/**
* @description Meshcentral Intel AMT Local Scanner
* @author Ylian Saint-Hilaire & Joko Sastriawan
* @version v0.0.1
*/

// Construct a Intel AMT Scanner object

function AMTScanner() {
    var emitterUtils = require('events').inherits(this);
    emitterUtils.createEvent('found');

    this.dgram = require('dgram');

    this.buildRmcpPing = function (tag) {
        var packet = Buffer.from('06000006000011BE80000000', 'hex');
        packet[9] = tag;
        return packet;
    };

    this.parseRmcpPacket = function (server, data, rinfo, func) {
        if (data == null || data.length < 20) return;
        var res = {};
        if (((data[12] == 0) || (data[13] != 0) || (data[14] != 1) || (data[15] != 0x57)) && (data[21] & 32)) {
            res.servertag = data[9];
            res.minorVersion = data[18] & 0x0F;
            res.majorVersion = (data[18] >> 4) & 0x0F;
            res.provisioningState = data[19] & 0x03; // Pre = 0, In = 1, Post = 2

            var openPort = (data[16] * 256) + data[17];
            var dualPorts = ((data[19] & 0x04) != 0) ? true : false;
            res.openPorts = [openPort];
            res.address = rinfo.address;
            if (dualPorts == true) { res.openPorts = [16992, 16993]; }
            if (func !== undefined) {
                func(server, res);
            }
        }
    }

    this.parseIPv4Range = function (range) {
        if (range == undefined || range == null) return null;
        var x = range.split('-');
        if (x.length == 2) { return { min: this.parseIpv4Addr(x[0]), max: this.parseIpv4Addr(x[1]) }; }
        x = range.split('/');
        if (x.length == 2) {
            var ip = this.parseIpv4Addr(x[0]), masknum = parseInt(x[1]), mask = 0;
            if (masknum <= 16 || masknum > 32) return null;
            masknum = 32 - masknum;
            for (var i = 0; i < masknum; i++) { mask = (mask << 1); mask++; }
            return { min: ip & (0xFFFFFFFF - mask), max: (ip & (0xFFFFFFFF - mask)) + mask };
        }
        x = this.parseIpv4Addr(range);
        if (x == null) return null;
        return { min: x, max: x };
    };

    // Parse IP address. Takes a 
    this.parseIpv4Addr = function (addr) {
        var x = addr.split('.');
        if (x.length == 4) { return (parseInt(x[0]) << 24) + (parseInt(x[1]) << 16) + (parseInt(x[2]) << 8) + (parseInt(x[3]) << 0); }
        return null;
    }

    // IP address number to string
    this.IPv4NumToStr = function (num) {
        return ((num >> 24) & 0xFF) + '.' + ((num >> 16) & 0xFF) + '.' + ((num >> 8) & 0xFF) + '.' + (num & 0xFF);
    }

    this.scan = function (rangestr, timeout, func) {
        var iprange = this.parseIPv4Range(rangestr);
        var rmcp = this.buildRmcpPing(0);
        var server = this.dgram.createSocket({ type: 'udp4' });
        server.parent = this;
        server.scanResults = [];
        server.on('error', function (err) { console.log('Error:' + err); });
        server.on('message', function (msg, rinfo) { if (rinfo.size > 4) { this.parent.parseRmcpPacket(this, msg, rinfo, function (s, res) { s.scanResults.push(res); }) }; });
        server.on('listening', function () { for (var i = iprange.min; i <= iprange.max; i++) { server.send(rmcp, 623, server.parent.IPv4NumToStr(i)); } });
        server.bind({ address: '0.0.0.0', port: 0, exclusive: true });
        var tmout = setTimeout(function cb() {
            //console.log("Server closed");
            //server.close();
            server.parent.emit('found', server.scanResults);
            if (func != null) { func(server.scanResults); }
            delete server;
        }, timeout);
    };
}

module.exports = AMTScanner;