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

/**
 * NavigationManager handles calendar navigation (prev/next/today buttons)
 * and week transitions with smooth animations
 */
export class NavigationManager {
  private eventBus: IEventBus;
  private currentWeek: Date;
  private targetWeek: Date;
  private animationQueue: number = 0;

  constructor(eventBus: IEventBus) {
    this.eventBus = 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();
    this.updateWeekInfo();
  }

  private setupEventListeners(): void {
    // 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);
    }
  }

  private animateTransition(direction: 'prev' | 'next', targetWeek: Date): void {
    const calendarContainer = document.querySelector('swp-calendar-container');
    const currentWeekContainer = document.querySelector('swp-week-container');
    
    if (!calendarContainer || !currentWeekContainer) {
      console.warn('NavigationManager: Required DOM elements not found');
      return;
    }
    
    // Create new week container (following POC structure)
    const newWeekContainer = document.createElement('swp-week-container');
    newWeekContainer.innerHTML = `
      <swp-week-header></swp-week-header>
      <swp-scrollable-content>
        <swp-time-grid>
          <swp-grid-lines></swp-grid-lines>
          <swp-day-columns></swp-day-columns>
        </swp-time-grid>
      </swp-scrollable-content>
    `;
    
    // Position new week off-screen
    newWeekContainer.style.position = 'absolute';
    newWeekContainer.style.top = '0';
    newWeekContainer.style.left = '0';
    newWeekContainer.style.width = '100%';
    newWeekContainer.style.height = '100%';
    newWeekContainer.style.transform = direction === 'next' ? 'translateX(100%)' : 'translateX(-100%)';
    
    // Add to calendar container
    calendarContainer.appendChild(newWeekContainer);
    
    // Notify other managers to render content for the new week
    this.eventBus.emit(EventTypes.WEEK_CONTAINER_CREATED, {
      container: newWeekContainer,
      weekStart: targetWeek
    });
    
    // Animate transition
    requestAnimationFrame(() => {
      // Slide out current week
      (currentWeekContainer as HTMLElement).style.transform = direction === 'next' ? 'translateX(-100%)' : 'translateX(100%)';
      (currentWeekContainer as HTMLElement).style.opacity = '0.5';
      
      // Slide in new week
      newWeekContainer.style.transform = 'translateX(0)';
      
      // Clean up after animation
      setTimeout(() => {
        currentWeekContainer.remove();
        newWeekContainer.style.position = 'relative';
        
        // Update currentWeek only after animation is complete
        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)
        });
        
      }, 400); // Match CSS transition duration
    });
  }

  private updateWeekInfo(): void {
    const weekNumber = DateUtils.getWeekNumber(this.currentWeek);
    const weekEnd = DateUtils.addDays(this.currentWeek, 6);
    const dateRange = DateUtils.formatDateRange(this.currentWeek, weekEnd);
    
    // Update week info in DOM
    const weekNumberElement = document.querySelector('swp-week-number');
    const dateRangeElement = document.querySelector('swp-date-range');
    
    if (weekNumberElement) {
      weekNumberElement.textContent = `Week ${weekNumber}`;
    }
    
    if (dateRangeElement) {
      dateRangeElement.textContent = dateRange;
    }
    
    // Notify other managers about week info update
    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)
    });
  }
}