import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../core/network/api_exception.dart';
import '../../models/statistics_response.dart';
import '../../providers/statistics_provider.dart';
import '../../utils/amount_util.dart';
import '../../widgets/state_views.dart';
import 'widgets/category_pie_card.dart';
import 'widgets/category_rank_list.dart';

/// 统计页：按日/周/月切换 + 汇总 + 分类占比饼图 + 分类明细
class StatisticsPage extends ConsumerWidget {
  const StatisticsPage({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final tab = ref.watch(statisticsTabProvider);
    final statsAsync = ref.watch(statisticsProvider(tab));

    return Scaffold(
      body: Container(
        width: double.infinity,
        height: double.infinity,
        decoration: const BoxDecoration(
          gradient: LinearGradient(
            begin: Alignment.topLeft,
            end: Alignment.bottomRight,
            colors: [Color(0xFFFFE5CC), Color(0xFFFFD4A8), Color(0xFFFFC08A)],
          ),
        ),
        child: SafeArea(
          child: ListView(
            physics: const AlwaysScrollableScrollPhysics(),
            padding: const EdgeInsets.fromLTRB(16, 12, 16, 0),
            children: [
              const Text(
                '统计分析',
                style: TextStyle(
                  fontSize: 20,
                  fontWeight: FontWeight.bold,
                  color: Color(0xFF5D4037),
                ),
              ),
              const SizedBox(height: 14),
              _tabBar(tab, ref),
              const SizedBox(height: 14),
              _content(ref, statsAsync),
              const SizedBox(height: 90), // 底部导航避让
            ],
          ),
        ),
      ),
    );
  }

  // ---- 时间粒度切换 ----
  Widget _tabBar(StatisticsTab current, WidgetRef ref) {
    return Container(
      padding: const EdgeInsets.all(4),
      decoration: BoxDecoration(
        color: Colors.white.withValues(alpha: 0.9),
        borderRadius: BorderRadius.circular(14),
        border: Border.all(color: const Color(0xFFC8956E)),
      ),
      child: Row(
        children: [
          _tabItem('按日', StatisticsTab.daily, current, ref),
          _tabItem('按周', StatisticsTab.weekly, current, ref),
          _tabItem('按月', StatisticsTab.monthly, current, ref),
        ],
      ),
    );
  }

  Widget _tabItem(String text, StatisticsTab tab, StatisticsTab current, WidgetRef ref) {
    final active = current == tab;
    return Expanded(
      child: GestureDetector(
        onTap: () => ref.read(statisticsTabProvider.notifier).set(tab),
        child: AnimatedContainer(
          duration: const Duration(milliseconds: 200),
          padding: const EdgeInsets.symmetric(vertical: 10),
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(10),
            gradient: active
                ? const LinearGradient(colors: [Color(0xFFC8956E), Color(0xFFF5D59E)])
                : null,
          ),
          child: Center(
            child: Text(
              text,
              style: TextStyle(
                fontSize: 14.5,
                fontWeight: FontWeight.w600,
                color: active ? const Color(0xFF5D4037) : const Color(0xFF8D6E63),
              ),
            ),
          ),
        ),
      ),
    );
  }

  // ---- 内容区 ----
  Widget _content(WidgetRef ref, AsyncValue<StatisticsResponse> statsAsync) {
    return statsAsync.when(
      loading: () => const LoadingView(),
      error: (e, _) => ErrorView(
        message: asApiException(e).message,
        onRetry: () => ref.invalidate(statisticsProvider),
      ),
      data: (stats) => Column(
        children: [
          _summaryCard(stats),
          const SizedBox(height: 12),
          if (stats.categoryStatistics.isEmpty)
            const EmptyView(title: '暂无统计数据', tip: '所选时间范围内还没有账单')
          else ...[
            CategoryPieCard(stats: stats),
            const SizedBox(height: 12),
            CategoryRankList(stats: stats),
          ],
        ],
      ),
    );
  }

  // ---- 汇总卡 ----
  Widget _summaryCard(StatisticsResponse stats) {
    return Container(
      padding: const EdgeInsets.symmetric(vertical: 18),
      decoration: BoxDecoration(
        borderRadius: BorderRadius.circular(18),
        gradient: const LinearGradient(
          colors: [Color(0xFFC8956E), Color(0xFFF5D59E), Color(0xFFFFD700)],
        ),
        boxShadow: [
          BoxShadow(
            color: const Color(0xFF5D4037).withValues(alpha: 0.18),
            blurRadius: 10,
            offset: const Offset(0, 4),
          ),
        ],
      ),
      child: Row(
        children: [
          _summaryItem('总收入', stats.totalIncome, const Color(0xFF1B5E20)),
          _vDivider(),
          _summaryItem('总支出', stats.totalExpense, const Color(0xFFB71C1C)),
          _vDivider(),
          _summaryItem('余额', stats.balance, const Color(0xFF3E2723)),
        ],
      ),
    );
  }

  Widget _summaryItem(String label, double amount, Color color) {
    return Expanded(
      child: Column(
        children: [
          Text(
            label,
            style: const TextStyle(fontSize: 12, color: Color(0xFF4E342E)),
          ),
          const SizedBox(height: 6),
          Text(
            '¥${formatAmount(amount)}',
            style: TextStyle(fontSize: 15, fontWeight: FontWeight.bold, color: color),
          ),
        ],
      ),
    );
  }

  Widget _vDivider() =>
      Container(width: 1, height: 26, color: const Color(0xFF5D4037).withValues(alpha: 0.25));
}