var crypto = require('crypto');

var appID  = "970ca35de60c44645bbae8a215061b33";//传参
var appCertificate = "5cfd2fd1755d40ecb72977518be15d3b";//传参
var channel = "7d72365eb983485397e3e3f9d460bdda"; //传参
var ts = 1446455472;
var r = 58964981;
var uid=2882341273; //传参
var expiredTs=1446455471;

var version = "005";
var noUpload = "0";
var audioVideoUpload = "3";

var encodeHMac = function(key, message) {
    return crypto.createHmac('sha1', key).update(message).digest('hex').toUpperCase();
};

var hexDecode = function(str) {
    return new Buffer(str, 'hex');
};

var Message = function(options) {
    options.pack = function() {
        var out = ByteBuf();
        return out.putUint16(options.serviceType)
            .putBytes(options.appID)
            .putUint32(options.unixTs)
            .putUint32(options.salt)
            .putString(options.channelName)
            .putUint32(options.uid)
            .putUint32(options.expiredTs)
            .putTreeMap(options.extra)
            .pack();
    }

    return options;
}

// InChannelPermissionKey
var ALLOW_UPLOAD_IN_CHANNEL = 1;

// Service Type
var MEDIA_CHANNEL_SERVICE = 1;
var RECORDING_SERVICE = 2;
var PUBLIC_SHARING_SERVICE = 3;
var IN_CHANNEL_PERMISSION = 4;

var inspectMediaChannelKey = function async(appID, appCertificate, channelName, unixTs, randomInt, uid, expiredTs) {
    var rawAppID =  hexDecode(appID);
    // console.log('App ID:\t\t\t ' + rawAppID.toString('hex').toUpperCase());

    var rawAppCertificate =  hexDecode(appCertificate);
    // console.log('App Certificate:\t ' + rawAppCertificate.toString('hex').toUpperCase());

    var serviceType = MEDIA_CHANNEL_SERVICE;
    var extra = null;
    var ByteBuf = function() {
        var that = {
            buffer: new Buffer(1024)
            , position: 0
        };
    
        that.buffer.fill(0);
    
        that.pack = function() {
            var out = new Buffer(that.position);
            that.buffer.copy(out, 0, 0, out.length);
            return out;
        };
    
        that.putUint16 = function(v) {
            try {
                console.log(typeof v)
                that.buffer.writeUInt16LE(v, that.position);
                that.position += 2;
            } catch (error) {
                console.log('buffer',error)
            }
            
            return that;
        };
    
        that.putUint32 = function(v) {
            that.buffer.writeUInt32LE(v, that.position);
            that.position += 4;
            return that;
        };
    
        that.putBytes = function(bytes) {
            that.putUint16(bytes.length);
            bytes.copy(that.buffer, that.position);
            that.position += bytes.length;
            return that;
        };
    
        that.putString = function(str) {
            return that.putBytes(new Buffer(str));
        };
    
        that.putTreeMap = function(map) {
            if (!map) {
                that.putUint16(0);
                return that;
            }
    
            that.putUint16(Object.keys(map).length);
            for (var key in map) {
                that.putUint16(key);
                that.putString(map[key]);
            }
    
            return that;
        };
    
        return that;
    }
    var Message = function(options) {
        
        options.pack = function() {
            var out = ByteBuf();
            return out.putUint16(options.serviceType)
                .putBytes(options.appID)
                .putUint32(options.unixTs)
                .putUint32(options.salt)
                .putString(options.channelName)
                .putUint32(options.uid)
                .putUint32(options.expiredTs)
                .putTreeMap(options.extra)
                .pack();
        }
    
        return options;
    }

    var m =  Message({
        serviceType: serviceType
        , appID: rawAppID
        , unixTs: unixTs
        , salt: randomInt
        , channelName: channelName
        , uid: uid
        , expiredTs: expiredTs
        , extra: extra
    });

    var toSign =  m.pack();
    // console.log("Message to sign:\t " + toSign.toString('hex').toUpperCase());

    var signature =  encodeHMac(rawAppCertificate, toSign);
    // console.log("Signature:\t\t " + signature.toString('hex').toUpperCase());
    var DynamicKey5Content = function(options) {
        options.pack = function() {
            var out = ByteBuf();
            return out.putUint16(options.serviceType)
                .putString(options.signature)
                .putBytes(options.appID)
                .putUint32(options.unixTs)
                .putUint32(options.salt)
                .putUint32(options.expiredTs)
                .putTreeMap(options.extra)
                .pack();
        }
    
        return options;
    }
    var content =  DynamicKey5Content({
        serviceType: serviceType
        , signature: signature
        , appID: hexDecode(appID)
        , unixTs: unixTs
        , salt: randomInt
        , expiredTs: expiredTs
        , extra: extra}).pack();
    // console.log("Content to encode:\t " + content.toString('hex').toUpperCase());

    var channelKey = version + content.toString('base64');
    // console.log("Channel key:\t\t " + channelKey);
    return channelKey;
};

var expected = "005AQAoAEJERTJDRDdFNkZDNkU0ODYxNkYxQTYwOUVFNTM1M0U5ODNCQjFDNDQQAJcMo13mDERkW7roohUGGzOwKDdW9buDA68oN1YAAA==";
//var result = inspectMediaChannelKey(appID, appCertificate, channel, ts, r, uid, expiredTs);
//console.log( (expected == result) ? "ok" : "failed");
module.exports = async(appIDa, appCertificatea, channela,uida)=>{
    let keys = await inspectMediaChannelKey(appIDa, appCertificatea, channela, ts, r, uida, expiredTs);
    if(expected == keys){
        return {
            code:200,
            channelKey:keys,
            uid:uida
        }
    }else {
        return {
            code:400,
            msg:"failed"
        }
    }
}