import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'package:intl/date_symbol_data_local.dart';
import 'package:shared_preferences/shared_preferences.dart';
import '../services/google_calendar_service.dart';
import '../utils/translations.dart';

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

  @override
  State<CalendarScreen> createState() => _CalendarScreenState();
}

class _CalendarScreenState extends State<CalendarScreen> {
  final GoogleCalendarService _calendarService = GoogleCalendarService();
  bool _isLoading = false;
  List<CalendarEvent> _events = [];
  String? _errorMessage;
  String _bulletColor = 'Blue';
  String _selectedLanguage = 'English';

  @override
  void initState() {
    super.initState();
    initializeDateFormatting('sl_SI', null); // Initialize Slovenian locale
    _loadBulletColor();
    _loadLanguage();
    _loadEvents();
  }

  String _t(String key) {
    return AppTranslations.translate(key, _selectedLanguage);
  }

  Future<void> _loadLanguage() async {
    final prefs = await SharedPreferences.getInstance();
    setState(() {
      _selectedLanguage = prefs.getString('language') ?? 'English';
    });
  }

  @override
  void dispose() {
    _calendarService.dispose();
    super.dispose();
  }

  Future<void> _loadBulletColor() async {
    final prefs = await SharedPreferences.getInstance();
    setState(() {
      _bulletColor = prefs.getString('bulletColor') ?? 'Blue';
    });
  }

  Color _getAccentColor() {
    switch (_bulletColor.toLowerCase()) {
      case 'blue':
        return Colors.blue;
      case 'green':
        return Colors.green;
      case 'yellow':
        return Colors.yellow;
      case 'purple':
        return Colors.purple;
      case 'cyan':
        return Colors.cyan;
      case 'teal':
        return Colors.teal;
      case 'indigo':
        return Colors.indigo;
      case 'pink':
        return Colors.pink;
      case 'lime':
        return Colors.lime;
      case 'mint':
        return Colors.greenAccent;
      case 'orange':
        return Colors.orange;
      case 'violet':
        return Colors.deepPurpleAccent;
      case 'amber':
        return Colors.amber;
      case 'brown':
        return Colors.brown;
      case 'grey':
        return Colors.grey;
      default:
        return Colors.blue;
    }
  }

  bool _isValidEvent(CalendarEvent event) {
    // Filter out events that are just single names or too short
    if (event.summary == null || event.summary!.trim().isEmpty) {
      return false;
    }

    final summary = event.summary!.trim();

    // Exclude if it's just a single word (likely just a name)
    if (!summary.contains(' ') && summary.length < 15) {
      return false;
    }

    return true;
  }

  Future<void> _loadEvents() async {
    setState(() {
      _isLoading = true;
      _errorMessage = null;
    });

    try {
      final events = await _calendarService.getEvents(
        startDate: DateTime.now(),
        endDate: DateTime.now().add(const Duration(days: 365)),
      );

      // Get today's date at midnight for comparison
      final now = DateTime.now();
      final today = DateTime(now.year, now.month, now.day);

      // Filter: valid events AND events from today onwards
      final filteredEvents = events.where((event) {
        if (!_isValidEvent(event)) return false;

        // Only include events that are today or in the future
        if (event.startTime != null) {
          final eventDate = DateTime(
            event.startTime!.year,
            event.startTime!.month,
            event.startTime!.day,
          );
          return eventDate.isAtSameMomentAs(today) || eventDate.isAfter(today);
        }
        return false;
      }).toList();

      filteredEvents.sort((a, b) {
        if (a.startTime == null) return 1;
        if (b.startTime == null) return -1;
        return a.startTime!.compareTo(b.startTime!);
      });

      if (mounted) {
        setState(() {
          _events = filteredEvents;
        });
      }
    } catch (e) {
      if (mounted) {
        setState(() {
          _errorMessage = 'Error loading events: $e';
        });
      }
    } finally {
      if (mounted) {
        setState(() => _isLoading = false);
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final accentColor = _getAccentColor();

    if (_isLoading && _events.isEmpty) {
      return Scaffold(
        body: Center(
          child: CircularProgressIndicator(color: accentColor),
        ),
      );
    }

    if (_errorMessage != null && _events.isEmpty) {
      return Scaffold(
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Icon(Icons.error_outline, size: 64, color: accentColor),
              const SizedBox(height: 24),
              Padding(
                padding: const EdgeInsets.symmetric(horizontal: 32),
                child: Text(
                  _errorMessage!,
                  textAlign: TextAlign.center,
                  style: const TextStyle(fontSize: 16),
                ),
              ),
              const SizedBox(height: 16),
              ElevatedButton.icon(
                onPressed: _loadEvents,
                icon: const Icon(Icons.refresh),
                label: Text(_t('Retry')),
                style: ElevatedButton.styleFrom(
                  backgroundColor: accentColor,
                  foregroundColor: Colors.white,
                ),
              ),
            ],
          ),
        ),
      );
    }

    return Scaffold(
      backgroundColor: Colors.white,
      body: RefreshIndicator(
        onRefresh: _loadEvents,
        color: accentColor,
        child: _events.isEmpty
            ? ListView(
                children: [
                  SizedBox(height: MediaQuery.of(context).size.height * 0.3),
                  Center(
                    child: Column(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: [
                        Icon(Icons.event_available, size: 64, color: Colors.grey[400]),
                        const SizedBox(height: 16),
                        Text(
                          _t('No upcoming events'),
                          style: const TextStyle(fontSize: 16, color: Colors.grey),
                        ),
                        const SizedBox(height: 8),
                        Text(
                          _t('Pull down to refresh'),
                          style: TextStyle(fontSize: 14, color: Colors.grey[400]),
                        ),
                      ],
                    ),
                  ),
                ],
              )
            : ListView.builder(
                itemCount: _events.length,
                padding: const EdgeInsets.all(8),
                itemBuilder: (context, index) {
                  final event = _events[index];
                  return _buildEventCard(event, accentColor);
                },
              ),
      ),
    );
  }

  Widget _buildEventCard(CalendarEvent event, Color accentColor) {
    final startTime = event.startTime;
    final isAllDay = event.isAllDay;

    // Format the date for display
    String dateText = '';
    bool isToday = false;
    if (startTime != null) {
      final now = DateTime.now();
      final today = DateTime(now.year, now.month, now.day);
      final eventDay = DateTime(startTime.year, startTime.month, startTime.day);
      final difference = eventDay.difference(today).inDays;

      if (difference == 0) {
        dateText = _t('Today');
        isToday = true;
      } else if (difference == 1) {
        dateText = _t('Tomorrow');
      } else {
        // Use locale based on selected language
        final locale = _selectedLanguage == 'Slovenian' ? 'sl_SI' : 'en_US';
        dateText = DateFormat('EEEE, MMMM d', locale).format(startTime);
        // Capitalize first letter of day and month
        if (dateText.isNotEmpty) {
          dateText = dateText[0].toUpperCase() + dateText.substring(1);
        }
      }
    }

    return Container(
      margin: const EdgeInsets.symmetric(vertical: 6, horizontal: 16),
      decoration: BoxDecoration(
        color: Colors.grey[300],
        borderRadius: BorderRadius.circular(12),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          // Date header
          Container(
            width: double.infinity,
            padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
            decoration: BoxDecoration(
              color: isToday
                  ? accentColor.withValues(alpha: 0.15)
                  : Colors.grey[200],
              borderRadius: const BorderRadius.only(
                topLeft: Radius.circular(12),
                topRight: Radius.circular(12),
              ),
            ),
            child: Row(
              children: [
                // Small colored indicator
                Container(
                  width: 4,
                  height: 16,
                  decoration: BoxDecoration(
                    color: accentColor,
                    borderRadius: BorderRadius.circular(2),
                  ),
                ),
                const SizedBox(width: 8),
                Text(
                  dateText,
                  style: TextStyle(
                    fontSize: 14,
                    fontWeight: FontWeight.bold,
                    color: isToday ? accentColor : Colors.black87,
                  ),
                ),
                if (isToday) ...[
                  const SizedBox(width: 8),
                  Container(
                    padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
                    decoration: BoxDecoration(
                      color: accentColor,
                      borderRadius: BorderRadius.circular(8),
                    ),
                    child: Text(
                      _t('NOW'),
                      style: const TextStyle(
                        fontSize: 10,
                        fontWeight: FontWeight.bold,
                        color: Colors.white,
                      ),
                    ),
                  ),
                ],
              ],
            ),
          ),
          // Main content
          Padding(
            padding: const EdgeInsets.all(16),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                // Title with icon
                Row(
                  children: [
                    Icon(Icons.event, size: 20, color: accentColor),
                    const SizedBox(width: 8),
                    Expanded(
                      child: Text(
                        event.summary ?? _t('Untitled Event'),
                        style: const TextStyle(
                          fontSize: 15,
                          fontWeight: FontWeight.w600,
                          color: Colors.black87,
                        ),
                      ),
                    ),
                  ],
                ),
                const SizedBox(height: 8),
                // Time range (if not all day)
                if (!isAllDay && startTime != null && event.endTime != null) ...[
                  _buildDetailRowInline(
                    icon: Icons.access_time,
                    value: '${DateFormat('HH:mm').format(startTime.toLocal())} - ${DateFormat('HH:mm').format(event.endTime!.toLocal())}',
                    accentColor: accentColor,
                  ),
                  const SizedBox(height: 6),
                ],
                if (isAllDay) ...[
                  _buildDetailRowInline(
                    icon: Icons.access_time,
                    value: _t('All day'),
                    accentColor: accentColor,
                  ),
                  const SizedBox(height: 6),
                ],
                // Location
                if (event.location != null && event.location!.isNotEmpty) ...[
                  _buildDetailRowInline(
                    icon: Icons.location_on,
                    value: event.location!,
                    accentColor: accentColor,
                  ),
                ],
              ],
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildDetailRowInline({
    required IconData icon,
    required String value,
    required Color accentColor,
  }) {
    return Row(
      children: [
        Icon(icon, size: 16, color: accentColor),
        const SizedBox(width: 6),
        Expanded(
          child: Text(
            value,
            style: const TextStyle(
              fontSize: 13,
              color: Colors.black87,
            ),
            maxLines: 1,
            overflow: TextOverflow.ellipsis,
          ),
        ),
      ],
    );
  }

}