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

import 'package:shelf/shelf.dart';
import 'package:shelf_router/shelf_router.dart';

import 'config/app_config.dart';
import 'util/vips.dart';
import 'domain/repositories/photo_repository.dart';
import 'domain/repositories/album_repository.dart';

final _config = AppConfig();
final vips = Vips(cacheDir: _config.cacheDir);
final albumRepository = AlbumRepository(basePath: _config.dataDir);
final photoRepository = PhotoRepository(_config.dataDir);

Response jsonResponse(dynamic data) {
  return Response.ok(
    jsonEncode(data),
    headers: {'content-type': 'application/json'},
  );
}

/// 创建 API v1 版本的路由
Router createApiV1Router() {
  final router = Router()
    ..get('/', _rootHandler)
    ..get("/album", _listAlbumHandler)
    ..get("/album/<id>", _getAlbumHandler)
    ..get("/album/<id>/photo", _getPhotosOfAlbumHandler)
    ..get('/photo/<id>', _getPhotoHandler)
    ..get('/photo/<id>/file', _getPhotoFileHandler)
    ..get('/photo/<id>/preview', _getPhotoPreviewHandler)
    ..get('/echo/<message>', _echoHandler);

  return router;
}

/// 创建主路由器，将 API v1 挂载到 /api/v1 路径下
Router createRouter() {
  final router = Router();

  // 将 API v1 路由挂载到 /api/v1 路径下
  router.mount('/api/v1', createApiV1Router().call);

  return router;
}

Response _rootHandler(Request req) {
  return Response.ok('Hello, World!\n');
}

Response _echoHandler(Request request) {
  final message = request.params['message'];
  return Response.ok('$message\n');
}

Future<Response> _listAlbumHandler(Request req) async {
  final albums = await albumRepository.getAllAlbums();
  final albumList = albums
      .map(
        (a) => {
          'id': a.id,
          'name': a.name,
          'createdAt': a.createdAt.toIso8601String(),
          'updatedAt': a.updatedAt.toIso8601String(),
        },
      )
      .toList();
  return jsonResponse(albumList);
}

Future<Response> _getAlbumHandler(Request req) async {
  final idParam = req.params['id'];
  if (idParam == null) {
    return Response.badRequest(body: 'Missing album id');
  }
  final id = int.tryParse(idParam);
  if (id == null) {
    return Response.badRequest(body: 'Invalid album id: $idParam');
  }
  final album = await albumRepository.getAlbumById(id);
  if (album == null) {
    return Response.notFound('Album not found');
  }
  return jsonResponse({'id': album.id, 'name': album.name});
}

Future<Response> _getPhotoHandler(Request req) async {
  final idParam = req.params['id'];
  if (idParam == null) {
    return Response.badRequest(body: 'Missing photo id');
  }
  final id = int.tryParse(idParam);
  if (id == null) {
    return Response.badRequest(body: 'Invalid photo id: $idParam');
  }

  final photo = await photoRepository.getPhotoById(id);
  if (photo == null) {
    return Response.notFound('Photo not found');
  }
  return jsonResponse(photo);
}

Future<Response> _getPhotoFileHandler(Request req) async {
  final idParam = req.params['id'];
  if (idParam == null) {
    return Response.badRequest(body: 'Missing photo id');
  }
  final id = int.tryParse(idParam);
  if (id == null) {
    return Response.badRequest(body: 'Invalid photo id: $idParam');
  }

  final photo = await photoRepository.getPhotoById(id);
  if (photo == null) {
    return Response.notFound('Photo not found');
  }

  final filePath = photo.filePath;
  final file = File(filePath);

  if (!await file.exists()) {
    return Response.notFound('File not found');
  }

  // ✅ 修复：使用 StreamController 包装，确保在客户端断开时关闭文件流
  final streamController = StreamController<List<int>>();
  final fileStream = file.openRead();

  // 订阅文件流，并将数据转发到响应流
  final subscription = fileStream.listen(
    streamController.add,
    onError: streamController.addError,
    onDone: streamController.close,
    cancelOnError: true,
  );

  // 当客户端取消订阅时（断开连接），取消文件流订阅并关闭文件
  streamController.onCancel = () {
    subscription.cancel();
    return Future.value();
  };

  return Response.ok(
    streamController.stream,
    headers: {
      'Content-Type': photo.mimeType,
      'Content-Length': photo.fileSize.toString(),
    },
  );
}

Future<Response> _getPhotosOfAlbumHandler(Request req) async {
  final idParam = req.params['id'];
  if (idParam == null) {
    return Response.badRequest(body: 'Missing album id');
  }
  final albumId = int.tryParse(idParam);
  if (albumId == null) {
    return Response.badRequest(body: 'Invalid album id: $idParam');
  }
  final photos = await photoRepository.getPhotosByAlbumId(albumId);
  return jsonResponse(photos);
}

Future<Response> _getPhotoPreviewHandler(Request req) async {
  final idParam = req.params['id'];
  if (idParam == null) {
    return Response.badRequest(body: 'Missing photo id');
  }
  final id = int.tryParse(idParam);
  if (id == null) {
    return Response.badRequest(body: 'Invalid photo id: $idParam');
  }

  final photo = await photoRepository.getPhotoById(id);
  if (photo == null) {
    return Response.notFound('Photo not found');
  }

  // 从查询参数获取宽度和高度
  final w = int.tryParse(req.url.queryParameters['w'] ?? '');
  final h = int.tryParse(req.url.queryParameters['h'] ?? '');

  final file = await vips.generatePreview(
    photo.filePath,
    w: w,
    h: h,
  );

  if (!await file.exists()) {
    return Response.notFound('File not found');
  }

  // ✅ 修复：使用 StreamController 包装，确保在客户端断开时关闭文件流
  final streamController = StreamController<List<int>>();
  final fileStream = file.openRead();

  // 订阅文件流，并将数据转发到响应流
  final subscription = fileStream.listen(
    streamController.add,
    onError: streamController.addError,
    onDone: streamController.close,
    cancelOnError: true,
  );

  // 当客户端取消订阅时（断开连接），取消文件流订阅并关闭文件
  streamController.onCancel = () {
    subscription.cancel();
    return Future.value();
  };

  return Response.ok(
    streamController.stream,
    headers: {
      'Content-Type': 'image/webp',
      'Content-Length': file.statSync().size.toString(),
    },
  );
}