import { Box } from '../../classes/display/box.js';
import { Scene } from '../../classes/display/scene.js';
import { Action } from '../../classes/display/action.js';
import { Actor } from '../../classes/display/actor.js';
import { debounce, delay, mochaRun } from '../../util/helpers.js';

describe('Debounce', () => {
  let scene;
  let caller;
  let debouncer;
  let method;

  let call;
  let execute;

  before(() => {
    const rootElement = document.getElementById('scene');
    const rootBox = new Box('rootBox', rootElement).flex();

    scene = new Scene('Debounce test', rootBox).withSequenceDiagram();
    caller = new Actor('Caller', scene);
    debouncer = new Actor('Debouncer', scene);
    method = new Actor('Target method', scene);

    call = new Action('call', scene);
    execute = new Action('execute', scene);
  });

  it('Suppresses extra events that occur within the specified window', async () => {
    let eventCount = 0;
    const event = sinon.spy(async () => {
      eventCount++;
      await execute.log(debouncer, method, eventCount);
    });

    await scene.sequence.startSection();
    await call.log(caller, debouncer, '1');
    await debounce(event, 500);
    await call.log(caller, debouncer, '2');
    await debounce(event, 500);

    await delay(500);
    event.should.have.been.calledOnce;

    await call.log(caller, debouncer, '3');
    await debounce(event, 500);
    await call.log(caller, debouncer, '4');
    await debounce(event, 500);

    eventCount.should.equal(2);
    event.should.have.been.calledTwice;
    await scene.sequence.endSection();
  });

  it('Propagates exceptions', async () => {
    const event = sinon.spy(async () => {
      await execute.log(debouncer, method, undefined, undefined, '-x');
      throw new Error('An error occurs in the callback');
    });
    await scene.sequence.startSection();

    try {
      await call.log(caller, debouncer);
      await debounce(event, 500);
    } catch (e) {
      event.should.have.been.calledOnce;
      e.should.exist;
      e.should.match(/An error occurs in the callback/);
    }
    await scene.sequence.endSection();
  });
});

mochaRun();