import 'dart:async';
import 'dart:io';
import 'dart:math' as math;

import 'package:camera/camera.dart';
import 'package:flutter/material.dart';

import '../../core/error/exceptions.dart';
import 'package:local_auth/local_auth.dart';

class OvalCameraCapturePage extends StatefulWidget {
  final bool isLogin;
  final Future<void> Function(File image, {required bool localAuth}) onCapture;

  const OvalCameraCapturePage({
    super.key,
    this.isLogin = true,
    required this.onCapture,
  });

  @override
  State<OvalCameraCapturePage> createState() => _OvalCameraCapturePageState();
}

class _OvalCameraCapturePageState extends State<OvalCameraCapturePage> {
  CameraController? _cameraController;

  bool _isCameraInitialized = false;
  String? _errorMessage;

  bool _isSuccess = false;
  bool _isSubmitting = false;

  // Timer countdown
  int _countdown = 3;
  Timer? _countdownTimer;
  bool _countdownStarted = false;

  // Local auth for 422
  final LocalAuthentication _localAuth = LocalAuthentication();
  bool _handlingAuth422 = false;
  File? _lastCapturedFile;

  @override
  void initState() {
    super.initState();
    _initializeCamera();
  }

  @override
  void dispose() {
    _countdownTimer?.cancel();
    _cameraController?.dispose();
    super.dispose();
  }

  Future<void> _initializeCamera() async {
    try {
      setState(() {
        _errorMessage = null;
        _isCameraInitialized = false;
        _isSuccess = false;
        _isSubmitting = false;
        _countdown = 3;
        _countdownStarted = false;
      });

      await _cameraController?.dispose();
      _cameraController = null;

      final cameras = await availableCameras();
      if (cameras.isEmpty) {
        if (!mounted) return;
        setState(() {
          _errorMessage = "لا توجد كاميرات متاحة على هذا الجهاز";
          _isCameraInitialized = false;
        });
        return;
      }

      final front = cameras.where(
        (c) => c.lensDirection == CameraLensDirection.front,
      );
      final selectedCamera = front.isNotEmpty ? front.first : cameras.first;

      _cameraController = CameraController(
        selectedCamera,
        ResolutionPreset.medium,
        enableAudio: false,
      );

      await _cameraController!.initialize();

      if (!mounted) return;

      setState(() {
        _isCameraInitialized = true;
      });

      _startCountdown();
    } catch (e) {
      if (!mounted) return;
      setState(() {
        _errorMessage = "خطأ في تهيئة الكاميرا: $e";
        _isCameraInitialized = false;
      });
    }
  }

  void _startCountdown() {
    if (_countdownStarted) return;
    _countdownStarted = true;
    _countdown = 3;

    _countdownTimer = Timer.periodic(const Duration(seconds: 1), (timer) {
      if (!mounted) {
        timer.cancel();
        return;
      }

      setState(() {
        _countdown--;
      });

      if (_countdown <= 0) {
        timer.cancel();
        _captureAndSubmit();
      }
    });
  }

  Future<bool?> _showLocalAuthDialog() {
    return showDialog<bool>(
      context: context,
      barrierDismissible: false,
      builder: (_) => AlertDialog(
        title: const Text('فشل التحقق بالوجه', textAlign: TextAlign.center),
        content: const Text(
          'لم يتم التعرف على الوجه.\n\nيرجى استخدام بصمة الإصبع أو رمز القفل (PIN/النمط) للمتابعة.',
          textAlign: TextAlign.center,
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, false),
            child: const Text('إلغاء'),
          ),
          ElevatedButton(
            onPressed: () => Navigator.pop(context, true),
            child: const Text('استخدام البصمة / رمز القفل'),
          ),
        ],
      ),
    );
  }

  Future<bool> _authenticateLocally() async {
    try {
      final isSupported = await _localAuth.isDeviceSupported();
      if (!isSupported) return false;

      return await _localAuth.authenticate(
        localizedReason: 'تأكيد هويتك لإكمال تسجيل الحضور.',
        options: const AuthenticationOptions(
          biometricOnly: false,
          stickyAuth: true,
          useErrorDialogs: true,
        ),
      );
    } catch (_) {
      return false;
    }
  }

  void _stopCameraCompletely() {
    _countdownTimer?.cancel();
    try {
      _cameraController?.dispose();
      _cameraController = null;
    } catch (e) {
      debugPrint("Error stopping camera: $e");
    }
  }

  Future<void> _captureAndSubmit() async {
    if (_cameraController == null) return;
    if (_isSubmitting || _isSuccess) return;

    setState(() {
      _isSubmitting = true;
      _errorMessage = null;
    });

    try {
      if (_cameraController == null ||
          !_cameraController!.value.isInitialized) {
        _handleScanError("الكاميرا غير جاهزة، حاول مرة أخرى");
        return;
      }

      final xFile = await _cameraController!.takePicture();
      final file = File(xFile.path);

      _lastCapturedFile = file;

      await widget.onCapture(file, localAuth: false);

      if (mounted) {
        setState(() {
          _isSuccess = true;
          _isSubmitting = false;
        });

        Future.delayed(const Duration(seconds: 1), () {
          if (mounted) {
            Navigator.of(context).pop(true);
          }
        });
      }
    } on ServerException catch (e) {
      final msg = e.message.toLowerCase();
      if (e.statusCode == 422 || msg.contains('face verification failed')) {
        await _handleFaceVerificationFailed422(e);
        return;
      }

      if (msg.contains('already logged in') ||
          msg.contains('مسجل دخول بالفعل')) {
        _stopCameraCompletely();
        if (mounted) {
          showDialog(
            context: context,
            barrierDismissible: false,
            builder: (_) => AlertDialog(
              title: const Text('تنبيه', textAlign: TextAlign.center),
              content: const Text(
                'أنت مسجل دخول بالفعل، لا يمكنك تسجيل الدخول مرة أخرى.',
                textAlign: TextAlign.center,
              ),
              actions: [
                TextButton(
                  onPressed: () {
                    Navigator.of(context).pop();
                    Navigator.of(context).pop();
                  },
                  child: const Text('حسناً'),
                ),
              ],
            ),
          );
        }
        return;
      }
      _handleScanError(e.message);
    } on NetworkException catch (e) {
      _handleScanError(e.message);
    } on CameraException catch (e) {
      _handleScanError("فشل التقاط الصورة: ${e.description ?? e.code}");
    } catch (e) {
      _handleScanError("حدث خطأ غير متوقع: $e");
    }
  }

  void _handleScanError(String msg) {
    if (!mounted) return;
    setState(() {
      _isSubmitting = false;
      _errorMessage = msg;
      _countdown = 3;
      _countdownStarted = false;
    });

    // Restart countdown after error
    _startCountdown();
  }

  Future<void> _handleFaceVerificationFailed422(ServerException e) async {
    if (!mounted) return;
    if (_handlingAuth422) return;

    _handlingAuth422 = true;

    setState(() {
      _isSubmitting = false;
      _errorMessage = null;
    });

    final proceed = await _showLocalAuthDialog();
    if (proceed != true) {
      _handlingAuth422 = false;
      _stopCameraCompletely();
      if (!mounted) return;
      Navigator.of(context).pop(false);
      return;
    }

    final ok = await _authenticateLocally();
    if (!ok) {
      _handlingAuth422 = false;
      _stopCameraCompletely();
      if (!mounted) return;
      Navigator.of(context).pop("local_auth_failed");
      return;
    }

    final file = _lastCapturedFile;
    if (file == null) {
      _handlingAuth422 = false;
      _stopCameraCompletely();
      if (!mounted) return;
      Navigator.of(context).pop("retry_missing_file");
      return;
    }

    setState(() {
      _isSubmitting = true;
    });

    try {
      await widget.onCapture(file, localAuth: true);

      if (!mounted) return;
      setState(() {
        _isSuccess = true;
        _isSubmitting = false;
      });

      Future.delayed(const Duration(seconds: 1), () {
        if (mounted) Navigator.of(context).pop(true);
      });
    } on ServerException catch (_) {
      _handlingAuth422 = false;
      _stopCameraCompletely();
      if (!mounted) return;
      Navigator.of(context).pop("retry_failed");
    } catch (_) {
      _handlingAuth422 = false;
      _stopCameraCompletely();
      if (!mounted) return;
      Navigator.of(context).pop("retry_failed");
    }
  }

  @override
  Widget build(BuildContext context) {
    if (_errorMessage != null && !_isCameraInitialized) {
      return Scaffold(
        backgroundColor: Colors.black,
        body: Center(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              const Icon(Icons.error, color: Colors.red, size: 48),
              const SizedBox(height: 16),
              Text(_errorMessage!, style: const TextStyle(color: Colors.white)),
              const SizedBox(height: 16),
              ElevatedButton(
                onPressed: _initializeCamera,
                child: const Text("إعادة المحاولة"),
              ),
            ],
          ),
        ),
      );
    }

    if (!_isCameraInitialized || _cameraController == null) {
      return const Scaffold(
        backgroundColor: Colors.black,
        body: Center(child: CircularProgressIndicator(color: Colors.red)),
      );
    }

    return Scaffold(
      backgroundColor: Colors.black,
      body: Stack(
        fit: StackFit.expand,
        children: [
          Center(child: CameraPreview(_cameraController!)),
          CustomPaint(
            painter: _OvalOverlayPainter(
              borderColor: _isSuccess
                  ? Colors.greenAccent
                  : (_countdown <= 1 ? Colors.orangeAccent : Colors.white70),
              progress: _countdownStarted
                  ? ((3 - _countdown) / 3).clamp(0.0, 1.0)
                  : 0,
            ),
          ),
          Positioned(
            top: 60,
            left: 0,
            right: 0,
            child: Column(
              children: [
                Text(
                  widget.isLogin ? "تسجيل الدخول" : "تسجيل خروج",
                  style: const TextStyle(
                    color: Colors.white,
                    fontSize: 24,
                    fontWeight: FontWeight.bold,
                    fontFamily: 'Cairo',
                  ),
                ),
                const SizedBox(height: 10),
                Container(
                  padding: const EdgeInsets.symmetric(
                    horizontal: 16,
                    vertical: 8,
                  ),
                  decoration: BoxDecoration(
                    color: Colors.black54,
                    borderRadius: BorderRadius.circular(20),
                  ),
                  child: Text(
                    _isSubmitting
                        ? "جاري التحقق..."
                        : _isSuccess
                            ? "تم بنجاح"
                            : "التقاط الصورة خلال $_countdown ثانية",
                    style: TextStyle(
                      color: _isSuccess ? Colors.greenAccent : Colors.white,
                      fontSize: 16,
                      fontWeight: FontWeight.w600,
                    ),
                  ),
                ),
              ],
            ),
          ),
          // Countdown number in center
          if (!_isSubmitting && !_isSuccess && _countdown > 0)
            Center(
              child: Text(
                '$_countdown',
                style: TextStyle(
                  color: Colors.white.withOpacity(0.7),
                  fontSize: 80,
                  fontWeight: FontWeight.bold,
                ),
              ),
            ),
          if (_isSubmitting)
            const Center(child: CircularProgressIndicator(color: Colors.white)),
          if (_isSuccess)
            const Center(
              child: Icon(Icons.check_circle, color: Colors.green, size: 80),
            ),
          if (_errorMessage != null && _isCameraInitialized)
            Positioned(
              bottom: 20,
              left: 0,
              right: 0,
              child: Container(
                color: Colors.black54,
                padding: const EdgeInsets.all(8),
                child: Text(
                  _errorMessage!,
                  style: const TextStyle(color: Colors.red),
                  textAlign: TextAlign.center,
                ),
              ),
            ),
        ],
      ),
    );
  }
}

class _OvalOverlayPainter extends CustomPainter {
  final Color borderColor;
  final double progress;

  _OvalOverlayPainter({required this.borderColor, required this.progress});

  @override
  void paint(Canvas canvas, Size size) {
    final width = size.width * 0.75;
    final height = size.height * 0.55;
    final center = Offset(size.width / 2, size.height / 2);
    final ovalRect = Rect.fromCenter(
      center: center,
      width: width,
      height: height,
    );

    final screenPath =
        Path()..addRect(Rect.fromLTWH(0, 0, size.width, size.height));
    final ovalPath = Path()..addOval(ovalRect);
    final overlayPath = Path.combine(
      PathOperation.difference,
      screenPath,
      ovalPath,
    );

    final bgPaint = Paint()
      ..color = Colors.black.withOpacity(0.6)
      ..style = PaintingStyle.fill;

    canvas.drawPath(overlayPath, bgPaint);

    final borderPaint = Paint()
      ..color = borderColor
      ..style = PaintingStyle.stroke
      ..strokeWidth = 4.0;

    canvas.drawOval(ovalRect, borderPaint);

    if (progress > 0) {
      final progressPaint = Paint()
        ..color = Colors.greenAccent
        ..style = PaintingStyle.stroke
        ..strokeWidth = 6.0
        ..strokeCap = StrokeCap.round;

      final startAngle = -math.pi / 2;
      final sweepAngle = 2 * math.pi * progress;

      canvas.drawArc(
        ovalRect.inflate(10),
        startAngle,
        sweepAngle,
        false,
        progressPaint,
      );
    }
  }

  @override
  bool shouldRepaint(covariant _OvalOverlayPainter oldDelegate) {
    return oldDelegate.borderColor != borderColor ||
        oldDelegate.progress != progress;
  }
}