import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:table_calendar/table_calendar.dart';
import 'package:intl/intl.dart';
import '../../../models/trip.dart';
import '../../../models/activity.dart';
import '../../../blocs/activity/activity_bloc.dart';
import '../../../blocs/activity/activity_state.dart';
import '../../../blocs/activity/activity_event.dart';

class CalendarPage extends StatefulWidget {
  final Trip trip;

  const CalendarPage({super.key, required this.trip});

  @override
  State<CalendarPage> createState() => _CalendarPageState();
}

class _CalendarPageState extends State<CalendarPage> {
  late DateTime _focusedDay;
  DateTime? _selectedDay;
  CalendarFormat _calendarFormat = CalendarFormat.month;

  @override
  void initState() {
    super.initState();
    _focusedDay = widget.trip.startDate;
    _selectedDay = _focusedDay;
  }

  List<Activity> _getActivitiesForDay(DateTime day, List<Activity> activities) {
    return activities.where((activity) {
      if (activity.date == null) return false;
      return isSameDay(activity.date, day);
    }).toList();
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);

    return Scaffold(
      appBar: AppBar(
        title: const Text('Calendrier du voyage'),
        backgroundColor: theme.colorScheme.surface,
        foregroundColor: theme.colorScheme.onSurface,
        elevation: 0,
      ),
      body: BlocBuilder<ActivityBloc, ActivityState>(
        builder: (context, state) {
          if (state is ActivityLoading) {
            return const Center(child: CircularProgressIndicator());
          }

          List<Activity> allActivities = [];
          if (state is ActivityLoaded) {
            allActivities = state.activities;
          } else if (state is ActivitySearchResults) {
            // Fallback if we are in search state, though ideally we should be in loaded state
            // This might happen if we navigate back and forth
          }

          // Filter approved activities
          final approvedActivities = allActivities.where((a) {
            return a.isApprovedByAllParticipants([
              ...widget.trip.participants,
              widget.trip.createdBy,
            ]);
          }).toList();

          final scheduledActivities = approvedActivities
              .where((a) => a.date != null)
              .toList();

          final unscheduledActivities = approvedActivities
              .where((a) => a.date == null)
              .toList();

          final selectedActivities = _getActivitiesForDay(
            _selectedDay ?? _focusedDay,
            scheduledActivities,
          );

          return Column(
            children: [
              TableCalendar(
                firstDay: DateTime.now().subtract(const Duration(days: 365)),
                lastDay: DateTime.now().add(const Duration(days: 365)),
                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) {
                  _focusedDay = focusedDay;
                },
                eventLoader: (day) {
                  return _getActivitiesForDay(day, scheduledActivities);
                },
                calendarBuilders: CalendarBuilders(
                  markerBuilder: (context, day, events) {
                    if (events.isEmpty) return null;
                    return Positioned(
                      bottom: 1,
                      child: Container(
                        width: 7,
                        height: 7,
                        decoration: BoxDecoration(
                          shape: BoxShape.circle,
                          color: theme.colorScheme.primary,
                        ),
                      ),
                    );
                  },
                ),
                calendarStyle: CalendarStyle(
                  todayDecoration: BoxDecoration(
                    color: theme.colorScheme.primary.withValues(alpha: 0.5),
                    shape: BoxShape.circle,
                  ),
                  selectedDecoration: BoxDecoration(
                    color: theme.colorScheme.primary,
                    shape: BoxShape.circle,
                  ),
                ),
              ),
              const Divider(),
              Expanded(
                child: Row(
                  children: [
                    // Scheduled Activities for Selected Day
                    Expanded(
                      flex: 3,
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Padding(
                            padding: const EdgeInsets.all(8.0),
                            child: Text(
                              'Activités du ${DateFormat('dd/MM/yyyy').format(_selectedDay!)}',
                              style: theme.textTheme.titleMedium,
                            ),
                          ),
                          Expanded(
                            child: selectedActivities.isEmpty
                                ? Center(
                                    child: Text(
                                      'Aucune activité prévue',
                                      style: theme.textTheme.bodyMedium
                                          ?.copyWith(
                                            color: theme.colorScheme.onSurface
                                                .withValues(alpha: 0.6),
                                          ),
                                    ),
                                  )
                                : ListView.builder(
                                    itemCount: selectedActivities.length,
                                    itemBuilder: (context, index) {
                                      final activity =
                                          selectedActivities[index];
                                      return ListTile(
                                        title: Text(activity.name),
                                        subtitle: Text(activity.category),
                                        trailing: IconButton(
                                          icon: const Icon(Icons.close),
                                          onPressed: () {
                                            context.read<ActivityBloc>().add(
                                              UpdateActivityDate(
                                                tripId: widget.trip.id!,
                                                activityId: activity.id,
                                                date: null,
                                              ),
                                            );
                                          },
                                        ),
                                      );
                                    },
                                  ),
                          ),
                        ],
                      ),
                    ),
                    const VerticalDivider(),
                    // Unscheduled Activities
                    Expanded(
                      flex: 2,
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Padding(
                            padding: const EdgeInsets.all(8.0),
                            child: Text(
                              'À planifier',
                              style: theme.textTheme.titleMedium,
                            ),
                          ),
                          Expanded(
                            child: unscheduledActivities.isEmpty
                                ? Center(
                                    child: Text(
                                      'Tout est planifié !',
                                      style: theme.textTheme.bodyMedium
                                          ?.copyWith(
                                            color: theme.colorScheme.onSurface
                                                .withValues(alpha: 0.6),
                                          ),
                                      textAlign: TextAlign.center,
                                    ),
                                  )
                                : ListView.builder(
                                    itemCount: unscheduledActivities.length,
                                    itemBuilder: (context, index) {
                                      final activity =
                                          unscheduledActivities[index];
                                      return Draggable<Activity>(
                                        data: activity,
                                        feedback: Material(
                                          elevation: 4,
                                          child: Container(
                                            padding: const EdgeInsets.all(8),
                                            color: theme.cardColor,
                                            child: Text(activity.name),
                                          ),
                                        ),
                                        child: ListTile(
                                          title: Text(
                                            activity.name,
                                            style: theme.textTheme.bodySmall,
                                          ),
                                          trailing: IconButton(
                                            icon: const Icon(Icons.arrow_back),
                                            onPressed: () {
                                              if (_selectedDay != null) {
                                                context
                                                    .read<ActivityBloc>()
                                                    .add(
                                                      UpdateActivityDate(
                                                        tripId: widget.trip.id!,
                                                        activityId: activity.id,
                                                        date: _selectedDay,
                                                      ),
                                                    );
                                              }
                                            },
                                          ),
                                        ),
                                      );
                                    },
                                  ),
                          ),
                        ],
                      ),
                    ),
                  ],
                ),
              ),
            ],
          );
        },
      ),
    );
  }
}