import 'dart:convert';
import 'package:flutter_test/flutter_test.dart';
import 'package:http/http.dart' as http;
import 'package:http/testing.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:siro_maps/core/services/device_fingerprint_service.dart';
import 'package:siro_maps/core/services/telemetry_tracking_service.dart';
import 'package:siro_maps/data/repositories/map_saas_repository.dart';

void main() {
  TestWidgetsFlutterBinding.ensureInitialized();

  late TelemetryTrackingService telemetryService;

  setUp(() {
    SharedPreferences.setMockInitialValues({});
    telemetryService = TelemetryTrackingService.instance;
    telemetryService.resetForTesting();
    DeviceFingerprintService.instance.setMockState(
      fingerprint: 'siro_test_hw_unit_test_device_123',
    );
  });

  group('TelemetryTrackingService Sampling & Stationary Filter Tests', () {
    test('Samples position only if at least 3 seconds have passed', () {
      final baseTime = DateTime(2026, 9, 15, 12, 0, 0);

      // First point at T=0
      final p1 = telemetryService.recordPosition(
        latitude: 31.9539,
        longitude: 35.9106,
        speedKmH: 45.0,
        heading: 90.0,
        now: baseTime,
      );
      expect(p1, isTrue);
      expect(telemetryService.bufferedPointCount, equals(1));

      // Attempt second point after only 1 second (T=1s) -> Should be rejected
      final p2 = telemetryService.recordPosition(
        latitude: 31.9540,
        longitude: 35.9107,
        speedKmH: 46.0,
        heading: 90.0,
        now: baseTime.add(const Duration(seconds: 1)),
      );
      expect(p2, isFalse);
      expect(telemetryService.bufferedPointCount, equals(1));

      // Attempt third point after 3 seconds (T=3s) -> Should be accepted
      final p3 = telemetryService.recordPosition(
        latitude: 31.9545,
        longitude: 35.9110,
        speedKmH: 48.0,
        heading: 92.0,
        now: baseTime.add(const Duration(seconds: 3)),
      );
      expect(p3, isTrue);
      expect(telemetryService.bufferedPointCount, equals(2));
    });

    test('Smart stationary filter suppresses redundant points when vehicle is stopped', () {
      final baseTime = DateTime(2026, 9, 15, 12, 0, 0);

      // Stop at intersection: initial point (speed = 0)
      final initial = telemetryService.recordPosition(
        latitude: 31.9500,
        longitude: 35.9100,
        speedKmH: 0.0,
        heading: 0.0,
        now: baseTime,
      );
      expect(initial, isTrue);
      expect(telemetryService.bufferedPointCount, equals(1));

      // After 5 seconds: still at same spot (speed = 0, distance = 0) -> filter out
      final duplicateAfter5s = telemetryService.recordPosition(
        latitude: 31.9500,
        longitude: 35.9100,
        speedKmH: 0.0,
        heading: 0.0,
        now: baseTime.add(const Duration(seconds: 5)),
      );
      expect(duplicateAfter5s, isFalse);
      expect(telemetryService.bufferedPointCount, equals(1));

      // After 35 seconds: still at same spot -> 30s heartbeat triggers!
      final heartbeatAfter35s = telemetryService.recordPosition(
        latitude: 31.9500,
        longitude: 35.9100,
        speedKmH: 0.0,
        heading: 0.0,
        now: baseTime.add(const Duration(seconds: 35)),
      );
      expect(heartbeatAfter35s, isTrue);
      expect(telemetryService.bufferedPointCount, equals(2));
    });
  });

  group('Telemetry Batch Upload & Offline Buffer Tests', () {
    test('Flushes batched telemetry to server in a single request', () async {
      List<dynamic> receivedPayloadPoints = [];

      final mockClient = MockClient((request) async {
        if (request.url.path.contains('/api/telemetry/batch')) {
          final body = jsonDecode(request.body) as Map<String, dynamic>;
          receivedPayloadPoints = body['points'] as List<dynamic>;
          return http.Response(jsonEncode({'success': true, 'count': receivedPayloadPoints.length}), 201);
        }
        return http.Response('Not Found', 404);
      });

      final mockRepo = MapSaasRepository(client: mockClient);

      // Record 3 points spaced by 3 seconds
      final baseTime = DateTime(2026, 9, 15, 12, 0, 0);
      telemetryService.recordPosition(
        latitude: 31.951,
        longitude: 35.911,
        speedKmH: 30,
        heading: 45,
        now: baseTime,
      );
      telemetryService.recordPosition(
        latitude: 31.952,
        longitude: 35.912,
        speedKmH: 35,
        heading: 45,
        now: baseTime.add(const Duration(seconds: 3)),
      );
      telemetryService.recordPosition(
        latitude: 31.953,
        longitude: 35.913,
        speedKmH: 40,
        heading: 50,
        now: baseTime.add(const Duration(seconds: 6)),
      );

      expect(telemetryService.bufferedPointCount, equals(3));

      // Flush buffer to backend
      final success = await telemetryService.flush(repository: mockRepo);
      expect(success, isTrue);
      expect(receivedPayloadPoints.length, equals(3));
      // Buffer should be empty after successful flush
      expect(telemetryService.bufferedPointCount, equals(0));
    });

    test('Retains points in offline buffer if batch upload encounters error', () async {
      final offlineClient = MockClient((request) async {
        return http.Response('Gateway Timeout', 504);
      });

      final mockRepo = MapSaasRepository(client: offlineClient);

      telemetryService.recordPosition(
        latitude: 31.951,
        longitude: 35.911,
        speedKmH: 20,
        heading: 10,
        now: DateTime(2026, 9, 15, 12, 0, 0),
      );

      expect(telemetryService.bufferedPointCount, equals(1));

      final success = await telemetryService.flush(repository: mockRepo);
      expect(success, isFalse);
      // Points must still be retained for next attempt
      expect(telemetryService.bufferedPointCount, equals(1));
    });
  });

  group('10-Day Periodic Updates & Maintenance Tests', () {
    test('Skips update if less than 10 days since last check', () async {
      final now = DateTime(2026, 9, 15, 12, 0, 0);
      final lastCheck = now.subtract(const Duration(days: 4)); // Only 4 days ago

      SharedPreferences.setMockInitialValues({
        TelemetryTrackingService.prefKeyLastPeriodicCheck: lastCheck.millisecondsSinceEpoch,
      });

      final prefs = await SharedPreferences.getInstance();
      final executed = await telemetryService.checkPeriodicUpdates(
        now: now,
        mockPrefs: prefs,
      );

      expect(executed, isFalse);
    });

    test('Executes maintenance cycle if 10 or more days elapsed', () async {
      final now = DateTime(2026, 9, 15, 12, 0, 0);
      final lastCheck = now.subtract(const Duration(days: 12)); // 12 days ago

      SharedPreferences.setMockInitialValues({
        TelemetryTrackingService.prefKeyLastPeriodicCheck: lastCheck.millisecondsSinceEpoch,
      });

      final prefs = await SharedPreferences.getInstance();
      final executed = await telemetryService.checkPeriodicUpdates(
        now: now,
        mockPrefs: prefs,
      );

      expect(executed, isTrue);
      final updatedTimestamp = prefs.getInt(TelemetryTrackingService.prefKeyLastPeriodicCheck);
      expect(updatedTimestamp, equals(now.millisecondsSinceEpoch));
    });
  });
}