<!doctype html>
<meta charset=utf-8>
<title>RTCDataChannel.prototype.bufferedAmount</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:
  //  createDataChannelPair
  //  awaitMessage
  //  blobToArrayBuffer
  //  assert_equals_array_buffer

  /*
    6.2.  RTCDataChannel
      interface RTCDataChannel : EventTarget {
        ...
        readonly  attribute unsigned long       bufferedAmount;
        void send(USVString data);
        void send(Blob data);
        void send(ArrayBuffer data);
        void send(ArrayBufferView data);
      };

      bufferedAmount
        The bufferedAmount attribute must return the number of bytes of application
        data (UTF-8 text and binary data) that have been queued using send() but that,
        as of the last time the event loop started executing a task, had not yet been
        transmitted to the network. (This thus includes any text sent during the
        execution of the current task, regardless of whether the user agent is able
        to transmit text asynchronously with script execution.) This does not include
        framing overhead incurred by the protocol, or buffering done by the operating
        system or network hardware. If the channel is closed, this attribute's value
        will only increase with each call to the send() method (the attribute does not
        reset to zero once the channel closes).


    [WebMessaging]
    interface MessageEvent : Event {
      readonly attribute any data;
      ...
    };
   */

  // Simple ASCII encoded string
  const helloString = 'hello';
  // ASCII encoded buffer representation of the string
  const helloBuffer = Uint8Array.of(0x68, 0x65, 0x6c, 0x6c, 0x6f);
  const helloBlob = new Blob([helloBuffer]);

  // Unicode string with multiple code units
  const unicodeString = '世界你好';
  // UTF-8 encoded buffer representation of the string
  const unicodeBuffer = Uint8Array.of(
    0xe4, 0xb8, 0x96, 0xe7, 0x95, 0x8c,
    0xe4, 0xbd, 0xa0, 0xe5, 0xa5, 0xbd);

  /*
    6.2.  send()
      3.  Execute the sub step that corresponds to the type of the methods argument:

          string object
            Let data be the object and increase the bufferedAmount attribute
            by the number of bytes needed to express data as UTF-8.
   */
  promise_test(t => {
    return createDataChannelPair()
    .then(([channel1, channel2]) => {
      channel1.send(unicodeString);
      assert_equals(channel1.bufferedAmount, unicodeBuffer.byteLength,
        'Expect bufferedAmount to be the byte length of the unicode string');

      return awaitMessage(channel2)
      .then(message => {
        assert_equals(channel1.bufferedAmount, 0,
          'Expect sender bufferedAmount to be reduced after message is sent');
      });
    });
  }, 'bufferedAmount should increase to byte length of encoded unicode string sent');

  /*
    6.2. send()
      3.  Execute the sub step that corresponds to the type of the methods argument:
          ArrayBuffer object
            Let data be the data stored in the buffer described by the ArrayBuffer
            object and increase the bufferedAmount attribute by the length of the
            ArrayBuffer in bytes.
   */
  promise_test(t => {
    return createDataChannelPair()
    .then(([channel1, channel2]) => {
      channel1.send(helloBuffer.buffer);
      assert_equals(channel1.bufferedAmount, helloBuffer.byteLength,
        'Expect bufferedAmount to increase to byte length of sent buffer');

      return awaitMessage(channel2)
      .then(messageBuffer => {
        assert_equals(channel1.bufferedAmount, 0,
          'Expect sender bufferedAmount to be reduced after message is sent');
      });
    });
  }, 'bufferedAmount should increase to byte length of buffer sent');

  /*
    6.2. send()
      3.  Execute the sub step that corresponds to the type of the methods argument:
          Blob object
            Let data be the raw data represented by the Blob object and increase
            the bufferedAmount attribute by the size of data, in bytes.
   */
  promise_test(t => {
    return createDataChannelPair()
    .then(([channel1, channel2]) => {
      channel1.send(helloBlob);
      assert_equals(channel1.bufferedAmount, helloBlob.size,
        'Expect bufferedAmount to increase to size of sent blob');

      return awaitMessage(channel2)
      .then(messageBuffer => {
        assert_equals(channel1.bufferedAmount, 0,
          'Expect sender bufferedAmount to be reduced after message is sent');
      });
    });
  }, 'bufferedAmount should increase to size of blob sent');

  // Test sending 3 messages: helloBuffer, unicodeString, helloBlob
  async_test(t => {
    let messageCount = 0;

    createDataChannelPair()
    .then(([channel1, channel2]) => {
      const onMessage = t.step_func(event => {
        const { data } = event;
        messageCount++;

        if(messageCount === 3) {
          assert_equals(channel1.bufferedAmount, 0,
            'Expect sender bufferedAmount to be reduced after message is sent');

          t.done();
        }
      });

      channel2.addEventListener('message', onMessage);

      channel1.send(helloBuffer);
      assert_equals(channel1.bufferedAmount, helloString.length,
        'Expect bufferedAmount to be the total length of all messages queued to send');

      channel1.send(unicodeString);
      assert_equals(channel1.bufferedAmount,
        helloString.length + unicodeBuffer.byteLength,
        'Expect bufferedAmount to be the total length of all messages queued to send');

      channel1.send(helloBlob);
      assert_equals(channel1.bufferedAmount,
        helloString.length*2 + unicodeBuffer.byteLength,
        'Expect bufferedAmount to be the total length of all messages queued to send');

    }).catch(t.step_func(err =>
      assert_unreached(`Unexpected promise rejection: ${err}`)));
  }, 'bufferedAmount should increase by byte length for each message sent');

  promise_test(async t => {
    const [channel1, channel2] = await createDataChannelPair();
    channel1.addEventListener('bufferedamountlow', t.step_func_done(() => {
      assert_true(channel1.bufferedAmount <= channel1.bufferedAmountLowThreshold);
    }));
    const eventWatcher = new EventWatcher(t, channel1, ['bufferedamountlow']);
    channel1.send(helloString);
    await eventWatcher.wait_for(['bufferedamountlow']);
  }, 'Data channel bufferedamountlow event fires after send() is complete');

  promise_test(async t => {
    const [channel1, channel2] = await createDataChannelPair();
    channel1.send(helloString);
    assert_equals(channel1.bufferedAmount, helloString.length);
    await awaitMessage(channel2);
    assert_equals(channel1.bufferedAmount, 0);
  }, 'Data channel bufferedamount is data.length on send(data)');

  promise_test(async t => {
    const [channel1, channel2] = await createDataChannelPair();
    channel1.send(helloString);
    assert_equals(channel1.bufferedAmount, helloString.length);
    assert_equals(channel1.bufferedAmount, helloString.length);
  }, 'Data channel bufferedamount returns the same amount if no more data is' +
     ' sent on the channel');

  promise_test(async t => {
    const [channel1, channel2] = await createDataChannelPair();
    let eventFireCount = 0;
    channel1.addEventListener('bufferedamountlow', t.step_func(() => {
      assert_true(channel1.bufferedAmount <= channel1.bufferedAmountLowThreshold);
      assert_equals(++eventFireCount, 1);
    }));
    const eventWatcher = new EventWatcher(t, channel1, ['bufferedamountlow']);
    channel1.send(helloString);
    assert_equals(channel1.bufferedAmount, helloString.length);
    channel1.send(helloString);
    assert_equals(channel1.bufferedAmount, 2 * helloString.length);
    await eventWatcher.wait_for(['bufferedamountlow']);
  }, 'Data channel bufferedamountlow event fires only once after multiple' +
    ' consecutive send() calls');

  promise_test(async t => {
    const [channel1, channel2] = await createDataChannelPair();
    const eventWatcher = new EventWatcher(t, channel1, ['bufferedamountlow']);
    channel1.send(helloString);
    assert_equals(channel1.bufferedAmount, helloString.length);
    await eventWatcher.wait_for(['bufferedamountlow']);
    assert_equals(await awaitMessage(channel2), helloString);
    channel1.send(helloString);
    assert_equals(channel1.bufferedAmount, helloString.length);
    await eventWatcher.wait_for(['bufferedamountlow']);
    assert_equals(await awaitMessage(channel2), helloString);
  }, 'Data channel bufferedamountlow event fires after each sent message');

</script>