// Copyright (c) 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import * as UI from '../../ui/legacy/legacy.js';

import animationScreenshotPopoverStyles from './animationScreenshotPopover.css.js';

export class AnimationScreenshotPopover extends UI.Widget.VBox {
  #frames: HTMLImageElement[];
  #rafId: number;
  #currentFrame: number;
  #progressBar: HTMLElement;
  #showFrame?: boolean;
  #endDelay?: number;
  constructor(images: HTMLImageElement[]) {
    super(true);
    this.registerRequiredCSS(animationScreenshotPopoverStyles);
    console.assert(images.length > 0);

    this.contentElement.classList.add('animation-screenshot-popover');
    this.#frames = images;
    for (const image of images) {
      this.contentElement.appendChild(image);
      image.style.display = 'none';
    }
    this.#rafId = 0;
    this.#currentFrame = 0;
    this.#frames[0].style.display = 'block';
    this.#progressBar = this.contentElement.createChild('div', 'animation-progress');
  }

  override wasShown(): void {
    super.wasShown();
    this.#rafId = this.contentElement.window().requestAnimationFrame(this.changeFrame.bind(this));
  }

  override willHide(): void {
    this.contentElement.window().cancelAnimationFrame(this.#rafId);
    this.#endDelay = undefined;
  }

  private changeFrame(): void {
    this.#rafId = this.contentElement.window().requestAnimationFrame(this.changeFrame.bind(this));

    if (this.#endDelay) {
      this.#endDelay--;
      return;
    }
    this.#showFrame = !this.#showFrame;
    if (!this.#showFrame) {
      return;
    }

    const numFrames = this.#frames.length;
    this.#frames[this.#currentFrame % numFrames].style.display = 'none';
    this.#currentFrame++;
    this.#frames[(this.#currentFrame) % numFrames].style.display = 'block';
    if (this.#currentFrame % numFrames === numFrames - 1) {
      this.#endDelay = 50;
    }
    this.#progressBar.style.width = (this.#currentFrame % numFrames + 1) / numFrames * 100 + '%';
  }
}