import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'package:japp_flutter/core/models/challenge_model.dart';
import 'package:japp_flutter/features/challenge/view_models/challenge_view_model.dart';
import 'package:provider/provider.dart';

class ChallengeListScreen extends StatefulWidget {
  const ChallengeListScreen({super.key});

  @override
  State<ChallengeListScreen> createState() => _ChallengeListScreenState();
}

class _ChallengeListScreenState extends State<ChallengeListScreen> {
  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      Provider.of<ChallengeListViewModel>(context, listen: false).fetchChallenges();
    });
  }

  @override
  Widget build(BuildContext context) {
    final viewModel = Provider.of<ChallengeListViewModel>(context);
    
    return Scaffold(
      appBar: AppBar(
        title: const Text('挑战列表'),
        actions: [
          IconButton(
            icon: const Icon(Icons.refresh),
            onPressed: viewModel.fetchChallenges,
          ),
        ],
      ),
      body: _buildBody(viewModel),
    );
  }

  Widget _buildBody(ChallengeListViewModel viewModel) {
    if (viewModel.isLoading) {
      return const Center(child: CircularProgressIndicator());
    }
    
    if (viewModel.error.isNotEmpty) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Icon(Icons.error, color: Colors.red, size: 48),
            const SizedBox(height: 16),
            Text(viewModel.error, style: const TextStyle(color: Colors.red)),
            const SizedBox(height: 16),
            ElevatedButton(
              onPressed: viewModel.fetchChallenges,
              child: const Text('重试'),
            ),
          ],
        ),
      );
    }
    
    if (viewModel.challenges.isEmpty) {
      return const Center(
        child: Text('暂无挑战', style: TextStyle(fontSize: 18)),
      );
    }
    
    return RefreshIndicator(
      onRefresh: viewModel.fetchChallenges,
      child: ListView.builder(
        padding: const EdgeInsets.all(16),
        itemCount: viewModel.challenges.length,
        itemBuilder: (context, index) {
          return ChallengeCard(challenge: viewModel.challenges[index]);
        },
      ),
    );
  }
}

class ChallengeCard extends StatelessWidget {
  final ChallengeModel challenge;

  const ChallengeCard({super.key, required this.challenge});

  Color _getDifficultyColor() {
    switch (challenge.difficulty) {
      case '简单':
        return Colors.green;
      case '中等':
        return Colors.orange;
      case '困难':
        return Colors.red;
      default:
        return Colors.grey;
    }
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);  // 获取当前主题
    
    return Card(
      elevation: 2,
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
      margin: const EdgeInsets.only(bottom: 16),
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              children: [
                Expanded(
                  child: Text(
                    challenge.title,
                    style: const TextStyle(
                      fontSize: 18,
                      fontWeight: FontWeight.bold,
                    ),
                  ),
                ),
                Chip(
                  label: Text(
                    challenge.difficulty,
                    style: const TextStyle(color: Colors.white),
                  ),
                  backgroundColor: _getDifficultyColor(),
                ),
              ],
            ),
            const SizedBox(height: 8),
            Text(
              challenge.description,
              style: TextStyle(color: Colors.grey[700], fontSize: 14),
            ),
            const SizedBox(height: 16),
            _buildProgressBar(context),
            const SizedBox(height: 12),
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                _buildInfoChip(
                  Icons.people,
                  '${challenge.participants}人参加',
                ),
                _buildInfoChip(
                  Icons.calendar_today,
                  '剩余${challenge.remainingDays}天',
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildProgressBar(BuildContext context) {
    final theme = Theme.of(context);
    final totalDays = challenge.endDate.difference(challenge.startDate).inDays;
    final passedDays = totalDays - challenge.remainingDays;
    final progress = passedDays / totalDays;

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text(
          '${(progress * 100).toStringAsFixed(0)}%',
          style: const TextStyle(fontSize: 12),
        ),
        const SizedBox(height: 4),
        LinearProgressIndicator(
          value: progress,
          backgroundColor: Colors.grey[200],
          borderRadius: BorderRadius.circular(10),
          minHeight: 8,
          color: theme.primaryColor,  // 使用主题色
        ),
        const SizedBox(height: 4),
        Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            Text(
              DateFormat('MM/dd').format(challenge.startDate),
              style: const TextStyle(fontSize: 12),
            ),
            Text(
              DateFormat('MM/dd').format(challenge.endDate),
              style: const TextStyle(fontSize: 12),
            ),
          ],
        ),
      ],
    );
  }

  Widget _buildInfoChip(IconData icon, String text) {
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
      decoration: BoxDecoration(
        color: Colors.grey[100],
        borderRadius: BorderRadius.circular(20),
      ),
      child: Row(
        children: [
          Icon(icon, size: 16, color: Colors.grey[600]),
          const SizedBox(width: 4),
          Text(text, style: TextStyle(color: Colors.grey[700])),
        ],
      ),
    );
  }
}