import { EventBus } from '../core/EventBus';
import { IEventBus, CalendarEvent } from '../types/CalendarTypes';
import { EventTypes } from '../constants/EventTypes';
import { calendarConfig } from '../core/CalendarConfig';
import { DateUtils } from '../utils/DateUtils';

/**
 * EventRenderer - Render events i DOM med positionering
 * Håndterer event positioning og overlap detection
 */
export class EventRenderer {
    private eventBus: IEventBus;

    constructor(eventBus: IEventBus) {
        this.eventBus = eventBus;
        this.setupEventListeners();
    }

    private setupEventListeners(): void {
        this.eventBus.on(EventTypes.EVENTS_LOADED, (event: Event) => {
            const customEvent = event as CustomEvent;
            const { events } = customEvent.detail;
            console.log('EventRenderer: Received EVENTS_LOADED with', events.length, 'events');
            // Store events but don't render yet - wait for grid to be ready
            this.pendingEvents = events;
            this.tryRenderEvents();
        });

        this.eventBus.on(EventTypes.GRID_RENDERED, () => {
            // Grid is ready, now we can render events
            this.tryRenderEvents();
        });

        this.eventBus.on(EventTypes.VIEW_RENDERED, () => {
            // Clear existing events when view changes
            this.clearEvents();
        });
    }

    private pendingEvents: CalendarEvent[] = [];

    private tryRenderEvents(): void {
        // Only render if we have both events and grid is ready
        console.log('EventRenderer: tryRenderEvents called, pending events:', this.pendingEvents.length);
        if (this.pendingEvents.length > 0) {
            const dayColumns = document.querySelectorAll('swp-day-column');
            console.log('EventRenderer: Found', dayColumns.length, 'day columns');
            if (dayColumns.length > 0) {
                this.renderEvents(this.pendingEvents);
                this.pendingEvents = []; // Clear pending events after rendering
            }
        }
    }

    private renderEvents(events: CalendarEvent[]): void {
        console.log('EventRenderer: renderEvents called with', events.length, 'events');
        
        // Clear existing events first
        this.clearEvents();

        // Get current week dates for filtering
        const currentWeekDates = this.getCurrentWeekDates();
        console.log('EventRenderer: Current week dates:', currentWeekDates.map(d => DateUtils.formatDate(d)));

        // Filter events for current week
        const currentWeekEvents = events.filter(event => {
            const eventDate = new Date(event.start);
            const eventDateStr = DateUtils.formatDate(eventDate);
            const isInCurrentWeek = currentWeekDates.some(weekDate =>
                DateUtils.formatDate(weekDate) === eventDateStr
            );
            console.log('EventRenderer: Event', event.title, 'on', eventDateStr, 'is in current week:', isInCurrentWeek);
            return isInCurrentWeek;
        });

        console.log('EventRenderer: Rendering', currentWeekEvents.length, 'events for current week');

        // Render each event in the correct day column
        currentWeekEvents.forEach(event => {
            const eventDate = new Date(event.start);
            const dayColumn = this.findDayColumn(eventDate);
            
            if (dayColumn) {
                const eventsLayer = dayColumn.querySelector('swp-events-layer');
                if (eventsLayer) {
                    console.log('EventRenderer: Rendering event', event.title, 'in day column for', DateUtils.formatDate(eventDate));
                    this.renderEvent(event, eventsLayer);
                } else {
                    console.warn('EventRenderer: No events layer found in day column for', DateUtils.formatDate(eventDate));
                }
            } else {
                console.warn('EventRenderer: No day column found for event date', DateUtils.formatDate(eventDate));
            }
        });

        // Emit event rendered
        this.eventBus.emit(EventTypes.EVENT_RENDERED, {
            count: currentWeekEvents.length
        });
    }

    /**
     * Get current week dates (Sunday to Saturday)
     */
    private getCurrentWeekDates(): Date[] {
        const today = new Date();
        const weekStart = DateUtils.getWeekStart(today, 0); // Sunday start
        const dates: Date[] = [];
        
        for (let i = 0; i < 7; i++) {
            const date = DateUtils.addDays(weekStart, i);
            dates.push(date);
        }
        
        return dates;
    }

    /**
     * Find day column for specific date
     */
    private findDayColumn(date: Date): HTMLElement | null {
        const dateStr = DateUtils.formatDate(date);
        const dayColumn = document.querySelector(`swp-day-column[data-date="${dateStr}"]`) as HTMLElement;
        console.log('EventRenderer: Looking for day column with date', dateStr, 'found:', !!dayColumn);
        return dayColumn;
    }

    private renderEvent(event: CalendarEvent, container: Element): void {
        const eventElement = document.createElement('swp-event');
        eventElement.dataset.eventId = event.id;
        eventElement.dataset.type = event.type;

        // Calculate position based on time
        const position = this.calculateEventPosition(event);
        eventElement.style.position = 'absolute';
        eventElement.style.top = `${position.top}px`;
        eventElement.style.height = `${position.height}px`;
        eventElement.style.left = '2px';
        eventElement.style.right = '2px';
        eventElement.style.zIndex = '10';

        // Format time for display
        const startTime = this.formatTime(event.start);
        const endTime = this.formatTime(event.end);

        // Create event content
        eventElement.innerHTML = `
            <swp-event-time>${startTime} - ${endTime}</swp-event-time>
            <swp-event-title>${event.title}</swp-event-title>
        `;

        // Add event listeners
        this.addEventListeners(eventElement, event);

        container.appendChild(eventElement);
    }

    private calculateEventPosition(event: CalendarEvent): { top: number; height: number } {
        const startDate = new Date(event.start);
        const endDate = new Date(event.end);
        
        // Use dayStartHour to match time-axis positioning
        const dayStartHour = calendarConfig.get('dayStartHour'); // 0 (midnight)
        const hourHeight = calendarConfig.get('hourHeight');

        // Calculate minutes from day start (midnight)
        const eventHour = startDate.getHours();
        const eventMinutes = startDate.getMinutes();
        const startMinutes = (eventHour - dayStartHour) * 60 + eventMinutes;
        
        // Calculate duration in minutes
        const duration = (endDate.getTime() - startDate.getTime()) / (1000 * 60);

        // Convert to pixels - this gives absolute position from top of time-grid
        const absoluteTop = startMinutes * (hourHeight / 60);
        const height = duration * (hourHeight / 60);

        // Get current scroll position to adjust for viewport
        const scrollableContent = document.querySelector('swp-scrollable-content') as HTMLElement;
        const scrollTop = scrollableContent ? scrollableContent.scrollTop : 0;
        
        // Calculate relative position within the visible viewport
        // Events are positioned relative to their day-column, not the scrollable content
        // So we use the absolute position directly
        const top = absoluteTop;

        console.log('EventRenderer: Position calculation for', event.title, {
            eventTime: `${eventHour}:${eventMinutes.toString().padStart(2, '0')}`,
            dayStartHour,
            startMinutes,
            duration,
            absoluteTop,
            scrollTop,
            finalTop: top,
            height
        });

        return { top, height };
    }

    private formatTime(isoString: string): string {
        const date = new Date(isoString);
        const hours = date.getHours();
        const minutes = date.getMinutes();
        
        const period = hours >= 12 ? 'PM' : 'AM';
        const displayHours = hours % 12 || 12;
        const displayMinutes = minutes.toString().padStart(2, '0');
        
        return `${displayHours}:${displayMinutes} ${period}`;
    }

    private addEventListeners(eventElement: HTMLElement, event: CalendarEvent): void {
        // Click handler
        eventElement.addEventListener('click', (e) => {
            e.stopPropagation();
            this.eventBus.emit(EventTypes.EVENT_SELECTED, {
                event,
                element: eventElement
            });
        });

        // Hover effects are handled by CSS
        eventElement.addEventListener('mouseenter', () => {
            eventElement.style.zIndex = '20';
        });

        eventElement.addEventListener('mouseleave', () => {
            eventElement.style.zIndex = '10';
        });
    }

    private clearEvents(): void {
        const eventsLayers = document.querySelectorAll('swp-events-layer');
        eventsLayers.forEach(layer => {
            layer.innerHTML = '';
        });
    }

    public refresh(): void {
        // Request fresh events from EventManager
        this.eventBus.emit(EventTypes.REFRESH_REQUESTED);
    }

    public destroy(): void {
        this.clearEvents();
    }
}