import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';
import '../services/odoo_service.dart';
import '../services/notification_service.dart';
import '../theme/app_theme.dart';
import 'notification_detail_screen.dart';

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

  @override
  State<NotificationsScreen> createState() => _NotificationsScreenState();
}

class _NotificationsScreenState extends State<NotificationsScreen> {
  List<dynamic> _notifications = [];
  List<String> _readIds = [];
  bool _isLoading = true;

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

  Future<void> _fetchNotifications() async {
    try {
      final client = OdooService().client;
      if (client == null) throw Exception('Not connected');

      final response = await client.callRPC(
        '/api/loyalty/fetch_notifications',
        'call',
        {'last_id': 0},
      );

      if (response != null && response['status'] == 'success') {
        final List<dynamic> fetched = response['data'] ?? [];
        final prefs = await SharedPreferences.getInstance();
        final readIds = prefs.getStringList('read_notification_ids') ?? [];

        if (mounted) {
          setState(() {
            _notifications = fetched;
            _readIds = readIds;
            _isLoading = false;
          });
        }
      } else {
        throw Exception('Invalid response from server');
      }
    } catch (e) {
      if (mounted) {
        setState(() => _isLoading = false);
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Error loading notifications: $e')),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Notifications')),
      body: _isLoading
          ? const Center(child: CircularProgressIndicator())
          : _notifications.isEmpty
              ? Center(
                  child: Column(
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      Icon(
                        Icons.notifications_none,
                        size: 64,
                        color: AppTheme.onSurfaceVariant.withValues(alpha: 0.4),
                      ),
                      const SizedBox(height: 16),
                      Text(
                        'No notifications yet.',
                        style: Theme.of(context).textTheme.bodyLarge?.copyWith(
                              color: AppTheme.onSurfaceVariant,
                            ),
                      ),
                    ],
                  ),
                )
              : RefreshIndicator(
                  onRefresh: _fetchNotifications,
                  child: ListView.separated(
                    padding: const EdgeInsets.symmetric(
                        horizontal: 16, vertical: 20),
                    itemCount: _notifications.length,
                    separatorBuilder: (_, __) => const SizedBox(height: 8),
                    itemBuilder: (context, index) {
                      final notif = _notifications[index];
                      final isUnread = !_readIds.contains((notif['id'] as int? ?? 0).toString());
                      return _NotificationCard(
                        notif: notif,
                        isUnread: isUnread,
                        onTap: () async {
                          final prefs = await SharedPreferences.getInstance();
                          final readIds = prefs.getStringList('read_notification_ids') ?? [];
                          final notifIdStr = (notif['id'] as int? ?? 0).toString();
                          if (!readIds.contains(notifIdStr)) {
                            readIds.add(notifIdStr);
                            await prefs.setStringList('read_notification_ids', readIds);

                            // Recalculate and update system badge count
                            final unreadCount = _notifications
                                .where((n) => !readIds.contains((n['id'] as int? ?? 0).toString()))
                                .length;
                            await NotificationService().setBadge(unreadCount);
                          }

                          if (!mounted) return;
                          await Navigator.push(
                            context,
                            MaterialPageRoute(
                              builder: (_) =>
                                  NotificationDetailScreen(notif: notif),
                            ),
                          );
                          _fetchNotifications();
                        },
                      );
                    },
                  ),
                ),
    );
  }
}

class _NotificationCard extends StatelessWidget {
  final dynamic notif;
  final bool isUnread;
  final VoidCallback onTap;

  const _NotificationCard({
    required this.notif,
    required this.isUnread,
    required this.onTap,
  });

  @override
  Widget build(BuildContext context) {
    final title = notif['title'] as String? ?? 'Notice';

    return Material(
      color: AppTheme.surfaceContainerLow,
      child: InkWell(
        onTap: onTap,
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 18),
          child: Row(
            children: [
              notif['has_image'] == true && notif['image_128'] != null
                  ? Container(
                      width: 42,
                      height: 42,
                      decoration: BoxDecoration(
                        shape: BoxShape.rectangle,
                        borderRadius: BorderRadius.circular(4),
                        image: DecorationImage(
                          image: MemoryImage(
                            base64Decode(notif['image_128'] as String),
                          ),
                          fit: BoxFit.cover,
                        ),
                      ),
                    )
                  : Container(
                      padding: const EdgeInsets.all(10),
                      decoration: BoxDecoration(
                        color: AppTheme.primary.withValues(alpha: 0.15),
                        shape: BoxShape.rectangle,
                      ),
                      child: const Icon(
                        Icons.campaign_outlined,
                        color: AppTheme.secondary,
                        size: 22,
                      ),
                    ),
              const SizedBox(width: 16),
              Expanded(
                child: Text(
                  title,
                  style: Theme.of(context).textTheme.titleSmall?.copyWith(
                        color: AppTheme.onSurface,
                        fontWeight: isUnread ? FontWeight.bold : FontWeight.normal,
                      ),
                  maxLines: 2,
                  overflow: TextOverflow.ellipsis,
                ),
              ),
              const SizedBox(width: 8),
              if (isUnread) ...[
                Container(
                  width: 8,
                  height: 8,
                  decoration: const BoxDecoration(
                    color: Colors.red,
                    shape: BoxShape.circle,
                  ),
                ),
                const SizedBox(width: 8),
              ],
              const Icon(
                Icons.chevron_right,
                color: AppTheme.onSurfaceVariant,
                size: 20,
              ),
            ],
          ),
        ),
      ),
    );
  }
}