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

/**
 * Abstract base class for event DOM elements
 */
export abstract class BaseEventElement {
  protected element: HTMLElement;
  protected event: CalendarEvent;

  protected constructor(event: CalendarEvent) {
    this.event = event;
    this.element = this.createElement();
    this.setDataAttributes();
  }

  /**
   * Create the underlying DOM element
   */
  protected abstract createElement(): HTMLElement;

  /**
   * Set standard data attributes on the element
   */
  protected setDataAttributes(): void {
    this.element.dataset.eventId = this.event.id;
    this.element.dataset.title = this.event.title;
    this.element.dataset.start = this.event.start.toISOString();
    this.element.dataset.end = this.event.end.toISOString();
    this.element.dataset.type = this.event.type;
    this.element.dataset.duration = this.event.metadata?.duration?.toString() || '60';
  }

  /**
   * Get the DOM element
   */
  public getElement(): HTMLElement {
    return this.element;
  }

  /**
   * Format time for display
   */
  protected formatTime(date: Date): string {
    const hours = date.getHours();
    const minutes = date.getMinutes();
    const period = hours >= 12 ? 'PM' : 'AM';
    const displayHours = hours > 12 ? hours - 12 : (hours === 0 ? 12 : hours);
    return `${displayHours}:${minutes.toString().padStart(2, '0')} ${period}`;
  }

  /**
   * Calculate event position for timed events
   */
  protected calculateEventPosition(): { top: number; height: number } {
    const gridSettings = calendarConfig.getGridSettings();
    const dayStartHour = gridSettings.dayStartHour;
    const hourHeight = gridSettings.hourHeight;

    const startMinutes = this.event.start.getHours() * 60 + this.event.start.getMinutes();
    const endMinutes = this.event.end.getHours() * 60 + this.event.end.getMinutes();
    const dayStartMinutes = dayStartHour * 60;

    const top = ((startMinutes - dayStartMinutes) / 60) * hourHeight;
    const durationMinutes = endMinutes - startMinutes;
    const height = (durationMinutes / 60) * hourHeight;

    return { top, height };
  }
}

/**
 * Timed event element (swp-event)
 */
export class SwpEventElement extends BaseEventElement {
  private constructor(event: CalendarEvent) {
    super(event);
    this.createInnerStructure();
    this.applyPositioning();
  }

  protected createElement(): HTMLElement {
    return document.createElement('swp-event');
  }

  /**
   * Create inner HTML structure
   */
  private createInnerStructure(): void {
    const startTime = this.formatTime(this.event.start);
    const endTime = this.formatTime(this.event.end);
    const durationMinutes = (this.event.end.getTime() - this.event.start.getTime()) / (1000 * 60);
    
    this.element.innerHTML = `
      <swp-event-time data-duration="${durationMinutes}">${startTime} - ${endTime}</swp-event-time>
      <swp-event-title>${this.event.title}</swp-event-title>
    `;
  }

  /**
   * Apply positioning styles
   */
  private applyPositioning(): void {
    const position = this.calculateEventPosition();
    this.element.style.position = 'absolute';
    this.element.style.top = `${position.top + 1}px`;
    this.element.style.height = `${position.height - 3}px`;
    this.element.style.left = '2px';
    this.element.style.right = '2px';
  }

  /**
   * Factory method to create a SwpEventElement from a CalendarEvent
   */
  public static fromCalendarEvent(event: CalendarEvent): SwpEventElement {
    return new SwpEventElement(event);
  }

  /**
   * Factory method to convert an all-day HTML element to a timed SwpEventElement
   */
  public static fromAllDayElement(allDayElement: HTMLElement): SwpEventElement {
    // Extract data from all-day element's dataset
    const eventId = allDayElement.dataset.eventId || '';
    const title = allDayElement.dataset.title || allDayElement.textContent || 'Untitled';
    const type = allDayElement.dataset.type || 'work';
    const startStr = allDayElement.dataset.start;
    const endStr = allDayElement.dataset.end;
    const durationStr = allDayElement.dataset.duration;

    if (!startStr || !endStr) {
      throw new Error('All-day element missing start/end dates');
    }

    // Parse dates and set reasonable 1-hour duration for timed event
    const originalStart = new Date(startStr);
    const duration = durationStr ? parseInt(durationStr) : 60; // Default 1 hour

    // For conversion, use current time or a reasonable default (9 AM)
    const now = new Date();
    const startDate = new Date(originalStart);
    startDate.setHours(now.getHours() || 9, now.getMinutes() || 0, 0, 0);
    
    const endDate = new Date(startDate);
    endDate.setMinutes(endDate.getMinutes() + duration);

    // Create CalendarEvent object
    const calendarEvent: CalendarEvent = {
      id: eventId,
      title: title,
      start: startDate,
      end: endDate,
      type: type,
      allDay: false,
      syncStatus: 'synced',
      metadata: {
        duration: duration.toString()
      }
    };

    return new SwpEventElement(calendarEvent);
  }
}

/**
 * All-day event element (swp-allday-event)
 */
export class SwpAllDayEventElement extends BaseEventElement {
  private columnIndex: number;

  private constructor(event: CalendarEvent, columnIndex: number) {
    super(event);
    this.columnIndex = columnIndex;
    this.setAllDayAttributes();
    this.createInnerStructure();
    this.applyGridPositioning();
  }

  protected createElement(): HTMLElement {
    return document.createElement('swp-allday-event');
  }

  /**
   * Set all-day specific attributes
   */
  private setAllDayAttributes(): void {
    this.element.dataset.allDay = "true";
    // Override start/end times to be full day
    const dateStr = this.event.start.toISOString().split('T')[0];
    this.element.dataset.start = `${dateStr}T00:00:00`;
    this.element.dataset.end = `${dateStr}T23:59:59`;
  }

  /**
   * Create inner structure (just text content for all-day events)
   */
  private createInnerStructure(): void {
    this.element.textContent = this.event.title;
  }

  /**
   * Apply CSS grid positioning
   */
  private applyGridPositioning(): void {
    this.element.style.gridColumn = this.columnIndex.toString();
  }

  /**
   * Factory method to create from CalendarEvent and target date
   */
  public static fromCalendarEvent(event: CalendarEvent, targetDate: string): SwpAllDayEventElement {
    // Calculate column index
    const dayHeaders = document.querySelectorAll('swp-day-header');
    let columnIndex = 1;
    dayHeaders.forEach((header, index) => {
      if ((header as HTMLElement).dataset.date === targetDate) {
        columnIndex = index + 1;
      }
    });

    return new SwpAllDayEventElement(event, columnIndex);
  }
}