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

/**
 * NavigationButtonsManager - Manages navigation button UI and state
 *
 * RESPONSIBILITY:
 * ===============
 * This manager owns all logic related to the <swp-nav-group> UI element.
 * It follows the principle that each functional UI element has its own manager.
 *
 * RESPONSIBILITIES:
 * - Handles button clicks on swp-nav-button elements
 * - Validates navigation actions (prev, next, today)
 * - Emits NAV_BUTTON_CLICKED events
 * - Manages button UI listeners
 *
 * EVENT FLOW:
 * ===========
 * User clicks button → validateAction() → emit event → NavigationManager handles navigation
 *
 * SUBSCRIBERS:
 * ============
 * - NavigationManager: Performs actual navigation logic (animations, grid updates, week calculations)
 */
export class NavigationButtons {
  private eventBus: IEventBus;
  private buttonListeners: Map<Element, EventListener> = new Map();

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

  /**
   * Setup click listeners on all navigation buttons
   */
  private setupButtonListeners(): void {
    const buttons = document.querySelectorAll('swp-nav-button[data-action]');

    buttons.forEach(button => {
      const clickHandler = (event: Event) => {
        event.preventDefault();
        const action = button.getAttribute('data-action');
        if (action && this.isValidAction(action)) {
          this.handleNavigation(action);
        }
      };

      button.addEventListener('click', clickHandler);
      this.buttonListeners.set(button, clickHandler);
    });
  }

  /**
   * Handle navigation action
   */
  private handleNavigation(action: string): void {
    // Emit navigation button clicked event
    this.eventBus.emit(CoreEvents.NAV_BUTTON_CLICKED, {
      action: action
    });
  }

  /**
   * Validate if string is a valid navigation action
   */
  private isValidAction(action: string): boolean {
    return ['prev', 'next', 'today'].includes(action);
  }
}