import { eventBus } from '../core/EventBus';
import { calendarConfig } from '../core/CalendarConfig';
import { CalendarTypeFactory } from '../factories/CalendarTypeFactory';
import { CoreEvents } from '../constants/CoreEvents';
import { HeaderRenderContext } from '../renderers/HeaderRenderer';
import { ResourceCalendarData } from '../types/CalendarTypes';

/**
 * HeaderManager - Handles all header-related event logic
 * Separates event handling from rendering concerns
 */
export class HeaderManager {
  private headerEventListener: ((event: Event) => void) | null = null;
  private headerMouseLeaveListener: ((event: Event) => void) | null = null;
  private cachedCalendarHeader: HTMLElement | null = null;

  constructor() {
    // Bind methods for event listeners
    this.setupHeaderDragListeners = this.setupHeaderDragListeners.bind(this);
    this.destroy = this.destroy.bind(this);
    
    // Listen for navigation events to update header
    this.setupNavigationListener();
  }

  /**
   * Initialize header with initial date
   */
  public initializeHeader(currentDate: Date, resourceData: ResourceCalendarData | null = null): void {
    this.updateHeader(currentDate, resourceData);
  }

  /**
   * Get cached calendar header element
   */
  private getCalendarHeader(): HTMLElement | null {
    if (!this.cachedCalendarHeader) {
      this.cachedCalendarHeader = document.querySelector('swp-calendar-header');
    }
    return this.cachedCalendarHeader;
  }

  /**
   * Setup header drag event listeners - REFACTORED to use mouseenter
   */
  public setupHeaderDragListeners(): void {
    const calendarHeader = this.getCalendarHeader();
    if (!calendarHeader) return;

    console.log('🎯 HeaderManager: Setting up drag listeners with mouseenter');

    // Track last processed date to avoid duplicates
    let lastProcessedDate: string | null = null;
    let lastProcessedTime = 0;

    // Use mouseenter instead of mouseover to avoid continuous firing
    this.headerEventListener = (event: Event) => {
      const target = event.target as HTMLElement;
      
      console.log('🖱️ HeaderManager: mouseenter detected on:', target.tagName, target.className);
      
      // Check if we're entering the all-day container OR the header area where container should be
      let allDayContainer = target.closest('swp-allday-container');
      
      // If no container exists, check if we're in the header and should create one via AllDayManager
      if (!allDayContainer && target.closest('swp-calendar-header')) {
        console.log('📍 HeaderManager: In header area but no all-day container exists, requesting creation...');
        
        // Emit event to AllDayManager to create container
        eventBus.emit('allday:ensure-container');
        
        // Try to find it again after creation
        allDayContainer = target.closest('swp-calendar-header')?.querySelector('swp-allday-container') as HTMLElement;
      }
      
      if (allDayContainer) {
        // SMART CHECK: Only calculate target date if there's an active drag operation
        const isDragActive = document.querySelector('.dragging') !== null;
        
        if (!isDragActive) {
          console.log('⏭️ HeaderManager: No active drag operation, skipping target date calculation');
          return;
        }
        
        console.log('📍 HeaderManager: Active drag detected, calculating target date...');
        
        // Calculate target date from mouse X coordinate
        const targetDate = this.calculateTargetDateFromMouseX(event as MouseEvent);
        
        console.log('🎯 HeaderManager: Calculated target date:', targetDate);
        
        if (targetDate) {
          const calendarType = calendarConfig.getCalendarMode();
          const headerRenderer = CalendarTypeFactory.getHeaderRenderer(calendarType);
          
          console.log('✅ HeaderManager: Emitting header:mouseover with targetDate:', targetDate);
          
          eventBus.emit('header:mouseover', {
            element: allDayContainer,
            targetDate,
            headerRenderer
          });
        } else {
          console.log('❌ HeaderManager: Could not calculate target date from mouse position');
        }
      }
    };

    // Header mouseleave listener
    this.headerMouseLeaveListener = (event: Event) => {
      console.log('🚪 HeaderManager: mouseleave detected');
      eventBus.emit('header:mouseleave', {
        element: event.target as HTMLElement
      });
    };

    // Use mouseenter with capture to catch events early
    calendarHeader.addEventListener('mouseenter', this.headerEventListener, true);
    calendarHeader.addEventListener('mouseleave', this.headerMouseLeaveListener);
    
    console.log('✅ HeaderManager: Event listeners attached (mouseenter + mouseleave)');
  }

  /**
   * Calculate target date from mouse X coordinate
   */
  private calculateTargetDateFromMouseX(event: MouseEvent): string | null {
    const dayHeaders = document.querySelectorAll('swp-day-header');
    const mouseX = event.clientX;
    
    console.log('🧮 HeaderManager: Calculating target date from mouseX:', mouseX);
    console.log('📊 HeaderManager: Found', dayHeaders.length, 'day headers');
    
    for (const header of dayHeaders) {
      const headerElement = header as HTMLElement;
      const rect = headerElement.getBoundingClientRect();
      const headerDate = headerElement.dataset.date;
      
      console.log('📏 HeaderManager: Checking header', headerDate, 'bounds:', {
        left: rect.left,
        right: rect.right,
        mouseX: mouseX,
        isWithin: mouseX >= rect.left && mouseX <= rect.right
      });
      
      // Check if mouse X is within this header's bounds
      if (mouseX >= rect.left && mouseX <= rect.right) {
        console.log('🎯 HeaderManager: Found matching header for date:', headerDate);
        return headerDate || null;
      }
    }
    
    console.log('❌ HeaderManager: No matching header found for mouseX:', mouseX);
    return null;
  }

  /**
   * Remove event listeners from header - UPDATED for mouseenter
   */
  private removeEventListeners(): void {
    const calendarHeader = this.getCalendarHeader();
    if (!calendarHeader) return;

    console.log('🧹 HeaderManager: Removing event listeners');

    if (this.headerEventListener) {
      // Remove mouseenter listener with capture flag
      calendarHeader.removeEventListener('mouseenter', this.headerEventListener, true);
      console.log('✅ HeaderManager: Removed mouseenter listener');
    }
    
    if (this.headerMouseLeaveListener) {
      calendarHeader.removeEventListener('mouseleave', this.headerMouseLeaveListener);
      console.log('✅ HeaderManager: Removed mouseleave listener');
    }
  }

  /**
   * Setup navigation event listener
   */
  private setupNavigationListener(): void {
    eventBus.on(CoreEvents.NAVIGATION_COMPLETED, (event) => {
      const { currentDate, resourceData } = (event as CustomEvent).detail;
      this.updateHeader(currentDate, resourceData);
    });

    // Also listen for date changes (including initial setup)
    eventBus.on(CoreEvents.DATE_CHANGED, (event) => {
      const { currentDate } = (event as CustomEvent).detail;
      this.updateHeader(currentDate, null);
    });

    // Listen for workweek header updates after grid rebuild
    eventBus.on('workweek:header-update', (event) => {
      const { currentDate } = (event as CustomEvent).detail;
      this.clearCache(); // Clear cache since DOM was cleared
      this.updateHeader(currentDate, null);
    });

  }

  /**
   * Update header content for navigation
   */
  private updateHeader(currentDate: Date, resourceData: ResourceCalendarData | null = null): void {
    const calendarHeader = this.getOrCreateCalendarHeader();
    if (!calendarHeader) return;

    // Remove existing event listeners BEFORE clearing content
    this.removeEventListeners();

    // Clear existing content
    calendarHeader.innerHTML = '';

    // Render new header content
    const calendarType = calendarConfig.getCalendarMode();
    const headerRenderer = CalendarTypeFactory.getHeaderRenderer(calendarType);
    
    const context: HeaderRenderContext = {
      currentWeek: currentDate,
      config: calendarConfig,
      resourceData: resourceData
    };

    headerRenderer.render(calendarHeader, context);

    // Setup event listeners on the new content
    this.setupHeaderDragListeners();

    // Notify other managers that header was rebuilt
    eventBus.emit('header:rebuilt', {
      headerElement: calendarHeader
    });
  }

  /**
   * Get or create calendar header element
   */
  private getOrCreateCalendarHeader(): HTMLElement | null {
    let calendarHeader = this.getCalendarHeader();
    
    if (!calendarHeader) {
      // Find grid container and create header
      const gridContainer = document.querySelector('swp-grid-container');
      if (gridContainer) {
        calendarHeader = document.createElement('swp-calendar-header');
        // Insert header as first child
        gridContainer.insertBefore(calendarHeader, gridContainer.firstChild);
        this.cachedCalendarHeader = calendarHeader;
      }
    }
    
    return calendarHeader;
  }


  /**
   * Clear cached header reference
   */
  public clearCache(): void {
    this.cachedCalendarHeader = null;
  }

  /**
   * Clean up resources and event listeners
   */
  public destroy(): void {
    this.removeEventListeners();
    
    // Clear references
    this.headerEventListener = null;
    this.headerMouseLeaveListener = null;
    
    this.clearCache();
  }
}