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<title>RTCPeerConnection.prototype.iceGatheringState</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="RTCPeerConnection-helper.js"></script>
<script>
  'use strict';

  // Test is based on the following editor draft:
  // https://w3c.github.io/webrtc-pc/archives/20170605/webrtc.html

  // The following helper functions are called from RTCPeerConnection-helper.js:
  // exchangeAnswer
  // exchangeIceCandidates
  // generateAudioReceiveOnlyOffer

  /*
    4.3.2.  Interface Definition
      interface RTCPeerConnection : EventTarget {
        ...
        readonly  attribute RTCIceGatheringState   iceGatheringState;
                  attribute EventHandler           onicegatheringstatechange;
      };

    4.4.2.  RTCIceGatheringState Enum
      enum RTCIceGatheringState {
        "new",
        "gathering",
        "complete"
      };

    5.6.  RTCIceTransport Interface
      interface RTCIceTransport {
        readonly attribute RTCIceGathererState  gatheringState;
        ...
      };

      enum RTCIceGathererState {
        "new",
        "gathering",
        "complete"
      };
   */

  /*
    4.4.2.  RTCIceGatheringState Enum
      new
        Any of the RTCIceTransport s are in the new gathering state and
        none of the transports are in the gathering state, or there are
        no transports.
   */
  test(t => {
    const pc = new RTCPeerConnection();
    t.add_cleanup(() => pc.close());

    assert_equals(pc.iceGatheringState, 'new');
  }, 'Initial iceGatheringState should be new');

  async_test(t => {
    const pc = new RTCPeerConnection();

    t.add_cleanup(() => pc.close());

    let reachedGathering = false;
    const onIceGatheringStateChange = t.step_func(() => {
      const { iceGatheringState } = pc;

      if(iceGatheringState === 'gathering') {
        reachedGathering = true;
      } else if(iceGatheringState === 'complete') {
        assert_true(reachedGathering, 'iceGatheringState should reach gathering before complete');
        t.done();
      }
    });

    assert_equals(pc.onicegatheringstatechange, null,
      'Expect connection to have icegatheringstatechange event');
    assert_equals(pc.iceGatheringState, 'new');

    pc.addEventListener('icegatheringstatechange', onIceGatheringStateChange);

    generateAudioReceiveOnlyOffer(pc)
    .then(offer => pc.setLocalDescription(offer))
    .then(err => t.step_func(err =>
      assert_unreached(`Unhandled rejection ${err.name}: ${err.message}`)));
  }, 'iceGatheringState should eventually become complete after setLocalDescription');

  promise_test(async t => {
    const pc1 = new RTCPeerConnection();
    t.add_cleanup(() => pc1.close());
    const pc2 = new RTCPeerConnection();
    t.add_cleanup(() => pc2.close());
    pc1.addTransceiver('audio', { direction: 'recvonly' });
    await initialOfferAnswerWithIceGatheringStateTransitions(
        pc1, pc2);

    expectNoMoreGatheringStateChanges(t, pc1);
    expectNoMoreGatheringStateChanges(t, pc2);

    await pc1.setLocalDescription(await pc1.createOffer());
    await pc2.setLocalDescription(await pc2.createOffer());

    await new Promise(r => t.step_timeout(r, 500));
  }, 'setLocalDescription(reoffer) with no new transports should not cause iceGatheringState to change');

  promise_test(async t => {
    const pc1 = new RTCPeerConnection();
    t.add_cleanup(() => pc1.close());

    expectNoMoreGatheringStateChanges(t, pc1);

    await pc1.setLocalDescription(await pc1.createOffer());

    await new Promise(r => t.step_timeout(r, 500));
  }, 'setLocalDescription() with no transports should not cause iceGatheringState to change');

  promise_test(async t => {
    const pc1 = new RTCPeerConnection();
    t.add_cleanup(() => pc1.close());
    const pc2 = new RTCPeerConnection();
    t.add_cleanup(() => pc2.close());
    pc1.addTransceiver('audio', { direction: 'recvonly' });
    await initialOfferAnswerWithIceGatheringStateTransitions(
        pc1, pc2);
    await pc1.setLocalDescription(await pc1.createOffer({iceRestart: true}));
    await iceGatheringStateTransitions(pc1, 'gathering', 'complete');
  }, 'setLocalDescription(reoffer) with a new transport should cause iceGatheringState to go to "checking" and then "complete"');

  promise_test(async t => {
    const pc1 = new RTCPeerConnection();
    t.add_cleanup(() => pc1.close());
    const pc2 = new RTCPeerConnection();
    t.add_cleanup(() => pc2.close());
    expectNoMoreGatheringStateChanges(t, pc2);
    pc1.addTransceiver('audio', { direction: 'recvonly' });
    const offer = await pc1.createOffer();
    await pc2.setRemoteDescription(offer);
    await pc2.setRemoteDescription(offer);
    await pc2.setRemoteDescription({type: 'rollback'});
    await pc2.setRemoteDescription(offer);
  }, 'sRD does not cause ICE gathering state changes');

  promise_test(async t => {
    const pc1 = new RTCPeerConnection();
    t.add_cleanup(() => pc1.close());
    const pc2 = new RTCPeerConnection();
    t.add_cleanup(() => pc2.close());
    pc1.addTransceiver('audio', { direction: 'recvonly' });
    await initialOfferAnswerWithIceGatheringStateTransitions(
        pc1, pc2);

    const pc1waiter = iceGatheringStateTransitions(pc1, 'new');
    const pc2waiter = iceGatheringStateTransitions(pc2, 'new');
    pc1.getTransceivers()[0].stop();
    await pc1.setLocalDescription(await pc1.createOffer());
    await pc2.setRemoteDescription(pc1.localDescription);
    await pc2.setLocalDescription(await pc2.createAnswer());
    assert_equals(pc2.getTransceivers().length, 0,
                 'PC2 transceivers should be invisible after negotiation');
    assert_equals(pc2.iceGatheringState, 'new');
    await pc2waiter;
    await pc1.setRemoteDescription(pc2.localDescription);
    assert_equals(pc1.getTransceivers().length, 0,
                  'PC1 transceivers should be invisible after negotiation');
    assert_equals(pc1.iceGatheringState, 'new');
    await pc1waiter;
  }, 'renegotiation that closes all transports should result in ICE gathering state "new"');

  /*
    4.3.2.  RTCIceGatheringState Enum
      new
        Any of the RTCIceTransports are in the "new" gathering state and none
        of the transports are in the "gathering" state, or there are no
        transports.

      gathering
        Any of the RTCIceTransport s are in the gathering state.

      complete
        At least one RTCIceTransport exists, and all RTCIceTransports are
        in the completed gathering state.

    5.6.  RTCIceGathererState
      gathering
        The RTCIceTransport is in the process of gathering candidates.

      complete
        The RTCIceTransport has completed gathering and the end-of-candidates
        indication for this transport has been sent. It will not gather candidates
        again until an ICE restart causes it to restart.
   */
  promise_test(async t => {
    const pc1 = new RTCPeerConnection();
    t.add_cleanup(() => pc1.close());
    const pc2 = new RTCPeerConnection();

    t.add_cleanup(() => pc2.close());

    const onIceGatheringStateChange = t.step_func(() => {
      const { iceGatheringState } = pc2;

      if(iceGatheringState === 'gathering') {
        const iceTransport = pc2.sctp.transport.iceTransport;

        assert_equals(iceTransport.gatheringState, 'gathering',
          'Expect ICE transport to be in gathering gatheringState when iceGatheringState is gathering');

      } else if(iceGatheringState === 'complete') {
        const iceTransport = pc2.sctp.transport.iceTransport;

        assert_equals(iceTransport.gatheringState, 'complete',
          'Expect ICE transport to be in complete gatheringState when iceGatheringState is complete');

        t.done();
      }
    });

    pc1.createDataChannel('test');

    // Spec bug w3c/webrtc-pc#1382
    // Because sctp is only defined when answer is set, we listen
    // to pc2 so that we can be confident that sctp is defined
    // when icegatheringstatechange event is fired.
    pc2.addEventListener('icegatheringstatechange', onIceGatheringStateChange);


    exchangeIceCandidates(pc1, pc2);

    await pc1.setLocalDescription();
    assert_equals(pc1.sctp.transport.iceTransport.gatheringState, 'new');
    await pc2.setRemoteDescription(pc1.localDescription);

    await exchangeAnswer(pc1, pc2);
  }, 'connection with one data channel should eventually have connected connection state');

  /*
    TODO
    5.6.  RTCIceTransport Interface
      new
        The RTCIceTransport was just created, and has not started gathering
        candidates yet.
   */
</script>