feat: Add initial backend server with user authentication, session management, and playlist CRUD functionality.

bin/api/playlists_handler.dart

@@ -0,0 +1,186 @@
+import 'dart:convert';
+import 'package:shelf/shelf.dart';
+import 'package:shelf_router/shelf_router.dart';
+import '../database/database.dart';
+
+class PlaylistsHandler {
+  final AppDatabase db;
+
+  PlaylistsHandler(this.db);
+
+  Router get router {
+    final router = Router();
+
+    router.get('/', _getPlaylists);
+    router.post('/', _createPlaylist);
+    router.put('/<id>', _updatePlaylist);
+    router.delete('/<id>', _deletePlaylist);
+
+    return router;
+  }
+
+  /// GET /api/playlists
+  Future<Response> _getPlaylists(Request request) async {
+    try {
+      final userId = request.context['userId'] as String?;
+      if (userId == null) {
+        return Response(401, body: jsonEncode({
+          'success': false,
+          'error': 'Unauthorized',
+        }), headers: {'Content-Type': 'application/json'});
+      }
+
+      final playlists = db.getPlaylists(userId);
+
+      return Response.ok(jsonEncode({
+        'playlists': playlists.map((p) => p.toJson()).toList(),
+      }), headers: {'Content-Type': 'application/json'});
+    } catch (e) {
+      return Response.internalServerError(
+        body: jsonEncode({'success': false, 'error': e.toString()}),
+        headers: {'Content-Type': 'application/json'},
+      );
+    }
+  }
+
+  /// POST /api/playlists
+  Future<Response> _createPlaylist(Request request) async {
+    try {
+      final userId = request.context['userId'] as String?;
+      if (userId == null) {
+        return Response(401, body: jsonEncode({
+          'success': false,
+          'error': 'Unauthorized',
+        }), headers: {'Content-Type': 'application/json'});
+      }
+
+      final payload = jsonDecode(await request.readAsString()) as Map<String, dynamic>;
+      final name = payload['name'] as String?;
+      final serverUrl = payload['serverUrl'] as String?;
+      final username = payload['username'] as String?;
+      final password = payload['password'] as String?;
+      final dns = payload['dns'] as String?;
+
+      if (name == null || serverUrl == null || username == null || password == null) {
+        return Response(400, body: jsonEncode({
+          'success': false,
+          'error': 'Missing required fields',
+        }), headers: {'Content-Type': 'application/json'});
+      }
+
+      final playlist = db.createPlaylist(
+        userId: userId,
+        name: name,
+        serverUrl: serverUrl,
+        username: username,
+        password: password,
+        dns: dns ?? serverUrl,
+      );
+
+      return Response.ok(jsonEncode({
+        'success': true,
+        'playlist': playlist.toJson(),
+      }), headers: {'Content-Type': 'application/json'});
+    } catch (e) {
+      return Response.internalServerError(
+        body: jsonEncode({'success': false, 'error': e.toString()}),
+        headers: {'Content-Type': 'application/json'},
+      );
+    }
+  }
+
+  /// PUT /api/playlists/:id
+  Future<Response> _updatePlaylist(Request request, String id) async {
+    try {
+      final userId = request.context['userId'] as String?;
+      if (userId == null) {
+        return Response(401, body: jsonEncode({
+          'success': false,
+          'error': 'Unauthorized',
+        }), headers: {'Content-Type': 'application/json'});
+      }
+
+      // Verify playlist belongs to user
+      final existing = db.getPlaylistById(id);
+      if (existing == null) {
+        return Response(404, body: jsonEncode({
+          'success': false,
+          'error': 'Playlist not found',
+        }), headers: {'Content-Type': 'application/json'});
+      }
+
+      if (existing.userId != userId) {
+        return Response(403, body: jsonEncode({
+          'success': false,
+          'error': 'Forbidden',
+        }), headers: {'Content-Type': 'application/json'});
+      }
+
+      final payload = jsonDecode(await request.readAsString()) as Map<String, dynamic>;
+      final name = payload['name'] as String? ?? existing.name;
+      final serverUrl = payload['serverUrl'] as String? ?? existing.serverUrl;
+      final username = payload['username'] as String? ?? existing.username;
+      final password = payload['password'] as String? ?? existing.password;
+      final dns = payload['dns'] as String? ?? existing.dns;
+
+      final playlist = db.updatePlaylist(
+        playlistId: id,
+        name: name,
+        serverUrl: serverUrl,
+        username: username,
+        password: password,
+        dns: dns,
+      );
+
+      return Response.ok(jsonEncode({
+        'success': true,
+        'playlist': playlist.toJson(),
+      }), headers: {'Content-Type': 'application/json'});
+    } catch (e) {
+      return Response.internalServerError(
+        body: jsonEncode({'success': false, 'error': e.toString()}),
+        headers: {'Content-Type': 'application/json'},
+      );
+    }
+  }
+
+  /// DELETE /api/playlists/:id
+  Future<Response> _deletePlaylist(Request request, String id) async {
+    try {
+      final userId = request.context['userId'] as String?;
+      if (userId == null) {
+        return Response(401, body: jsonEncode({
+          'success': false,
+          'error': 'Unauthorized',
+        }), headers: {'Content-Type': 'application/json'});
+      }
+
+      // Verify playlist belongs to user
+      final existing = db.getPlaylistById(id);
+      if (existing == null) {
+        return Response(404,body: jsonEncode({
+          'success': false,
+          'error': 'Playlist not found',
+        }), headers: {'Content-Type': 'application/json'});
+      }
+
+      if (existing.userId != userId) {
+        return Response(403, body: jsonEncode({
+          'success': false,
+          'error': 'Forbidden',
+        }), headers: {'Content-Type': 'application/json'});
+      }
+
+      db.deletePlaylist(id);
+
+      return Response.ok(jsonEncode({
+        'success': true,
+      }), headers: {'Content-Type': 'application/json'});
+    } catch (e) {
+      return Response.internalServerError(
+        body: jsonEncode({'success': false, 'error': e.toString()}),
+        headers: {'Content-Type': 'application/json'},
+      );
+    }
+  }
+}