import 'dart:async';
import 'package:flutter/material.dart';
import 'package:kmobile/api/services/auth_service.dart';
import 'package:kmobile/di/injection.dart';
import 'package:kmobile/features/auth/screens/sms_verification_helper.dart';

class VerificationScreen extends StatefulWidget {
  final String customerNo;
  final String password;

  const VerificationScreen({
    super.key,
    required this.customerNo,
    required this.password,
  });

  @override
  State<VerificationScreen> createState() => _VerificationScreenState();
}

class _VerificationScreenState extends State<VerificationScreen> {
  String _statusMessage = "Starting verification...";
  Timer? _timer;
  int _countdown = 120;
  bool _isVerifying = false;
  bool _verificationFailed = false;

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

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

  void _startTimer() {
    _timer?.cancel(); // Cancel any existing timer
    _countdown = 120;
    _timer = Timer.periodic(const Duration(seconds: 1), (timer) {
      if (_countdown > 0) {
        setState(() {
          _countdown--;
        });
      } else {
        _timer?.cancel();
        if (mounted) {
          setState(() {
            _statusMessage = "Verification timed out. Please try again.";
            _isVerifying = false;
            _verificationFailed = true;
          });
        }
      }
    });
  }

  Future<void> _startVerificationProcess() async {
    setState(() {
      _isVerifying = true;
      _verificationFailed = false;
      _statusMessage = "Starting verification...";
    });
    _startTimer();

    // 1. Send SMS
    setState(() {
      _statusMessage = "SMS sending...";
    });
    final smsHelper = SmsVerificationHelper();
    final uuid = await smsHelper.initiateSmsSequence(context: context);

    if (uuid != null && mounted) {
      // SMS sending was successful, now wait before verifying.
      setState(() {
        _statusMessage = "SMS sent. Waiting for network delivery...";
      });

      // Adding a 10-second delay to account for SMS network latency.
      await Future.delayed(const Duration(seconds: 10));

      if (!mounted) return;

      // 2. Verify SIM
      setState(() {
        _statusMessage = "Verifying with server...";
      });

      final authService = getIt<AuthService>();
      try {
        await authService.simVerify(uuid, widget.customerNo);

        setState(() {
          _statusMessage = "Verification successful!";
          _isVerifying = false;
        });
        _timer?.cancel();

        // Pop with success result
        Navigator.of(context).pop(true);
      } catch (e) {
        setState(() {
          _statusMessage = e.toString();
          _isVerifying = false;
          _verificationFailed = true;
        });
      }
    } else if (mounted) {
      setState(() {
        _statusMessage =
            "SMS sending failed. Please check permissions and try again.";
        _isVerifying = false;
        _verificationFailed = true;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text("Device Verification"),
        automaticallyImplyLeading: !_isVerifying,
      ),
      body: Center(
        child: Padding(
          padding: const EdgeInsets.all(24.0),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              if (_isVerifying) const CircularProgressIndicator(),
              if (!_isVerifying && _verificationFailed)
                const Icon(Icons.error_outline, color: Colors.red, size: 50),
              if (!_isVerifying && !_verificationFailed)
                const Icon(Icons.check_circle_outline,
                    color: Colors.green, size: 50),
              const SizedBox(height: 32),
              Text(
                _statusMessage,
                textAlign: TextAlign.center,
                style: const TextStyle(fontSize: 18),
              ),
              const SizedBox(height: 16),
              if (_isVerifying)
                Text(
                  "Time remaining: $_countdown seconds",
                  style: const TextStyle(fontSize: 16, color: Colors.grey),
                ),
              if (_verificationFailed && !_isVerifying) ...[
                const SizedBox(height: 20),
                ElevatedButton(
                  onPressed: _startVerificationProcess,
                  child: const Text('Retry'),
                ),
              ]
            ],
          ),
        ),
      ),
    );
  }
}