:
              break;
            case TaskStatus.notFound:
              logError(
                  'Failed to download model, not found: $filename. URL: $url');
              EasyThrottle.cancel(filename);
              completer.completeError(
                'Failed to download model: $filename. URL: $url',
                StackTrace.current,
              );
              break;
            case TaskStatus.complete:
              EasyThrottle.cancel(filename);
              dlManager.update(
                this,
                DownloadState(
                  currentProgress: size,
                  totalSize: size,
                  startTime: startTime,
                ),
              );
              ref.invalidate(modelFileExistsProvider(path));
              logInfo('[AiModelViewModel._download]  downloaded model: $path');
              completer.complete();
              break;
            case TaskStatus.failed:
              EasyThrottle.cancel(filename);
              completer.completeError(
                'Failed to download model: $filename. URL: $url',
                StackTrace.current,
              );
              break;
          }
        },
      ));
      loggy.debug('[AiModelViewModel._download] await download returned');
    }

    return completer.future;
  }
}