/* eslint-disable @typescript-eslint/no-unsafe-argument */
/**
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at

 * http://www.apache.org/licenses/LICENSE-2.0

 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import {
  requestIdleCallback,
  cancelIdleCallback,
  DEFAULT_REQUEST_ID,
} from './utils/compatible';

interface Task {
  id: string;
  handler: () => void;
}

export default class TaskScheduler {
  private readonly _tasks: Task[];

  private _requestIdleCallbackId = DEFAULT_REQUEST_ID;

  constructor(tasks?: Task[]) {
    this._tasks = tasks ?? [];
    this._operateTasks();
  }

  private _operateTasks(fn?: () => void): void {
    if (this._requestIdleCallbackId !== DEFAULT_REQUEST_ID) {
      cancelIdleCallback(this._requestIdleCallbackId);
      this._requestIdleCallbackId = DEFAULT_REQUEST_ID;
    }
    fn?.();
    this._requestIdleCallbackId = requestIdleCallback((deadline) => {
      this._runTasks(deadline);
    });
  }

  private _runTasks(deadline: IdleDeadline): void {
    while (deadline.timeRemaining() > 0 && this._tasks.length > 0) {
      const task = this._tasks.shift();
      task?.handler();
    }
    if (this._tasks.length > 0) {
      this._requestIdleCallbackId = requestIdleCallback((deadline) => {
        this._runTasks(deadline);
      });
    }
  }

  addTask(task: Task): this {
    this._operateTasks(() => {
      const index = this._tasks.findIndex((t) => t.id === task.id);
      if (index > -1) {
        this._tasks[index] = task;
      } else {
        this._tasks.push(task);
      }
    });
    return this;
  }

  removeTask(id: string): this {
    this._operateTasks(() => {
      const index = this._tasks.findIndex((t) => t.id === id);
      if (index > -1) {
        this._tasks.splice(index, 1);
      }
    });
    return this;
  }
}