import { IEventBus } from '../types/CalendarTypes.js';
import { DateUtils } from '../utils/DateUtils.js';
import { EventTypes } from '../constants/EventTypes.js';
import { NavigationRenderer } from '../renderers/NavigationRenderer.js';

/**
 * NavigationManager handles calendar navigation (prev/next/today buttons)
 * with simplified CSS Grid approach
 */
export class NavigationManager {
  private eventBus: IEventBus;
  private navigationRenderer: NavigationRenderer;
  private currentWeek: Date;
  private targetWeek: Date;
  private animationQueue: number = 0;

  constructor(eventBus: IEventBus) {
    console.log('🧭 NavigationManager: Constructor called');
    this.eventBus = eventBus;
    this.navigationRenderer = new NavigationRenderer(eventBus);
    this.currentWeek = DateUtils.getWeekStart(new Date(), 0); // Sunday start like POC
    this.targetWeek = new Date(this.currentWeek);
    this.init();
  }

  private init(): void {
    this.setupEventListeners();
    // Don't update week info immediately - wait for DOM to be ready
    console.log('NavigationManager: Waiting for CALENDAR_INITIALIZED before updating DOM');
  }

  private setupEventListeners(): void {
    // Initial DOM update when calendar is initialized
    this.eventBus.on(EventTypes.CALENDAR_INITIALIZED, () => {
      console.log('NavigationManager: Received CALENDAR_INITIALIZED, updating week info');
      this.updateWeekInfo();
    });

    // Listen for navigation button clicks
    document.addEventListener('click', (e) => {
      const target = e.target as HTMLElement;
      const navButton = target.closest('[data-action]') as HTMLElement;
      
      if (!navButton) return;
      
      const action = navButton.dataset.action;
      
      switch (action) {
        case 'prev':
          this.navigateToPreviousWeek();
          break;
        case 'next':
          this.navigateToNextWeek();
          break;
        case 'today':
          this.navigateToToday();
          break;
      }
    });

    // Listen for external navigation requests
    this.eventBus.on(EventTypes.NAVIGATE_TO_DATE, (event: Event) => {
      const customEvent = event as CustomEvent;
      const targetDate = new Date(customEvent.detail.date);
      this.navigateToDate(targetDate);
    });
  }

  private navigateToPreviousWeek(): void {
    this.targetWeek.setDate(this.targetWeek.getDate() - 7);
    const weekToShow = new Date(this.targetWeek);
    this.animationQueue++;
    this.animateTransition('prev', weekToShow);
  }

  private navigateToNextWeek(): void {
    this.targetWeek.setDate(this.targetWeek.getDate() + 7);
    const weekToShow = new Date(this.targetWeek);
    this.animationQueue++;
    this.animateTransition('next', weekToShow);
  }

  private navigateToToday(): void {
    const today = new Date();
    const todayWeekStart = DateUtils.getWeekStart(today, 0);
    
    // Reset to today
    this.targetWeek = new Date(todayWeekStart);
    
    const currentTime = this.currentWeek.getTime();
    const targetTime = todayWeekStart.getTime();
    
    if (currentTime < targetTime) {
      this.animationQueue++;
      this.animateTransition('next', todayWeekStart);
    } else if (currentTime > targetTime) {
      this.animationQueue++;
      this.animateTransition('prev', todayWeekStart);
    }
  }

  private navigateToDate(date: Date): void {
    const weekStart = DateUtils.getWeekStart(date, 0);
    this.targetWeek = new Date(weekStart);
    
    const currentTime = this.currentWeek.getTime();
    const targetTime = weekStart.getTime();
    
    if (currentTime < targetTime) {
      this.animationQueue++;
      this.animateTransition('next', weekStart);
    } else if (currentTime > targetTime) {
      this.animationQueue++;
      this.animateTransition('prev', weekStart);
    }
  }

  /**
   * Animation transition using pre-rendered containers when available
   */
  private animateTransition(direction: 'prev' | 'next', targetWeek: Date): void {
    const container = document.querySelector('swp-calendar-container');
    const currentGrid = container?.querySelector('swp-grid-container:not([data-prerendered])');
    
    if (!container || !currentGrid) {
      console.warn('NavigationManager: Required DOM elements not found');
      return;
    }

    console.log(`NavigationManager: Starting ${direction} animation to ${targetWeek.toDateString()}`);

    let newGrid: HTMLElement;

    // Always create a fresh container for consistent behavior
    console.log('NavigationManager: Creating new container');
    newGrid = this.navigationRenderer.renderContainer(container as HTMLElement, targetWeek);

    // Clear any existing transforms before animation
    newGrid.style.transform = '';
    (currentGrid as HTMLElement).style.transform = '';

    // Animate transition using Web Animations API
    const slideOutAnimation = (currentGrid as HTMLElement).animate([
      { transform: 'translateX(0)', opacity: '1' },
      { transform: direction === 'next' ? 'translateX(-100%)' : 'translateX(100%)', opacity: '0.5' }
    ], {
      duration: 400,
      easing: 'ease-in-out',
      fill: 'forwards'
    });

    const slideInAnimation = newGrid.animate([
      { transform: direction === 'next' ? 'translateX(100%)' : 'translateX(-100%)' },
      { transform: 'translateX(0)' }
    ], {
      duration: 400,
      easing: 'ease-in-out',
      fill: 'forwards'
    });

    // Handle animation completion
    slideInAnimation.addEventListener('finish', () => {
      // Cleanup: Remove all old grids except the new one
      const allGrids = container.querySelectorAll('swp-grid-container');
      for (let i = 0; i < allGrids.length - 1; i++) {
        allGrids[i].remove();
      }

      // Reset positioning
      newGrid.style.position = 'relative';
      newGrid.removeAttribute('data-prerendered');
      
      // Update state
      this.currentWeek = new Date(targetWeek);
      this.animationQueue--;
      
      // If this was the last queued animation, ensure we're in sync
      if (this.animationQueue === 0) {
        this.currentWeek = new Date(this.targetWeek);
      }
      
      // Update week info and notify other managers
      this.updateWeekInfo();
      this.eventBus.emit(EventTypes.WEEK_CHANGED, {
        weekStart: this.currentWeek,
        weekEnd: DateUtils.addDays(this.currentWeek, 6)
      });


      // Emit animation complete event for ScrollManager
      this.eventBus.emit(EventTypes.NAVIGATION_ANIMATION_COMPLETE, {
        direction,
        weekStart: this.currentWeek
      });
      
      console.log(`NavigationManager: Completed ${direction} animation`);
    });
  }

  private updateWeekInfo(): void {
    const weekNumber = DateUtils.getWeekNumber(this.currentWeek);
    const weekEnd = DateUtils.addDays(this.currentWeek, 6);
    const dateRange = DateUtils.formatDateRange(this.currentWeek, weekEnd);
    
    // Notify other managers about week info update - DOM manipulation should happen via events
    this.eventBus.emit(EventTypes.WEEK_INFO_UPDATED, {
      weekNumber,
      dateRange,
      weekStart: this.currentWeek,
      weekEnd
    });
  }

  /**
   * Get current week start date
   */
  getCurrentWeek(): Date {
    return new Date(this.currentWeek);
  }

  /**
   * Get target week (where navigation is heading)
   */
  getTargetWeek(): Date {
    return new Date(this.targetWeek);
  }

  /**
   * Check if navigation animation is in progress
   */
  isAnimating(): boolean {
    return this.animationQueue > 0;
  }

  /**
   * Force navigation to specific week without animation
   */
  setWeek(weekStart: Date): void {
    this.currentWeek = new Date(weekStart);
    this.targetWeek = new Date(weekStart);
    this.updateWeekInfo();
    
    this.eventBus.emit(EventTypes.WEEK_CHANGED, {
      weekStart: this.currentWeek,
      weekEnd: DateUtils.addDays(this.currentWeek, 6)
    });
  }

  // Rendering methods moved to NavigationRenderer for better separation of concerns
}