Event Management

/**
 * An injectable service that provides event management for Angular
 * through a browser plug-in system.
 */
class EventManager {
  /**
   * Initializes an instance of the event-manager service
   * @param plugins - Array of EventManagerPlugin instances
   * @param _zone - NgZone for handling zone-aware event execution
   */
  constructor(plugins: EventManagerPlugin[], _zone: NgZone);

  /**
   * Registers a handler for a specific element and event
   * @param element - The HTML element to listen on
   * @param eventName - The name of the event to listen for
   * @param handler - The event handler function
   * @param options - Optional listener options (passive, once, capture, etc.)
   * @returns A function that removes the event listener when called
   */
  addEventListener(element: HTMLElement, eventName: string, handler: Function, options?: ListenerOptions): Function;

  /**
   * Gets the NgZone instance used by this EventManager
   * @returns The NgZone instance
   */
  getZone(): NgZone;
}

import { EventManager, EVENT_MANAGER_PLUGINS } from "@angular/platform-browser";
import { NgZone, Injectable } from "@angular/core";

@Injectable()
export class CustomEventService {
  constructor(
    private eventManager: EventManager,
    private zone: NgZone
  ) {}

  addCustomListener(element: HTMLElement, eventName: string, callback: Function) {
    // Add event listener through the event manager
    const removeListener = this.eventManager.addEventListener(
      element, 
      eventName, 
      (event) => {
        this.zone.run(() => callback(event));
      }
    );

    return removeListener;
  }

  addMultipleListeners(element: HTMLElement, events: Record<string, Function>) {
    const removeListeners: Function[] = [];

    Object.entries(events).forEach(([eventName, handler]) => {
      const remove = this.eventManager.addEventListener(element, eventName, handler);
      removeListeners.push(remove);
    });

    return () => removeListeners.forEach(remove => remove());
  }
}

/**
 * Base class for event manager plugins.
 * Plugins extend the event system to handle specific event types or patterns.
 */
abstract class EventManagerPlugin {
  /** Reference to the EventManager instance */
  manager: EventManager;

  /**
   * Determines if this plugin supports the given event name
   * @param eventName - The event name to check
   * @returns True if this plugin can handle the event
   */
  abstract supports(eventName: string): boolean;

  /**
   * Adds an event listener for the supported event
   * @param element - The HTML element to listen on
   * @param eventName - The name of the event to listen for
   * @param handler - The event handler function
   * @returns A function that removes the event listener when called
   */
  abstract addEventListener(element: HTMLElement, eventName: string, handler: Function, options?: ListenerOptions): Function;
}

import { EventManagerPlugin } from "@angular/platform-browser";

// Custom plugin for handling special events
export class CustomEventPlugin extends EventManagerPlugin {
  supports(eventName: string): boolean {
    return eventName.startsWith('custom:');
  }

  addEventListener(element: HTMLElement, eventName: string, handler: Function): Function {
    const actualEventName = eventName.substring(7); // Remove 'custom:' prefix
    
    const wrappedHandler = (event: Event) => {
      // Add custom processing
      const customEvent = this.processEvent(event);
      handler(customEvent);
    };

    element.addEventListener(actualEventName, wrappedHandler);
    
    return () => element.removeEventListener(actualEventName, wrappedHandler);
  }

  private processEvent(event: Event): CustomEvent {
    // Add custom event processing logic
    return new CustomEvent('processed', { detail: event });
  }
}

/**
 * NgModule that provides Hammer.js gesture support for Angular applications
 */
class HammerModule {}

/**
 * Configuration class for customizing Hammer.js gesture recognition
 */
class HammerGestureConfig {
  /** List of hammer events that should be handled */
  events: string[];
  
  /** Override configuration for specific gestures */
  overrides: { [key: string]: Object };

  /**
   * Creates a Hammer.js instance for the given element
   * @param element - The HTML element to attach gestures to
   * @returns A configured Hammer.js instance
   */
  buildHammer(element: HTMLElement): HammerInstance;
}

import { NgModule } from "@angular/core";
import { HammerModule, HammerGestureConfig, HAMMER_GESTURE_CONFIG } from "@angular/platform-browser";

// Custom Hammer configuration
export class CustomHammerConfig extends HammerGestureConfig {
  overrides = {
    'swipe': { velocity: 0.4, threshold: 20 },
    'pinch': { enable: false },
    'rotate': { enable: false }
  };

  events: string[] = [
    'tap',
    'press',
    'swipe',
    'swipeleft',
    'swiperight',
    'swipeup',
    'swipedown'
  ];
}

@NgModule({
  imports: [HammerModule],
  providers: [
    {
      provide: HAMMER_GESTURE_CONFIG,
      useClass: CustomHammerConfig
    }
  ]
})
export class GestureModule {}

// Component using gestures
@Component({
  selector: 'app-swipe-card',
  template: `
    <div class="card" 
         (swipeleft)="onSwipeLeft()" 
         (swiperight)="onSwipeRight()"
         (tap)="onTap()"
         (press)="onPress()">
      Swipe me!
    </div>
  `
})
export class SwipeCardComponent {
  onSwipeLeft() {
    console.log('Swiped left');
  }

  onSwipeRight() {
    console.log('Swiped right');
  }

  onTap() {
    console.log('Tapped');
  }

  onPress() {
    console.log('Long pressed');
  }
}

/**
 * Injection token for configuring Hammer.js gesture recognition
 */
const HAMMER_GESTURE_CONFIG: InjectionToken<HammerGestureConfig>;

/**
 * Injection token for providing a Hammer.js loader function
 */
const HAMMER_LOADER: InjectionToken<HammerLoader>;

/**
 * Injection token for providing event manager plugins
 */
const EVENT_MANAGER_PLUGINS: InjectionToken<EventManagerPlugin[]>;

import { 
  HAMMER_GESTURE_CONFIG, 
  HAMMER_LOADER, 
  HammerGestureConfig 
} from "@angular/platform-browser";

// Custom Hammer loader for lazy loading
const customHammerLoader: HammerLoader = () => {
  return import('hammerjs').then(() => {
    console.log('Hammer.js loaded');
  });
};

// Providers configuration
@NgModule({
  providers: [
    {
      provide: HAMMER_LOADER,
      useValue: customHammerLoader
    },
    {
      provide: HAMMER_GESTURE_CONFIG,
      useClass: CustomHammerConfig
    }
  ]
})
export class AppModule {}

/**
 * Interface defining the Hammer.js instance API
 */
interface HammerInstance {
  /** Add an event listener */
  on(eventName: string, callback?: Function): void;
  
  /** Remove an event listener */
  off(eventName: string, callback?: Function): void;
  
  /** Destroy the Hammer instance */
  destroy?(): void;
}

/**
 * Type for Hammer.js loader function
 */
type HammerLoader = () => Promise<void>;

/**
 * Options for configuring event listeners (from @angular/core)
 */
type ListenerOptions = boolean | AddEventListenerOptions;

const hammerEvents = [
  // Pan events
  'pan', 'panstart', 'panmove', 'panend', 'pancancel',
  'panleft', 'panright', 'panup', 'pandown',
  
  // Pinch events
  'pinch', 'pinchstart', 'pinchmove', 'pinchend', 'pinchcancel',
  'pinchin', 'pinchout',
  
  // Press events
  'press', 'pressup',
  
  // Rotate events
  'rotate', 'rotatestart', 'rotatemove', 'rotateend', 'rotatecancel',
  
  // Swipe events
  'swipe', 'swipeleft', 'swiperight', 'swipeup', 'swipedown',
  
  // Tap events
  'tap'
];