import 'package:flutter/material.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';
import '../services/notification_service.dart';
import '../services/database_helper.dart';

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

  @override
  State<PendingNotificationsScreen> createState() => _PendingNotificationsScreenState();
}

class _PendingNotificationsScreenState extends State<PendingNotificationsScreen> {
  List<PendingNotificationRequest> _pendingNotifications = [];
  List<Map<String, dynamic>> _trackedNotifications = [];
  bool _isLoading = true;

  @override
  void initState() {
    super.initState();
    _loadNotifications();
  }

  Future<void> _loadNotifications() async {
    setState(() {
      _isLoading = true;
    });

    try {
      // Get system pending notifications
      final notificationService = NotificationService();
      final systemPending = await notificationService.getPendingNotifications();
      
      // Get tracked notifications from database (including retries)
      final trackedNotifications = await DatabaseHelper.instance.getPendingNotifications();
      
      // Combine and sort by scheduled time (soonest first)
      final allNotifications = <Map<String, dynamic>>[];
      
      // Add system notifications
      for (final notification in systemPending) {
        allNotifications.add({
          'id': notification.id,
          'title': notification.title ?? 'Notification',
          'body': notification.body ?? '',
          'scheduledTime': DateTime.now(), // PendingNotificationRequest doesn't have scheduledTime
          'type': 'system',
          'isRetry': false,
          'retryCount': 0,
        });
      }
      
      // Add tracked notifications from database
      for (final notification in trackedNotifications) {
        final scheduledTime = DateTime.parse(notification['scheduledTime']).toLocal();
        allNotifications.add({
          'id': notification['notificationId'],
          'title': 'Time for ${notification['supplementName'] ?? 'Supplement'}',
          'body': 'Take your supplement',
          'scheduledTime': scheduledTime,
          'type': 'tracked',
          'status': notification['status'],
          'isRetry': notification['status'] == 'retrying',
          'retryCount': notification['retryCount'] ?? 0,
          'supplementName': notification['supplementName'],
          'supplementId': notification['supplementId'],
        });
      }
      
      // Sort by scheduled time (soonest first)
      allNotifications.sort((a, b) {
        final timeA = a['scheduledTime'] as DateTime;
        final timeB = b['scheduledTime'] as DateTime;
        return timeA.compareTo(timeB);
      });
      
      setState(() {
        _pendingNotifications = systemPending;
        _trackedNotifications = trackedNotifications;
        _isLoading = false;
      });
    } catch (e) {
      print('Error loading notifications: $e');
      setState(() {
        _isLoading = false;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Pending Notifications'),
        actions: [
          IconButton(
            icon: const Icon(Icons.refresh),
            onPressed: _loadNotifications,
            tooltip: 'Refresh',
          ),
        ],
      ),
      body: _isLoading
          ? const Center(child: CircularProgressIndicator())
          : RefreshIndicator(
              onRefresh: _loadNotifications,
              child: _buildNotificationsList(),
            ),
    );
  }

  Widget _buildNotificationsList() {
    if (_pendingNotifications.isEmpty && _trackedNotifications.isEmpty) {
      return const Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              Icons.notifications_off,
              size: 64,
              color: Colors.grey,
            ),
            SizedBox(height: 16),
            Text(
              'No pending notifications',
              style: TextStyle(
                fontSize: 18,
                color: Colors.grey,
              ),
            ),
            SizedBox(height: 8),
            Text(
              'All caught up!',
              style: TextStyle(
                color: Colors.grey,
              ),
            ),
          ],
        ),
      );
    }

    // Combine and sort all notifications
    final allNotifications = <Map<String, dynamic>>[];
    
    // Add system notifications
    for (final notification in _pendingNotifications) {
      allNotifications.add({
        'id': notification.id,
        'title': notification.title ?? 'Notification',
        'body': notification.body ?? '',
        'scheduledTime': DateTime.now(), // PendingNotificationRequest doesn't have scheduledTime
        'type': 'system',
        'isRetry': false,
        'retryCount': 0,
      });
    }
    
    // Add tracked notifications from database
    for (final notification in _trackedNotifications) {
      final scheduledTime = DateTime.parse(notification['scheduledTime']).toLocal();
      allNotifications.add({
        'id': notification['notificationId'],
        'title': 'Time for ${notification['supplementName'] ?? 'Supplement'}',
        'body': 'Take your supplement',
        'scheduledTime': scheduledTime,
        'type': 'tracked',
        'status': notification['status'],
        'isRetry': notification['status'] == 'retrying',
        'retryCount': notification['retryCount'] ?? 0,
        'supplementName': notification['supplementName'],
        'supplementId': notification['supplementId'],
      });
    }
    
    // Sort by scheduled time (soonest first)
    allNotifications.sort((a, b) {
      final timeA = a['scheduledTime'] as DateTime;
      final timeB = b['scheduledTime'] as DateTime;
      return timeA.compareTo(timeB);
    });

    return ListView.builder(
      padding: const EdgeInsets.all(16),
      itemCount: allNotifications.length,
      itemBuilder: (context, index) {
        final notification = allNotifications[index];
        return _buildNotificationCard(notification);
      },
    );
  }

  Widget _buildNotificationCard(Map<String, dynamic> notification) {
    final scheduledTime = notification['scheduledTime'] as DateTime;
    final now = DateTime.now();
    final isOverdue = scheduledTime.isBefore(now);
    final isRetry = notification['isRetry'] as bool;
    final retryCount = notification['retryCount'] as int;
    final type = notification['type'] as String;
    
    final timeUntil = scheduledTime.difference(now);
    String timeText;
    
    if (isOverdue) {
      final overdue = now.difference(scheduledTime);
      if (overdue.inDays > 0) {
        timeText = 'Overdue by ${overdue.inDays}d ${overdue.inHours % 24}h';
      } else if (overdue.inHours > 0) {
        timeText = 'Overdue by ${overdue.inHours}h ${overdue.inMinutes % 60}m';
      } else {
        timeText = 'Overdue by ${overdue.inMinutes}m';
      }
    } else {
      if (timeUntil.inDays > 0) {
        timeText = 'In ${timeUntil.inDays}d ${timeUntil.inHours % 24}h';
      } else if (timeUntil.inHours > 0) {
        timeText = 'In ${timeUntil.inHours}h ${timeUntil.inMinutes % 60}m';
      } else {
        timeText = 'In ${timeUntil.inMinutes}m';
      }
    }

    return Card(
      margin: const EdgeInsets.only(bottom: 12),
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              children: [
                Expanded(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(
                        notification['title'] ?? 'Notification',
                        style: Theme.of(context).textTheme.titleMedium?.copyWith(
                          fontWeight: FontWeight.bold,
                        ),
                      ),
                      if (notification['body'] != null) ...[
                        const SizedBox(height: 4),
                        Text(
                          notification['body'],
                          style: Theme.of(context).textTheme.bodyMedium,
                        ),
                      ],
                    ],
                  ),
                ),
                Column(
                  crossAxisAlignment: CrossAxisAlignment.end,
                  children: [
                    if (isRetry) ...[
                      Container(
                        padding: const EdgeInsets.symmetric(
                          horizontal: 8,
                          vertical: 4,
                        ),
                        decoration: BoxDecoration(
                          color: Colors.orange.withOpacity(0.2),
                          borderRadius: BorderRadius.circular(12),
                          border: Border.all(color: Colors.orange.withOpacity(0.5)),
                        ),
                        child: Text(
                          'Retry #$retryCount',
                          style: TextStyle(
                            fontSize: 12,
                            color: Colors.orange.shade700,
                            fontWeight: FontWeight.bold,
                          ),
                        ),
                      ),
                      const SizedBox(height: 4),
                    ],
                    Container(
                      padding: const EdgeInsets.symmetric(
                        horizontal: 8,
                        vertical: 4,
                      ),
                      decoration: BoxDecoration(
                        color: type == 'system' 
                            ? Colors.blue.withOpacity(0.2) 
                            : Colors.green.withOpacity(0.2),
                        borderRadius: BorderRadius.circular(12),
                        border: Border.all(
                          color: type == 'system' 
                              ? Colors.blue.withOpacity(0.5) 
                              : Colors.green.withOpacity(0.5),
                        ),
                      ),
                      child: Text(
                        type == 'system' ? 'System' : 'Tracked',
                        style: TextStyle(
                          fontSize: 12,
                          color: type == 'system' 
                              ? Colors.blue.shade700 
                              : Colors.green.shade700,
                          fontWeight: FontWeight.bold,
                        ),
                      ),
                    ),
                  ],
                ),
              ],
            ),
            const SizedBox(height: 12),
            Row(
              children: [
                Icon(
                  isOverdue ? Icons.schedule_outlined : Icons.access_time,
                  size: 16,
                  color: isOverdue ? Colors.red : Colors.grey,
                ),
                const SizedBox(width: 8),
                Text(
                  '${_formatTime(scheduledTime)} • $timeText',
                  style: TextStyle(
                    color: isOverdue ? Colors.red : Colors.grey.shade700,
                    fontWeight: isOverdue ? FontWeight.bold : FontWeight.normal,
                  ),
                ),
              ],
            ),
            if (type == 'tracked' && notification['supplementName'] != null) ...[
              const SizedBox(height: 8),
              Row(
                children: [
                  const Icon(
                    Icons.medication,
                    size: 16,
                    color: Colors.grey,
                  ),
                  const SizedBox(width: 8),
                  Text(
                    notification['supplementName'],
                    style: TextStyle(
                      color: Colors.grey.shade700,
                      fontStyle: FontStyle.italic,
                    ),
                  ),
                ],
              ),
            ],
          ],
        ),
      ),
    );
  }

  String _formatTime(DateTime dateTime) {
    final now = DateTime.now();
    final today = DateTime(now.year, now.month, now.day);
    final tomorrow = today.add(const Duration(days: 1));
    final notificationDate = DateTime(dateTime.year, dateTime.month, dateTime.day);
    
    String timeStr = '${dateTime.hour.toString().padLeft(2, '0')}:${dateTime.minute.toString().padLeft(2, '0')}';
    
    if (notificationDate == today) {
      return 'Today $timeStr';
    } else if (notificationDate == tomorrow) {
      return 'Tomorrow $timeStr';
    } else {
      return '${dateTime.day}/${dateTime.month} $timeStr';
    }
  }
}