/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

/// <reference types="node" />

import * as cluster from 'cluster';
import {EventEmitter} from 'events';

import {startWorker} from '../../../src/execution/cluster/worker';
import {Task, TaskCompletedCallback, TaskProcessingOutcome} from '../../../src/execution/tasks/api';
import {MockLogger} from '../../helpers/mock_logger';
import {mockProperty} from '../../helpers/spy_utils';


describe('startWorker()', () => {
  const runAsClusterMaster = mockProperty(cluster, 'isMaster');
  const mockProcessSend = mockProperty(process, 'send');
  let processSendSpy: jasmine.Spy;
  let compileFnSpy: jasmine.Spy;
  let createCompileFnSpy: jasmine.Spy;
  let mockLogger: MockLogger;

  beforeEach(() => {
    compileFnSpy = jasmine.createSpy('compileFn');
    createCompileFnSpy = jasmine.createSpy('createCompileFn').and.returnValue(compileFnSpy);

    processSendSpy = jasmine.createSpy('process.send');
    mockProcessSend(processSendSpy);

    mockLogger = new MockLogger();
  });

  describe('(on cluster master)', () => {
    beforeEach(() => runAsClusterMaster(true));

    it('should throw an error', async () => {
      await expectAsync(startWorker(mockLogger, createCompileFnSpy))
          .toBeRejectedWithError('Tried to run cluster worker on the master process.');
      expect(createCompileFnSpy).not.toHaveBeenCalled();
    });
  });

  describe('(on cluster worker)', () => {
    // The `cluster.worker` property is normally `undefined` on the master process and set to the
    // current `cluster.worker` on worker processes.
    const mockClusterWorker = mockProperty(cluster, 'worker');

    beforeEach(() => {
      runAsClusterMaster(false);
      mockClusterWorker(Object.assign(new EventEmitter(), {id: 42}) as cluster.Worker);
    });

    it('should create the `compileFn()`', () => {
      startWorker(mockLogger, createCompileFnSpy);
      expect(createCompileFnSpy).toHaveBeenCalledWith(jasmine.any(Function));
    });

    it('should set up `compileFn()` to send `task-completed` messages to master', () => {
      startWorker(mockLogger, createCompileFnSpy);
      const onTaskCompleted: TaskCompletedCallback = createCompileFnSpy.calls.argsFor(0)[0];

      onTaskCompleted(null as any, TaskProcessingOutcome.Processed, null);
      expect(processSendSpy).toHaveBeenCalledTimes(1);
      expect(processSendSpy)
          .toHaveBeenCalledWith(
              {type: 'task-completed', outcome: TaskProcessingOutcome.Processed, message: null});

      processSendSpy.calls.reset();

      onTaskCompleted(null as any, TaskProcessingOutcome.Failed, 'error message');
      expect(processSendSpy).toHaveBeenCalledTimes(1);
      expect(processSendSpy).toHaveBeenCalledWith({
        type: 'task-completed',
        outcome: TaskProcessingOutcome.Failed,
        message: 'error message',
      });
    });

    it('should return a promise (that is never resolved)', done => {
      const promise = startWorker(mockLogger, createCompileFnSpy);

      expect(promise).toEqual(jasmine.any(Promise));

      promise.then(
          () => done.fail('Expected promise not to resolve'),
          () => done.fail('Expected promise not to reject'));

      // We can't wait forever to verify that the promise is not resolved, but at least verify
      // that it is not resolved immediately.
      setTimeout(done, 100);
    });

    it('should handle `process-task` messages', () => {
      const mockTask = {
        entryPoint: {name: 'foo'},
        formatProperty: 'es2015',
        processDts: true,
      } as unknown as Task;

      startWorker(mockLogger, createCompileFnSpy);
      cluster.worker.emit('message', {type: 'process-task', task: mockTask});

      expect(compileFnSpy).toHaveBeenCalledWith(mockTask);
      expect(processSendSpy).not.toHaveBeenCalled();

      expect(mockLogger.logs.debug[0]).toEqual([
        '[Worker #42] Processing task: {entryPoint: foo, formatProperty: es2015, processDts: true}',
      ]);
    });

    it('should send errors during task processing back to the master process', () => {
      const mockTask = {
        entryPoint: {name: 'foo'},
        formatProperty: 'es2015',
        processDts: true,
      } as unknown as Task;

      let err: string|Error;
      compileFnSpy.and.callFake(() => {
        throw err;
      });

      startWorker(mockLogger, createCompileFnSpy);

      err = 'Error string.';
      cluster.worker.emit('message', {type: 'process-task', task: mockTask});
      expect(processSendSpy).toHaveBeenCalledWith({type: 'error', error: err});

      err = new Error('Error object.');
      cluster.worker.emit('message', {type: 'process-task', task: mockTask});
      expect(processSendSpy).toHaveBeenCalledWith({type: 'error', error: err.stack});
    });

    it('should throw, when an unknown message type is received', () => {
      startWorker(mockLogger, createCompileFnSpy);
      cluster.worker.emit('message', {type: 'unknown', foo: 'bar'});

      expect(compileFnSpy).not.toHaveBeenCalled();
      expect(processSendSpy).toHaveBeenCalledWith({
        type: 'error',
        error: jasmine.stringMatching(
            'Error: \\[Worker #42\\] Invalid message received: {"type":"unknown","foo":"bar"}'),
      });
    });
  });
});