/**
 * DragHoverManager - Handles event hover tracking
 * Fully autonomous - listens to mouse events and manages hover state independently
 */

import { IEventBus } from '../types/CalendarTypes';

export class DragHoverManager {
  private isHoverTrackingActive = false;
  private currentHoveredEvent: HTMLElement | null = null;
  private calendarContainer: HTMLElement | null = null;

  constructor(private eventBus: IEventBus) {
    this.init();
  }

  private init(): void {
    // Wait for DOM to be ready
    setTimeout(() => {
      this.calendarContainer = document.querySelector('swp-calendar-container');
      if (this.calendarContainer) {
        this.setupEventListeners();
      }
    }, 100);

    // Listen to drag start to deactivate hover tracking
    this.eventBus.on('drag:start', () => {
      this.deactivateTracking();
    });
  }

  private setupEventListeners(): void {
    if (!this.calendarContainer) return;

    // Listen to mouseenter on events (using event delegation)
    this.calendarContainer.addEventListener('mouseenter', (e) => {
      const target = e.target as HTMLElement;
      const eventElement = target.closest<HTMLElement>('swp-event');

      if (eventElement) {
        this.handleEventMouseEnter(e as MouseEvent, eventElement);
      }
    }, true); // Use capture phase

    // Listen to mousemove globally to track when mouse leaves event bounds
    document.body.addEventListener('mousemove', (e: MouseEvent) => {
      if (this.isHoverTrackingActive && e.buttons === 0) {
        this.checkEventHover(e);
      }
    });
  }

  /**
   * Handle mouse enter on swp-event - activate hover tracking
   */
  private handleEventMouseEnter(event: MouseEvent, eventElement: HTMLElement): void {
    // Only handle hover if mouse button is up
    if (event.buttons === 0) {
      // Clear any previous hover first
      if (this.currentHoveredEvent && this.currentHoveredEvent !== eventElement) {
        this.currentHoveredEvent.classList.remove('hover');
      }

      this.isHoverTrackingActive = true;
      this.currentHoveredEvent = eventElement;
      eventElement.classList.add('hover');

      this.eventBus.emit('event:hover:start', { element: eventElement });
    }
  }

  /**
   * Check if mouse is still over the currently hovered event
   */
  private checkEventHover(event: MouseEvent): void {
    // Only track hover when active and mouse button is up
    if (!this.isHoverTrackingActive || !this.currentHoveredEvent) return;

    const rect = this.currentHoveredEvent.getBoundingClientRect();
    const mouseX = event.clientX;
    const mouseY = event.clientY;

    // Check if mouse is still within the current hovered event
    const isStillInside = mouseX >= rect.left && mouseX <= rect.right &&
      mouseY >= rect.top && mouseY <= rect.bottom;

    // If mouse left the event
    if (!isStillInside) {
      // Only disable tracking and clear if mouse is NOT pressed (allow resize to work)
      if (event.buttons === 0) {
        this.isHoverTrackingActive = false;
        this.clearEventHover();
      }
    }
  }

  /**
   * Clear hover state
   */
  private clearEventHover(): void {
    if (this.currentHoveredEvent) {
      this.currentHoveredEvent.classList.remove('hover');
      this.eventBus.emit('event:hover:end', { element: this.currentHoveredEvent });
      this.currentHoveredEvent = null;
    }
  }

  /**
   * Deactivate hover tracking and clear any current hover
   * Called via event bus when drag starts
   */
  private deactivateTracking(): void {
    this.isHoverTrackingActive = false;
    this.clearEventHover();
  }
}