Implement data sync and cleanup

backend/bin/server.dart

@@ -0,0 +1,67 @@
+import 'dart:io';
+import 'dart:convert';
+import 'package:shelf/shelf.dart';
+import 'package:shelf/shelf_io.dart' as io;
+import 'package:shelf_router/shelf_router.dart';
+import 'package:tracker_backend/database.dart';
+
+void main(List<String> args) async {
+  // Use port 8090 as requested
+  final port = 8090;
+  final db = TrackerDatabase();
+
+  final app = Router();
+
+  app.get('/', (Request request) {
+    return Response.ok('Tracker Sync Server Running');
+  });
+
+  // Simple Sync Endpoint (Push)
+  // Expects JSON: { "userId": "...", "entries": [ ... ] }
+  app.post('/sync/push', (Request request) async {
+    try {
+      final payload = await request.readAsString();
+      final data = jsonDecode(payload);
+      final userId = data['userId'];
+      final entries = data['entries'] as List;
+
+      print('Received sync push for $userId with ${entries.length} entries');
+
+      for (var entry in entries) {
+        // Basic upsert handling
+        db.upsertCycleEntry(userId, entry);
+      }
+
+      return Response.ok(
+          jsonEncode({'status': 'success', 'synced': entries.length}));
+    } catch (e) {
+      print('Sync Error: $e');
+      return Response.internalServerError(body: 'Sync Failed: $e');
+    }
+  });
+
+  // Pull Endpoint
+  // GET /sync/pull?userId=...
+  app.get('/sync/pull', (Request request) {
+    final userId = request.url.queryParameters['userId'];
+    if (userId == null) return Response.badRequest(body: 'Missing userId');
+
+    final entries = db.getCycleEntries(userId);
+    return Response.ok(jsonEncode({'entries': entries}));
+  });
+
+  // Enable CORS
+  final handler = Pipeline().addMiddleware((innerHandler) {
+    return (request) async {
+      final response = await innerHandler(request);
+      return response.change(headers: {
+        'Access-Control-Allow-Origin': '*',
+        'Access-Control-Allow-Methods': 'GET, POST, OPTIONS',
+        'Access-Control-Allow-Headers': 'Origin, Content-Type',
+      });
+    };
+  }).addHandler(app);
+
+  final server = await io.serve(handler, InternetAddress.anyIPv4, port);
+  print('Server running on localhost:${server.port}');
+}