import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../../core/theme/app_theme.dart';
import '../../models/finance.dart';
import '../../providers/finance_provider.dart';
import '../../widgets/data_table_card.dart';
import '../../widgets/page_scaffold.dart';

class FinanceScreen extends ConsumerWidget {
  const FinanceScreen({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return PageScaffold(
      title: '财务管理',
      tabs: const [
        Tab(text: '全部记录'),
        Tab(text: '应付账款'),
        Tab(text: '应收账款'),
      ],
      tabViews: [
        _FinanceTab(typeFilter: ''),
        _FinanceTab(typeFilter: 'payable'),
        _FinanceTab(typeFilter: 'receivable'),
      ],
    );
  }
}

// Each tab has its own independent state — avoids shared-provider conflicts
class _FinanceTab extends ConsumerStatefulWidget {
  final String typeFilter;
  const _FinanceTab({required this.typeFilter});

  @override
  ConsumerState<_FinanceTab> createState() => _FinanceTabState();
}

class _FinanceTabState extends ConsumerState<_FinanceTab> {
  late String _month;
  int _page = 1;

  // We drive fetches by maintaining a Future locally, bypassing the global provider
  late Future<List<FinanceRecord>> _future;

  @override
  void initState() {
    super.initState();
    final now = DateTime.now();
    _month = '${now.year}-${now.month.toString().padLeft(2, '0')}';
    _fetch();
  }

  void _fetch() {
    _future = ref
        .read(financeRepositoryProvider)
        .listRecords(
          type: widget.typeFilter.isEmpty ? null : widget.typeFilter,
          month: _month,
          page: _page,
          pageSize: 50,
        )
        .then((r) => r.data);
  }

  void _refetch() {
    setState(() => _fetch());
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder<List<FinanceRecord>>(
      future: _future,
      builder: (context, snap) {
        if (snap.connectionState == ConnectionState.waiting) {
          return const Center(child: CircularProgressIndicator());
        }
        if (snap.hasError) {
          return Center(
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                Text('加载失败：${snap.error}',
                    style: const TextStyle(color: AppTheme.danger)),
                const SizedBox(height: 12),
                ElevatedButton(
                    onPressed: _refetch, child: const Text('重试')),
              ],
            ),
          );
        }
        return _buildContent(snap.data ?? []);
      },
    );
  }

  Widget _buildContent(List<FinanceRecord> records) {
    final totalAmount = records.fold(0.0, (s, r) => s + r.amount);
    final totalBalance = records.fold(0.0, (s, r) => s + r.balance);
    final totalPaid = totalAmount - totalBalance;

    return Column(
      children: [
        // Summary bar (only for type-filtered tabs)
        if (widget.typeFilter.isNotEmpty && records.isNotEmpty)
          Container(
            color: AppTheme.background,
            padding: const EdgeInsets.all(12),
            child: Row(
              children: [
                _SummaryCard(
                  title: '本期总额',
                  value: '¥${(totalAmount / 10000).toStringAsFixed(2)}万',
                  icon: Icons.account_balance_wallet,
                  color: AppTheme.primary,
                ),
                const SizedBox(width: 12),
                _SummaryCard(
                  title: '已结清',
                  value: '¥${(totalPaid / 10000).toStringAsFixed(2)}万',
                  icon: Icons.check_circle,
                  color: AppTheme.success,
                ),
                const SizedBox(width: 12),
                _SummaryCard(
                  title: '未结清',
                  value: '¥${(totalBalance / 10000).toStringAsFixed(2)}万',
                  icon: Icons.pending_actions,
                  color: AppTheme.danger,
                ),
              ],
            ),
          ),
        if (widget.typeFilter.isNotEmpty && records.isNotEmpty)
          const Divider(height: 1),
        Expanded(
          child: DataTableCard(
            totalCount: records.length,
            page: _page,
            onPageChanged: (p) {
              setState(() {
                _page = p;
                _fetch();
              });
            },
            toolbar: Row(
              children: [
                const Spacer(),
                _MonthSelector(
                  value: _month,
                  onChanged: (v) {
                    _month = v;
                    _page = 1;
                    _refetch();
                  },
                ),
              ],
            ),
            columns: const [
              DataColumn(label: Text('日期')),
              DataColumn(label: Text('类型')),
              DataColumn(label: Text('往来单位')),
              DataColumn(label: Text('关联单据')),
              DataColumn(label: Text('金额'), numeric: true),
              DataColumn(label: Text('余额'), numeric: true),
              DataColumn(label: Text('备注')),
            ],
            rows: records.isEmpty
                ? [
                    DataRow(cells: [
                      const DataCell(SizedBox()),
                      const DataCell(Text('暂无记录',
                          style: TextStyle(color: AppTheme.textSecondary))),
                      const DataCell(SizedBox()),
                      const DataCell(SizedBox()),
                      const DataCell(SizedBox()),
                      const DataCell(SizedBox()),
                      const DataCell(SizedBox()),
                    ])
                  ]
                : records
                    .map((r) => DataRow(cells: [
                          DataCell(Text(
                            r.recordDate?.substring(0, 10) ?? '-',
                            style: const TextStyle(fontSize: 12),
                          )),
                          DataCell(_TypeBadge(r.typeLabel)),
                          DataCell(SizedBox(
                            width: 160,
                            child: Text(r.partnerName ?? '-',
                                overflow: TextOverflow.ellipsis),
                          )),
                          DataCell(Text(
                            r.refType != null && r.refId != null
                                ? '${r.refType!.replaceAll('_', '-')}#${r.refId}'
                                : '-',
                            style: const TextStyle(
                                fontSize: 11,
                                fontFamily: 'monospace',
                                color: AppTheme.primary),
                          )),
                          DataCell(Text(
                            '¥${r.amount.toStringAsFixed(2)}',
                            style: const TextStyle(fontWeight: FontWeight.w500),
                          )),
                          DataCell(Text(
                            '¥${r.balance.toStringAsFixed(2)}',
                            style: TextStyle(
                              color: r.balance > 0
                                  ? AppTheme.danger
                                  : AppTheme.textSecondary,
                              fontWeight: FontWeight.w600,
                            ),
                          )),
                          DataCell(SizedBox(
                            width: 160,
                            child: Text(r.remark ?? '-',
                                overflow: TextOverflow.ellipsis,
                                style: const TextStyle(
                                    fontSize: 12,
                                    color: AppTheme.textSecondary)),
                          )),
                        ]))
                    .toList(),
          ),
        ),
      ],
    );
  }
}

class _TypeBadge extends StatelessWidget {
  final String label;
  const _TypeBadge(this.label);

  @override
  Widget build(BuildContext context) {
    Color bg, fg;
    switch (label) {
      case '应收账款':
        bg = const Color(0xFFE3F2FD);
        fg = AppTheme.primary;
        break;
      case '应付账款':
        bg = const Color(0xFFFFEBEE);
        fg = AppTheme.danger;
        break;
      case '收款':
        bg = const Color(0xFFE8F5E9);
        fg = AppTheme.success;
        break;
      case '付款':
        bg = const Color(0xFFFFF3E0);
        fg = AppTheme.accent;
        break;
      default:
        bg = const Color(0xFFF5F5F5);
        fg = AppTheme.textSecondary;
    }
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 2),
      decoration:
          BoxDecoration(color: bg, borderRadius: BorderRadius.circular(3)),
      child: Text(label,
          style: TextStyle(
              color: fg, fontSize: 12, fontWeight: FontWeight.w500)),
    );
  }
}

class _SummaryCard extends StatelessWidget {
  final String title;
  final String value;
  final IconData icon;
  final Color color;

  const _SummaryCard({
    required this.title,
    required this.value,
    required this.icon,
    required this.color,
  });

  @override
  Widget build(BuildContext context) {
    return Expanded(
      child: Container(
        height: 72,
        padding: const EdgeInsets.symmetric(horizontal: 16),
        decoration: BoxDecoration(
          color: AppTheme.surface,
          borderRadius: BorderRadius.circular(4),
          border: Border.all(color: AppTheme.border, width: 0.5),
        ),
        child: Row(
          children: [
            Container(
              width: 40,
              height: 40,
              decoration: BoxDecoration(
                color: color.withOpacity(0.1),
                borderRadius: BorderRadius.circular(8),
              ),
              child: Icon(icon, color: color, size: 22),
            ),
            const SizedBox(width: 12),
            Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                Text(title,
                    style: const TextStyle(
                        fontSize: 12, color: AppTheme.textSecondary)),
                const SizedBox(height: 4),
                Text(value,
                    style: TextStyle(
                        fontSize: 18,
                        fontWeight: FontWeight.w700,
                        color: color)),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

class _MonthSelector extends StatelessWidget {
  final String value;
  final ValueChanged<String> onChanged;

  const _MonthSelector({required this.value, required this.onChanged});

  @override
  Widget build(BuildContext context) {
    final now = DateTime.now();
    final months = List.generate(12, (i) {
      final d = DateTime(now.year, now.month - i, 1);
      return '${d.year}-${d.month.toString().padLeft(2, '0')}';
    });
    final safeValue = months.contains(value) ? value : months.first;

    return Container(
      height: 36,
      padding: const EdgeInsets.symmetric(horizontal: 8),
      decoration: BoxDecoration(
        border: Border.all(color: AppTheme.border),
        borderRadius: BorderRadius.circular(4),
        color: AppTheme.surface,
      ),
      child: DropdownButtonHideUnderline(
        child: DropdownButton<String>(
          value: safeValue,
          items: months
              .map((m) => DropdownMenuItem(
                  value: m,
                  child: Text(m, style: const TextStyle(fontSize: 13))))
              .toList(),
          onChanged: (v) => onChanged(v!),
          style:
              const TextStyle(fontSize: 13, color: AppTheme.textPrimary),
        ),
      ),
    );
  }
}