// Copyright 1998-2019 Epic Games, Inc. All Rights Reserved.
// universal module definition - read https://www.davidbcalhoun.com/2014/what-is-amd-commonjs-and-umd/

(function (root, factory) {
    if (typeof define === 'function' && define.amd) {
        // AMD. Register as an anonymous module.
        define(["./adapter"], factory);
    } else if (typeof exports === 'object') {
        // Node. Does not work with strict CommonJS, but
        // only CommonJS-like environments that support module.exports,
        // like Node.
        module.exports = factory(require("./adapter"));
    } else {
        // Browser globals (root is window)
        root.webRtcPlayer = factory(root.adapter);
    }
}(this, function (adapter) {

    function webRtcPlayer(parOptions) {
    	parOptions = parOptions || {};
    	
        var self = this;

        //**********************
        //Config setup
        //**********************;
		this.cfg = parOptions.peerConnectionOptions || {};
		this.cfg.sdpSemantics = 'unified-plan';
        this.pcClient = null;
        this.dcClient = null;
        this.tnClient = null;

        this.sdpConstraints = {
          offerToReceiveAudio: 1,
          offerToReceiveVideo: 1
        };

        // See https://www.w3.org/TR/webrtc/#dom-rtcdatachannelinit for values
        this.dataChannelOptions = {ordered: true};

        //**********************
        //Functions
        //**********************

        //Create Video element and expose that as a parameter
        createWebRtcVideo = function() {
            var video = document.createElement('video');

            video.id = "streamingVideo";
            video.playsInline = true;
            video.addEventListener('loadedmetadata', function(e){
                if(self.onVideoInitialised){
                    self.onVideoInitialised();
                }
            }, true);
            return video;
        }

        this.video = createWebRtcVideo();

        onsignalingstatechange = function(state) {
            console.info('signaling state change:', state)
        };

        oniceconnectionstatechange = function(state) {
            console.info('ice connection state change:', state)
        };

        onicegatheringstatechange = function(state) {
            console.info('ice gathering state change:', state)
        };

        handleOnTrack = function(e){
            console.log('handleOnTrack', e.streams);
            if (self.video.srcObject !== e.streams[0]) {
                console.log('setting video stream from ontrack');
                self.video.srcObject = e.streams[0];
            }
        };

        setupDataChannel = function(pc, label, options) {
            try {
                var datachannel = pc.createDataChannel(label, options)
                console.log(`Created datachannel (${label})`)
                
                datachannel.onopen = function (e) {
                  console.log(`data channel (${label}) connect`)
                  if(self.onDataChannelConnected){
                    self.onDataChannelConnected();
                  }
                }

                datachannel.onclose = function (e) {
                  console.log(`data channel (${label}) closed`)
                }

                datachannel.onmessage = function (e) {
                  console.log(`Got message (${label})`, e.data)
                  if (self.onDataChannelMessage)
                    self.onDataChannelMessage(e.data);
                }

                return datachannel;
            } catch (e) { 
                console.warn('No data channel', e);
                return null;
            }
        }

        onicecandidate = function (e) {
            console.log('ICE candidate', e)
            if (e.candidate) {
                self.onWebRtcCandidate(JSON.stringify(e.candidate));
            }
        };

        handleCreateOffer = function (pc) {
            pc.createOffer(self.sdpConstraints).then(function (offerDesc) {
            	pc.setLocalDescription(offerDesc);
            	if (self.onWebRtcOffer) {
            		// (andriy): increase start bitrate from 300 kbps to 20 mbps and max bitrate from 2.5 mbps to 100 mbps
                    // (100 mbps means we don't restrict encoder at all)
                    // after we `setLocalDescription` because other browsers are not so happy to see google-specific config
            		offerDesc.sdp = offerDesc.sdp.replace(/(a=fmtp:\d+ .*level-asymmetry-allowed=.*)\r\n/gm, "$1;x-google-start-bitrate=20000;x-google-max-bitrate=100000\r\n");
            		//console.log('Sending offer: ', offerDesc)
            		self.onWebRtcOffer(JSON.stringify(offerDesc));
                }
            },
            function () { console.warn("Couldn't create offer") });
        }
        
        setupPeerConnection = function (pc) {
        	if (pc.SetBitrate)
        		console.log("Hurray! there's RTCPeerConnection.SetBitrate function");

            //Setup peerConnection events
            pc.onsignalingstatechange = onsignalingstatechange;
            pc.oniceconnectionstatechange = oniceconnectionstatechange;
            pc.onicegatheringstatechange = onicegatheringstatechange;

            pc.ontrack = handleOnTrack;
            pc.onicecandidate = onicecandidate;
        };

        generateAggregatedStatsFunction = function(){
            if(!self.aggregatedStats)
                self.aggregatedStats = {};

            return function(stats){
                //console.log('Printing Stats');

                let newStat = {};
                stats.forEach(stat => {
                    //console.log(JSON.stringify(stat))
                    if (stat.type == 'inbound-rtp' 
                        && !stat.isRemote 
                        && (stat.mediaType == 'video' || stat.id.toLowerCase().includes('video'))) {

                        newStat.timestamp = stat.timestamp;
                        newStat.bytesReceived = stat.bytesReceived;
                        newStat.framesDecoded = stat.framesDecoded;
                        newStat.packetsLost = stat.packetsLost;
                        newStat.bytesReceivedStart = self.aggregatedStats && self.aggregatedStats.bytesReceivedStart ? self.aggregatedStats.bytesReceivedStart : stat.bytesReceived;
                        newStat.framesDecodedStart = self.aggregatedStats && self.aggregatedStats.framesDecodedStart ? self.aggregatedStats.framesDecodedStart : stat.framesDecoded;
                        newStat.timestampStart = self.aggregatedStats && self.aggregatedStats.timestampStart ? self.aggregatedStats.timestampStart : stat.timestamp;

                        if(self.aggregatedStats && self.aggregatedStats.timestamp){
                            if(self.aggregatedStats.bytesReceived){
                                // bitrate = bits received since last time / number of ms since last time
                                //This is automatically in kbits (where k=1000) since time is in ms and stat we want is in seconds (so a '* 1000' then a '/ 1000' would negate each other)
                                newStat.bitrate = 8 * (newStat.bytesReceived - self.aggregatedStats.bytesReceived) / (newStat.timestamp - self.aggregatedStats.timestamp);
                                newStat.bitrate = Math.floor(newStat.bitrate);
                                newStat.lowBitrate = self.aggregatedStats.lowBitrate && self.aggregatedStats.lowBitrate < newStat.bitrate ? self.aggregatedStats.lowBitrate : newStat.bitrate
                                newStat.highBitrate = self.aggregatedStats.highBitrate && self.aggregatedStats.highBitrate > newStat.bitrate ? self.aggregatedStats.highBitrate : newStat.bitrate
                            }

                            if(self.aggregatedStats.bytesReceivedStart){
                                newStat.avgBitrate = 8 * (newStat.bytesReceived - self.aggregatedStats.bytesReceivedStart) / (newStat.timestamp - self.aggregatedStats.timestampStart);
                                newStat.avgBitrate = Math.floor(newStat.avgBitrate);
                            }

                            if(self.aggregatedStats.framesDecoded){
                                // framerate = frames decoded since last time / number of seconds since last time
                                newStat.framerate = (newStat.framesDecoded - self.aggregatedStats.framesDecoded) / ((newStat.timestamp - self.aggregatedStats.timestamp) / 1000);
                                newStat.framerate = Math.floor(newStat.framerate);
                                newStat.lowFramerate = self.aggregatedStats.lowFramerate && self.aggregatedStats.lowFramerate < newStat.framerate ? self.aggregatedStats.lowFramerate : newStat.framerate
                                newStat.highFramerate = self.aggregatedStats.highFramerate && self.aggregatedStats.highFramerate > newStat.framerate ? self.aggregatedStats.highFramerate : newStat.framerate
                            }

                            if(self.aggregatedStats.framesDecodedStart){
                                newStat.avgframerate = (newStat.framesDecoded - self.aggregatedStats.framesDecodedStart) / ((newStat.timestamp - self.aggregatedStats.timestampStart) / 1000);
                                newStat.avgframerate = Math.floor(newStat.avgframerate);
                            }
                        }
                    }

                    //Read video track stats
                    if(stat.type == 'track' && stat.trackIdentifier == 'video_label'){
                        newStat.framesDropped = stat.framesDropped;
                        newStat.framesReceived = stat.framesReceived;
                        newStat.framesDroppedPercentage = stat.framesDropped / stat.framesReceived * 100;
                        newStat.frameHeight = stat.frameHeight;
                        newStat.frameWidth = stat.frameWidth;
                        newStat.frameHeightStart = self.aggregatedStats && self.aggregatedStats.frameHeightStart ? self.aggregatedStats.frameHeightStart : stat.frameHeight;
                        newStat.frameWidthStart = self.aggregatedStats && self.aggregatedStats.frameWidthStart ? self.aggregatedStats.frameWidthStart : stat.frameWidth;
                    }

                    if(stat.type =='candidate-pair' && stat.hasOwnProperty('currentRoundTripTime')){
                        newStat.currentRoundTripTime = stat.currentRoundTripTime;
                    }
                });

                //console.log(JSON.stringify(newStat));
                self.aggregatedStats = newStat;

                if(self.onAggregatedStats)
                    self.onAggregatedStats(newStat)
            }
        };

        //**********************
        //Public functions
        //**********************

        //This is called when revceiving new ice candidates individually instead of part of the offer
        //This is currently not used but would be called externally from this class
        this.handleCandidateFromServer = function(iceCandidate) {
            console.log("ICE candidate: ", iceCandidate);
            let candidate = new RTCIceCandidate(iceCandidate);
            self.pcClient.addIceCandidate(candidate).then(_=>{
                console.log('ICE candidate successfully added');
            });
        };

        //Called externaly to create an offer for the server
        this.createOffer = function() {
            if(self.pcClient){
                console.log("Closing existing PeerConnection")
                self.pcClient.close();
                self.pcClient = null;
            }
            self.pcClient = new RTCPeerConnection(self.cfg);
            setupPeerConnection(self.pcClient);
            self.dcClient = setupDataChannel(self.pcClient, 'cirrus', self.dataChannelOptions);
            handleCreateOffer(self.pcClient);
        };

        //Called externaly when an answer is received from the server
        this.receiveAnswer = function(answer) {
            console.log('Received answer', answer);
            var answerDesc = new RTCSessionDescription(answer);
            self.pcClient.setRemoteDescription(answerDesc);
        };

        this.close = function(){
            if(self.pcClient){
                console.log("Closing existing peerClient")
                self.pcClient.close();
                self.pcClient = null;
            }
            if(self.aggregateStatsIntervalId)
                clearInterval(self.aggregateStatsIntervalId);
        }

        //Sends data across the datachannel
        this.send = function(data){
            if(self.dcClient && self.dcClient.readyState == 'open'){
                //console.log('Sending data on dataconnection', self.dcClient)
                self.dcClient.send(data);
            }
        };

        this.getStats = function(onStats){
            if(self.pcClient && onStats){
                self.pcClient.getStats(null).then((stats) => { onStats(stats); });
            }
        }

        this.aggregateStats = function(checkInterval){
            let calcAggregatedStats = generateAggregatedStatsFunction();
            let printAggregatedStats = () => { self.getStats(calcAggregatedStats); }
            self.aggregateStatsIntervalId = setInterval(printAggregatedStats, checkInterval);
        }
    };

    return webRtcPlayer;
  
}));