import { isBrowser } from './browser';

/** 空闲时间基准为 10ms */
export const IDLE_FREE_TIME = 10;
/**
 * 幕后任务协作调度 API
 * 用 requestIdleCallback() 来在浏览器空闲时运行高耗时、低优先级的任务
 * @see https://developer.mozilla.org/zh-CN/docs/Web/API/Background_Tasks_API#%E5%9B%9E%E9%80%80%E5%88%B0_settimeout
 */
(function () {
  if (!isBrowser) {
    return;
  }
  window.requestIdleCallback =
    window.requestIdleCallback ||
    ((handler) => {
      const startTime = Date.now();

      return setTimeout(() => {
        handler({
          didTimeout: false,
          timeRemaining() {
            return Math.max(0, 50.0 - (Date.now() - startTime));
          },
        });
      }, 1);
    });

  window.cancelIdleCallback =
    window.cancelIdleCallback ||
    ((id) => {
      clearTimeout(id);
    });
})();