import 'package:flutter/material.dart';
import '../../../../app/theme/app_colors.dart';
import '../../../../app/theme/app_typography.dart';
import '../../../../app/theme/app_spacing.dart';

/// 对账与结算报表页面
///
/// 支持按日/周/月/季度查看对账数据
/// 包含：汇总卡片、对账明细表、自动对账状态、差异调查、导出功能
class ReconciliationPage extends StatefulWidget {
  const ReconciliationPage({super.key});

  @override
  State<ReconciliationPage> createState() => _ReconciliationPageState();
}

class _ReconciliationPageState extends State<ReconciliationPage> {
  String _selectedPeriod = '月';
  final _periods = ['日', '周', '月', '季度'];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('对账与结算'),
        actions: [
          IconButton(
            icon: const Icon(Icons.download_rounded),
            onPressed: () => _showExportDialog(context),
            tooltip: '导出报表',
          ),
        ],
      ),
      body: SingleChildScrollView(
        padding: const EdgeInsets.all(20),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            // Period Selector
            _buildPeriodSelector(),
            const SizedBox(height: 20),

            // Summary Cards
            _buildSummaryCards(),
            const SizedBox(height: 24),

            // Auto-reconciliation Status
            _buildAutoReconciliationStatus(),
            const SizedBox(height: 24),

            // Reconciliation Table
            _buildReconciliationTable(),
            const SizedBox(height: 24),

            // Discrepancy Details
            _buildDiscrepancySection(),
            const SizedBox(height: 24),

            // Export Buttons
            _buildExportButtons(),
          ],
        ),
      ),
    );
  }

  // ============================================================
  // Period Selector
  // ============================================================

  Widget _buildPeriodSelector() {
    return Container(
      padding: const EdgeInsets.all(4),
      decoration: BoxDecoration(
        color: AppColors.gray50,
        borderRadius: BorderRadius.circular(AppSpacing.radiusSm),
      ),
      child: Row(
        children: _periods.map((p) {
          final isSelected = _selectedPeriod == p;
          return Expanded(
            child: GestureDetector(
              onTap: () => setState(() => _selectedPeriod = p),
              child: Container(
                padding: const EdgeInsets.symmetric(vertical: 10),
                decoration: BoxDecoration(
                  color: isSelected ? AppColors.surface : Colors.transparent,
                  borderRadius: BorderRadius.circular(AppSpacing.radiusSm - 2),
                  boxShadow: isSelected ? AppSpacing.shadowSm : null,
                ),
                child: Center(
                  child: Text(
                    p,
                    style: AppTypography.labelMedium.copyWith(
                      color: isSelected ? AppColors.primary : AppColors.textSecondary,
                      fontWeight: isSelected ? FontWeight.w600 : FontWeight.w400,
                    ),
                  ),
                ),
              ),
            ),
          );
        }).toList(),
      ),
    );
  }

  // ============================================================
  // Summary Cards
  // ============================================================

  Widget _buildSummaryCards() {
    final summaries = [
      ('应结金额', '\$132,490', AppColors.primary, Icons.account_balance_rounded),
      ('已结金额', '\$118,200', AppColors.success, Icons.check_circle_rounded),
      ('待结金额', '\$12,180', AppColors.warning, Icons.schedule_rounded),
      ('差异金额', '\$2,110', AppColors.error, Icons.error_outline_rounded),
    ];

    return GridView.builder(
      shrinkWrap: true,
      physics: const NeverScrollableScrollPhysics(),
      gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
        crossAxisCount: 2,
        mainAxisSpacing: 12,
        crossAxisSpacing: 12,
        childAspectRatio: 1.6,
      ),
      itemCount: summaries.length,
      itemBuilder: (context, index) {
        final (label, value, color, icon) = summaries[index];
        return Container(
          padding: const EdgeInsets.all(14),
          decoration: BoxDecoration(
            color: AppColors.surface,
            borderRadius: BorderRadius.circular(AppSpacing.radiusMd),
            border: Border.all(color: AppColors.borderLight),
          ),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [
              Row(
                children: [
                  Icon(icon, color: color, size: 16),
                  const SizedBox(width: 6),
                  Text(label, style: AppTypography.bodySmall),
                ],
              ),
              Text(
                value,
                style: AppTypography.h2.copyWith(color: color),
              ),
            ],
          ),
        );
      },
    );
  }

  // ============================================================
  // Auto-reconciliation Status
  // ============================================================

  Widget _buildAutoReconciliationStatus() {
    const matchRate = 96.8;
    return Container(
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: AppColors.surface,
        borderRadius: BorderRadius.circular(AppSpacing.radiusMd),
        border: Border.all(color: AppColors.borderLight),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              Container(
                width: 36,
                height: 36,
                decoration: BoxDecoration(
                  color: AppColors.successLight,
                  borderRadius: BorderRadius.circular(AppSpacing.radiusSm),
                ),
                child: const Icon(Icons.auto_fix_high_rounded, color: AppColors.success, size: 18),
              ),
              const SizedBox(width: 12),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text('自动对账', style: AppTypography.labelMedium),
                    Text('上次运行: 今天 06:00', style: AppTypography.caption),
                  ],
                ),
              ),
              Container(
                padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 4),
                decoration: BoxDecoration(
                  color: AppColors.successLight,
                  borderRadius: BorderRadius.circular(AppSpacing.radiusFull),
                ),
                child: Text(
                  '运行中',
                  style: AppTypography.caption.copyWith(
                    color: AppColors.success,
                    fontWeight: FontWeight.w600,
                  ),
                ),
              ),
            ],
          ),
          const SizedBox(height: 16),
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [
              Text('匹配率', style: AppTypography.bodySmall),
              Text(
                '$matchRate%',
                style: AppTypography.labelMedium.copyWith(color: AppColors.success),
              ),
            ],
          ),
          const SizedBox(height: 8),
          ClipRRect(
            borderRadius: BorderRadius.circular(4),
            child: LinearProgressIndicator(
              value: matchRate / 100,
              backgroundColor: AppColors.gray100,
              valueColor: const AlwaysStoppedAnimation(AppColors.success),
              minHeight: 8,
            ),
          ),
          const SizedBox(height: 12),
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [
              _buildMiniStat('已匹配', '4,832', AppColors.success),
              _buildMiniStat('待核查', '158', AppColors.warning),
              _buildMiniStat('有差异', '12', AppColors.error),
            ],
          ),
        ],
      ),
    );
  }

  Widget _buildMiniStat(String label, String value, Color color) {
    return Column(
      children: [
        Text(
          value,
          style: AppTypography.labelLarge.copyWith(color: color),
        ),
        const SizedBox(height: 2),
        Text(label, style: AppTypography.caption),
      ],
    );
  }

  // ============================================================
  // Reconciliation Table
  // ============================================================

  Widget _buildReconciliationTable() {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text('对账明细', style: AppTypography.h3),
        const SizedBox(height: 12),
        Container(
          decoration: BoxDecoration(
            color: AppColors.surface,
            borderRadius: BorderRadius.circular(AppSpacing.radiusMd),
            border: Border.all(color: AppColors.borderLight),
          ),
          child: Column(
            children: [
              // Table Header
              Container(
                padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 12),
                decoration: const BoxDecoration(
                  color: AppColors.gray50,
                  borderRadius: BorderRadius.only(
                    topLeft: Radius.circular(12),
                    topRight: Radius.circular(12),
                  ),
                ),
                child: Row(
                  children: [
                    Expanded(flex: 2, child: Text('期间', style: AppTypography.labelSmall)),
                    Expanded(flex: 2, child: Text('应结', style: AppTypography.labelSmall)),
                    Expanded(flex: 2, child: Text('实结', style: AppTypography.labelSmall)),
                    Expanded(flex: 2, child: Text('差异', style: AppTypography.labelSmall)),
                    Expanded(flex: 2, child: Text('状态', style: AppTypography.labelSmall)),
                  ],
                ),
              ),
              // Table Rows
              ..._mockReconciliationData.map((row) {
                final (period, expected, actual, diff, status) = row;
                return Container(
                  padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 12),
                  decoration: const BoxDecoration(
                    border: Border(
                      bottom: BorderSide(color: AppColors.borderLight, width: 0.5),
                    ),
                  ),
                  child: Row(
                    children: [
                      Expanded(
                        flex: 2,
                        child: Text(period, style: AppTypography.bodySmall.copyWith(color: AppColors.textPrimary)),
                      ),
                      Expanded(
                        flex: 2,
                        child: Text(expected, style: AppTypography.bodySmall.copyWith(color: AppColors.textPrimary)),
                      ),
                      Expanded(
                        flex: 2,
                        child: Text(actual, style: AppTypography.bodySmall.copyWith(color: AppColors.textPrimary)),
                      ),
                      Expanded(
                        flex: 2,
                        child: Text(
                          diff,
                          style: AppTypography.bodySmall.copyWith(
                            color: diff == '\$0' ? AppColors.textTertiary : AppColors.error,
                          ),
                        ),
                      ),
                      Expanded(
                        flex: 2,
                        child: _buildReconciliationStatus(status),
                      ),
                    ],
                  ),
                );
              }),
            ],
          ),
        ),
      ],
    );
  }

  Widget _buildReconciliationStatus(String status) {
    Color color;
    Color bgColor;
    switch (status) {
      case '已对账':
        color = AppColors.success;
        bgColor = AppColors.successLight;
        break;
      case '有差异':
        color = AppColors.error;
        bgColor = AppColors.errorLight;
        break;
      default:
        color = AppColors.warning;
        bgColor = AppColors.warningLight;
    }
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
      decoration: BoxDecoration(
        color: bgColor,
        borderRadius: BorderRadius.circular(AppSpacing.radiusFull),
      ),
      child: Text(
        status,
        style: TextStyle(fontSize: 10, color: color, fontWeight: FontWeight.w600),
        textAlign: TextAlign.center,
      ),
    );
  }

  // ============================================================
  // Discrepancy Details
  // ============================================================

  Widget _buildDiscrepancySection() {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            Text('差异调查', style: AppTypography.h3),
            Container(
              padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 3),
              decoration: BoxDecoration(
                color: AppColors.errorLight,
                borderRadius: BorderRadius.circular(AppSpacing.radiusFull),
              ),
              child: Text(
                '3 项待处理',
                style: AppTypography.caption.copyWith(
                  color: AppColors.error,
                  fontWeight: FontWeight.w600,
                ),
              ),
            ),
          ],
        ),
        const SizedBox(height: 12),
        ..._mockDiscrepancies.map((d) {
          final (desc, amount, investigationStatus, date) = d;
          Color statusColor;
          switch (investigationStatus) {
            case '调查中':
              statusColor = AppColors.warning;
              break;
            case '已解决':
              statusColor = AppColors.success;
              break;
            default:
              statusColor = AppColors.error;
          }
          return Container(
            margin: const EdgeInsets.only(bottom: 10),
            padding: const EdgeInsets.all(14),
            decoration: BoxDecoration(
              color: AppColors.surface,
              borderRadius: BorderRadius.circular(AppSpacing.radiusMd),
              border: Border.all(color: AppColors.borderLight),
            ),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Row(
                  children: [
                    Expanded(
                      child: Text(desc, style: AppTypography.labelMedium),
                    ),
                    Container(
                      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 3),
                      decoration: BoxDecoration(
                        color: statusColor.withValues(alpha: 0.1),
                        borderRadius: BorderRadius.circular(AppSpacing.radiusFull),
                      ),
                      child: Text(
                        investigationStatus,
                        style: AppTypography.caption.copyWith(
                          color: statusColor,
                          fontWeight: FontWeight.w600,
                        ),
                      ),
                    ),
                  ],
                ),
                const SizedBox(height: 8),
                Row(
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: [
                    Text(
                      '差异金额: $amount',
                      style: AppTypography.bodySmall.copyWith(color: AppColors.error),
                    ),
                    Text(date, style: AppTypography.caption),
                  ],
                ),
              ],
            ),
          );
        }),
      ],
    );
  }

  // ============================================================
  // Export Buttons
  // ============================================================

  Widget _buildExportButtons() {
    return Container(
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: AppColors.surface,
        borderRadius: BorderRadius.circular(AppSpacing.radiusMd),
        border: Border.all(color: AppColors.borderLight),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text('导出报表', style: AppTypography.h3),
          const SizedBox(height: 14),
          Row(
            children: [
              Expanded(
                child: OutlinedButton.icon(
                  onPressed: () {
                    // TODO: Export reconciliation report as PDF
                  },
                  icon: const Icon(Icons.picture_as_pdf_rounded, size: 18),
                  label: const Text('导出 PDF'),
                  style: OutlinedButton.styleFrom(
                    minimumSize: const Size(0, 48),
                    foregroundColor: AppColors.error,
                    side: const BorderSide(color: AppColors.error, width: 1),
                  ),
                ),
              ),
              const SizedBox(width: 12),
              Expanded(
                child: OutlinedButton.icon(
                  onPressed: () {
                    // TODO: Export reconciliation report as Excel
                  },
                  icon: const Icon(Icons.table_chart_rounded, size: 18),
                  label: const Text('导出 Excel'),
                  style: OutlinedButton.styleFrom(
                    minimumSize: const Size(0, 48),
                    foregroundColor: AppColors.success,
                    side: const BorderSide(color: AppColors.success, width: 1),
                  ),
                ),
              ),
            ],
          ),
        ],
      ),
    );
  }

  // ============================================================
  // Export Dialog
  // ============================================================

  void _showExportDialog(BuildContext context) {
    showDialog(
      context: context,
      builder: (ctx) => SimpleDialog(
        title: const Text('导出对账报表'),
        children: [
          SimpleDialogOption(
            onPressed: () => Navigator.pop(ctx),
            child: const Row(
              children: [
                Icon(Icons.picture_as_pdf_rounded, color: AppColors.error, size: 20),
                SizedBox(width: 12),
                Text('导出 PDF'),
              ],
            ),
          ),
          SimpleDialogOption(
            onPressed: () => Navigator.pop(ctx),
            child: const Row(
              children: [
                Icon(Icons.table_chart_rounded, color: AppColors.success, size: 20),
                SizedBox(width: 12),
                Text('导出 Excel'),
              ],
            ),
          ),
          SimpleDialogOption(
            onPressed: () => Navigator.pop(ctx),
            child: const Row(
              children: [
                Icon(Icons.description_rounded, color: AppColors.info, size: 20),
                SizedBox(width: 12),
                Text('导出 CSV'),
              ],
            ),
          ),
        ],
      ),
    );
  }
}

// ============================================================
// Mock Data
// ============================================================

const _mockReconciliationData = [
  ('2026年1月', '\$32,100', '\$32,100', '\$0', '已对账'),
  ('2025年12月', '\$28,450', '\$28,450', '\$0', '已对账'),
  ('2025年11月', '\$25,800', '\$24,690', '\$1,110', '有差异'),
  ('2025年10月', '\$30,200', '\$30,200', '\$0', '已对账'),
  ('2025年9月', '\$22,940', '\$22,940', '\$0', '已对账'),
  ('2025年8月', '\$18,600', '\$17,600', '\$1,000', '有差异'),
  ('2025年7月', '\$15,400', '\$15,400', '\$0', '待对账'),
];

const _mockDiscrepancies = [
  ('11月退款差异 - 部分退款未入账', '\$780', '调查中', '2025-12-15'),
  ('11月手续费差异 - 费率计算偏差', '\$330', '调查中', '2025-12-12'),
  ('8月核销结算延迟', '\$1,000', '已解决', '2025-09-20'),
];