import { CalendarEvent } from '../types/CalendarTypes';
import { calendarConfig } from '../core/CalendarConfig';
import { TimeFormatter } from '../utils/TimeFormatter';
import { PositionUtils } from '../utils/PositionUtils';
import { EventLayout } from '../utils/AllDayLayoutEngine';

/**
 * 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 using TimeFormatter
   */
  protected formatTime(date: Date): string {
    return TimeFormatter.formatTime(date);
  }

  /**
   * Calculate event position for timed events using PositionUtils
   */
  protected calculateEventPosition(): { top: number; height: number } {
    return PositionUtils.calculateEventPosition(this.event.start, this.event.end);
  }
}

/**
 * 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 timeRange = TimeFormatter.formatTimeRange(this.event.start, this.event.end);
    const durationMinutes = (this.event.end.getTime() - this.event.start.getTime()) / (1000 * 60);

    this.element.innerHTML = `
      <swp-event-time data-duration="${durationMinutes}">${timeRange}</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.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);
  }

  /**
   * Create a clone of this SwpEventElement with "clone-" prefix
   */
  public createClone(): SwpEventElement {
    // Clone the underlying DOM element
    const clonedElement = this.element.cloneNode(true) as HTMLElement;

    // Create new SwpEventElement instance from the cloned DOM
    const clonedSwpEvent = SwpEventElement.fromExistingElement(clonedElement);

    // Apply "clone-" prefix to ID
    clonedSwpEvent.updateEventId(`clone-${this.event.id}`);

    // Cache original duration for drag operations
    const originalDuration = this.getOriginalEventDuration();
    clonedSwpEvent.element.dataset.originalDuration = originalDuration.toString();

    // Set height from original element
    clonedSwpEvent.element.style.height = this.element.style.height || `${this.element.getBoundingClientRect().height}px`;

    return clonedSwpEvent;
  }

  /**
   * Factory method to create SwpEventElement from existing DOM element
   */
  public static fromExistingElement(element: HTMLElement): SwpEventElement {
    // Extract CalendarEvent data from DOM element
    const event = this.extractCalendarEventFromElement(element);

    // Create new instance but replace the created element with the existing one
    const swpEvent = new SwpEventElement(event);
    swpEvent.element = element;

    return swpEvent;
  }

  /**
   * Update the event ID in both the CalendarEvent and DOM element
   */
  private updateEventId(newId: string): void {
    this.event.id = newId;
    this.element.dataset.eventId = newId;
  }

  /**
   * Extract original event duration from DOM element
   */
  private getOriginalEventDuration(): number {
    const timeElement = this.element.querySelector('swp-event-time');
    if (timeElement) {
      const duration = timeElement.getAttribute('data-duration');
      if (duration) {
        return parseInt(duration);
      }
    }
    return 60; // Fallback
  }

  /**
   * Extract CalendarEvent from DOM element
   */
  public static extractCalendarEventFromElement(element: HTMLElement): CalendarEvent {
    return {
      id: element.dataset.eventId || '',
      title: element.dataset.title || '',
      start: new Date(element.dataset.start || ''),
      end: new Date(element.dataset.end || ''),
      type: element.dataset.type || 'work',
      allDay: false,
      syncStatus: 'synced',
      metadata: {
        duration: element.dataset.duration
      }
    };
  }

  /**
   * 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 (now using unified swp-event tag)
 */
export class SwpAllDayEventElement extends BaseEventElement {

  constructor(event: CalendarEvent) {
    super(event);
    this.setAllDayAttributes();
    this.createInnerStructure();
    // this.applyGridPositioning();
  }

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

  /**
   * Set all-day specific attributes
   */
  private setAllDayAttributes(): void {
    this.element.dataset.allDay = "true";
    this.element.dataset.start = this.event.start.toISOString();
    this.element.dataset.end = this.event.end.toISOString();
  }

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

  /**
   * Apply CSS grid positioning
   */
  public applyGridPositioning(layout: EventLayout): void {
    const gridArea = `${layout.row} / ${layout.startColumn} / ${layout.row + 1} / ${layout.endColumn + 1}`;
    this.element.style.gridArea = gridArea;
  }

}