import 'dart:async';

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

import '../../../application/wallet/exchange_form/exchange_form_bloc.dart';
import '../../../application/wallet/wallet_history_loader/wallet_history_loader_bloc.dart';
import '../../../application/wallet/wallet_loader/wallet_loader_bloc.dart';
import '../../../common/extension/extension.dart';
import '../../../common/function/app_function.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 '../pin/pin_guard.dart';
import '../pin/widgets/pin_sheet.dart';
import 'wallet_ui.dart';
import 'widgets/wallet_confirm_dialog.dart';
import 'widgets/wallet_history_section.dart';
import 'widgets/wallet_result_view.dart';

/// Tukar EnakCoin → EnakPoint (§8.1).
@RoutePage()
class ExchangePage extends StatefulWidget implements AutoRouteWrapper {
  const ExchangePage({super.key});

  @override
  State<ExchangePage> createState() => _ExchangePageState();

  @override
  Widget wrappedRoute(BuildContext context) => MultiBlocProvider(
    providers: [
      BlocProvider(create: (_) => getIt<ExchangeFormBloc>()),
      // Riwayat dilihat dari sisi EnakPoint: berapa poin yang didapat.
      BlocProvider(
        create: (_) => getIt<WalletHistoryLoaderBloc>()
          ..add(
            const WalletHistoryLoaderEvent.filterChanged(
              types: [WalletTransactionType.exchangeIn],
            ),
          ),
      ),
    ],
    child: this,
  );
}

class _ExchangePageState extends State<ExchangePage> {
  final TextEditingController _coinsController = TextEditingController();
  final ScrollController _scrollController = ScrollController();
  Timer? _debounce;

  /// Kurs terakhir yang diketahui, tetap ditampilkan selama preview baru
  /// sedang dihitung.
  ExchangePreview? _rate;

  @override
  void initState() {
    super.initState();
    context.read<WalletLoaderBloc>().add(const WalletLoaderEvent.fetched());
    _scrollController.addListener(_onScroll);
  }

  @override
  void dispose() {
    _debounce?.cancel();
    _coinsController.dispose();
    _scrollController.dispose();
    super.dispose();
  }

  void _onScroll() {
    final position = _scrollController.position;
    if (position.pixels >= position.maxScrollExtent - 200) {
      context.read<WalletHistoryLoaderBloc>().add(
        const WalletHistoryLoaderEvent.loadedMore(),
      );
    }
  }

  Future<void> _onRefresh() async {
    context.read<WalletLoaderBloc>().add(const WalletLoaderEvent.fetched());
    final history = context.read<WalletHistoryLoaderBloc>();
    history.add(const WalletHistoryLoaderEvent.refreshed());
    await history.stream.firstWhere((s) => !s.isFetching);
  }

  void _onCoinsChanged(String value) {
    _debounce?.cancel();
    _debounce = Timer(const Duration(milliseconds: 500), () {
      if (!mounted) return;
      context.read<ExchangeFormBloc>().add(
        ExchangeFormEvent.coinsChanged(int.tryParse(digitsOnly(value)) ?? 0),
      );
    });
  }

  /// Isi jumlah langsung tanpa debounce, mis. dari tombol "Tukar semua".
  void _fillCoins(int coins) {
    _debounce?.cancel();
    final text = coins.thousandFormat;
    _coinsController.value = TextEditingValue(
      text: text,
      selection: TextSelection.collapsed(offset: text.length),
    );
    context.read<ExchangeFormBloc>().add(ExchangeFormEvent.coinsChanged(coins));
  }

  /// Bulatkan ke bawah ke kelipatan kurs bila kursnya sudah diketahui.
  int _roundToRate(int coins) {
    final step = _rate?.coinAmount ?? 0;
    return step > 0 ? coins - coins % step : coins;
  }

  Future<void> _confirm(ExchangeFormState state) async {
    dismissKeyboard(context);
    final preview = state.preview!;
    final confirmed = await showWalletConfirmDialog(
      context,
      title: 'Tukar EnakCoin?',
      message:
          'Tukar ${preview.coins.thousandFormat} EnakCoin menjadi '
          '${preview.points.thousandFormat} EnakPoint. Penukaran tidak bisa '
          'dibatalkan.',
      confirmLabel: 'Tukar',
    );
    if (!confirmed || !mounted) return;
    if (!await ensurePinReady(context) || !mounted) return;

    final success = await showPinSheet(
      context,
      title: 'Tukar EnakCoin',
      onSubmit: (pin) async {
        final bloc = context.read<ExchangeFormBloc>();
        bloc.add(ExchangeFormEvent.submitted(pin));
        final result = await bloc.stream.firstWhere((s) => !s.isSubmitting);
        return result.failureOption.toNullable();
      },
    );

    if (success && mounted) {
      context.read<WalletLoaderBloc>().add(const WalletLoaderEvent.fetched());
    }
  }

  void _showFailure(WalletFailure failure) {
    if (failure.isPinError) return;

    if (failure.isNetworkError) {
      AppFlushbar.showError(
        context,
        'Koneksi terputus, status penukaran belum diketahui. Tekan Tukar lagi '
        'untuk mengulang. Saldo tidak akan terpotong dua kali.',
      );
      return;
    }

    AppFlushbar.showError(
      context,
      walletFailureMessage(
        failure,
        rejectedMessage:
            'Penukaran tidak bisa diproses. Periksa jumlah dan saldo '
            'EnakCoin kamu.',
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return MultiBlocListener(
      listeners: [
        BlocListener<ExchangeFormBloc, ExchangeFormState>(
          listenWhen: (p, c) => p.failureOption != c.failureOption,
          listener: (context, state) =>
              state.failureOption.fold(() {}, _showFailure),
        ),
        BlocListener<ExchangeFormBloc, ExchangeFormState>(
          listenWhen: (p, c) => p.preview != c.preview && c.preview != null,
          listener: (context, state) => setState(() => _rate = state.preview),
        ),
      ],
      child: BlocBuilder<ExchangeFormBloc, ExchangeFormState>(
        builder: (context, state) {
          final result = state.result;
          return Scaffold(
            backgroundColor: AppColor.background,
            appBar: AppBar(title: const Text('Tukar EnakCoin')),
            body: AnimatedSwitcher(
              duration: const Duration(milliseconds: 300),
              child: result != null
                  ? KeyedSubtree(
                      key: const ValueKey('success'),
                      child: _buildSuccess(result),
                    )
                  : KeyedSubtree(
                      key: const ValueKey('form'),
                      child: _buildForm(state),
                    ),
            ),
          );
        },
      ),
    );
  }

  Widget _buildForm(ExchangeFormState state) {
    return RefreshIndicator(
      color: AppColor.primary,
      onRefresh: _onRefresh,
      child: CustomScrollView(
        controller: _scrollController,
        physics: const AlwaysScrollableScrollPhysics(),
        keyboardDismissBehavior: ScrollViewKeyboardDismissBehavior.onDrag,
        slivers: [
          SliverPadding(
            padding: const EdgeInsets.fromLTRB(16, 16, 16, 28),
            sliver: SliverToBoxAdapter(
              child: BlocBuilder<WalletLoaderBloc, WalletLoaderState>(
                buildWhen: (p, c) =>
                    p.summary != c.summary || p.hasLoaded != c.hasLoaded,
                builder: (context, walletState) =>
                    _buildFormContent(state, walletState),
              ),
            ),
          ),
          SliverPadding(
            padding: const EdgeInsets.fromLTRB(16, 0, 16, 32),
            sliver: WalletHistorySection(
              title: 'Riwayat penukaran',
              emptyIcon: Icons.currency_exchange_rounded,
              emptyTitle: 'Belum ada penukaran',
              emptySubtitle: (_) =>
                  'EnakPoint yang kamu dapat dari tukar EnakCoin akan '
                  'muncul di sini.',
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildFormContent(
    ExchangeFormState state,
    WalletLoaderState walletState,
  ) {
    final summary = walletState.summary;
    final coinBalance = summary.coinBalance;
    final exceedsBalance = walletState.hasLoaded && state.coins > coinBalance;
    final preview = state.preview;
    final points = preview != null && preview.valid && !exceedsBalance
        ? preview.points
        : 0;
    final maxCoins = _roundToRate(coinBalance);

    return Column(
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: [
        _ExchangeCard(
          label: 'Kamu tukar',
          currency: WalletCurrency.coin,
          trailing: Text(
            walletState.hasLoaded
                ? 'Saldo ${coinBalance.thousandFormat}'
                : 'Memuat saldo…',
            style: AppStyle.sm.copyWith(color: AppColor.textSecondary),
          ),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              TextField(
                controller: _coinsController,
                keyboardType: TextInputType.number,
                textInputAction: TextInputAction.done,
                enabled: !state.isSubmitting,
                cursorColor: AppColor.primary,
                inputFormatters: [ThousandsInputFormatter()],
                onChanged: _onCoinsChanged,
                style: AppStyle.h4.copyWith(fontWeight: FontWeight.w700),
                decoration: InputDecoration(
                  hintText: '0',
                  hintStyle: AppStyle.h4.copyWith(
                    color: AppColor.textLight,
                    fontWeight: FontWeight.w700,
                  ),
                  border: InputBorder.none,
                  enabledBorder: InputBorder.none,
                  focusedBorder: InputBorder.none,
                  disabledBorder: InputBorder.none,
                  isDense: true,
                  contentPadding: const EdgeInsets.symmetric(vertical: 8),
                ),
              ),
              Align(
                alignment: Alignment.centerLeft,
                child: _QuickChip(
                  label: 'Tukar semua',
                  onTap:
                      walletState.hasLoaded &&
                          maxCoins > 0 &&
                          !state.isSubmitting
                      ? () => _fillCoins(maxCoins)
                      : null,
                ),
              ),
            ],
          ),
        ),
        const SizedBox(height: 8),
        Stack(
          clipBehavior: Clip.none,
          children: [
            _ExchangeCard(
              label: 'Kamu dapat',
              currency: WalletCurrency.point,
              highlighted: points > 0,
              trailing: Text(
                walletState.hasLoaded
                    ? 'Saldo ${summary.pointBalance.thousandFormat}'
                    : '',
                style: AppStyle.sm.copyWith(color: AppColor.textSecondary),
              ),
              child: Padding(
                padding: const EdgeInsets.symmetric(vertical: 8),
                child: AnimatedOpacity(
                  duration: const Duration(milliseconds: 200),
                  opacity: state.isPreviewing ? 0.35 : 1,
                  child: TweenAnimationBuilder<int>(
                    tween: IntTween(begin: 0, end: points),
                    duration: const Duration(milliseconds: 450),
                    curve: Curves.easeOutCubic,
                    builder: (context, value, _) => Text(
                      value.thousandFormat,
                      style: AppStyle.h4.copyWith(
                        fontWeight: FontWeight.w700,
                        color: points > 0
                            ? AppColor.success
                            : AppColor.textLight,
                      ),
                    ),
                  ),
                ),
              ),
            ),
            const Positioned(
              top: -24,
              left: 0,
              right: 0,
              child: Center(child: _SwapBadge()),
            ),
          ],
        ),
        const SizedBox(height: 12),
        AnimatedSize(
          duration: const Duration(milliseconds: 200),
          curve: Curves.easeOut,
          alignment: Alignment.topCenter,
          child: AnimatedSwitcher(
            duration: const Duration(milliseconds: 200),
            child: _buildStatus(state, exceedsBalance),
          ),
        ),
        const SizedBox(height: 20),
        AppElevatedButton(
          title: 'Tukar',
          height: 48,
          isLoading: state.isSubmitting,
          onPressed: state.canSubmit && !exceedsBalance
              ? () => _confirm(state)
              : null,
        ),
      ],
    );
  }

  /// Satu baris keterangan di bawah kartu: kurs, proses hitung, atau error.
  Widget _buildStatus(ExchangeFormState state, bool exceedsBalance) {
    if (state.isPreviewing) {
      return const _StatusLine(
        key: ValueKey('previewing'),
        icon: SpinKitThreeBounce(color: AppColor.primary, size: 14),
        text: 'Menghitung…',
      );
    }

    if (exceedsBalance) {
      return const _StatusLine(
        key: ValueKey('exceeds'),
        icon: Icon(
          Icons.error_outline_rounded,
          size: 16,
          color: AppColor.error,
        ),
        text: 'Melebihi saldo EnakCoin kamu',
        color: AppColor.error,
      );
    }

    final previewFailure = state.previewFailureOption.toNullable();
    if (previewFailure != null) {
      return _StatusLine(
        key: const ValueKey('failure'),
        icon: const Icon(
          Icons.error_outline_rounded,
          size: 16,
          color: AppColor.error,
        ),
        text: walletFailureMessage(
          previewFailure,
          rejectedMessage: 'Jumlah EnakCoin tidak valid.',
        ),
        color: AppColor.error,
      );
    }

    final preview = state.preview;
    if (preview != null && !preview.valid) {
      final rounded = _roundToRate(state.coins);
      return _StatusLine(
        key: const ValueKey('invalid'),
        icon: const Icon(
          Icons.error_outline_rounded,
          size: 16,
          color: AppColor.error,
        ),
        text:
            preview.reason ??
            'Jumlah harus kelipatan ${preview.coinAmount.thousandFormat} '
                'EnakCoin.',
        color: AppColor.error,
        action: rounded > 0 && rounded != state.coins
            ? _QuickChip(
                label: 'Pakai ${rounded.thousandFormat}',
                onTap: () => _fillCoins(rounded),
              )
            : null,
      );
    }

    final rate = _rate;
    if (rate == null) {
      return const _StatusLine(
        key: ValueKey('hint'),
        icon: Icon(
          Icons.info_outline_rounded,
          size: 16,
          color: AppColor.textSecondary,
        ),
        text: 'Masukkan jumlah EnakCoin untuk melihat kurs penukaran.',
      );
    }

    return _StatusLine(
      key: const ValueKey('rate'),
      icon: const Icon(
        Icons.currency_exchange_rounded,
        size: 16,
        color: AppColor.textSecondary,
      ),
      text:
          'Kurs ${rate.coinAmount.thousandFormat} EnakCoin = '
          '${rate.pointAmount.thousandFormat} EnakPoint · penukaran tidak '
          'bisa dibatalkan',
    );
  }

  Widget _buildSuccess(ExchangeResult result) {
    return WalletResultView(
      title: 'Penukaran berhasil',
      amountText: '+${result.points.thousandFormat} EnakPoint',
      lines: [
        'Ditukar dari ${result.coins.thousandFormat} EnakCoin',
        'Saldo sekarang: ${result.pointBalance.thousandFormat} EnakPoint · '
            '${result.coinBalance.thousandFormat} EnakCoin',
        ...result.lots
            .where((lot) => lot.expiresAt != null)
            .map(
              (lot) =>
                  '${lot.amount.thousandFormat} EnakPoint ini berlaku sampai '
                  '${formatWibDate(lot.expiresAt!)}',
            ),
      ],
      onDone: () => context.router.maybePop(),
    );
  }
}

/// Kartu satu sisi penukaran (asal atau tujuan).
class _ExchangeCard extends StatelessWidget {
  const _ExchangeCard({
    required this.label,
    required this.currency,
    required this.trailing,
    required this.child,
    this.highlighted = false,
  });

  final String label;
  final WalletCurrency currency;
  final Widget trailing;
  final Widget child;
  final bool highlighted;

  @override
  Widget build(BuildContext context) {
    return AnimatedContainer(
      duration: const Duration(milliseconds: 250),
      padding: const EdgeInsets.fromLTRB(16, 14, 16, 14),
      decoration: BoxDecoration(
        color: highlighted ? AppColor.successWithOpacity(0.06) : AppColor.white,
        borderRadius: BorderRadius.circular(AppValue.borderRadius),
        border: Border.all(
          color: highlighted
              ? AppColor.successWithOpacity(0.4)
              : AppColor.white,
        ),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              Text(
                label,
                style: AppStyle.sm.copyWith(
                  color: AppColor.textSecondary,
                  fontWeight: FontWeight.w600,
                ),
              ),
              const Spacer(),
              trailing,
            ],
          ),
          const SizedBox(height: 4),
          Row(
            children: [
              Expanded(child: child),
              const SizedBox(width: 12),
              Container(
                padding: const EdgeInsets.fromLTRB(6, 6, 12, 6),
                decoration: BoxDecoration(
                  color: AppColor.background,
                  borderRadius: BorderRadius.circular(20),
                ),
                child: Row(
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    WalletCurrencyIcon(currency: currency, size: 24),
                    const SizedBox(width: 6),
                    Text(
                      currency.label,
                      style: AppStyle.sm.copyWith(fontWeight: FontWeight.w700),
                    ),
                  ],
                ),
              ),
            ],
          ),
        ],
      ),
    );
  }
}

/// Lingkaran panah di antara dua kartu.
class _SwapBadge extends StatelessWidget {
  const _SwapBadge();

  @override
  Widget build(BuildContext context) {
    return Container(
      width: 40,
      height: 40,
      decoration: BoxDecoration(
        color: AppColor.primary,
        shape: BoxShape.circle,
        border: Border.all(color: AppColor.background, width: 4),
      ),
      child: const Icon(
        Icons.arrow_downward_rounded,
        size: 18,
        color: AppColor.white,
      ),
    );
  }
}

class _QuickChip extends StatelessWidget {
  const _QuickChip({required this.label, required this.onTap});

  final String label;
  final VoidCallback? onTap;

  @override
  Widget build(BuildContext context) {
    final enabled = onTap != null;
    return Material(
      color: enabled ? AppColor.primaryWithOpacity(0.08) : AppColor.background,
      borderRadius: BorderRadius.circular(20),
      child: InkWell(
        onTap: onTap,
        borderRadius: BorderRadius.circular(20),
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
          child: Text(
            label,
            style: AppStyle.xs.copyWith(
              color: enabled ? AppColor.primary : AppColor.textLight,
              fontWeight: FontWeight.w700,
            ),
          ),
        ),
      ),
    );
  }
}

class _StatusLine extends StatelessWidget {
  const _StatusLine({
    super.key,
    required this.icon,
    required this.text,
    this.color = AppColor.textSecondary,
    this.action,
  });

  final Widget icon;
  final String text;
  final Color color;
  final Widget? action;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 4),
      child: Row(
        children: [
          SizedBox(width: 20, child: Center(child: icon)),
          const SizedBox(width: 6),
          Expanded(
            child: Text(text, style: AppStyle.xs.copyWith(color: color)),
          ),
          if (action != null) ...[const SizedBox(width: 8), action!],
        ],
      ),
    );
  }
}