src/videotile/DefaultVideoElementResolutionMonitor.ts

// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

import VideoElementResolutionMonitor, {
  VideoElementResolutionObserver,
} from './VideoElementResolutionMonitor';
export default class DefaultVideoElementResolutionMonitor implements VideoElementResolutionMonitor {
  private observerQueue = new Set<VideoElementResolutionObserver>();
  private resizeObserver: ResizeObserver;
  private element: HTMLVideoElement | null = null;

  constructor() {
    this.resizeObserver = new ResizeObserver(entries => {
      for (const entry of entries) {
        const { width, height } = entry.contentRect;
        this.notifyObservers(width, height);
      }
    });
  }

  private notifyObservers(newWidth: number, newHeight: number): void {
    for (const observer of this.observerQueue) {
      observer.videoElementResolutionChanged(newWidth, newHeight);
    }
  }

  registerObserver(observer: VideoElementResolutionObserver): void {
    this.observerQueue.add(observer);
  }

  removeObserver(observer: VideoElementResolutionObserver): void {
    this.observerQueue.delete(observer);
  }

  bindVideoElement(newElement: HTMLVideoElement | null): void {
    if (this.element === newElement) {
      return;
    }
    if (this.element) {
      this.resizeObserver.unobserve(this.element);
    }
    this.element = newElement;
    if (this.element) {
      this.resizeObserver.observe(this.element);
    }
  }
}