import { IEventBus, ICalendarEvent } from '../types/CalendarTypes';
import { CoreEvents } from '../constants/CoreEvents';
import { Configuration } from '../configurations/CalendarConfig';
import { DateService } from '../utils/DateService';
import { IEventRepository } from '../repositories/IEventRepository';

/**
 * EventManager - Event lifecycle and CRUD operations
 * Delegates all data operations to IEventRepository
 * No longer maintains in-memory cache - repository is single source of truth
 */
export class EventManager {

    private dateService: DateService;
    private config: Configuration;
    private repository: IEventRepository;

    constructor(
        private eventBus: IEventBus,
        dateService: DateService,
        config: Configuration,
        repository: IEventRepository
    ) {
        this.dateService = dateService;
        this.config = config;
        this.repository = repository;
    }

    /**
     * Load event data from repository
     * No longer caches - delegates to repository
     */
    public async loadData(): Promise<void> {
        try {
            // Just ensure repository is ready - no caching
            await this.repository.loadEvents();
        } catch (error) {
            console.error('Failed to load event data:', error);
            throw error;
        }
    }

    /**
     * Get all events from repository
     */
    public async getEvents(copy: boolean = false): Promise<ICalendarEvent[]> {
        const events = await this.repository.loadEvents();
        return copy ? [...events] : events;
    }

    /**
     * Get event by ID from repository
     */
    public async getEventById(id: string): Promise<ICalendarEvent | undefined> {
        const events = await this.repository.loadEvents();
        return events.find(event => event.id === id);
    }

    /**
     * Get event by ID and return event info for navigation
     * @param id Event ID to find
     * @returns Event with navigation info or null if not found
     */
    public async getEventForNavigation(id: string): Promise<{ event: ICalendarEvent; eventDate: Date } | null> {
        const event = await this.getEventById(id);
        if (!event) {
            return null;
        }

        // Validate event dates
        const validation = this.dateService.validateDate(event.start);
        if (!validation.valid) {
            console.warn(`EventManager: Invalid event start date for event ${id}:`, validation.error);
            return null;
        }

        // Validate date range
        if (!this.dateService.isValidRange(event.start, event.end)) {
            console.warn(`EventManager: Invalid date range for event ${id}: start must be before end`);
            return null;
        }

        return {
            event,
            eventDate: event.start
        };
    }

    /**
     * Navigate to specific event by ID
     * Emits navigation events for other managers to handle
     * @param eventId Event ID to navigate to
     * @returns true if event found and navigation initiated, false otherwise
     */
    public async navigateToEvent(eventId: string): Promise<boolean> {
        const eventInfo = await this.getEventForNavigation(eventId);
        if (!eventInfo) {
            console.warn(`EventManager: Event with ID ${eventId} not found`);
            return false;
        }

        const { event, eventDate } = eventInfo;

        // Emit navigation request event
        this.eventBus.emit(CoreEvents.NAVIGATE_TO_EVENT, {
            eventId,
            event,
            eventDate,
            eventStartTime: event.start
        });

        return true;
    }

    /**
     * Get events that overlap with a given time period
     */
    public async getEventsForPeriod(startDate: Date, endDate: Date): Promise<ICalendarEvent[]> {
        const events = await this.repository.loadEvents();
        // Event overlaps period if it starts before period ends AND ends after period starts
        return events.filter(event => {
            return event.start <= endDate && event.end >= startDate;
        });
    }

    /**
     * Create a new event and add it to the calendar
     * Delegates to repository with source='local'
     */
    public async addEvent(event: Omit<ICalendarEvent, 'id'>): Promise<ICalendarEvent> {
        const newEvent = await this.repository.createEvent(event, 'local');

        this.eventBus.emit(CoreEvents.EVENT_CREATED, {
            event: newEvent
        });

        return newEvent;
    }

    /**
     * Update an existing event
     * Delegates to repository with source='local'
     */
    public async updateEvent(id: string, updates: Partial<ICalendarEvent>): Promise<ICalendarEvent | null> {
        try {
            const updatedEvent = await this.repository.updateEvent(id, updates, 'local');

            this.eventBus.emit(CoreEvents.EVENT_UPDATED, {
                event: updatedEvent
            });

            return updatedEvent;
        } catch (error) {
            console.error(`Failed to update event ${id}:`, error);
            return null;
        }
    }

    /**
     * Delete an event
     * Delegates to repository with source='local'
     */
    public async deleteEvent(id: string): Promise<boolean> {
        try {
            await this.repository.deleteEvent(id, 'local');

            this.eventBus.emit(CoreEvents.EVENT_DELETED, {
                eventId: id
            });

            return true;
        } catch (error) {
            console.error(`Failed to delete event ${id}:`, error);
            return false;
        }
    }

    /**
     * Handle remote update from SignalR
     * Delegates to repository with source='remote'
     */
    public async handleRemoteUpdate(event: ICalendarEvent): Promise<void> {
        try {
            await this.repository.updateEvent(event.id, event, 'remote');

            this.eventBus.emit(CoreEvents.REMOTE_UPDATE_RECEIVED, {
                event
            });

            this.eventBus.emit(CoreEvents.EVENT_UPDATED, {
                event
            });
        } catch (error) {
            console.error(`Failed to handle remote update for event ${event.id}:`, error);
        }
    }
}