import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:intl/intl.dart';
import '../../data/models/maintenance_dto.dart';
import 'controllers/maintenance_controller.dart';
import 'maintenance_form_dialog.dart';

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

  @override
  State<MaintenanceAlertDashboard> createState() => _MaintenanceAlertDashboardState();
}

class _MaintenanceAlertDashboardState extends State<MaintenanceAlertDashboard> {
  @override
  void initState() {
    super.initState();
    
    // 초기 데이터 로드
    WidgetsBinding.instance.addPostFrameCallback((_) {
      final controller = context.read<MaintenanceController>();
      controller.loadAlerts();
      controller.loadMaintenances(refresh: true);
    });
  }
  
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.grey[100],
      body: Consumer<MaintenanceController>(
        builder: (context, controller, child) {
          if (controller.isLoading && controller.upcomingAlerts.isEmpty) {
            return const Center(child: CircularProgressIndicator());
          }
          
          return RefreshIndicator(
            onRefresh: () async {
              await controller.loadAlerts();
            },
            child: SingleChildScrollView(
              padding: const EdgeInsets.all(24),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  _buildHeader(controller),
                  const SizedBox(height: 24),
                  _buildAlertSections(controller),
                  const SizedBox(height: 24),
                  _buildQuickActions(controller),
                ],
              ),
            ),
          );
        },
      ),
    );
  }
  
  Widget _buildHeader(MaintenanceController controller) {
    return Container(
      padding: const EdgeInsets.all(20),
      decoration: BoxDecoration(
        gradient: LinearGradient(
          colors: [Theme.of(context).primaryColor, Theme.of(context).primaryColor.withValues(alpha: 0.8)],
          begin: Alignment.topLeft,
          end: Alignment.bottomRight,
        ),
        borderRadius: BorderRadius.circular(12),
        boxShadow: [
          BoxShadow(
            color: Theme.of(context).primaryColor.withValues(alpha: 0.3),
            blurRadius: 10,
            offset: const Offset(0, 4),
          ),
        ],
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [
              Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  const Text(
                    '유지보수 알림 대시보드',
                    style: TextStyle(
                      fontSize: 24,
                      fontWeight: FontWeight.bold,
                      color: Colors.white,
                    ),
                  ),
                  const SizedBox(height: 4),
                  Text(
                    '${DateFormat('yyyy년 MM월 dd일').format(DateTime.now())} 기준',
                    style: TextStyle(
                      fontSize: 14,
                      color: Colors.white.withValues(alpha: 0.9),
                    ),
                  ),
                ],
              ),
              IconButton(
                icon: const Icon(Icons.refresh, color: Colors.white),
                onPressed: () {
                  controller.loadAlerts();
                },
                tooltip: '새로고침',
              ),
            ],
          ),
          const SizedBox(height: 16),
          Row(
            children: [
              _buildHeaderStat(
                Icons.warning_amber,
                '긴급',
                controller.overdueAlerts.length.toString(),
                Colors.red[300]!,
              ),
              const SizedBox(width: 16),
              _buildHeaderStat(
                Icons.schedule,
                '예정',
                controller.upcomingAlerts.length.toString(),
                Colors.orange[300]!,
              ),
              const SizedBox(width: 16),
              _buildHeaderStat(
                Icons.check_circle,
                '완료',
                '0', // 통계 API가 없어 고정값
                Colors.green[300]!,
              ),
            ],
          ),
        ],
      ),
    );
  }
  
  Widget _buildHeaderStat(IconData icon, String label, String value, Color color) {
    return Expanded(
      child: Container(
        padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
        decoration: BoxDecoration(
          color: Colors.white.withValues(alpha: 0.2),
          borderRadius: BorderRadius.circular(8),
        ),
        child: Row(
          children: [
            Icon(icon, color: color, size: 24),
            const SizedBox(width: 8),
            Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  label,
                  style: TextStyle(
                    fontSize: 12,
                    color: Colors.white.withValues(alpha: 0.9),
                  ),
                ),
                Text(
                  value,
                  style: const TextStyle(
                    fontSize: 18,
                    fontWeight: FontWeight.bold,
                    color: Colors.white,
                  ),
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }
  
  
  Widget _buildStatCard(String title, String value, IconData icon, Color color) {
    return Column(
      children: [
        Icon(icon, color: color, size: 32),
        const SizedBox(height: 8),
        Text(
          value,
          style: TextStyle(
            fontSize: 20,
            fontWeight: FontWeight.bold,
            color: color,
          ),
        ),
        const SizedBox(height: 4),
        Text(
          title,
          style: TextStyle(
            fontSize: 12,
            color: Colors.grey[600],
          ),
        ),
      ],
    );
  }
  
  Widget _buildAlertSections(MaintenanceController controller) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        // 지연된 유지보수
        if (controller.overdueAlerts.isNotEmpty) ...[
          _buildAlertSection(
            '⚠️ 지연된 유지보수',
            controller.overdueAlerts,
            Colors.red,
            true,
          ),
          const SizedBox(height: 20),
        ],
        
        // 예정된 유지보수
        if (controller.upcomingAlerts.isNotEmpty) ...[
          _buildAlertSection(
            '📅 예정된 유지보수',
            controller.upcomingAlerts,
            Colors.orange,
            false,
          ),
        ],
        
        // 알림이 없는 경우
        if (controller.overdueAlerts.isEmpty && controller.upcomingAlerts.isEmpty)
          Center(
            child: Container(
              padding: const EdgeInsets.all(40),
              child: Column(
                children: [
                  Icon(Icons.check_circle_outline, size: 64, color: Colors.green[400]),
                  const SizedBox(height: 16),
                  Text(
                    '모든 유지보수가 정상입니다',
                    style: TextStyle(
                      fontSize: 18,
                      color: Colors.grey[600],
                    ),
                  ),
                ],
              ),
            ),
          ),
      ],
    );
  }
  
  Widget _buildAlertSection(
    String title,
    List<MaintenanceDto> alerts,
    Color color,
    bool isOverdue,
  ) {
    // 우선순위별로 정렬
    final sortedAlerts = List<MaintenanceDto>.from(alerts)
      ..sort((a, b) {
        // MaintenanceDto에는 priority와 daysUntilDue가 없으므로 등록일순으로 정렬
        return b.registeredAt.compareTo(a.registeredAt);
      });
    
    return Container(
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(12),
        boxShadow: [
          BoxShadow(
            color: Colors.grey.withValues(alpha: 0.1),
            blurRadius: 10,
            offset: const Offset(0, 2),
          ),
        ],
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Container(
            padding: const EdgeInsets.all(16),
            decoration: BoxDecoration(
              color: color.withValues(alpha: 0.1),
              borderRadius: const BorderRadius.only(
                topLeft: Radius.circular(12),
                topRight: Radius.circular(12),
              ),
            ),
            child: Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                Text(
                  title,
                  style: TextStyle(
                    fontSize: 18,
                    fontWeight: FontWeight.bold,
                    color: color,
                  ),
                ),
                Chip(
                  label: Text(
                    '${alerts.length}건',
                    style: const TextStyle(color: Colors.white, fontSize: 12),
                  ),
                  backgroundColor: color,
                  padding: const EdgeInsets.symmetric(horizontal: 8),
                ),
              ],
            ),
          ),
          ListView.separated(
            shrinkWrap: true,
            physics: const NeverScrollableScrollPhysics(),
            itemCount: sortedAlerts.length > 5 ? 5 : sortedAlerts.length,
            separatorBuilder: (context, index) => const Divider(height: 1),
            itemBuilder: (context, index) {
              final alert = sortedAlerts[index];
              return _buildAlertCard(alert, isOverdue);
            },
          ),
          if (sortedAlerts.length > 5)
            Container(
              padding: const EdgeInsets.all(12),
              child: Center(
                child: TextButton(
                  onPressed: () => _showAllAlerts(context, sortedAlerts, title),
                  child: Text('${sortedAlerts.length - 5}개 더 보기'),
                ),
              ),
            ),
        ],
      ),
    );
  }
  
  Widget _buildAlertCard(MaintenanceDto alert, bool isOverdue) {
    // MaintenanceDto 필드에 맞게 수정
    final typeColor = alert.maintenanceType == 'O' ? Colors.blue : Colors.green;
    final typeIcon = alert.maintenanceType == 'O' ? Icons.build : Icons.computer;
    
    // 예상 마감일 계산 (startedAt + periodMonth)
    DateTime? scheduledDate;
    scheduledDate = DateTime(alert.startedAt.year, alert.startedAt.month + alert.periodMonth, alert.startedAt.day);
    int daysUntil = scheduledDate.difference(DateTime.now()).inDays;
    
    return ListTile(
      leading: CircleAvatar(
        backgroundColor: typeColor.withValues(alpha: 0.2),
        child: Icon(typeIcon, color: typeColor, size: 20),
      ),
      title: Text(
        'Equipment History #${alert.equipmentHistoryId}',
        style: const TextStyle(fontWeight: FontWeight.w500),
      ),
      subtitle: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const SizedBox(height: 4),
          if (scheduledDate != null)
            Text(
              isOverdue
                  ? '${daysUntil.abs()}일 지연'
                  : '$daysUntil일 후 예정',
              style: TextStyle(
                color: isOverdue ? Colors.red : Colors.orange,
                fontWeight: FontWeight.w500,
              ),
            ),
          const SizedBox(height: 2),
          if (scheduledDate != null)
            Text(
              '예정일: ${DateFormat('yyyy-MM-dd').format(scheduledDate)}',
              style: TextStyle(fontSize: 12, color: Colors.grey[600]),
            ),
          if (alert.periodMonth != null)
            Text(
              '주기: ${alert.periodMonth}개월',
              style: TextStyle(fontSize: 12, color: Colors.grey[600]),
            ),
        ],
      ),
      trailing: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        crossAxisAlignment: CrossAxisAlignment.end,
        children: [
          Chip(
            label: Text(
              alert.maintenanceType == 'O' ? '현장' : '원격',
              style: const TextStyle(fontSize: 11, color: Colors.white),
            ),
            backgroundColor: typeColor,
            padding: EdgeInsets.zero,
            materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
          ),
          const SizedBox(height: 4),
          Text(
            '비용: 미지원', // 백엔드에 비용 필드 없음
            style: TextStyle(fontSize: 12, color: Colors.grey[600]),
          ),
        ],
      ),
      onTap: () => _showMaintenanceDetails(alert.id!),
    );
  }
  
  Widget _buildQuickActions(MaintenanceController controller) {
    return Container(
      padding: const EdgeInsets.all(20),
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(12),
        boxShadow: [
          BoxShadow(
            color: Colors.grey.withValues(alpha: 0.1),
            blurRadius: 10,
            offset: const Offset(0, 2),
          ),
        ],
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const Text(
            '빠른 작업',
            style: TextStyle(
              fontSize: 18,
              fontWeight: FontWeight.bold,
            ),
          ),
          const SizedBox(height: 16),
          Row(
            children: [
              Expanded(
                child: _buildActionButton(
                  '새 유지보수 등록',
                  Icons.add_circle,
                  Colors.blue,
                  () => _showCreateMaintenanceDialog(),
                ),
              ),
              const SizedBox(width: 12),
              Expanded(
                child: _buildActionButton(
                  '일정 보기',
                  Icons.calendar_month,
                  Colors.green,
                  () => Navigator.pushNamed(context, '/maintenance/schedule'),
                ),
              ),
            ],
          ),
          const SizedBox(height: 12),
          Row(
            children: [
              Expanded(
                child: _buildActionButton(
                  '보고서 생성',
                  Icons.description,
                  Colors.orange,
                  () => _generateReport(controller),
                ),
              ),
              const SizedBox(width: 12),
              Expanded(
                child: _buildActionButton(
                  '엑셀 내보내기',
                  Icons.file_download,
                  Colors.purple,
                  () => _exportToExcel(controller),
                ),
              ),
            ],
          ),
        ],
      ),
    );
  }
  
  Widget _buildActionButton(
    String label,
    IconData icon,
    Color color,
    VoidCallback onPressed,
  ) {
    return ElevatedButton.icon(
      onPressed: onPressed,
      icon: Icon(icon, size: 20),
      label: Text(label),
      style: ElevatedButton.styleFrom(
        backgroundColor: color,
        foregroundColor: Colors.white,
        padding: const EdgeInsets.symmetric(vertical: 12),
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(8),
        ),
      ),
    );
  }
  
  
  void _showAllAlerts(BuildContext context, List<MaintenanceDto> alerts, String title) {
    showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      builder: (context) => DraggableScrollableSheet(
        initialChildSize: 0.7,
        minChildSize: 0.5,
        maxChildSize: 0.95,
        expand: false,
        builder: (context, scrollController) => Container(
          padding: const EdgeInsets.all(16),
          child: Column(
            children: [
              Text(
                title,
                style: Theme.of(context).textTheme.titleLarge,
              ),
              const SizedBox(height: 16),
              Expanded(
                child: ListView.separated(
                  controller: scrollController,
                  itemCount: alerts.length,
                  separatorBuilder: (context, index) => const Divider(),
                  itemBuilder: (context, index) {
                    final alert = alerts[index];
                    return _buildAlertCard(alert, title.contains('지연'));
                  },
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
  
  void _showMaintenanceDetails(int maintenanceId) {
    final controller = context.read<MaintenanceController>();
    final maintenance = controller.maintenances.firstWhere(
      (m) => m.id == maintenanceId,
      orElse: () => MaintenanceDto(
        equipmentHistoryId: 0,
        startedAt: DateTime.now(),
        endedAt: DateTime.now(),
        periodMonth: 0,
        maintenanceType: 'O',
        registeredAt: DateTime.now(),
      ),
    );
    
    if (maintenance.id != 0) {
      showDialog(
        context: context,
        builder: (context) => MaintenanceFormDialog(maintenance: maintenance),
      ).then((result) {
        if (result == true) {
          controller.loadAlerts();
          controller.loadMaintenances(refresh: true);
        }
      });
    }
  }
  
  void _showCreateMaintenanceDialog() {
    showDialog(
      context: context,
      builder: (context) => const MaintenanceFormDialog(),
    ).then((result) {
      if (result == true) {
        final controller = context.read<MaintenanceController>();
        controller.loadAlerts();
        controller.loadMaintenances(refresh: true);
      }
    });
  }
  
  void _generateReport(MaintenanceController controller) {
    ScaffoldMessenger.of(context).showSnackBar(
      const SnackBar(
        content: Text('보고서 생성 기능은 준비 중입니다'),
        backgroundColor: Colors.orange,
      ),
    );
  }
  
  void _exportToExcel(MaintenanceController controller) {
    ScaffoldMessenger.of(context).showSnackBar(
      const SnackBar(
        content: Text('엑셀 내보내기 기능은 준비 중입니다'),
        backgroundColor: Colors.purple,
      ),
    );
  }
}