/**
 * Copyright (c) 2012 The Chromium Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

// This file requires these functions to be defined globally by someone else:
// function handleMessage(peerConnection, message)
// function createPeerConnection(stun_server)
// function setupCall(peerConnection)
// function answerCall(peerConnection, message)

// Currently these functions are supplied by jsep01_call.js.

/**
 * This object represents the call.
 * @private
 */
var gPeerConnection = null;

/**
 * True if we are accepting incoming calls.
 * @private
 */
var gAcceptsIncomingCalls = true;

/**
 * Our peer id as assigned by the peerconnection_server.
 * @private
 */
var gOurPeerId = null;

/**
 * The client id we use to identify to peerconnection_server.
 * @private
 */
var gOurClientName = null;

/**
 * The URL to the peerconnection_server.
 * @private
 */
var gServerUrl = null;

/**
 * The remote peer's id. We receive this one either when we connect (in the case
 * our peer connects before us) or in a notification later.
 * @private
 */
var gRemotePeerId = null;

/**
 * Whether or not to auto-respond by adding our local stream when we are called.
 * @private
 */
var gAutoAddLocalToPeerConnectionStreamWhenCalled = true;

/**
 * The one and only data channel.
 * @private
 */
var gDataChannel = null;

/**
 * The DTMF sender.
 * @private
 */
var gDtmfSender = null;

/**
 * We need a STUN server for some API calls.
 * @private
 */
var STUN_SERVER = 'stun.l.google.com:19302';

// Public interface to PyAuto test.


/**
 * Connects to the provided peerconnection_server.
 *
 * @param{string} serverUrl The server URL in string form without an ending
 *     slash, something like http://localhost:8888.
 * @param{string} clientName The name to use when connecting to the server.
 */
function connect(serverUrl, clientName) {
  if (gOurPeerId != null)
    throw failTest('connecting, but is already connected.');

  debug('Connecting to ' + serverUrl + ' as ' + clientName);
  gServerUrl = serverUrl;
  gOurClientName = clientName;

  request = new XMLHttpRequest();
  request.open('GET', serverUrl + '/sign_in?' + clientName, true);
  debug(serverUrl + '/sign_in?' + clientName);
  request.onreadystatechange = function() {
    connectCallback_(request);
  }
  request.send();
}

/**
 * Checks if the remote peer has connected. Returns peer-connected if that is
 * the case, otherwise no-peer-connected.
 */
function remotePeerIsConnected() {
  if (gRemotePeerId == null)
    returnToTest('no-peer-connected');
  else
    returnToTest('peer-connected');
}

/**
 * Creates a peer connection. Must be called before most other public functions
 * in this file.
 */
function preparePeerConnection() {
  if (gPeerConnection != null)
    throw failTest('creating peer connection, but we already have one.');

  gPeerConnection = createPeerConnection(STUN_SERVER);
  returnToTest('ok-peerconnection-created');
}

/**
 * Negotiates a call with the other side. This will create a peer connection on
 * the other side if there isn't one. The other side will automatically add any
 * stream it has unless doNotAutoAddLocalStreamWhenCalled() has been called.
 *
 * To call this method we need to be aware of the other side, e.g. we must be
 * connected to peerconnection_server and we must have exactly one peer on that
 * server.
 *
 * This method may be called any number of times. If you haven't added any
 * streams to the call, an "empty" call will result. The method will return
 * ok-negotiating immediately to the test if the negotiation was successfully
 * sent.
 */
function negotiateCall() {
  if (gPeerConnection == null)
    throw failTest('negotiating call, but we have no peer connection.');
  if (gOurPeerId == null)
    throw failTest('negotiating call, but not connected.');
  if (gRemotePeerId == null)
    throw failTest('negotiating call, but missing remote peer.');

  setupCall(gPeerConnection);
  returnToTest('ok-negotiating');
}

/**
 * Adds the local stream to the peer connection. You will have to re-negotiate
 * the call for this to take effect in the call.
 */
function addLocalStream() {
  if (gPeerConnection == null)
    throw failTest('adding local stream, but we have no peer connection.');

  addLocalStreamToPeerConnection(gPeerConnection);
  returnToTest('ok-added');
}

/**
 * Loads a file with WebAudio and plays it through the peer connection.
 *
 * The loadAudioAndAddToPeerConnection will return ok-added to the test when
 * the sound is loaded and added to the peer connection. The sound will start
 * playing when you call playAudioFile.
 *
 * @param url URL pointing to the file to play. You can assume that you can
 *     serve files from the repository's file system. For instance, to serve a
 *     file from chrome/test/data/pyauto_private/webrtc/file.wav, pass in a path
 *     relative to this directory (e.g. ../pyauto_private/webrtc/file.wav).
 */
function addAudioFile(url) {
  if (gPeerConnection == null)
    throw failTest('adding audio file, but we have no peer connection.');

  loadAudioAndAddToPeerConnection(url, gPeerConnection);
}

/**
 * Must be called after addAudioFile.
 */
function playAudioFile() {
  if (gPeerConnection == null)
    throw failTest('trying to play file, but we have no peer connection.');

  playPreviouslyLoadedAudioFile(gPeerConnection);
  returnToTest('ok-playing');
}

/**
 * Removes the local stream from the peer connection. You will have to
 * re-negotiate the call for this to take effect in the call.
 */
function removeLocalStream() {
  if (gPeerConnection == null)
    throw failTest('attempting to remove local stream, but no call is up');

  removeLocalStreamFromPeerConnection(gPeerConnection);
  returnToTest('ok-local-stream-removed');
}

/**
 * (see getReadyState)
 */
function getPeerConnectionReadyState() {
  returnToTest(getReadyState());
}

/**
 * Toggles the remote audio stream's enabled state on the peer connection, given
 * that a call is active. Returns ok-[typeToToggle]-toggled-to-[true/false]
 * on success.
 *
 * @param selectAudioOrVideoTrack: A function that takes a remote stream as
 *     argument and returns a track (e.g. either the video or audio track).
 * @param typeToToggle: Either "audio" or "video" depending on what the selector
 *     function selects.
 */
function toggleRemoteStream(selectAudioOrVideoTrack, typeToToggle) {
  if (gPeerConnection == null)
    throw failTest('Tried to toggle remote stream, ' +
                   'but have no peer connection.');
  if (gPeerConnection.getRemoteStreams().length == 0)
    throw failTest('Tried to toggle remote stream, ' +
                   'but not receiving any stream.');

  var track = selectAudioOrVideoTrack(gPeerConnection.getRemoteStreams()[0]);
  toggle_(track, 'remote', typeToToggle);
}

/**
 * See documentation on toggleRemoteStream (this function is the same except
 * we are looking at local streams).
 */
function toggleLocalStream(selectAudioOrVideoTrack, typeToToggle) {
  if (gPeerConnection == null)
    throw failTest('Tried to toggle local stream, ' +
                   'but have no peer connection.');
  if (gPeerConnection.getLocalStreams().length == 0)
    throw failTest('Tried to toggle local stream, but there is no local ' +
                   'stream in the call.');

  var track = selectAudioOrVideoTrack(gPeerConnection.getLocalStreams()[0]);
  toggle_(track, 'local', typeToToggle);
}

/**
 * Hangs up a started call. Returns ok-call-hung-up on success. This tab will
 * not accept any incoming calls after this call.
 */
function hangUp() {
  if (gPeerConnection == null)
    throw failTest('hanging up, but has no peer connection');
  if (getReadyState() != 'active')
    throw failTest('hanging up, but ready state is not active (no call up).');
  sendToPeer(gRemotePeerId, 'BYE');
  closeCall_();
  gAcceptsIncomingCalls = false;
  returnToTest('ok-call-hung-up');
}

/**
 * Start accepting incoming calls again after a hangup.
 */
function acceptIncomingCallsAgain() {
  gAcceptsIncomingCalls = true;
}

/**
 * Do not auto-add the local stream when called.
 */
function doNotAutoAddLocalStreamWhenCalled() {
  gAutoAddLocalToPeerConnectionStreamWhenCalled = false;
}

/**
 * Disconnects from the peerconnection server. Returns ok-disconnected on
 * success.
 */
function disconnect() {
  if (gOurPeerId == null)
    throw failTest('Disconnecting, but we are not connected.');

  request = new XMLHttpRequest();
  request.open('GET', gServerUrl + '/sign_out?peer_id=' + gOurPeerId, false);
  request.send();
  gOurPeerId = null;
  returnToTest('ok-disconnected');
}

/**
 * Creates a DataChannel on the current PeerConnection. Only one DataChannel can
 * be created on each PeerConnection.
 * Returns ok-datachannel-created on success.
 */
function createDataChannelOnPeerConnection() {
  if (gPeerConnection == null)
    throw failTest('Tried to create data channel, ' +
        'but have no peer connection.');

  createDataChannel(gPeerConnection, gOurClientName);
  returnToTest('ok-datachannel-created');
}

/**
 * Close the DataChannel on the current PeerConnection.
 * Returns ok-datachannel-close on success.
 */
function closeDataChannelOnPeerConnection() {
  if (gPeerConnection == null)
    throw failTest('Tried to close data channel, ' +
        'but have no peer connection.');

  closeDataChannel(gPeerConnection);
  returnToTest('ok-datachannel-close');
}

/**
 * Creates a DTMF sender on the current PeerConnection.
 * Returns ok-dtmfsender-created on success.
 */
function createDtmfSenderOnPeerConnection() {
  if (gPeerConnection == null)
    throw failTest('Tried to create DTMF sender, ' +
        'but have no peer connection.');

  createDtmfSender(gPeerConnection);
  returnToTest('ok-dtmfsender-created');
}

/**
 * Send DTMF tones on the gDtmfSender.
 * Returns ok-dtmf-sent on success.
 */
function insertDtmfOnSender(tones, duration, interToneGap) {
  if (gDtmfSender == null)
    throw failTest('Tried to insert DTMF tones, ' +
        'but have no DTMF sender.');

  insertDtmf(tones, duration, interToneGap);
  returnToTest('ok-dtmf-sent');
}

// Public interface to signaling implementations, such as JSEP.

/**
 * Sends a message to a peer through the peerconnection_server.
 */
function sendToPeer(peer, message) {
  var messageToLog = message.sdp ? message.sdp : message;
  debug('Sending message ' + messageToLog + ' to peer ' + peer + '.');

  var request = new XMLHttpRequest();
  var url = gServerUrl + '/message?peer_id=' + gOurPeerId + '&to=' + peer;
  request.open('POST', url, false);
  request.setRequestHeader('Content-Type', 'text/plain');
  request.send(message);
}

/**
 * Returns true if we are disconnected from peerconnection_server.
 */
function isDisconnected() {
  return gOurPeerId == null;
}

/**
 * @return {!string} The current peer connection's ready state, or
 *     'no-peer-connection' if there is no peer connection up.
 *
 * NOTE: The PeerConnection states are changing and until chromium has
 *       implemented the new states we have to use this interim solution of
 *       always assuming that the PeerConnection is 'active'.
 */
function getReadyState() {
  if (gPeerConnection == null)
    return 'no-peer-connection';

  return 'active';
}

// Internals.

/** @private */
function toggle_(track, localOrRemote, audioOrVideo) {
  if (!track)
    throw failTest('Tried to toggle ' + localOrRemote + ' ' + audioOrVideo +
             ' stream, but has no such stream.');

  track.enabled = !track.enabled;
  returnToTest('ok-' + audioOrVideo + '-toggled-to-' + track.enabled);
}

/** @private */
function connectCallback_(request) {
  debug('Connect callback: ' + request.status + ', ' + request.readyState);
  if (request.status == 0) {
    debug('peerconnection_server doesn\'t seem to be up.');
    returnToTest('failed-to-connect');
  }
  if (request.readyState == 4 && request.status == 200) {
    gOurPeerId = parseOurPeerId_(request.responseText);
    gRemotePeerId = parseRemotePeerIdIfConnected_(request.responseText);
    startHangingGet_(gServerUrl, gOurPeerId);
    returnToTest('ok-connected');
  }
}

/** @private */
function parseOurPeerId_(responseText) {
  // According to peerconnection_server's protocol.
  var peerList = responseText.split('\n');
  return parseInt(peerList[0].split(',')[1]);
}

/** @private */
function parseRemotePeerIdIfConnected_(responseText) {
  var peerList = responseText.split('\n');
  if (peerList.length == 1) {
    // No peers have connected yet - we'll get their id later in a notification.
    return null;
  }
  var remotePeerId = null;
  for (var i = 0; i < peerList.length; i++) {
    if (peerList[i].length == 0)
      continue;

    var parsed = peerList[i].split(',');
    var name = parsed[0];
    var id = parsed[1];

    if (id != gOurPeerId) {
      debug('Found remote peer with name ' + name + ', id ' +
            id + ' when connecting.');

      // There should be at most one remote peer in this test.
      if (remotePeerId != null)
        throw failTest('Expected just one remote peer in this test: ' +
                       'found several.');

      // Found a remote peer.
      remotePeerId = id;
    }
  }
  return remotePeerId;
}

/** @private */
function startHangingGet_(server, ourId) {
  if (isDisconnected())
    return;
  hangingGetRequest = new XMLHttpRequest();
  hangingGetRequest.onreadystatechange = function() {
    hangingGetCallback_(hangingGetRequest, server, ourId);
  }
  hangingGetRequest.ontimeout = function() {
    hangingGetTimeoutCallback_(hangingGetRequest, server, ourId);
  }
  callUrl = server + '/wait?peer_id=' + ourId;
  debug('Sending ' + callUrl);
  hangingGetRequest.open('GET', callUrl, true);
  hangingGetRequest.send();
}

/** @private */
function hangingGetCallback_(hangingGetRequest, server, ourId) {
  if (hangingGetRequest.readyState != 4)
    return;
  if (hangingGetRequest.status == 0) {
    // Code 0 is not possible if the server actually responded.
    throw failTest('Previous request was malformed, or server is unavailable.');
  }
  if (hangingGetRequest.status != 200) {
    throw failTest('Error ' + hangingGetRequest.status + ' from server: ' +
             hangingGetRequest.statusText);
  }
  var targetId = readResponseHeader_(hangingGetRequest, 'Pragma');
  if (targetId == ourId)
    handleServerNotification_(hangingGetRequest.responseText);
  else
    handlePeerMessage_(targetId, hangingGetRequest.responseText);

  hangingGetRequest.abort();
  restartHangingGet_(server, ourId);
}

/** @private */
function hangingGetTimeoutCallback_(hangingGetRequest, server, ourId) {
  debug('Hanging GET times out, re-issuing...');
  hangingGetRequest.abort();
  restartHangingGet_(server, ourId);
}

/** @private */
function handleServerNotification_(message) {
  var parsed = message.split(',');
  if (parseInt(parsed[2]) == 1) {
    // Peer connected - this must be our remote peer, and it must mean we
    // connected before them (except if we happened to connect to the server
    // at precisely the same moment).
    debug('Found remote peer with name ' + parsed[0] + ', id ' +
          parsed[1] + ' when connecting.');
    gRemotePeerId = parseInt(parsed[1]);
  }
}

/** @private */
function closeCall_() {
  if (gPeerConnection == null)
    throw failTest('Closing call, but no call active.');
  gPeerConnection.close();
  gPeerConnection = null;
}

/** @private */
function handlePeerMessage_(peerId, message) {
  debug('Received message from peer ' + peerId + ': ' + message);
  if (peerId != gRemotePeerId) {
    addTestFailure('Received notification from unknown peer ' + peerId +
                   ' (only know about ' + gRemotePeerId + '.');
    return;
  }
  if (message.search('BYE') == 0) {
    debug('Received BYE from peer: closing call');
    closeCall_();
    return;
  }
  if (gPeerConnection == null && gAcceptsIncomingCalls) {
    // The other side is calling us.
    debug('We are being called: answer...');

    gPeerConnection = createPeerConnection(STUN_SERVER);
    if (gAutoAddLocalToPeerConnectionStreamWhenCalled &&
        obtainGetUserMediaResult() == 'ok-got-stream') {
      debug('We have a local stream, so hook it up automatically.');
      addLocalStreamToPeerConnection(gPeerConnection);
    }
    answerCall(gPeerConnection, message);
    return;
  }
  handleMessage(gPeerConnection, message);
}

/** @private */
function restartHangingGet_(server, ourId) {
  window.setTimeout(function() {
    startHangingGet_(server, ourId);
  }, 0);
}

/** @private */
function readResponseHeader_(request, key) {
  var value = request.getResponseHeader(key)
  if (value == null || value.length == 0) {
    addTestFailure('Received empty value ' + value +
                   ' for response header key ' + key + '.');
    return -1;
  }
  return parseInt(value);
}