import { moduleFor, ApplicationTestCase } from 'internal-test-helpers';
import { run } from '@ember/runloop';
import EmberApplication from '..';

let jQuery, application, Application;
let readyWasCalled, domReady, readyCallbacks;

// We are using a small mock of jQuery because jQuery is third-party code with
// very well-defined semantics, and we want to confirm that a jQuery stub run
// in a more minimal server environment that implements this behavior will be
// sufficient for Ember's requirements.
moduleFor(
  'Application readiness',
  class extends ApplicationTestCase {
    constructor() {
      super();

      readyWasCalled = 0;
      readyCallbacks = [];

      let jQueryInstance = {
        ready(callback) {
          readyCallbacks.push(callback);
          if (jQuery.isReady) {
            domReady();
          }
        },
      };

      jQuery = function() {
        return jQueryInstance;
      };
      jQuery.isReady = false;

      let domReadyCalled = 0;
      domReady = function() {
        if (domReadyCalled !== 0) {
          return;
        }
        domReadyCalled++;
        for (let i = 0; i < readyCallbacks.length; i++) {
          readyCallbacks[i]();
        }
      };

      Application = EmberApplication.extend({
        $: jQuery,

        ready() {
          readyWasCalled++;
        },
      });
    }

    teardown() {
      if (application) {
        run(() => application.destroy());
        jQuery = readyCallbacks = domReady = Application = application = undefined;
      }
    }

    // These tests are confirming that if the callbacks passed into jQuery's ready hook is called
    // synchronously during the application's initialization, we get the same behavior as if
    // it was triggered after initialization.

    ["@test Application's ready event is called right away if jQuery is already ready"](assert) {
      jQuery.isReady = true;

      run(() => {
        application = Application.create({ router: false });

        assert.equal(readyWasCalled, 0, 'ready is not called until later');
      });

      assert.equal(readyWasCalled, 1, 'ready was called');

      domReady();

      assert.equal(readyWasCalled, 1, "application's ready was not called again");
    }

    ["@test Application's ready event is called after the document becomes ready"](assert) {
      run(() => {
        application = Application.create({ router: false });
      });

      assert.equal(readyWasCalled, 0, "ready wasn't called yet");

      domReady();

      assert.equal(readyWasCalled, 1, 'ready was called now that DOM is ready');
    }

    ["@test Application's ready event can be deferred by other components"](assert) {
      run(() => {
        application = Application.create({ router: false });
        application.deferReadiness();
      });

      assert.equal(readyWasCalled, 0, "ready wasn't called yet");

      domReady();

      assert.equal(readyWasCalled, 0, "ready wasn't called yet");

      run(() => {
        application.advanceReadiness();
        assert.equal(readyWasCalled, 0);
      });

      assert.equal(readyWasCalled, 1, 'ready was called now all readiness deferrals are advanced');
    }

    ["@test Application's ready event can be deferred by other components"](assert) {
      jQuery.isReady = false;

      run(() => {
        application = Application.create({ router: false });
        application.deferReadiness();
        assert.equal(readyWasCalled, 0, "ready wasn't called yet");
      });

      domReady();

      assert.equal(readyWasCalled, 0, "ready wasn't called yet");

      run(() => {
        application.advanceReadiness();
      });

      assert.equal(readyWasCalled, 1, 'ready was called now all readiness deferrals are advanced');

      expectAssertion(() => {
        application.deferReadiness();
      });
    }
  }
);