import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import '../../services/auth_service.dart';
import 'reset_password_screen.dart';

class VerifyResetOtpScreen extends StatefulWidget {
  final String email;

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

  @override
  State<VerifyResetOtpScreen> createState() => _VerifyResetOtpScreenState();
}

class _VerifyResetOtpScreenState extends State<VerifyResetOtpScreen> {
  final List<TextEditingController> controllers = List.generate(
    6,
    (_) => TextEditingController(),
  );

  final List<FocusNode> focusNodes = List.generate(6, (_) => FocusNode());

  bool isLoading = false;
  bool isResendLoading = false;

  int resendTimer = 60;
  Timer? timer;

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

  void startTimer() {
    resendTimer = 60;

    timer = Timer.periodic(const Duration(seconds: 1), (t) {
      if (resendTimer == 0) {
        t.cancel();
      } else {
        setState(() {
          resendTimer--;
        });
      }
    });
  }

  String getOtp() {
    return controllers.map((e) => e.text.trim()).join();
  }

  Future<void> verifyOtp() async {
    String otp = getOtp();

    if (otp.length != 6) {
      _showSnackBar("OTP harus 6 digit", Colors.orange);
      return;
    }

    setState(() => isLoading = true);

    final result = await AuthService.verifyResetOtp(
      email: widget.email,
      otp: otp,
    );

    setState(() => isLoading = false);

    if (!mounted) return;

    if (result['success']) {
      Navigator.push(
        context,
        MaterialPageRoute(
          builder: (_) => ResetPasswordScreen(email: widget.email, otp: otp),
        ),
      );
    } else {
      _showSnackBar(result['message'] ?? "OTP salah", Colors.red);
    }
  }

  void resendOtp() async {
    setState(() {
      isResendLoading = true;
    });

    final result = await AuthService.forgotPassword(widget.email);

    setState(() {
      isResendLoading = false;
    });

    if (!mounted) return;

    if (result['status'] == true) {
      _showSnackBar("OTP berhasil dikirim ulang", Colors.green);
      startTimer();
    } else {
      _showSnackBar(result['message'], Colors.red);
    }
  }

  void onOtpChanged(int index, String value) {
    /// jika user paste OTP (misal 123456)
    if (value.length > 1) {
      final otpChars = value.split('');

      for (int i = 0; i < otpChars.length && i < 6; i++) {
        controllers[i].text = otpChars[i];
      }

      focusNodes[5].requestFocus();

      if (otpChars.length == 6) {
        verifyOtp();
      }

      setState(() {});
      return;
    }

    /// jika mengetik angka → pindah ke kotak berikutnya
    if (value.isNotEmpty) {
      if (index < 5) {
        focusNodes[index + 1].requestFocus();
      }
    }

    /// jika menghapus → langsung pindah ke kotak sebelumnya
    if (value.isEmpty) {
      if (index > 0) {
        focusNodes[index - 1].requestFocus();
        controllers[index - 1].selection = TextSelection.fromPosition(
          TextPosition(offset: controllers[index - 1].text.length),
        );
      }
    }

    String otp = getOtp();

    if (otp.length == 6) {
      verifyOtp();
    }
  }

  Widget buildOtpBox(int index) {
    return SizedBox(
      width: 45,
      child: TextField(
        controller: controllers[index],
        focusNode: focusNodes[index],
        keyboardType: TextInputType.number,
        textAlign: TextAlign.center,
        maxLength: 1,
        autofillHints: const [AutofillHints.oneTimeCode],
        inputFormatters: [FilteringTextInputFormatter.digitsOnly],

        decoration: InputDecoration(
          counterText: "",
          border: OutlineInputBorder(borderRadius: BorderRadius.circular(12)),
        ),

        onChanged: (value) {
          onOtpChanged(index, value);
        },
      ),
    );
  }

  void _showSnackBar(String msg, Color color) {
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(msg),
        backgroundColor: color,
        behavior: SnackBarBehavior.floating,
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(10)),
      ),
    );
  }

  @override
  void dispose() {
    timer?.cancel();

    for (var c in controllers) {
      c.dispose();
    }

    for (var f in focusNodes) {
      f.dispose();
    }

    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: const Color(0xFFF5F7FA),

      body: SafeArea(
        child: Center(
          child: SingleChildScrollView(
            padding: const EdgeInsets.all(24),

            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                Image.asset('assets/images/logopolije.png', height: 100),

                const SizedBox(height: 16),

                const Text(
                  "Verifikasi OTP",
                  style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
                ),

                const Text(
                  "Masukkan kode OTP untuk reset password",
                  style: TextStyle(color: Colors.grey),
                  textAlign: TextAlign.center,
                ),

                const SizedBox(height: 30),

                Container(
                  padding: const EdgeInsets.all(20),

                  decoration: BoxDecoration(
                    color: Colors.white,
                    borderRadius: BorderRadius.circular(20),

                    boxShadow: [
                      BoxShadow(
                        color: Colors.black.withOpacity(0.05),
                        blurRadius: 20,
                        offset: const Offset(0, 10),
                      ),
                    ],
                  ),

                  child: Column(
                    children: [
                      Row(
                        mainAxisAlignment: MainAxisAlignment.spaceBetween,
                        children: List.generate(6, buildOtpBox),
                      ),

                      const SizedBox(height: 25),

                      SizedBox(
                        width: double.infinity,
                        height: 55,

                        child: ElevatedButton(
                          onPressed: isLoading ? null : verifyOtp,

                          style: ElevatedButton.styleFrom(
                            backgroundColor: const Color(0xFF2F5BEA),

                            shape: RoundedRectangleBorder(
                              borderRadius: BorderRadius.circular(12),
                            ),
                          ),

                          child:
                              isLoading
                                  ? const CircularProgressIndicator(
                                    color: Colors.white,
                                  )
                                  : const Text(
                                    "Verifikasi OTP",
                                    style: TextStyle(
                                      fontWeight: FontWeight.bold,
                                      color: Colors.white,
                                    ),
                                  ),
                        ),
                      ),
                    ],
                  ),
                ),

                const SizedBox(height: 25),

                resendTimer > 0
                    ? Text(
                      "Kirim ulang OTP dalam $resendTimer detik",
                      style: const TextStyle(color: Colors.grey),
                    )
                    : isResendLoading
                    ? const Padding(
                      padding: EdgeInsets.all(8.0),
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                    : GestureDetector(
                      onTap: resendOtp,
                      child: const Text(
                        "Kirim ulang OTP",
                        style: TextStyle(
                          color: Color(0xFF2F5BEA),
                          fontWeight: FontWeight.bold,
                        ),
                      ),
                    ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}