// Event rendering strategy interface and implementations

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

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

/**
 * Base class for event renderers with common functionality
 */
export abstract class BaseEventRenderer implements EventRendererStrategy {
  protected dateCalculator: DateCalculator;

  constructor(config: CalendarConfig) {
    this.dateCalculator = new DateCalculator(config);
  }
  renderEvents(events: CalendarEvent[], container: HTMLElement, config: CalendarConfig): void {
    console.log('BaseEventRenderer: renderEvents called with', events.length, 'events');
    
    // NOTE: Removed clearEvents() to support sliding animation
    // With sliding animation, multiple grid containers exist simultaneously
    // clearEvents() would remove events from all containers, breaking the animation
    // Events are now rendered directly into the new container without clearing

    // Events should already be filtered by EventManager - no need to filter here
    console.log('BaseEventRenderer: Rendering', events.length, 'pre-filtered events');

    // Find columns in the specific container
    const columns = this.getColumns(container);
    console.log(`BaseEventRenderer: Found ${columns.length} columns in container`);

    columns.forEach(column => {
      const columnEvents = this.getEventsForColumn(column, events);
      console.log(`BaseEventRenderer: Rendering ${columnEvents.length} events in column`);
      
      const eventsLayer = column.querySelector('swp-events-layer');
      if (eventsLayer) {
        columnEvents.forEach(event => {
          console.log(`BaseEventRenderer: Rendering event "${event.title}" in events layer`);
          this.renderEvent(event, eventsLayer, config);
        });
        
        // Debug: Verify events were actually added
        const renderedEvents = eventsLayer.querySelectorAll('swp-event');
        console.log(`BaseEventRenderer: Events layer now has ${renderedEvents.length} events`);
      } else {
        console.warn('BaseEventRenderer: No events layer found in column');
      }
    });
  }

  // Abstract methods that subclasses must implement
  protected abstract getColumns(container: HTMLElement): HTMLElement[];
  protected abstract getEventsForColumn(column: HTMLElement, events: CalendarEvent[]): CalendarEvent[];

  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 - 3}px`; //adjusted so bottom does not cover horizontal time lines.

    // Color is now handled by CSS classes based on data-type attribute

    // Format time for display
    const startTime = this.dateCalculator.formatTime(new Date(event.start));
    const endTime = this.dateCalculator.formatTime(new Date(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);
    
    console.log(`BaseEventRenderer: Created event element for "${event.title}":`, {
      top: eventElement.style.top,
      height: eventElement.style.height,
      dataType: eventElement.dataset.type,
      position: eventElement.style.position,
      innerHTML: eventElement.innerHTML
    });
  }

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

    console.log('Event positioning calculation:', {
      eventTime: `${startDate.getHours()}:${startDate.getMinutes()}`,
      startMinutes,
      endMinutes,
      dayStartMinutes,
      dayStartHour,
      hourHeight,
      top,
      height
    });

    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(container?: HTMLElement): void {
    const selector = 'swp-event';
    const existingEvents = container 
      ? container.querySelectorAll(selector)
      : document.querySelectorAll(selector);
    
    if (existingEvents.length > 0) {
      console.log(`BaseEventRenderer: Clearing ${existingEvents.length} events`, 
        container ? 'from container' : 'globally');
    }
    existingEvents.forEach(event => event.remove());
  }
}

/**
 * Date-based event renderer
 */
export class DateEventRenderer extends BaseEventRenderer {
  protected getColumns(container: HTMLElement): HTMLElement[] {
    const columns = container.querySelectorAll('swp-day-column');
    console.log('DateEventRenderer: Found', columns.length, 'day columns in container');
    return Array.from(columns) as HTMLElement[];
  }

  protected getEventsForColumn(column: HTMLElement, events: CalendarEvent[]): CalendarEvent[] {
    const columnDate = column.dataset.date;
    if (!columnDate) {
      console.log(`DateEventRenderer: Column has no dataset.date`);
      return [];
    }

    const columnEvents = events.filter(event => {
      const eventDate = new Date(event.start);
      const eventDateStr = this.dateCalculator.formatISODate(eventDate);
      const matches = eventDateStr === columnDate;
      
      if (!matches) {
        if(event.title == 'Architecture Planning')
        console.log(`DateEventRenderer: Event ${event.title} (${eventDateStr}) does not match column (${columnDate})`);
      }
      
      return matches;
    });

    console.log(`DateEventRenderer: Column ${columnDate} has ${columnEvents.length} events from ${events.length} total`);
    return columnEvents;
  }
}

/**
 * Resource-based event renderer
 */
export class ResourceEventRenderer extends BaseEventRenderer {
  protected getColumns(container: HTMLElement): HTMLElement[] {
    const columns = container.querySelectorAll('swp-resource-column');
    console.log('ResourceEventRenderer: Found', columns.length, 'resource columns in container');
    return Array.from(columns) as HTMLElement[];
  }

  protected getEventsForColumn(column: HTMLElement, events: CalendarEvent[]): CalendarEvent[] {
    const resourceName = column.dataset.resource;
    if (!resourceName) return [];

    const columnEvents = events.filter(event => {
      return event.resource?.name === resourceName;
    });

    console.log(`ResourceEventRenderer: Resource ${resourceName} has ${columnEvents.length} events`);
    return columnEvents;
  }
}