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

/**
 * 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;
            // 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
        if (this.pendingEvents.length > 0) {
            const dayColumns = document.querySelectorAll('swp-day-column');
            if (dayColumns.length > 0) {
                this.renderEvents(this.pendingEvents);
                this.pendingEvents = []; // Clear pending events after rendering
            }
        }
    }

    private renderEvents(events: CalendarEvent[]): void {
        console.log(`EventRenderer: Rendering ${events.length} events`);
        
        // Clear existing events first
        this.clearEvents();

        // Group events by day for better rendering
        const eventsByDay = this.groupEventsByDay(events);

        // Render events for each day
        Object.entries(eventsByDay).forEach(([dayIndex, dayEvents]) => {
            this.renderDayEvents(parseInt(dayIndex), dayEvents);
        });

        this.eventBus.emit(EventTypes.EVENT_RENDERED, {
            count: events.length
        });
    }

    private groupEventsByDay(events: CalendarEvent[]): Record<number, CalendarEvent[]> {
        const grouped: Record<number, CalendarEvent[]> = {};

        events.forEach(event => {
            const day = event.metadata?.day || 0;
            if (!grouped[day]) {
                grouped[day] = [];
            }
            grouped[day].push(event);
        });

        return grouped;
    }

    private renderDayEvents(dayIndex: number, events: CalendarEvent[]): void {
        // Sort events by start time
        const sortedEvents = events.sort((a, b) => a.start.localeCompare(b.start));

        sortedEvents.forEach(event => {
            // Find the appropriate events container for this event
            const eventContainer = this.findEventContainer(event, dayIndex);
            if (eventContainer) {
                this.renderEvent(event, eventContainer);
            }
        });
    }

    private findEventContainer(event: CalendarEvent, dayIndex: number): Element | null {
        // Debug: Log what we're looking for
        console.log(`EventRenderer: Looking for day ${dayIndex} using POC structure`);
        
        // Check what day columns actually exist
        const dayColumns = document.querySelectorAll('swp-day-column');
        console.log(`EventRenderer: Found ${dayColumns.length} day columns total`);
        
        // Check first few columns to see their attributes
        for (let i = 0; i < Math.min(3, dayColumns.length); i++) {
            const column = dayColumns[i] as HTMLElement;
            console.log(`Column ${i}:`, {
                dayIndex: column.dataset.dayIndex,
                date: column.dataset.date,
                tagName: column.tagName
            });
        }
        
        // Find the day column that corresponds to the event's day
        const dayColumn = document.querySelector(`swp-day-column[data-dayIndex="${dayIndex}"]`);
        if (!dayColumn) {
            console.warn(`EventRenderer: Day column for day ${dayIndex} not found`);
            return null;
        }
        
        // Find the events layer within this day column
        const eventsLayer = dayColumn.querySelector('swp-events-layer');
        if (!eventsLayer) {
            console.warn(`EventRenderer: Events layer not found in day column for day ${dayIndex}`);
            return null;
        }
        
        return eventsLayer;
    }

    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);
        
        const startHour = calendarConfig.get('dayStartHour');
        const hourHeight = calendarConfig.get('hourHeight');

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

        // Convert to pixels
        const top = startMinutes * (hourHeight / 60);
        const height = duration * (hourHeight / 60);

        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();
    }
}