import 'package:flutter/material.dart';
import '../../../../app/theme/app_colors.dart';
import '../../../../app/i18n/app_localizations.dart';
import '../../../../core/services/issuer_finance_service.dart';

/// 财务管理页面
///
/// 法币展示，不暴露链上稳定币细节
/// 包含：销售收入、Breakage收入、手续费、保证金、冻结款、提现、对账报表
class FinancePage extends StatelessWidget {
  const FinancePage({super.key});

  @override
  Widget build(BuildContext context) {
    return DefaultTabController(
      length: 3,
      child: Scaffold(
        appBar: AppBar(
          title: Text(context.t('finance_title')),
          actions: [
            IconButton(
              icon: const Icon(Icons.download_rounded),
              onPressed: () => _showExportDialog(context),
            ),
          ],
          bottom: TabBar(
            tabs: [
              Tab(text: context.t('finance_tab_overview')),
              Tab(text: context.t('finance_tab_transactions')),
              Tab(text: context.t('finance_tab_reconciliation')),
            ],
          ),
        ),
        body: const TabBarView(
          children: [
            _OverviewTab(),
            _TransactionDetailTab(),
            _ReconciliationTab(),
          ],
        ),
      ),
    );
  }

  void _showExportDialog(BuildContext context) {
    showDialog(
      context: context,
      builder: (ctx) => SimpleDialog(
        title: Text(context.t('finance_export_title')),
        children: [
          SimpleDialogOption(onPressed: () => Navigator.pop(ctx), child: Text(context.t('finance_export_csv'))),
          SimpleDialogOption(onPressed: () => Navigator.pop(ctx), child: Text(context.t('finance_export_excel'))),
          SimpleDialogOption(onPressed: () => Navigator.pop(ctx), child: Text(context.t('finance_export_pdf'))),
        ],
      ),
    );
  }
}

class _OverviewTab extends StatefulWidget {
  const _OverviewTab();

  @override
  State<_OverviewTab> createState() => _OverviewTabState();
}

class _OverviewTabState extends State<_OverviewTab> {
  final _financeService = IssuerFinanceService();

  bool _isLoading = true;
  String? _error;
  FinanceBalance? _balance;
  FinanceStats? _stats;

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

  Future<void> _loadData() async {
    setState(() {
      _isLoading = true;
      _error = null;
    });

    try {
      final results = await Future.wait([
        _financeService.getBalance(),
        _financeService.getStats(),
      ]);
      if (!mounted) return;
      setState(() {
        _balance = results[0] as FinanceBalance;
        _stats = results[1] as FinanceStats;
        _isLoading = false;
      });
    } catch (e) {
      debugPrint('[FinancePage] loadData error: $e');
      if (!mounted) return;
      setState(() {
        _isLoading = false;
        _error = e.toString();
      });
    }
  }

  Future<void> _handleWithdraw() async {
    if (_balance == null || _balance!.withdrawable <= 0) return;

    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: Text(context.t('finance_confirm_withdraw')),
        content: Text('${context.t('finance_withdraw_amount')}: \$${_balance!.withdrawable.toStringAsFixed(2)}'),
        actions: [
          TextButton(onPressed: () => Navigator.pop(ctx, false), child: Text(context.t('cancel'))),
          ElevatedButton(onPressed: () => Navigator.pop(ctx, true), child: Text(context.t('confirm'))),
        ],
      ),
    );

    if (confirmed != true) return;

    try {
      await _financeService.withdraw(_balance!.withdrawable);
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(context.t('finance_withdraw_submitted')), backgroundColor: AppColors.success),
      );
      _loadData();
    } catch (e) {
      debugPrint('[FinancePage] withdraw error: $e');
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('${context.t('finance_withdraw_failed')}: $e'), backgroundColor: AppColors.error),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    if (_isLoading) {
      return const Center(child: CircularProgressIndicator());
    }

    if (_error != null) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Icon(Icons.error_outline, size: 48, color: AppColors.textTertiary),
            const SizedBox(height: 16),
            Text(_error!, style: const TextStyle(color: AppColors.textSecondary)),
            const SizedBox(height: 16),
            ElevatedButton(onPressed: _loadData, child: Text(context.t('retry'))),
          ],
        ),
      );
    }

    return RefreshIndicator(
      onRefresh: _loadData,
      child: SingleChildScrollView(
        physics: const AlwaysScrollableScrollPhysics(),
        padding: const EdgeInsets.all(20),
        child: Column(
          children: [
            // Balance Card
            Container(
              padding: const EdgeInsets.all(20),
              decoration: BoxDecoration(
                gradient: AppColors.primaryGradient,
                borderRadius: BorderRadius.circular(16),
              ),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(context.t('finance_withdrawable'), style: TextStyle(fontSize: 13, color: Colors.white.withValues(alpha: 0.7))),
                  const SizedBox(height: 4),
                  Text(
                    '\$${_balance?.withdrawable.toStringAsFixed(2) ?? '0.00'}',
                    style: const TextStyle(fontSize: 32, fontWeight: FontWeight.w700, color: Colors.white),
                  ),
                  const SizedBox(height: 16),
                  SizedBox(
                    width: double.infinity,
                    child: ElevatedButton(
                      onPressed: _handleWithdraw,
                      style: ElevatedButton.styleFrom(
                        backgroundColor: Colors.white,
                        foregroundColor: AppColors.primary,
                      ),
                      child: Text(context.t('finance_withdraw')),
                    ),
                  ),
                ],
              ),
            ),
            const SizedBox(height: 20),

            // Financial Stats
            _buildFinanceStatsGrid(context),
            const SizedBox(height: 20),

            // Guarantee Fund
            _buildGuaranteeFundCard(context),
            const SizedBox(height: 20),

            // Revenue Trend
            Container(
              padding: const EdgeInsets.all(16),
              decoration: BoxDecoration(
                color: AppColors.surface,
                borderRadius: BorderRadius.circular(12),
                border: Border.all(color: AppColors.borderLight),
              ),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(context.t('finance_revenue_trend'), style: const TextStyle(fontSize: 15, fontWeight: FontWeight.w600)),
                  const SizedBox(height: 16),
                  Container(
                    height: 160,
                    decoration: BoxDecoration(
                      color: AppColors.gray50,
                      borderRadius: BorderRadius.circular(8),
                    ),
                    child: Center(child: Text(context.t('finance_revenue_chart'), style: const TextStyle(color: AppColors.textTertiary))),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildFinanceStatsGrid(BuildContext context) {
    final s = _stats;
    final statItems = [
      (context.t('finance_sales_income'), '\$${s?.salesAmount.toStringAsFixed(0) ?? '0'}', AppColors.success),
      (context.t('finance_breakage_income'), '\$${s?.breakageIncome.toStringAsFixed(0) ?? '0'}', AppColors.info),
      (context.t('finance_platform_fee'), '-\$${s?.platformFee.toStringAsFixed(0) ?? '0'}', AppColors.error),
      (context.t('finance_pending_settlement'), '\$${s?.pendingSettlement.toStringAsFixed(0) ?? '0'}', AppColors.warning),
      (context.t('finance_withdrawn'), '\$${s?.withdrawnAmount.toStringAsFixed(0) ?? '0'}', AppColors.textSecondary),
      (context.t('finance_total_income'), '\$${s?.totalRevenue.toStringAsFixed(0) ?? '0'}', AppColors.primary),
    ];

    return GridView.builder(
      shrinkWrap: true,
      physics: const NeverScrollableScrollPhysics(),
      gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
        crossAxisCount: 2,
        mainAxisSpacing: 12,
        crossAxisSpacing: 12,
        childAspectRatio: 2,
      ),
      itemCount: statItems.length,
      itemBuilder: (context, index) {
        final (label, value, color) = statItems[index];
        return Container(
          padding: const EdgeInsets.all(14),
          decoration: BoxDecoration(
            color: AppColors.surface,
            borderRadius: BorderRadius.circular(12),
            border: Border.all(color: AppColors.borderLight),
          ),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [
              Text(label, style: const TextStyle(fontSize: 12, color: AppColors.textSecondary)),
              Text(value, style: TextStyle(fontSize: 17, fontWeight: FontWeight.w700, color: color)),
            ],
          ),
        );
      },
    );
  }

  Widget _buildGuaranteeFundCard(BuildContext context) {
    return Container(
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: AppColors.surface,
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: AppColors.borderLight),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              const Icon(Icons.shield_rounded, color: AppColors.info, size: 20),
              const SizedBox(width: 8),
              Text(context.t('finance_guarantee_title'), style: const TextStyle(fontSize: 15, fontWeight: FontWeight.w600)),
            ],
          ),
          const SizedBox(height: 16),
          _buildRow(context.t('finance_guarantee_deposit'), '\$${_balance?.pending.toStringAsFixed(0) ?? '0'}'),
          _buildRow(context.t('finance_frozen_sales'), '--'),
          _buildRow(context.t('finance_frozen_ratio'), '--'),
          const SizedBox(height: 12),
          SwitchListTile(
            title: Text(context.t('finance_auto_freeze'), style: const TextStyle(fontSize: 14)),
            subtitle: Text(context.t('finance_auto_freeze_desc')),
            value: true,
            onChanged: (_) {
              // TODO: Toggle auto-freeze setting
            },
            activeColor: AppColors.primary,
            contentPadding: EdgeInsets.zero,
          ),
        ],
      ),
    );
  }

  Widget _buildRow(String label, String value) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 4),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: [
          Text(label, style: const TextStyle(fontSize: 13, color: AppColors.textSecondary)),
          Text(value, style: const TextStyle(fontSize: 14, fontWeight: FontWeight.w500)),
        ],
      ),
    );
  }
}

class _TransactionDetailTab extends StatefulWidget {
  const _TransactionDetailTab();

  @override
  State<_TransactionDetailTab> createState() => _TransactionDetailTabState();
}

class _TransactionDetailTabState extends State<_TransactionDetailTab> {
  final _financeService = IssuerFinanceService();

  bool _isLoading = true;
  String? _error;
  List<TransactionModel> _transactions = [];

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

  Future<void> _loadTransactions() async {
    setState(() {
      _isLoading = true;
      _error = null;
    });

    try {
      final result = await _financeService.getTransactions();
      if (!mounted) return;
      setState(() {
        _transactions = result.items;
        _isLoading = false;
      });
    } catch (e) {
      debugPrint('[FinancePage] loadTransactions error: $e');
      if (!mounted) return;
      setState(() {
        _isLoading = false;
        _error = e.toString();
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    if (_isLoading) {
      return const Center(child: CircularProgressIndicator());
    }

    if (_error != null) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Icon(Icons.error_outline, size: 48, color: AppColors.textTertiary),
            const SizedBox(height: 16),
            Text(_error!, style: const TextStyle(color: AppColors.textSecondary)),
            const SizedBox(height: 16),
            ElevatedButton(onPressed: _loadTransactions, child: Text(context.t('retry'))),
          ],
        ),
      );
    }

    if (_transactions.isEmpty) {
      return Center(
        child: Text(context.t('finance_no_transactions'), style: const TextStyle(color: AppColors.textSecondary)),
      );
    }

    return RefreshIndicator(
      onRefresh: _loadTransactions,
      child: ListView.separated(
        padding: const EdgeInsets.all(20),
        itemCount: _transactions.length,
        separatorBuilder: (_, __) => const Divider(height: 1),
        itemBuilder: (context, index) {
          final tx = _transactions[index];
          final isPositive = tx.amount >= 0;
          final color = isPositive ? AppColors.success : AppColors.error;
          return ListTile(
            contentPadding: const EdgeInsets.symmetric(vertical: 6),
            title: Text(tx.description, style: const TextStyle(fontSize: 14)),
            subtitle: Text(
              _formatTime(tx.createdAt),
              style: const TextStyle(fontSize: 12, color: AppColors.textTertiary),
            ),
            trailing: Text(
              '${isPositive ? '+' : ''}\$${tx.amount.toStringAsFixed(2)}',
              style: TextStyle(fontSize: 15, fontWeight: FontWeight.w600, color: color),
            ),
          );
        },
      ),
    );
  }

  String _formatTime(DateTime dt) {
    final now = DateTime.now();
    final isToday = dt.year == now.year && dt.month == now.month && dt.day == now.day;
    final timeStr = '${dt.hour.toString().padLeft(2, '0')}:${dt.minute.toString().padLeft(2, '0')}';
    if (isToday) return '${context.t('finance_today')} $timeStr';
    final yesterday = now.subtract(const Duration(days: 1));
    final isYesterday = dt.year == yesterday.year && dt.month == yesterday.month && dt.day == yesterday.day;
    if (isYesterday) return '${context.t('finance_yesterday')} $timeStr';
    return '${dt.month}/${dt.day} $timeStr';
  }
}

class _ReconciliationTab extends StatefulWidget {
  const _ReconciliationTab();

  @override
  State<_ReconciliationTab> createState() => _ReconciliationTabState();
}

class _ReconciliationTabState extends State<_ReconciliationTab> {
  final _financeService = IssuerFinanceService();

  bool _isLoading = true;
  String? _error;
  Map<String, dynamic> _reconciliation = {};

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

  Future<void> _loadReconciliation() async {
    setState(() {
      _isLoading = true;
      _error = null;
    });

    try {
      final data = await _financeService.getReconciliation();
      if (!mounted) return;
      setState(() {
        _reconciliation = data;
        _isLoading = false;
      });
    } catch (e) {
      debugPrint('[FinancePage] loadReconciliation error: $e');
      if (!mounted) return;
      setState(() {
        _isLoading = false;
        _error = e.toString();
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    if (_isLoading) {
      return const Center(child: CircularProgressIndicator());
    }

    if (_error != null) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Icon(Icons.error_outline, size: 48, color: AppColors.textTertiary),
            const SizedBox(height: 16),
            Text(_error!, style: const TextStyle(color: AppColors.textSecondary)),
            const SizedBox(height: 16),
            ElevatedButton(onPressed: _loadReconciliation, child: Text(context.t('retry'))),
          ],
        ),
      );
    }

    final reports = (_reconciliation['reports'] as List?)?.cast<Map<String, dynamic>>() ?? [];

    return RefreshIndicator(
      onRefresh: _loadReconciliation,
      child: ListView(
        physics: const AlwaysScrollableScrollPhysics(),
        padding: const EdgeInsets.all(20),
        children: [
          // Generate New
          OutlinedButton.icon(
            onPressed: () {
              // TODO: Trigger reconciliation report generation
            },
            icon: const Icon(Icons.add_rounded),
            label: Text(context.t('finance_generate_report')),
            style: OutlinedButton.styleFrom(
              minimumSize: const Size(double.infinity, 48),
            ),
          ),
          const SizedBox(height: 20),

          if (reports.isEmpty)
            Center(
              child: Padding(
                padding: const EdgeInsets.all(32),
                child: Text(context.t('finance_no_reports'), style: const TextStyle(color: AppColors.textSecondary)),
              ),
            )
          else
            ...reports.map((r) {
              final title = r['title'] ?? '';
              final summary = r['summary'] ?? '';
              final status = r['status'] ?? '--';
              return Container(
                margin: const EdgeInsets.only(bottom: 12),
                padding: const EdgeInsets.all(16),
                decoration: BoxDecoration(
                  color: AppColors.surface,
                  borderRadius: BorderRadius.circular(12),
                  border: Border.all(color: AppColors.borderLight),
                ),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Row(
                      mainAxisAlignment: MainAxisAlignment.spaceBetween,
                      children: [
                        Expanded(
                          child: Text(title, style: const TextStyle(fontSize: 15, fontWeight: FontWeight.w600)),
                        ),
                        Container(
                          padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 2),
                          decoration: BoxDecoration(
                            color: AppColors.successLight,
                            borderRadius: BorderRadius.circular(999),
                          ),
                          child: Text(status, style: const TextStyle(fontSize: 11, color: AppColors.success)),
                        ),
                      ],
                    ),
                    const SizedBox(height: 6),
                    Text(summary, style: const TextStyle(fontSize: 12, color: AppColors.textSecondary)),
                    const SizedBox(height: 12),
                    Row(
                      children: [
                        TextButton.icon(
                          onPressed: () {
                            // TODO: Navigate to reconciliation detail view
                          },
                          icon: const Icon(Icons.visibility_rounded, size: 16),
                          label: Text(context.t('view')),
                        ),
                        TextButton.icon(
                          onPressed: () {
                            // TODO: Export reconciliation report
                          },
                          icon: const Icon(Icons.download_rounded, size: 16),
                          label: Text(context.t('export')),
                        ),
                      ],
                    ),
                  ],
                ),
              );
            }),
        ],
      ),
    );
  }
}