import 'dart:async';
import 'package:flutter/material.dart';
import 'package:pin_code_fields/pin_code_fields.dart';
import 'package:supabase_flutter/supabase_flutter.dart';

class OtpScreen extends StatefulWidget {
  final String email;
  final String userId;

  const OtpScreen({
    super.key,
    required this.email,
    required this.userId,
  });

  @override
  State<OtpScreen> createState() => _OtpScreenState();
}

class _OtpScreenState extends State<OtpScreen> {
  final _otpController = TextEditingController();
  bool _isLoading = false;
  int _resendCooldown = 60;
  String _enteredOtp = '';
  late Timer _timer;
  final Color primaryColor = const Color(0xFF056839); // Dark Green from your branding

  @override
  void initState() {
    super.initState();
    _startCooldown();
    // Consider sending an initial OTP request here if not done prior to this screen
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (mounted) { // Ensure the widget is still mounted
        _showInitialOtpInfo();
      }
    });
  }

  void _showInitialOtpInfo() {
      _showSuccessSnackbar('Kode OTP telah dikirim ke email Anda untuk verifikasi akun.');
  }

  void _startCooldown() {
    _timer = Timer.periodic(const Duration(seconds: 1), (timer) {
      if (!mounted) {
        timer.cancel();
        return;
      }
      if (_resendCooldown > 0) {
        setState(() => _resendCooldown--);
      } else {
        timer.cancel();
      }
    });
  }

  Future<void> _verifyOtp(String otp) async {
    if (!mounted) return;
    setState(() => _isLoading = true);

    try {
      final cleanOtp = otp.trim();
      if (cleanOtp.length != 6) {
        _showErrorSnackbar('Kode OTP harus 6 digit.');
        return;
      }

      final AuthResponse res = await Supabase.instance.client.auth.verifyOTP(
        email: widget.email,
        token: cleanOtp,
        type: OtpType.signup,
      );

      if (res.session == null) {
        if (!mounted) return;
        _showErrorSnackbar('OTP tidak valid atau telah kedaluwarsa.');
        return;
      }

      if (!mounted) return;
      _showSuccessSnackbar('Selamat Datang di Aplikasi TaniSM4RT!');
      Navigator.of(context).pushNamedAndRemoveUntil(
        '/home', 
        (Route<dynamic> route) => false,
      );

    } catch (e) {
      String errorMessage = 'Verifikasi gagal. Silakan coba lagi.';
      if (e is AuthException) {
        if (e.statusCode == '403' || e.message.contains('Token has expired or is invalid')) {
          errorMessage = 'Kode OTP telah kedaluwarsa atau tidak valid. Silakan minta kode baru.';
        } else if (e.message.contains('Invalid OTP')) {
          errorMessage = 'Kode OTP tidak valid. Silakan coba lagi.';
        }
      } else {
         errorMessage = 'Verifikasi gagal karena kesalahan teknis. Mohon coba lagi nanti.';
      }
      _otpController.clear();
      setState(() => _enteredOtp = '');
      _showErrorSnackbar(errorMessage);
    } finally {
      if (mounted) setState(() => _isLoading = false);
    }
  }

 Future<void> _resendOtp() async {
    if (!mounted) return;
    setState(() {
      _resendCooldown = 60;
      _isLoading = true;
    });
    _startCooldown();

    try {
      // Resend OTP for email verification
      await Supabase.instance.client.auth.resend(
        type: OtpType.signup, 
        email: widget.email
      );
      _showSuccessSnackbar('Kode OTP baru telah dikirim. Silakan cek email Anda (termasuk folder spam).');
      _otpController.clear();
      setState(() => _enteredOtp = '');
    } catch (e) {
      String errorMessage = 'Gagal mengirim ulang OTP. Mohon coba lagi nanti.';
      if (e is AuthException) {
        errorMessage = 'Gagal mengirim ulang OTP. Periksa koneksi atau coba beberapa saat lagi.';
      } else {
        errorMessage = 'Gagal mengirim ulang OTP karena kesalahan teknis. Mohon coba lagi nanti.';
      }
      _showErrorSnackbar(errorMessage);
    } finally {
      if (mounted) setState(() => _isLoading = false);
    }
  }

  void _showErrorSnackbar(String message) {
    if (!mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(message, style: const TextStyle(color: Colors.white)),
        backgroundColor: Colors.redAccent,
        behavior: SnackBarBehavior.floating,
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(10)),
        duration: const Duration(seconds: 3),
      ),
    );
  }

  void _showSuccessSnackbar(String message) {
    if (!mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(message, style: const TextStyle(color: Colors.white)),
        backgroundColor: primaryColor, // Use primaryColor for success
        behavior: SnackBarBehavior.floating,
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(10)),
        duration: const Duration(seconds: 3),
      ),
    );
  }

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

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);

    return Scaffold(
      backgroundColor: Colors.grey[100],
      appBar: AppBar(
        title: const Text(
          'Verifikasi Akun',
           style: TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
        ),
        backgroundColor: primaryColor,
        elevation: 0,
        iconTheme: const IconThemeData(color: Colors.white),
      ),
      body: SingleChildScrollView(
        padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 32),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            Image.asset('assets/images/logo.png', height: 100),
            const SizedBox(height: 32),
            Text(
              'Verifikasi Email Anda',
              textAlign: TextAlign.center,
              style: theme.textTheme.headlineSmall?.copyWith(
                fontWeight: FontWeight.bold,
                color: Colors.black87,
              ),
            ),
            const SizedBox(height: 12),
            Text(
              'Kode verifikasi 6 digit telah dikirim ke email Anda:',
              textAlign: TextAlign.center,
              style: theme.textTheme.bodyMedium?.copyWith(color: Colors.black54),
            ),
            const SizedBox(height: 8),
            Text(
              widget.email,
              textAlign: TextAlign.center,
              style: theme.textTheme.bodyLarge?.copyWith(
                color: primaryColor,
                fontWeight: FontWeight.bold,
              ),
            ),
            const SizedBox(height: 32),
            PinCodeTextField(
              appContext: context,
              length: 6,
              controller: _otpController,
              keyboardType: TextInputType.number,
              animationType: AnimationType.fade,
              pinTheme: PinTheme(
                shape: PinCodeFieldShape.box,
                borderRadius: BorderRadius.circular(12),
                fieldHeight: 50,
                fieldWidth: 45,
                activeFillColor: Colors.white,
                inactiveFillColor: Colors.white,
                selectedFillColor: Colors.white,
                activeColor: primaryColor,
                inactiveColor: Colors.grey.shade300,
                selectedColor: primaryColor,
                borderWidth: 1,
              ),
              enableActiveFill: true,
              onChanged: (value) {
                if (mounted) setState(() => _enteredOtp = value);
              },
              onCompleted: (otp) {
                if (mounted) {
                  setState(() => _enteredOtp = otp);
                  _verifyOtp(otp);
                }
              },
              beforeTextPaste: (text) => true, // Allow pasting
              autoDisposeControllers: false, // Important for manual controller management
            ),
            const SizedBox(height: 24),
            ElevatedButton(
              style: ElevatedButton.styleFrom(
                backgroundColor: primaryColor,
                padding: const EdgeInsets.symmetric(vertical: 16),
                shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
                elevation: 2,
              ),
              onPressed: _isLoading || _enteredOtp.length != 6 ? null : () => _verifyOtp(_enteredOtp),
              child: _isLoading
                  ? const SizedBox(height: 24, width: 24, child: CircularProgressIndicator(color: Colors.white, strokeWidth: 3))
                  : const Text('Verifikasi Kode', style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold, color: Colors.white)),
            ),
            const SizedBox(height: 16),
            TextButton(
              onPressed: _resendCooldown > 0 || _isLoading ? null : _resendOtp,
              child: Text(
                _resendCooldown > 0
                    ? 'Kirim ulang OTP dalam $_resendCooldown detik'
                    : 'Kirim Ulang OTP',
                style: TextStyle(color: _resendCooldown > 0 ? Colors.grey : primaryColor, fontWeight: FontWeight.bold),
              ),
            ),
          ],
        ),
      ),
    );
  }
}