import 'dart:async';

import 'package:auto_route/auto_route.dart';
import 'package:dartz/dartz.dart' hide State;
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:flutter_spinkit/flutter_spinkit.dart';

import '../../../application/auth/auth_bloc.dart';
import '../../../application/pin/pin_setup_form/pin_setup_form_bloc.dart';
import '../../../common/theme/theme.dart';
import '../../../domain/wallet/wallet.dart';
import '../../../injection.dart';
import '../../components/button/button.dart';
import '../../components/toast/flushbar.dart';
import '../wallet/wallet_ui.dart';
import 'pin_rules.dart';
import 'widgets/pin_code_field.dart';

enum _Step { otp, pin, confirm, done }

/// Buat PIN (§6.2) atau lupa PIN (§6.4). Pop dengan `true` bila berhasil.
@RoutePage()
class PinSetupPage extends StatefulWidget implements AutoRouteWrapper {
  const PinSetupPage({super.key, required this.purpose});

  final PinOtpPurpose purpose;

  @override
  State<PinSetupPage> createState() => _PinSetupPageState();

  @override
  Widget wrappedRoute(BuildContext context) => BlocProvider(
    create: (_) =>
        getIt<PinSetupFormBloc>()..add(PinSetupFormEvent.otpRequested(purpose)),
    child: this,
  );
}

class _PinSetupPageState extends State<PinSetupPage> {
  final TextEditingController _otpController = TextEditingController();
  final TextEditingController _pinController = TextEditingController();

  _Step _step = _Step.otp;
  String _otpCode = '';
  String _pin = '';
  String? _errorText;
  Timer? _ticker;

  bool get _isReset => widget.purpose == PinOtpPurpose.reset;

  @override
  void initState() {
    super.initState();
    _ticker = Timer.periodic(const Duration(seconds: 1), (_) {
      if (mounted) setState(() {});
    });
  }

  @override
  void dispose() {
    _ticker?.cancel();
    _otpController.dispose();
    _pinController.dispose();
    _pin = '';
    super.dispose();
  }

  void _goTo(_Step step, {String? error}) {
    setState(() {
      _step = step;
      _errorText = error;
    });
    _pinController.clear();
  }

  void _onOtpCompleted(String code) {
    _otpCode = code;
    _goTo(_Step.pin);
  }

  void _onPinCompleted(String value) {
    if (_step == _Step.pin) {
      final error = validateNewPin(
        value,
        birthDate: context.read<AuthBloc>().state.user.birthDate,
      );
      if (error != null) {
        _goTo(_Step.pin, error: error);
        return;
      }
      _pin = value;
      _goTo(_Step.confirm);
      return;
    }

    if (value != _pin) {
      _pin = '';
      _goTo(_Step.pin, error: 'PIN tidak sama. Silakan ulangi.');
      return;
    }

    context.read<PinSetupFormBloc>().add(
      PinSetupFormEvent.submitted(
        otpCode: _otpCode,
        pin: _pin,
        confirmPin: value,
      ),
    );
    _pinController.clear();
  }

  void _onSubmitResult(Either<WalletFailure, Unit> either) {
    either.fold(
      (f) {
        _pin = '';
        f.maybeMap(
          rejected: (_) {
            _otpController.clear();
            _goTo(
              _Step.otp,
              error:
                  'Kode OTP salah atau sudah kedaluwarsa, atau PIN tidak '
                  'memenuhi syarat. Silakan ulangi.',
            );
          },
          orElse: () {
            _goTo(_Step.pin);
            AppFlushbar.showError(context, walletFailureMessage(f));
          },
        );
      },
      (_) {
        _pin = '';
        _goTo(_Step.done);
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return BlocConsumer<PinSetupFormBloc, PinSetupFormState>(
      listenWhen: (p, c) =>
          p.failureOrSuccessOption != c.failureOrSuccessOption ||
          p.otpFailureOption != c.otpFailureOption,
      listener: (context, state) {
        state.failureOrSuccessOption.fold(() {}, _onSubmitResult);
        state.otpFailureOption.fold(() {}, (f) {
          final isRateLimited = f.maybeMap(
            tooManyRequests: (_) => true,
            orElse: () => false,
          );
          if (!isRateLimited) {
            AppFlushbar.showError(context, walletFailureMessage(f));
          }
        });
      },
      builder: (context, state) {
        return PopScope(
          canPop: _step != _Step.done,
          onPopInvokedWithResult: (didPop, _) {
            if (!didPop && _step == _Step.done) Navigator.of(context).pop(true);
          },
          child: Scaffold(
            appBar: AppBar(title: Text(_isReset ? 'Lupa PIN' : 'Buat PIN')),
            body: SafeArea(
              child: Padding(
                padding: const EdgeInsets.all(20),
                child: _step == _Step.done ? _buildDone() : _buildForm(state),
              ),
            ),
          ),
        );
      },
    );
  }

  Widget _buildForm(PinSetupFormState state) {
    final isOtp = _step == _Step.otp;

    final title = switch (_step) {
      _Step.otp => 'Masukkan kode verifikasi',
      _Step.pin => _isReset ? 'Buat PIN baru' : 'Buat PIN',
      _Step.confirm => 'Konfirmasi PIN',
      _Step.done => '',
    };

    final description = switch (_step) {
      _Step.otp =>
        'Kami mengirim kode 6 digit ke WhatsApp nomor kamu yang terdaftar.',
      _Step.pin =>
        'PIN 6 digit dipakai untuk membuat kode bayar, tukar EnakCoin, dan '
            'transfer. PIN berbeda dengan password login.',
      _Step.confirm => 'Masukkan kembali PIN yang sama.',
      _Step.done => '',
    };

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        _buildStepIndicator(),
        const SizedBox(height: 20),
        Text(title, style: AppStyle.xl.copyWith(fontWeight: FontWeight.w700)),
        const SizedBox(height: 8),
        Text(
          description,
          style: AppStyle.md.copyWith(color: AppColor.textSecondary),
        ),
        const SizedBox(height: 28),
        if (isOtp && state.otp == null)
          Center(
            child: state.isRequestingOtp
                ? const SpinKitFadingCircle(color: AppColor.primary, size: 32)
                : AppOutlineButton(
                    title: 'Kirim kode',
                    onPressed: _canResend(state) ? _requestOtp : null,
                  ),
          )
        else
          PinCodeField(
            key: ValueKey(_step),
            controller: isOtp ? _otpController : _pinController,
            obscure: !isOtp,
            enabled: !state.isSubmitting,
            hasError: _errorText != null,
            onCompleted: isOtp ? _onOtpCompleted : _onPinCompleted,
          ),
        const SizedBox(height: 16),
        if (state.isSubmitting)
          const Center(
            child: SpinKitFadingCircle(color: AppColor.primary, size: 28),
          )
        else if (_errorText != null)
          Text(
            _errorText!,
            style: AppStyle.md.copyWith(
              color: AppColor.error,
              fontWeight: FontWeight.w600,
            ),
          ),
        if (isOtp && state.otp != null) ...[
          const SizedBox(height: 16),
          _buildResend(state),
        ],
      ],
    );
  }

  bool _canResend(PinSetupFormState state) =>
      !state.isRequestingOtp &&
      (state.resendAvailableAt == null ||
          DateTime.now().isAfter(state.resendAvailableAt!));

  void _requestOtp() {
    _otpController.clear();
    setState(() => _errorText = null);
    context.read<PinSetupFormBloc>().add(
      PinSetupFormEvent.otpRequested(widget.purpose),
    );
  }

  Widget _buildResend(PinSetupFormState state) {
    final availableAt = state.resendAvailableAt;
    if (availableAt != null && DateTime.now().isBefore(availableAt)) {
      return Center(
        child: Text(
          'Kirim ulang kode dalam '
          '${formatCountdown(availableAt.difference(DateTime.now()))}',
          style: AppStyle.sm.copyWith(color: AppColor.textSecondary),
        ),
      );
    }

    return Center(
      child: TextButton(
        onPressed: _canResend(state) ? _requestOtp : null,
        child: Text(
          state.isRequestingOtp ? 'Mengirim...' : 'Kirim ulang kode',
          style: AppStyle.md.copyWith(
            color: AppColor.success,
            fontWeight: FontWeight.w600,
          ),
        ),
      ),
    );
  }

  Widget _buildStepIndicator() {
    final index = _Step.values.indexOf(_step);
    return Row(
      children: List.generate(3, (i) {
        return Expanded(
          child: Container(
            height: 4,
            margin: EdgeInsets.only(right: i == 2 ? 0 : 6),
            decoration: BoxDecoration(
              color: i <= index ? AppColor.primary : AppColor.border,
              borderRadius: BorderRadius.circular(2),
            ),
          ),
        );
      }),
    );
  }

  Widget _buildDone() {
    return Column(
      children: [
        const Spacer(),
        const Icon(Icons.verified_user, color: AppColor.success, size: 72),
        const SizedBox(height: 16),
        Text(
          _isReset ? 'PIN berhasil direset' : 'PIN berhasil dibuat',
          style: AppStyle.xl.copyWith(fontWeight: FontWeight.w700),
          textAlign: TextAlign.center,
        ),
        const SizedBox(height: 8),
        Text(
          _isReset
              ? 'Demi keamanan, transfer keluar ditahan selama 24 jam. '
                    'Kode bayar dan tukar EnakCoin tetap bisa dipakai.'
              : 'Gunakan PIN ini untuk membuat kode bayar, tukar EnakCoin, '
                    'dan transfer. Jangan beritahu PIN kepada siapa pun.',
          style: AppStyle.md.copyWith(color: AppColor.textSecondary),
          textAlign: TextAlign.center,
        ),
        const Spacer(),
        AppElevatedButton(
          title: 'Selesai',
          onPressed: () => Navigator.of(context).pop(true),
        ),
      ],
    );
  }
}