import 'package:decimal/decimal.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import 'package:intl/intl.dart';

import '../../../core/l10n/app_localizations.dart';
import '../../../core/theme/app_colors.dart';
import '../../../core/utils/top_toast.dart';
import '../../../data/models/finance/staking_config.dart';
import '../../../providers/auth_provider.dart';
import '../../../providers/market_provider.dart';
import '../../../providers/staking_provider.dart';

bool _financeIsDark(BuildContext context) =>
    Theme.of(context).brightness == Brightness.dark;

Color _financePageBg(BuildContext context) => _financeIsDark(context)
    ? AppColors.darkBg
    : Theme.of(context).colorScheme.surface;

Color _financePrimaryText(BuildContext context) => _financeIsDark(context)
    ? Colors.white
    : Theme.of(context).colorScheme.onSurface;

Color _financeSecondaryText(BuildContext context) =>
    _financePrimaryText(context).withAlpha(160);

Color _financeLabelText(BuildContext context) =>
    _financePrimaryText(context).withAlpha(140);

Color _financeFieldBg(BuildContext context) =>
    _financePrimaryText(context).withAlpha(14);

Color _financeFieldBorder(BuildContext context) =>
    _financePrimaryText(context).withAlpha(40);

class StakingScreen extends ConsumerStatefulWidget {
  const StakingScreen({
    super.key,
    this.configId,
    this.showAppBar = true,
  });

  final String? configId;
  final bool showAppBar;

  @override
  ConsumerState<StakingScreen> createState() => _StakingScreenState();
}

class _StakingScreenState extends ConsumerState<StakingScreen> {
  final _amountController = TextEditingController();

  @override
  void initState() {
    super.initState();
    Future.microtask(() {
      ref.read(stakingProvider.notifier).init(configId: widget.configId);
      ref.read(marketProvider.notifier).loadSpotIfNeeded();
    });
  }

  @override
  void dispose() {
    _amountController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final state = ref.watch(stakingProvider);
    final config = state.selectedConfig;
    final isLoggedIn = ref.watch(isLoggedInProvider);

    if (!state.isLoadingConfig && config == null) {
      final emptyBody = _EmptyState(
        message: state.errorMessage ?? l10n.financeConfigNotFound,
      );
      if (!widget.showAppBar) {
        return ColoredBox(
          color: _financePageBg(context),
          child: emptyBody,
        );
      }
      return Scaffold(
        backgroundColor: _financePageBg(context),
        appBar: AppBar(
          backgroundColor: Colors.transparent,
          foregroundColor: _financePrimaryText(context),
          elevation: 0,
          title: Text(
            l10n.financeIdoTitle,
            style: TextStyle(color: _financePrimaryText(context)),
          ),
          centerTitle: true,
        ),
        body: emptyBody,
      );
    }

    final coinUnit = config?.coinUnit ?? 'IBIT';
    final symbol = '${coinUnit.toUpperCase()}USDT';
    final ticker = ref.watch(spotTickerProvider(symbol));
    final unitPrice = _usdtPrice(coinUnit, ticker?.lastPrice ?? 0);
    final rulesText = config == null ? '' : _rulesText(l10n, config);
    final displayUnit = _displayCoinUnit(coinUnit);
    final unlockText =
        config == null ? '—' : _formatUnlockDate(_estimatedUnlockDate(config));

    final pageBody = ListView(
      padding: const EdgeInsets.only(bottom: 32),
      children: [
          _HeroSection(
            l10n: l10n,
            rulesText: rulesText,
            loadingRules: state.isLoadingConfig,
          ),
          Padding(
            padding: const EdgeInsets.fromLTRB(16, 0, 16, 0),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  l10n.financeJoinPresale,
                  style: TextStyle(
                    color: _financePrimaryText(context),
                    fontSize: 22,
                    fontWeight: FontWeight.w600,
                  ),
                ),
                const SizedBox(height: 24),
                _LabelRow(
                  label: l10n.financeSubscribeQty,
                  actionLabel: l10n.goSpotTrade,
                  onAction:
                      config == null ? null : () => _goToSpotTrade(config),
                ),
                const SizedBox(height: 12),
                _LabelRow(label: l10n.financeCorrespondingPrice),
                const SizedBox(height: 12),
                _AvailableMetaRow(
                  l10n: l10n,
                  amount: _fmtAmount(state.fundingAvailable),
                  unit: displayUnit,
                  loading: state.isRefreshingBalance,
                  onFillAll: state.isRefreshingBalance
                      ? null
                      : () => _fillAllAmount(state.fundingAvailable),
                ),
                const SizedBox(height: 12),
                _UnitPriceMetaRow(
                  l10n: l10n,
                  unitPrice: unitPrice,
                ),
                const SizedBox(height: 12),
                _FieldInput(
                  controller: _amountController,
                  suffix: displayUnit,
                  onChanged: (_) => setState(() {}),
                ),
                const SizedBox(height: 12),
                Row(
                  children: [
                    Expanded(
                      child: _FieldInput(
                        readOnly: true,
                        value: _priceUsdtText(unitPrice),
                        suffix: 'USDT',
                      ),
                    ),
                    const SizedBox(width: 12),
                    _TransferButton(
                      label: l10n.stakingTransfer,
                      onPressed: () => _openSpotFundTransfer(isLoggedIn),
                    ),
                  ],
                ),
                const SizedBox(height: 32),
                Center(
                  child: ConstrainedBox(
                    constraints: const BoxConstraints(maxWidth: 360),
                    child: SizedBox(
                      width: double.infinity,
                      height: 48,
                      child: ElevatedButton(
                        onPressed: state.isSubmitting ||
                                config == null ||
                                state.isLoadingConfig
                            ? null
                            : () => _submitStake(isLoggedIn),
                        style: ElevatedButton.styleFrom(
                          backgroundColor: AppColors.brand,
                          foregroundColor: Colors.black,
                          disabledBackgroundColor:
                              AppColors.brand.withAlpha(128),
                          shape: const StadiumBorder(),
                          elevation: 0,
                        ),
                        child: state.isSubmitting
                            ? const SizedBox(
                                width: 18,
                                height: 18,
                                child: CircularProgressIndicator(
                                  strokeWidth: 2,
                                ),
                              )
                            : Text(
                                l10n.financeConfirmPresale,
                                style: const TextStyle(
                                  fontSize: 16,
                                  fontWeight: FontWeight.w600,
                                ),
                              ),
                      ),
                    ),
                  ),
                ),
                const SizedBox(height: 20),
                Text(
                  state.isLoadingConfig
                      ? l10n.financeEstimatedUnlockLine('—')
                      : l10n.financeEstimatedUnlockLine(unlockText),
                  textAlign: TextAlign.center,
                  style: TextStyle(
                    color: _financeSecondaryText(context),
                    fontSize: 13,
                  ),
                ),
                if (!isLoggedIn) ...[
                  const SizedBox(height: 12),
                  Wrap(
                    alignment: WrapAlignment.center,
                    crossAxisAlignment: WrapCrossAlignment.center,
                    children: [
                      Text(
                        l10n.financeLoginToStake,
                        style: TextStyle(
                          color: _financeSecondaryText(context),
                          fontSize: 12,
                        ),
                      ),
                      GestureDetector(
                        onTap: () => context.push(
                          '/login?redirect=${Uri.encodeComponent('/finance/ido')}',
                        ),
                        child: Text(
                          l10n.login,
                          style: const TextStyle(
                            color: AppColors.brand,
                            fontSize: 12,
                          ),
                        ),
                      ),
                    ],
                  ),
                ],
              ],
            ),
          ),
      ],
    );

    if (!widget.showAppBar) {
      return ColoredBox(
        color: _financePageBg(context),
        child: pageBody,
      );
    }

    return Scaffold(
      backgroundColor: _financePageBg(context),
      appBar: AppBar(
        backgroundColor: Colors.transparent,
        foregroundColor: _financePrimaryText(context),
        elevation: 0,
        title: Text(
          l10n.financeIdoTitle,
          style: TextStyle(color: _financePrimaryText(context)),
        ),
        centerTitle: true,
      ),
      body: pageBody,
    );
  }

  Decimal _usdtPrice(String coinUnit, double wsPrice) {
    if (coinUnit.toUpperCase() == 'USDT') {
      return Decimal.one;
    }
    return Decimal.tryParse(wsPrice.toString()) ?? Decimal.zero;
  }

  String _priceUsdtText(Decimal unitPrice) {
    final qty = Decimal.tryParse(_amountController.text) ?? Decimal.zero;
    if (qty <= Decimal.zero || unitPrice <= Decimal.zero) {
      return '0.00';
    }
    final total = qty * unitPrice;
    return NumberFormat('#,##0.00', 'en_US').format(total.toDouble());
  }

  int _lockMonths(StakingConfig config) {
    final days = config.lockDays;
    return days <= 0 ? 1 : (days / 30).ceil().clamp(1, 999999);
  }

  int _releaseMonths(StakingConfig config) {
    if (config.releaseType != 1) {
      return 0;
    }
    final rate = double.tryParse(config.releaseRate) ?? 0;
    final periodDays = config.releasePeriod <= 0 ? 1 : config.releasePeriod;
    if (rate <= 0) {
      return (periodDays / 30).ceil().clamp(1, 999999);
    }
    final batches = (1 / rate).ceil();
    final totalDays = batches * periodDays;
    return (totalDays / 30).ceil().clamp(1, 999999);
  }

  String _rulesText(AppLocalizations l10n, StakingConfig config) {
    final lock = _lockMonths(config);
    if (config.releaseType == 1 && _releaseMonths(config) > 0) {
      return l10n.financeIdoRuleBatch('$lock', '${_releaseMonths(config)}');
    }
    return l10n.financeIdoRuleOnce('$lock');
  }

  String _displayCoinUnit(String coinUnit) {
    final unit = coinUnit.trim();
    if (unit.isEmpty) {
      return 'iBit';
    }
    if (unit.toUpperCase() == 'IBIT') {
      return 'iBit';
    }
    return unit;
  }

  String _fmtAmount(String value, {int maxFrac = 8}) {
    final parsed = double.tryParse(value);
    if (parsed == null || !parsed.isFinite) {
      return '0';
    }
    if (parsed == 0) {
      return '0';
    }
    return NumberFormat('#,##0.${'#' * maxFrac}', 'en_US').format(parsed);
  }

  DateTime _estimatedUnlockDate(StakingConfig config) {
    return DateTime.now().add(Duration(days: config.lockDays));
  }

  String _formatUnlockDate(DateTime date) {
    String pad(int n) {
      return n.toString().padLeft(2, '0');
    }
    return '${date.year}/${pad(date.month)}/${pad(date.day)} '
        '${pad(date.hour)}:${pad(date.minute)}:${pad(date.second)}';
  }

  void _fillAllAmount(String amount) {
    final parsed = double.tryParse(amount);
    if (parsed != null && parsed > 0) {
      _amountController.text = amount;
      setState(() {});
    }
  }

  void _goToSpotTrade(StakingConfig config) {
    final symbol = '${config.coinUnit.toUpperCase()}USDT';
    context.push('/market/spot/$symbol');
  }

  Future<void> _openSpotFundTransfer(bool isLoggedIn) async {
    if (!isLoggedIn) {
      context.push('/login?redirect=${Uri.encodeComponent('/finance/ido')}');
      return;
    }
    await context.push(
      '/asset/transfer?from=SPOT&to=SPOT_TRADING&symbol=IBIT&preferSymbol=1&bridgeOnly=1',
    );
    if (!mounted) {
      return;
    }
    await ref.read(stakingProvider.notifier).refreshBalances();
  }

  Future<void> _submitStake(bool isLoggedIn) async {
    final l10n = AppLocalizations.of(context)!;
    if (!isLoggedIn) {
      context.push('/login?redirect=${Uri.encodeComponent('/finance/ido')}');
      return;
    }
    final amount = _amountController.text.trim();
    final err = await ref.read(stakingProvider.notifier).submitStake(amount);
    if (!mounted) {
      return;
    }
    if (err == null) {
      _amountController.clear();
      showTopToast(
        context,
        message: l10n.financeStakeSuccess,
        backgroundColor: AppColors.rise,
      );
      setState(() {});
      return;
    }
    showTopToast(context, message: _resolveStakeError(err, l10n));
  }

  String _resolveStakeError(String err, AppLocalizations l10n) {
    if (err == 'errNeedLogin') {
      return l10n.financeLoginToStake;
    }
    if (err == 'errEnterAmount') {
      return l10n.financeAmountRequired;
    }
    if (err == 'errExceedBalance') {
      return l10n.errExceedBalance;
    }
    if (err.startsWith('errAmountBelowMin:')) {
      return l10n.financeBelowMin(err.substring('errAmountBelowMin:'.length));
    }
    if (err.startsWith('errAmountAboveMax:')) {
      return l10n.financeAboveMax(err.substring('errAmountAboveMax:'.length));
    }
    return err;
  }
}

class _EmptyState extends StatelessWidget {
  const _EmptyState({required this.message});

  final String message;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(24),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Text(
              message,
              textAlign: TextAlign.center,
              style: TextStyle(color: _financeSecondaryText(context)),
            ),
            const SizedBox(height: 16),
            TextButton(
              onPressed: () => context.go('/'),
              child: Text(l10n.home),
            ),
          ],
        ),
      ),
    );
  }
}

class _HeroSection extends StatelessWidget {
  const _HeroSection({
    required this.l10n,
    required this.rulesText,
    this.loadingRules = false,
  });

  final AppLocalizations l10n;
  final String rulesText;
  final bool loadingRules;

  @override
  Widget build(BuildContext context) {
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.fromLTRB(16, 8, 16, 24),
      decoration: const BoxDecoration(
        gradient: LinearGradient(
          begin: Alignment.topCenter,
          end: Alignment.bottomCenter,
          colors: [
            Color(0x0AF0B90B),
            Colors.transparent,
          ],
          stops: [0.0, 0.7],
        ),
      ),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  l10n.financeIdoTitle,
                  style: TextStyle(
                    color: _financePrimaryText(context),
                    fontSize: 40,
                    fontWeight: FontWeight.w700,
                    height: 1.1,
                    letterSpacing: 0.8,
                  ),
                ),
                const SizedBox(height: 16),
                if (loadingRules)
                  Container(
                    height: 40,
                    width: double.infinity,
                    decoration: BoxDecoration(
                      color: _financePrimaryText(context).withAlpha(14),
                      borderRadius: BorderRadius.circular(6),
                    ),
                  )
                else
                  Text.rich(
                    TextSpan(
                      children: [
                        TextSpan(
                          text: l10n.financeIdoRuleLabel,
                          style: TextStyle(color: _financeLabelText(context)),
                        ),
                        TextSpan(text: rulesText),
                      ],
                    ),
                    style: TextStyle(
                      color: _financePrimaryText(context).withAlpha(191),
                      fontSize: 15,
                      height: 1.75,
                    ),
                  ),
              ],
            ),
          ),
          const SizedBox(width: 12),
          Image.asset(
            'assets/images/finance/staking_hero.png',
            width: 120,
            height: 120,
            fit: BoxFit.contain,
          ),
        ],
      ),
    );
  }
}

class _LabelRow extends StatelessWidget {
  const _LabelRow({
    required this.label,
    this.actionLabel,
    this.onAction,
  });

  final String label;
  final String? actionLabel;
  final VoidCallback? onAction;

  @override
  Widget build(BuildContext context) {
    return Row(
      children: [
        Text(
          label,
          style: TextStyle(
            color: _financeLabelText(context),
            fontSize: 14,
          ),
        ),
        if (actionLabel != null && onAction != null) ...[
          const Spacer(),
          _LinkAction(label: actionLabel!, onTap: onAction!),
        ],
      ],
    );
  }
}

class _AvailableMetaRow extends StatelessWidget {
  const _AvailableMetaRow({
    required this.l10n,
    required this.amount,
    required this.unit,
    required this.onFillAll,
    this.loading = false,
  });

  final AppLocalizations l10n;
  final String amount;
  final String unit;
  final VoidCallback? onFillAll;
  final bool loading;

  @override
  Widget build(BuildContext context) {
    return Row(
      children: [
        Expanded(
          child: Text.rich(
            TextSpan(
              text: '${l10n.financeAvailableIbit}: ',
              style: TextStyle(
                  color: _financeSecondaryText(context), fontSize: 13),
              children: [
                TextSpan(
                  text: amount,
                  style: const TextStyle(
                    color: AppColors.brand,
                    fontWeight: FontWeight.w600,
                  ),
                ),
                TextSpan(text: ' $unit'),
              ],
            ),
          ),
        ),
        if (onFillAll != null)
          _LinkAction(label: l10n.all, onTap: onFillAll!)
        else if (loading)
          const SizedBox(
            width: 14,
            height: 14,
            child: CircularProgressIndicator(strokeWidth: 1.5),
          ),
      ],
    );
  }
}

class _UnitPriceMetaRow extends StatelessWidget {
  const _UnitPriceMetaRow({
    required this.l10n,
    required this.unitPrice,
  });

  final AppLocalizations l10n;
  final Decimal unitPrice;

  @override
  Widget build(BuildContext context) {
    if (unitPrice <= Decimal.zero) {
      return const SizedBox(height: 20);
    }
    return Text(
      l10n.financeIbitUnitPriceLine(
        NumberFormat('#,##0.0000', 'en_US').format(unitPrice.toDouble()),
      ),
      style: TextStyle(
        color: _financeSecondaryText(context),
        fontSize: 13,
      ),
    );
  }
}

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

  final String label;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: onTap,
      child: Text(
        label,
        style: const TextStyle(
          color: AppColors.brand,
          fontSize: 13,
        ),
      ),
    );
  }
}

class _FieldInput extends StatelessWidget {
  const _FieldInput({
    this.controller,
    this.value,
    this.suffix,
    this.onChanged,
    this.readOnly = false,
  });

  final TextEditingController? controller;
  final String? value;
  final String? suffix;
  final ValueChanged<String>? onChanged;
  final bool readOnly;

  @override
  Widget build(BuildContext context) {
    final valueStyle = TextStyle(
      color: _financePrimaryText(context),
      fontSize: 16,
      height: 1.2,
      fontFeatures: const [FontFeature.tabularFigures()],
    );
    final inputDecoration = InputDecoration(
      border: InputBorder.none,
      enabledBorder: InputBorder.none,
      focusedBorder: InputBorder.none,
      disabledBorder: InputBorder.none,
      errorBorder: InputBorder.none,
      focusedErrorBorder: InputBorder.none,
      filled: false,
      isDense: true,
      isCollapsed: true,
      contentPadding: EdgeInsets.zero,
      hintText: '0',
      hintStyle: TextStyle(
        color: _financePrimaryText(context).withAlpha(64),
        fontSize: 16,
        height: 1.2,
        fontFeatures: const [FontFeature.tabularFigures()],
      ),
    );
    return Container(
      height: 52,
      padding: const EdgeInsets.symmetric(horizontal: 16),
      decoration: BoxDecoration(
        color: readOnly
            ? _financePrimaryText(context).withAlpha(8)
            : _financeFieldBg(context),
        border: Border.all(color: _financeFieldBorder(context)),
        borderRadius: BorderRadius.circular(12),
      ),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.center,
        children: [
          Expanded(
            child: readOnly
                ? Align(
                    alignment: Alignment.centerLeft,
                    child: Text(
                      value ?? '0.00',
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                      style: valueStyle,
                    ),
                  )
                : Theme(
                    data: Theme.of(context).copyWith(
                      inputDecorationTheme: const InputDecorationTheme(
                        filled: false,
                        fillColor: Colors.transparent,
                        border: InputBorder.none,
                        enabledBorder: InputBorder.none,
                        focusedBorder: InputBorder.none,
                        disabledBorder: InputBorder.none,
                        errorBorder: InputBorder.none,
                        focusedErrorBorder: InputBorder.none,
                        contentPadding: EdgeInsets.zero,
                        isDense: true,
                      ),
                    ),
                    child: TextField(
                      controller: controller,
                      readOnly: readOnly,
                      keyboardType: const TextInputType.numberWithOptions(
                        decimal: true,
                      ),
                      style: valueStyle,
                      cursorColor: AppColors.brand,
                      decoration: inputDecoration,
                      onChanged: onChanged,
                    ),
                  ),
          ),
          if (suffix != null) ...[
            const SizedBox(width: 12),
            Text(
              suffix!,
              style: TextStyle(
                color: _financeLabelText(context),
                fontSize: 14,
              ),
            ),
          ],
        ],
      ),
    );
  }
}

class _TransferButton extends StatelessWidget {
  const _TransferButton({required this.label, required this.onPressed});

  final String label;
  final VoidCallback onPressed;

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      height: 52,
      child: OutlinedButton(
        onPressed: onPressed,
        style: OutlinedButton.styleFrom(
          side: const BorderSide(color: AppColors.brand),
          foregroundColor: AppColors.brand,
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(12),
          ),
          padding: const EdgeInsets.symmetric(horizontal: 20),
        ),
        child: Text(
          label,
          style: const TextStyle(fontSize: 14, fontWeight: FontWeight.w500),
        ),
      ),
    );
  }
}