// Event rendering strategy interface and implementations

import { CalendarEvent } from '../types/CalendarTypes';
import { CalendarConfig } from '../core/CalendarConfig';
import { DateUtils } from '../utils/DateUtils';

/**
 * Interface for event rendering strategies
 */
export interface EventRendererStrategy {
  findColumn(event: CalendarEvent): HTMLElement | null;
  renderEvents(events: CalendarEvent[], config: CalendarConfig): void;
  clearEvents(): void;
}

/**
 * Base class for event renderers with common functionality
 */
export abstract class BaseEventRenderer implements EventRendererStrategy {
  abstract findColumn(event: CalendarEvent): HTMLElement | null;

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

    // Filter out all-day events (handled by GridManager)
    const nonAllDayEvents = events.filter(event => !event.allDay);
    console.log('BaseEventRenderer: Rendering', nonAllDayEvents.length, 'non-all-day events');

    // Render each event in the correct column
    nonAllDayEvents.forEach(event => {
      const column = this.findColumn(event);
      
      if (column) {
        const eventsLayer = column.querySelector('swp-events-layer');
        if (eventsLayer) {
          this.renderEvent(event, eventsLayer, config);
        } else {
          console.warn('BaseEventRenderer: No events layer found in column for event', event.title);
        }
      } else {
        console.warn('BaseEventRenderer: No column found for event', event.title);
      }
    });
  }

  protected renderEvent(event: CalendarEvent, container: Element, config: CalendarConfig): 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, config);
    eventElement.style.position = 'absolute';
    eventElement.style.top = `${position.top + 1}px`;
    eventElement.style.height = `${position.height - 1}px`;

    // Set color
    eventElement.style.backgroundColor = event.metadata?.color || '#3498db';

    // 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>
    `;

    container.appendChild(eventElement);
  }

  protected calculateEventPosition(event: CalendarEvent, config: CalendarConfig): { top: number; height: number } {
    const startDate = new Date(event.start);
    const endDate = new Date(event.end);
    
    const dayStartHour = config.get('dayStartHour');
    const hourHeight = config.get('hourHeight');

    // Calculate minutes from visible day start
    const startMinutes = startDate.getHours() * 60 + startDate.getMinutes();
    const endMinutes = endDate.getHours() * 60 + endDate.getMinutes();
    const dayStartMinutes = dayStartHour * 60;

    // Calculate top position (subtract day start to align with time axis)
    const top = ((startMinutes - dayStartMinutes) / 60) * hourHeight;
    
    // Calculate height
    const durationMinutes = endMinutes - startMinutes;
    const height = (durationMinutes / 60) * hourHeight;

    return { top, height };
  }

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

  clearEvents(): void {
    const existingEvents = document.querySelectorAll('swp-event');
    existingEvents.forEach(event => event.remove());
  }
}

/**
 * Date-based event renderer
 */
export class DateEventRenderer extends BaseEventRenderer {
  findColumn(event: CalendarEvent): HTMLElement | null {
    const eventDate = new Date(event.start);
    const dateStr = DateUtils.formatDate(eventDate);
    const dayColumn = document.querySelector(`swp-day-column[data-date="${dateStr}"]`) as HTMLElement;
    console.log('DateEventRenderer: Looking for day column with date', dateStr, 'found:', !!dayColumn);
    return dayColumn;
  }
}

/**
 * Resource-based event renderer
 */
export class ResourceEventRenderer extends BaseEventRenderer {
  findColumn(event: CalendarEvent): HTMLElement | null {
    if (!event.resourceName) {
      console.warn('ResourceEventRenderer: Event has no resourceName', event);
      return null;
    }

    const resourceColumn = document.querySelector(`swp-resource-column[data-resource="${event.resourceName}"]`) as HTMLElement;
    console.log('ResourceEventRenderer: Looking for resource column with name', event.resourceName, 'found:', !!resourceColumn);
    return resourceColumn;
  }
}