import 'dart:ui';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:fl_chart/fl_chart.dart';
import '../../providers/bill_provider.dart';
import '../../widgets/stat_card.dart';
import '../../constants.dart';
import '../../theme/colors.dart';

class StatisticsScreen extends ConsumerStatefulWidget {
  const StatisticsScreen({super.key});

  @override
  ConsumerState<StatisticsScreen> createState() => _StatisticsScreenState();
}

class _StatisticsScreenState extends ConsumerState<StatisticsScreen> {
  int _monthOffset = 0;

  DateTime get _selectedDate {
    final now = DateTime.now();
    return DateTime(now.year, now.month + _monthOffset, 1);
  }

  String get _displayMonth {
    return '${_selectedDate.year}年${_selectedDate.month.toString().padLeft(2, '0')}月';
  }

  List<Bill> _filterBillsByMonth(List<Bill> bills) {
    return bills.where((bill) {
      final billDate = DateTime.tryParse(bill.date);
      if (billDate == null) return false;
      return billDate.year == _selectedDate.year && billDate.month == _selectedDate.month;
    }).toList();
  }

  Map<String, double> _getCategoryTotals(List<Bill> bills, bool isExpense) {
    final Map<String, double> totals = {};
    for (final bill in bills) {
      if (isExpense ? bill.isExpense : bill.isIncome) {
        totals[bill.category] = (totals[bill.category] ?? 0) + bill.amount;
      }
    }
    return totals;
  }

  Map<int, double> _getDailyTotals(List<Bill> bills) {
    final Map<int, double> totals = {};
    for (final bill in bills) {
      if (bill.isExpense) {
        final billDate = DateTime.tryParse(bill.date);
        if (billDate != null) {
          totals[billDate.day] = (totals[billDate.day] ?? 0) + bill.amount;
        }
      }
    }
    return totals;
  }

  List<Map<String, dynamic>> _getMonthlyComparison(List<Bill> bills) {
    final now = DateTime.now();
    final List<Map<String, dynamic>> result = [];
    
    for (int i = 5; i >= 0; i--) {
      final date = DateTime(now.year, now.month - i, 1);
      final monthBills = bills.where((bill) {
        final billDate = DateTime.tryParse(bill.date);
        return billDate != null && billDate.year == date.year && billDate.month == date.month;
      }).toList();
      
      double income = 0;
      double expense = 0;
      for (final bill in monthBills) {
        if (bill.isIncome) income += bill.amount;
        else expense += bill.amount;
      }
      
      result.add({
        'month': '${date.year}-${date.month.toString().padLeft(2, '0')}',
        'income': income,
        'expense': expense,
      });
    }
    return result;
  }

  @override
  Widget build(BuildContext context) {
    final billsAsync = ref.watch(billProvider);
    
    return Scaffold(
      backgroundColor: AppColors.pageBg,
      body: billsAsync.when(
        loading: () => const Center(child: CircularProgressIndicator()),
        error: (e, _) => Center(child: Text('Error: $e')),
        data: (bills) {
          final monthBills = _filterBillsByMonth(bills);
          
          double totalIncome = 0;
          double totalExpense = 0;
          for (final bill in monthBills) {
            if (bill.isIncome) totalIncome += bill.amount;
            else totalExpense += bill.amount;
          }
          final balance = totalIncome - totalExpense;
          
          final expenseCategories = _getCategoryTotals(monthBills, true);
          final incomeCategories = _getCategoryTotals(monthBills, false);
          final dailyTotals = _getDailyTotals(monthBills);
          final monthlyComparison = _getMonthlyComparison(bills);
          
          return CustomScrollView(
            slivers: [
              _buildHeader(),
              SliverToBoxAdapter(
                child: Padding(
                  padding: const EdgeInsets.all(16),
                  child: Column(
                    children: [
                      _buildMonthSelector(),
                      const SizedBox(height: 16),
                      _buildStatCards(totalIncome, totalExpense, balance),
                      const SizedBox(height: 20),
                      _buildPieChart(totalExpense, balance),
                      const SizedBox(height: 20),
                      _buildCategoryRanking(expenseCategories, true),
                      const SizedBox(height: 20),
                      _buildCategoryRanking(incomeCategories, false),
                      const SizedBox(height: 20),
                      _buildDailyBarChart(dailyTotals),
                      const SizedBox(height: 20),
                      _buildMonthlyComparison(monthlyComparison),
                      const SizedBox(height: 40),
                    ],
                  ),
                ),
              ),
            ],
          );
        },
      ),
    );
  }

  Widget _buildHeader() {
    return SliverAppBar(
      expandedHeight: 100,
      floating: false,
      pinned: true,
      backgroundColor: AppColors.brand,
      flexibleSpace: FlexibleSpaceBar(
        title: const Text(
          '统计',
          style: TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
        ),
        background: Container(
          decoration: const BoxDecoration(
            gradient: LinearGradient(
              begin: Alignment.topLeft,
              end: Alignment.bottomRight,
              colors: [AppColors.brand, AppColors.brandLight],
            ),
          ),
        ),
      ),
    );
  }

  Widget _buildMonthSelector() {
    return Container(
      padding: const EdgeInsets.symmetric(vertical: 8, horizontal: 16),
      decoration: BoxDecoration(
        color: AppColors.cardBg,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: Colors.white.withOpacity(0.8)),
      ),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: [
          IconButton(
            icon: const Icon(Icons.chevron_left, color: AppColors.textPrimary),
            onPressed: () => setState(() => _monthOffset--),
          ),
          Text(
            _displayMonth,
            style: const TextStyle(
              fontSize: 16,
              fontWeight: FontWeight.w600,
              color: AppColors.textPrimary,
            ),
          ),
          IconButton(
            icon: const Icon(Icons.chevron_right, color: AppColors.textPrimary),
            onPressed: _monthOffset < 0 ? () => setState(() => _monthOffset++) : null,
          ),
        ],
      ),
    );
  }

  Widget _buildStatCards(double income, double expense, double balance) {
    return Row(
      children: [
        Expanded(
          child: StatCard(
            label: '收入',
            value: '¥${income.toStringAsFixed(2)}',
            color: AppColors.income,
          ),
        ),
        const SizedBox(width: 8),
        Expanded(
          child: StatCard(
            label: '支出',
            value: '¥${expense.toStringAsFixed(2)}',
            color: AppColors.expense,
          ),
        ),
        const SizedBox(width: 8),
        Expanded(
          child: StatCard(
            label: '结余',
            value: '¥${balance.toStringAsFixed(2)}',
            color: balance >= 0 ? AppColors.income : AppColors.expense,
          ),
        ),
      ],
    );
  }

  Widget _buildPieChart(double expense, double balance) {
    final total = expense + balance;
    final usedPercent = total > 0 ? (expense / total * 100) : 0.0;
    final remainingPercent = total > 0 ? (balance / total * 100) : 0.0;
    
    return Container(
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: AppColors.cardBg,
        borderRadius: BorderRadius.circular(20),
        border: Border.all(color: Colors.white.withOpacity(0.8)),
        boxShadow: [
          BoxShadow(
            color: AppColors.brand.withOpacity(0.1),
            blurRadius: 20,
            offset: const Offset(0, 8),
          ),
        ],
      ),
      child: ClipRRect(
        borderRadius: BorderRadius.circular(20),
        child: BackdropFilter(
          filter: ImageFilter.blur(sigmaX: 20, sigmaY: 20),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              const Text(
                '预算使用',
                style: TextStyle(
                  fontSize: 16,
                  fontWeight: FontWeight.w600,
                  color: AppColors.textPrimary,
                ),
              ),
              const SizedBox(height: 16),
              SizedBox(
                height: 180,
                child: total > 0
                    ? PieChart(
                        PieChartData(
                          sectionsSpace: 2,
                          centerSpaceRadius: 40,
                          sections: [
                            PieChartSectionData(
                              value: expense,
                              color: AppColors.expense,
                              title: '${usedPercent.toStringAsFixed(1)}%',
                              titleStyle: const TextStyle(
                                fontSize: 12,
                                fontWeight: FontWeight.bold,
                                color: Colors.white,
                              ),
                              radius: 50,
                            ),
                            PieChartSectionData(
                              value: balance,
                              color: AppColors.income,
                              title: '${remainingPercent.toStringAsFixed(1)}%',
                              titleStyle: const TextStyle(
                                fontSize: 12,
                                fontWeight: FontWeight.bold,
                                color: Colors.white,
                              ),
                              radius: 50,
                            ),
                          ],
                        ),
                      )
                    : const Center(
                        child: Text(
                          '暂无数据',
                          style: TextStyle(color: AppColors.textSecondary),
                        ),
                      ),
              ),
              const SizedBox(height: 16),
              Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  _buildLegendItem('已支出', AppColors.expense),
                  const SizedBox(width: 24),
                  _buildLegendItem('剩余', AppColors.income),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildLegendItem(String label, Color color) {
    return Row(
      children: [
        Container(
          width: 12,
          height: 12,
          decoration: BoxDecoration(
            color: color,
            borderRadius: BorderRadius.circular(3),
          ),
        ),
        const SizedBox(width: 6),
        Text(
          label,
          style: const TextStyle(
            fontSize: 12,
            color: AppColors.textSecondary,
          ),
        ),
      ],
    );
  }

  Widget _buildCategoryRanking(Map<String, double> categories, bool isExpense) {
    if (categories.isEmpty) {
      return Container(
        padding: const EdgeInsets.all(16),
        decoration: BoxDecoration(
          color: AppColors.cardBg,
          borderRadius: BorderRadius.circular(20),
          border: Border.all(color: Colors.white.withOpacity(0.8)),
        ),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(
              isExpense ? '支出分类' : '收入分类',
              style: const TextStyle(
                fontSize: 16,
                fontWeight: FontWeight.w600,
                color: AppColors.textPrimary,
              ),
            ),
            const SizedBox(height: 16),
            const Center(
              child: Text(
                '暂无数据',
                style: TextStyle(color: AppColors.textSecondary),
              ),
            ),
          ],
        ),
      );
    }

    final sortedEntries = categories.entries.toList()
      ..sort((a, b) => b.value.compareTo(a.value));
    final maxAmount = sortedEntries.first.value;

    return Container(
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: AppColors.cardBg,
        borderRadius: BorderRadius.circular(20),
        border: Border.all(color: Colors.white.withOpacity(0.8)),
      ),
      child: ClipRRect(
        borderRadius: BorderRadius.circular(20),
        child: BackdropFilter(
          filter: ImageFilter.blur(sigmaX: 20, sigmaY: 20),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                isExpense ? '支出分类' : '收入分类',
                style: const TextStyle(
                  fontSize: 16,
                  fontWeight: FontWeight.w600,
                  color: AppColors.textPrimary,
                ),
              ),
              const SizedBox(height: 16),
              ...sortedEntries.take(6).map((entry) {
                final emoji = AppConstants.categoryEmoji(entry.key);
                final progress = maxAmount > 0 ? entry.value / maxAmount : 0.0;
                
                return Padding(
                  padding: const EdgeInsets.only(bottom: 12),
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Row(
                        children: [
                          Text(emoji, style: const TextStyle(fontSize: 16)),
                          const SizedBox(width: 8),
                          Expanded(
                            child: Text(
                              entry.key,
                              style: const TextStyle(
                                fontSize: 13,
                                color: AppColors.textPrimary,
                              ),
                            ),
                          ),
                          Text(
                            '¥${entry.value.toStringAsFixed(2)}',
                            style: TextStyle(
                              fontSize: 13,
                              fontWeight: FontWeight.w600,
                              color: isExpense ? AppColors.expense : AppColors.income,
                            ),
                          ),
                        ],
                      ),
                      const SizedBox(height: 6),
                      ClipRRect(
                        borderRadius: BorderRadius.circular(4),
                        child: LinearProgressIndicator(
                          value: progress,
                          backgroundColor: Colors.grey.shade200,
                          valueColor: AlwaysStoppedAnimation(
                            isExpense ? AppColors.expense : AppColors.income,
                          ),
                          minHeight: 6,
                        ),
                      ),
                    ],
                  ),
                );
              }),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildDailyBarChart(Map<int, double> dailyTotals) {
    final spots = <FlSpot>[];
    for (int day = 1; day <= 31; day++) {
      spots.add(FlSpot(day.toDouble(), dailyTotals[day] ?? 0));
    }
    
    final maxY = dailyTotals.values.isEmpty 
        ? 100.0 
        : dailyTotals.values.reduce((a, b) => a > b ? a : b) * 1.2;

    return Container(
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: AppColors.cardBg,
        borderRadius: BorderRadius.circular(20),
        border: Border.all(color: Colors.white.withOpacity(0.8)),
      ),
      child: ClipRRect(
        borderRadius: BorderRadius.circular(20),
        child: BackdropFilter(
          filter: ImageFilter.blur(sigmaX: 20, sigmaY: 20),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              const Text(
                '日消费趋势',
                style: TextStyle(
                  fontSize: 16,
                  fontWeight: FontWeight.w600,
                  color: AppColors.textPrimary,
                ),
              ),
              const SizedBox(height: 16),
              SizedBox(
                height: 180,
                child: BarChart(
                  BarChartData(
                    alignment: BarChartAlignment.spaceAround,
                    maxY: maxY,
                    barTouchData: BarTouchData(
                      touchTooltipData: BarTouchTooltipData(
                        getTooltipItem: (group, groupIndex, rod, rodIndex) {
                          return BarTooltipItem(
                            '¥${rod.toY.toStringAsFixed(2)}',
                            const TextStyle(color: Colors.white, fontSize: 12),
                          );
                        },
                      ),
                    ),
                    titlesData: FlTitlesData(
                      show: true,
                      bottomTitles: AxisTitles(
                        sideTitles: SideTitles(
                          showTitles: true,
                          getTitlesWidget: (value, meta) {
                            if (value.toInt() % 5 == 0) {
                              return Text(
                                '${value.toInt()}日',
                                style: const TextStyle(
                                  fontSize: 10,
                                  color: AppColors.textSecondary,
                                ),
                              );
                            }
                            return const SizedBox.shrink();
                          },
                          reservedSize: 20,
                        ),
                      ),
                      leftTitles: AxisTitles(
                        sideTitles: SideTitles(
                          showTitles: true,
                          getTitlesWidget: (value, meta) {
                            return Text(
                              '¥${value.toInt()}',
                              style: const TextStyle(
                                fontSize: 10,
                                color: AppColors.textSecondary,
                              ),
                            );
                          },
                          reservedSize: 40,
                        ),
                      ),
                      topTitles: const AxisTitles(sideTitles: SideTitles(showTitles: false)),
                      rightTitles: const AxisTitles(sideTitles: SideTitles(showTitles: false)),
                    ),
                    gridData: FlGridData(
                      show: true,
                      drawVerticalLine: false,
                      horizontalInterval: maxY / 4,
                      getDrawingHorizontalLine: (value) {
                        return FlLine(
                          color: Colors.grey.shade200,
                          strokeWidth: 1,
                        );
                      },
                    ),
                    borderData: FlBorderData(show: false),
                    barGroups: List.generate(31, (index) {
                      final day = index + 1;
                      final value = dailyTotals[day] ?? 0;
                      return BarChartGroupData(
                        x: day,
                        barRods: [
                          BarChartRodData(
                            toY: value,
                            color: AppColors.brand,
                            width: 8,
                            borderRadius: const BorderRadius.vertical(top: Radius.circular(4)),
                          ),
                        ],
                      );
                    }),
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildMonthlyComparison(List<Map<String, dynamic>> months) {
    double maxValue = 0;
    for (final month in months) {
      final income = month['income'] as double;
      final expense = month['expense'] as double;
      if (income > maxValue) maxValue = income;
      if (expense > maxValue) maxValue = expense;
    }
    if (maxValue == 0) maxValue = 1000;

    return Container(
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: AppColors.cardBg,
        borderRadius: BorderRadius.circular(20),
        border: Border.all(color: Colors.white.withOpacity(0.8)),
      ),
      child: ClipRRect(
        borderRadius: BorderRadius.circular(20),
        child: BackdropFilter(
          filter: ImageFilter.blur(sigmaX: 20, sigmaY: 20),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              const Text(
                '月度对比',
                style: TextStyle(
                  fontSize: 16,
                  fontWeight: FontWeight.w600,
                  color: AppColors.textPrimary,
                ),
              ),
              const SizedBox(height: 16),
              ...months.map((month) {
                final monthStr = month['month'] as String;
                final income = month['income'] as double;
                final expense = month['expense'] as double;
                final monthLabel = monthStr.substring(5);
                
                return Padding(
                  padding: const EdgeInsets.only(bottom: 12),
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Row(
                        mainAxisAlignment: MainAxisAlignment.spaceBetween,
                        children: [
                          Text(
                            '$monthLabel月',
                            style: const TextStyle(
                              fontSize: 12,
                              color: AppColors.textSecondary,
                            ),
                          ),
                          Row(
                            children: [
                              Text(
                                '收¥${income.toStringAsFixed(0)}',
                                style: const TextStyle(
                                  fontSize: 11,
                                  color: AppColors.income,
                                ),
                              ),
                              const SizedBox(width: 8),
                              Text(
                                '支¥${expense.toStringAsFixed(0)}',
                                style: const TextStyle(
                                  fontSize: 11,
                                  color: AppColors.expense,
                                ),
                              ),
                            ],
                          ),
                        ],
                      ),
                      const SizedBox(height: 6),
                      Row(
                        children: [
                          Expanded(
                            child: ClipRRect(
                              borderRadius: BorderRadius.circular(3),
                              child: LinearProgressIndicator(
                                value: maxValue > 0 ? income / maxValue : 0,
                                backgroundColor: Colors.grey.shade200,
                                valueColor: const AlwaysStoppedAnimation(AppColors.income),
                                minHeight: 8,
                              ),
                            ),
                          ),
                          const SizedBox(width: 8),
                          Expanded(
                            child: ClipRRect(
                              borderRadius: BorderRadius.circular(3),
                              child: LinearProgressIndicator(
                                value: maxValue > 0 ? expense / maxValue : 0,
                                backgroundColor: Colors.grey.shade200,
                                valueColor: const AlwaysStoppedAnimation(AppColors.expense),
                                minHeight: 8,
                              ),
                            ),
                          ),
                        ],
                      ),
                    ],
                  ),
                );
              }),
            ],
          ),
        ),
      ),
    );
  }
}