import { Debugger } from '../diagnostics/Debugger';
import { Exception } from '../baseframework/Exceptions';

/**
 *  Model for the arguments of the AsyncCompleted event
 *
 * @export
 * @class AsyncCompletedEventArgs
 * @wType System.ComponentModel.AsyncCompletedEventArgs
 */
export class AsyncCompletedEventArgs {
  private _cancelled: boolean = false;
  private _error: Exception = null;
  private _state: object = null;

  /**
   * Creates an instance of AsyncCompletedEventArgs.
   * @param {Exception} error Any error that occurred during the asynchronous operation.
   * @param {boolean} cancelled A value that indicates whether the asynchronous operation was canceled.
   * @param {object} userState The optional user-supplied state object that is used to identify the task that raised the Completed event.
   * @memberof AsyncCompletedEventArgs
   */
  constructor(error: Exception, cancelled: boolean, userState: object) {
    this._cancelled = cancelled;
    this._error = error;
    this._state = userState;
  }

  /**
   * Raises a user-supplied exception if an asynchronous operation failed.
   *
   * @protected
   * @memberof AsyncCompletedEventArgs
   */
  protected RaiseExceptionIfNecessary(): void {
    if (this.Error != null)
      Debugger.Throw(
        'Async_ExceptionOccurred: ' + new Error(this.Error.description)
      );
    if (this.Cancelled) Debugger.Throw('Async_OperationCancelled');
  }

  /**
   * Gets a value that indicates whether an asynchronous operation has been canceled.
   *
   * @readonly
   * @type {boolean}
   * @memberof AsyncCompletedEventArgs
   */
  public get Cancelled(): boolean {
    return this._cancelled;
  }
  /**
   * Gets a value that indicates which error occurred during an asynchronous operation.
   *
   * @readonly
   * @type {Exception}
   * @memberof AsyncCompletedEventArgs
   */
  public get Error(): Exception {
    return this._error;
  }
  /**
   * Gets the unique identifier for the asynchronous task.
   *
   * @readonly
   * @type {object}
   * @memberof AsyncCompletedEventArgs
   */
  public get UserState(): object {
    return this._state;
  }
}