import 'package:flutter/material.dart';
import 'package:table_calendar/table_calendar.dart';

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

  @override
  State<CalendarTab> createState() => _CalendarTabState();
}

class _CalendarTabState extends State<CalendarTab> {
  CalendarFormat _calendarFormat = CalendarFormat.month;
  DateTime _focusedDay = DateTime.now();
  DateTime? _selectedDay;
  Map<DateTime, List<Map<String, dynamic>>> _events = {};

  @override
  void initState() {
    super.initState();
    _selectedDay = DateTime.now();
    final now = DateTime.now();
    _focusedDay = DateTime(now.year, now.month, now.day);

    // Beispiel-Events
    _events = {
      _focusedDay: [
        {
          'title': 'Ganzkörper Workout',
          'time': '09:00',
          'duration': '45 Minuten',
        },
        {'title': 'Yoga Session', 'time': '17:30', 'duration': '30 Minuten'},
      ],
      _focusedDay.add(const Duration(days: 1)): [
        {'title': 'HIIT Training', 'time': '08:00', 'duration': '30 Minuten'},
      ],
    };
  }

  List<Map<String, dynamic>> _getEventsForDay(DateTime day) {
    return _events[DateTime(day.year, day.month, day.day)] ?? [];
  }

  @override
  Widget build(BuildContext context) {
    final firstDay = DateTime.utc(1900, 1, 1);
    final lastDay = DateTime.utc(2999, 12, 31);

    if (_focusedDay.isBefore(firstDay)) {
      _focusedDay = firstDay;
    } else if (_focusedDay.isAfter(lastDay)) {
      _focusedDay = lastDay;
    }

    return Scaffold(
      appBar: AppBar(
        title: const Text('Trainingsplan'),
        actions: [
          IconButton(
            icon: const Icon(Icons.add),
            onPressed: () {
              // TODO: Implement add workout to calendar
            },
          ),
        ],
      ),
      body: Column(
        children: [
          TableCalendar(
            firstDay: firstDay,
            lastDay: lastDay,
            focusedDay: _focusedDay,
            calendarFormat: _calendarFormat,
            selectedDayPredicate: (day) {
              return isSameDay(_selectedDay, day);
            },
            onDaySelected: (selectedDay, focusedDay) {
              setState(() {
                _selectedDay = selectedDay;
                _focusedDay = focusedDay;
              });
            },
            onFormatChanged: (format) {
              setState(() {
                _calendarFormat = format;
              });
            },
            onPageChanged: (focusedDay) {
              setState(() {
                _focusedDay = focusedDay;
              });
            },
            eventLoader: _getEventsForDay,
            calendarStyle: const CalendarStyle(
              markersMaxCount: 1,
              markerDecoration: BoxDecoration(
                color: Colors.blue,
                shape: BoxShape.circle,
              ),
            ),
          ),
          const Divider(),
          Expanded(
            child:
                _getEventsForDay(_selectedDay!).isEmpty
                    ? const Center(
                      child: Column(
                        mainAxisAlignment: MainAxisAlignment.center,
                        children: [
                          Icon(Icons.event_busy, size: 64, color: Colors.grey),
                          SizedBox(height: 16),
                          Text(
                            'Keine Trainings geplant',
                            style: TextStyle(fontSize: 18, color: Colors.grey),
                          ),
                          SizedBox(height: 8),
                          Text(
                            'Füge Trainings zu deinem Kalender hinzu',
                            style: TextStyle(fontSize: 14, color: Colors.grey),
                          ),
                        ],
                      ),
                    )
                    : ListView.builder(
                      padding: const EdgeInsets.all(16),
                      itemCount: _getEventsForDay(_selectedDay!).length,
                      itemBuilder: (context, index) {
                        final event = _getEventsForDay(_selectedDay!)[index];
                        return Card(
                          margin: const EdgeInsets.only(bottom: 16),
                          child: ListTile(
                            leading: Container(
                              width: 48,
                              height: 48,
                              decoration: BoxDecoration(
                                color: Colors.blue[100],
                                borderRadius: BorderRadius.circular(8),
                              ),
                              child: const Icon(
                                Icons.fitness_center,
                                color: Colors.blue,
                              ),
                            ),
                            title: Text(
                              event['title'],
                              style: const TextStyle(
                                fontWeight: FontWeight.bold,
                              ),
                            ),
                            subtitle: Text(
                              '${event['time']} • ${event['duration']}',
                            ),
                            trailing: IconButton(
                              icon: const Icon(Icons.delete_outline),
                              onPressed: () {
                                // TODO: Implement delete workout from calendar
                              },
                            ),
                          ),
                        );
                      },
                    ),
          ),
        ],
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          // TODO: Implement add workout to calendar
        },
        child: const Icon(Icons.add),
      ),
    );
  }
}