import { Mixin, on, addListener, removeListener, sendEvent, hasListeners } from '..';
import { moduleFor, AbstractTestCase } from 'internal-test-helpers';

moduleFor(
  'system/props/events_test',
  class extends AbstractTestCase {
    ['@test listener should receive event - removing should remove'](assert) {
      let obj = {};
      let count = 0;

      function F() {
        count++;
      }

      addListener(obj, 'event!', F);
      assert.equal(count, 0, 'nothing yet');

      sendEvent(obj, 'event!');
      assert.equal(count, 1, 'received event');

      removeListener(obj, 'event!', F);

      count = 0;
      sendEvent(obj, 'event!');
      assert.equal(count, 0, 'received event');
    }

    ['@test listeners should be inherited'](assert) {
      let count = 0;

      let obj = {
        func() {
          count++;
        },
      };

      addListener(obj, 'event!', null, 'func');

      let obj2 = Object.create(obj);

      assert.equal(count, 0, 'nothing yet');

      sendEvent(obj2, 'event!');
      assert.equal(count, 1, 'received event');

      removeListener(obj2, 'event!', null, 'func');

      count = 0;
      sendEvent(obj2, 'event!');
      assert.equal(count, 0, 'did not receive event');

      sendEvent(obj, 'event!');
      assert.equal(count, 1, 'should still invoke on parent');
    }

    ['@test adding a listener more than once should only invoke once'](assert) {
      let count = 0;
      let obj = {
        func() {
          count++;
        },
      };

      addListener(obj, 'event!', null, 'func');
      addListener(obj, 'event!', null, 'func');

      sendEvent(obj, 'event!');
      assert.equal(count, 1, 'should only invoke once');
    }

    ['@test adding a listener with a target should invoke with target'](assert) {
      let obj = {};
      let target;

      target = {
        count: 0,
        method() {
          this.count++;
        },
      };

      addListener(obj, 'event!', target, target.method);
      sendEvent(obj, 'event!');
      assert.equal(target.count, 1, 'should invoke');
    }

    ['@test adding a listener with string method should lookup method on event delivery'](assert) {
      let obj = {};
      let target;

      target = {
        count: 0,
        method() {},
      };

      addListener(obj, 'event!', target, 'method');
      sendEvent(obj, 'event!');
      assert.equal(target.count, 0, 'should invoke but do nothing');

      target.method = function() {
        this.count++;
      };
      sendEvent(obj, 'event!');
      assert.equal(target.count, 1, 'should invoke now');
    }

    ['@test calling sendEvent with extra params should be passed to listeners'](assert) {
      let obj = {};
      let params = null;
      addListener(obj, 'event!', function() {
        params = Array.prototype.slice.call(arguments);
      });

      sendEvent(obj, 'event!', ['foo', 'bar']);
      assert.deepEqual(params, ['foo', 'bar'], 'params should be saved');
    }

    ['@test hasListeners tells you if there are listeners for a given event'](assert) {
      let obj = {};

      function F() {}
      function F2() {}

      assert.equal(hasListeners(obj, 'event!'), false, 'no listeners at first');

      addListener(obj, 'event!', F);
      addListener(obj, 'event!', F2);

      assert.equal(hasListeners(obj, 'event!'), true, 'has listeners');

      removeListener(obj, 'event!', F);
      assert.equal(hasListeners(obj, 'event!'), true, 'has listeners');

      removeListener(obj, 'event!', F2);
      assert.equal(hasListeners(obj, 'event!'), false, 'has no more listeners');

      addListener(obj, 'event!', F);
      assert.equal(hasListeners(obj, 'event!'), true, 'has listeners');
    }

    ['@test calling removeListener without method should remove all listeners'](assert) {
      expectDeprecation(() => {
        let obj = {};
        function F() {}
        function F2() {}

        assert.equal(hasListeners(obj, 'event!'), false, 'no listeners at first');

        addListener(obj, 'event!', F);
        addListener(obj, 'event!', F2);

        assert.equal(hasListeners(obj, 'event!'), true, 'has listeners');
        removeListener(obj, 'event!');

        assert.equal(hasListeners(obj, 'event!'), false, 'has no more listeners');
      }, /The remove all functionality of removeListener and removeObserver has been deprecated/);
    }

    ['@test a listener can be added as part of a mixin'](assert) {
      let triggered = 0;
      let MyMixin = Mixin.create({
        foo1: on('bar', function() {
          triggered++;
        }),

        foo2: on('bar', function() {
          triggered++;
        }),
      });

      let obj = {};
      MyMixin.apply(obj);

      sendEvent(obj, 'bar');
      assert.equal(triggered, 2, 'should invoke listeners');
    }

    [`@test 'on' asserts for invalid arguments`]() {
      expectAssertion(() => {
        Mixin.create({
          foo1: on('bar'),
        });
      }, 'on expects function as last argument');

      expectAssertion(() => {
        Mixin.create({
          foo1: on(function() {}),
        });
      }, 'on called without valid event names');
    }

    ['@test a listener added as part of a mixin may be overridden'](assert) {
      let triggered = 0;
      let FirstMixin = Mixin.create({
        foo: on('bar', function() {
          triggered++;
        }),
      });
      let SecondMixin = Mixin.create({
        foo: on('baz', function() {
          triggered++;
        }),
      });

      let obj = {};
      FirstMixin.apply(obj);
      SecondMixin.apply(obj);

      sendEvent(obj, 'bar');
      assert.equal(triggered, 0, 'should not invoke from overridden property');

      sendEvent(obj, 'baz');
      assert.equal(triggered, 1, 'should invoke from subclass property');
    }
  }
);