const Core = require('./core');

class Ventrilo extends Core {
    constructor() {
        super();
        this.byteorder = 'be';
    }

    async run(state) {
        const data = await this.sendCommand(2,'');
        state.raw = splitFields(data.toString());
        for (const client of state.raw.CLIENTS) {
            client.name = client.NAME;
            delete client.NAME;
            client.ping = parseInt(client.PING);
            delete client.PING;
            state.players.push(client);
        }
        delete state.raw.CLIENTS;

        if('NAME' in state.raw) state.name = state.raw.NAME;
        if('MAXCLIENTS' in state.raw) state.maxplayers = state.raw.MAXCLIENTS;
        if(this.trueTest(state.raw.AUTH)) state.password = true;
    }
    async sendCommand(cmd,password) {
        const body = Buffer.alloc(16);
        body.write(password,0,15,'utf8');
        const encrypted = encrypt(cmd,body);

        const packets = {};
        return await this.udpSend(encrypted, (buffer) => {
            if(buffer.length < 20) return;
            const data = decrypt(buffer);

            if(data.zero !== 0) return;
            packets[data.packetNum] = data.body;
            if(Object.keys(packets).length !== data.packetTotal) return;

            const out = [];
            for(let i = 0; i < data.packetTotal; i++) {
                if(!(i in packets)) throw new Error('Missing packet #'+i);
                out.push(packets[i]);
            }
            return Buffer.concat(out);
        });
    }
}

function splitFields(str,subMode) {
    let splitter,delim;
    if(subMode) {
        splitter = '=';
        delim = ',';
    } else {
        splitter = ': ';
        delim = '\n';
    }

    const split = str.split(delim);
    const out = {};
    if(!subMode) {
        out.CHANNELS = [];
        out.CLIENTS = [];
    }
    for (const one of split) {
        const equal = one.indexOf(splitter);
        const key = equal === -1 ? one : one.substr(0,equal);
        if(!key || key === '\0') continue;
        const value = equal === -1 ? '' : one.substr(equal+splitter.length);
        if(!subMode && key === 'CHANNEL') out.CHANNELS.push(splitFields(value,true));
        else if(!subMode && key === 'CLIENT') out.CLIENTS.push(splitFields(value,true));
        else out[key] = value;
    }
    return out;
}

function randInt(min,max) {
    return Math.floor(Math.random()*(max-min+1)+min)
}

function crc(body) {
    let crc = 0;
    for(let i = 0; i < body.length; i++) {
        crc = crc_table[crc>>8] ^ body.readUInt8(i) ^ (crc<<8);
        crc &= 0xffff;
    }
    return crc;
}

function encrypt(cmd,body) {
    const headerKeyStart = randInt(0,0xff);
    const headerKeyAdd = randInt(1,0xff);
    const bodyKeyStart = randInt(0,0xff);
    const bodyKeyAdd = randInt(1,0xff);

    const header = Buffer.alloc(20);
    header.writeUInt8(headerKeyStart,0);
    header.writeUInt8(headerKeyAdd,1);
    header.writeUInt16BE(cmd,4);
    header.writeUInt16BE(body.length,8);
    header.writeUInt16BE(body.length,10);
    header.writeUInt16BE(1,12);
    header.writeUInt16BE(0,14);
    header.writeUInt8(bodyKeyStart,16);
    header.writeUInt8(bodyKeyAdd,17);
    header.writeUInt16BE(crc(body),18);

    let offset = headerKeyStart;
    for(let i = 2; i < header.length; i++) {
        let val = header.readUInt8(i);
        val += code_head.charCodeAt(offset) + ((i-2) % 5);
        val = val & 0xff;
        header.writeUInt8(val,i);
        offset = (offset+headerKeyAdd) & 0xff;
    }

    offset = bodyKeyStart;
    for(let i = 0; i < body.length; i++) {
        let val = body.readUInt8(i);
        val += code_body.charCodeAt(offset) + (i % 72);
        val = val & 0xff;
        body.writeUInt8(val,i);
        offset = (offset+bodyKeyAdd) & 0xff;
    }

    return Buffer.concat([header,body]);
}
function decrypt(data) {
    const header = data.slice(0,20);
    const body = data.slice(20);
    const headerKeyStart = header.readUInt8(0);
    const headerKeyAdd = header.readUInt8(1);

    let offset = headerKeyStart;
    for(let i = 2; i < header.length; i++) {
        let val = header.readUInt8(i);
        val -= code_head.charCodeAt(offset) + ((i-2) % 5);
        val = val & 0xff;
        header.writeUInt8(val,i);
        offset = (offset+headerKeyAdd) & 0xff;
    }

    const bodyKeyStart = header.readUInt8(16);
    const bodyKeyAdd = header.readUInt8(17);
    offset = bodyKeyStart;
    for(let i = 0; i < body.length; i++) {
        let val = body.readUInt8(i);
        val -= code_body.charCodeAt(offset) + (i % 72);
        val = val & 0xff;
        body.writeUInt8(val,i);
        offset = (offset+bodyKeyAdd) & 0xff;
    }

    // header format:
    // key, zero, cmd, echo, totallength, thislength
    // totalpacket, packetnum, body key, crc
    return {
        zero: header.readUInt16BE(2),
        cmd: header.readUInt16BE(4),
        packetTotal: header.readUInt16BE(12),
        packetNum: header.readUInt16BE(14),
        body: body
    };
}

const code_head =
    '\x80\xe5\x0e\x38\xba\x63\x4c\x99\x88\x63\x4c\xd6\x54\xb8\x65\x7e'+
    '\xbf\x8a\xf0\x17\x8a\xaa\x4d\x0f\xb7\x23\x27\xf6\xeb\x12\xf8\xea'+
    '\x17\xb7\xcf\x52\x57\xcb\x51\xcf\x1b\x14\xfd\x6f\x84\x38\xb5\x24'+
    '\x11\xcf\x7a\x75\x7a\xbb\x78\x74\xdc\xbc\x42\xf0\x17\x3f\x5e\xeb'+
    '\x74\x77\x04\x4e\x8c\xaf\x23\xdc\x65\xdf\xa5\x65\xdd\x7d\xf4\x3c'+
    '\x4c\x95\xbd\xeb\x65\x1c\xf4\x24\x5d\x82\x18\xfb\x50\x86\xb8\x53'+
    '\xe0\x4e\x36\x96\x1f\xb7\xcb\xaa\xaf\xea\xcb\x20\x27\x30\x2a\xae'+
    '\xb9\x07\x40\xdf\x12\x75\xc9\x09\x82\x9c\x30\x80\x5d\x8f\x0d\x09'+
    '\xa1\x64\xec\x91\xd8\x8a\x50\x1f\x40\x5d\xf7\x08\x2a\xf8\x60\x62'+
    '\xa0\x4a\x8b\xba\x4a\x6d\x00\x0a\x93\x32\x12\xe5\x07\x01\x65\xf5'+
    '\xff\xe0\xae\xa7\x81\xd1\xba\x25\x62\x61\xb2\x85\xad\x7e\x9d\x3f'+
    '\x49\x89\x26\xe5\xd5\xac\x9f\x0e\xd7\x6e\x47\x94\x16\x84\xc8\xff'+
    '\x44\xea\x04\x40\xe0\x33\x11\xa3\x5b\x1e\x82\xff\x7a\x69\xe9\x2f'+
    '\xfb\xea\x9a\xc6\x7b\xdb\xb1\xff\x97\x76\x56\xf3\x52\xc2\x3f\x0f'+
    '\xb6\xac\x77\xc4\xbf\x59\x5e\x80\x74\xbb\xf2\xde\x57\x62\x4c\x1a'+
    '\xff\x95\x6d\xc7\x04\xa2\x3b\xc4\x1b\x72\xc7\x6c\x82\x60\xd1\x0d';

const code_body =
    '\x82\x8b\x7f\x68\x90\xe0\x44\x09\x19\x3b\x8e\x5f\xc2\x82\x38\x23'+
    '\x6d\xdb\x62\x49\x52\x6e\x21\xdf\x51\x6c\x76\x37\x86\x50\x7d\x48'+
    '\x1f\x65\xe7\x52\x6a\x88\xaa\xc1\x32\x2f\xf7\x54\x4c\xaa\x6d\x7e'+
    '\x6d\xa9\x8c\x0d\x3f\xff\x6c\x09\xb3\xa5\xaf\xdf\x98\x02\xb4\xbe'+
    '\x6d\x69\x0d\x42\x73\xe4\x34\x50\x07\x30\x79\x41\x2f\x08\x3f\x42'+
    '\x73\xa7\x68\xfa\xee\x88\x0e\x6e\xa4\x70\x74\x22\x16\xae\x3c\x81'+
    '\x14\xa1\xda\x7f\xd3\x7c\x48\x7d\x3f\x46\xfb\x6d\x92\x25\x17\x36'+
    '\x26\xdb\xdf\x5a\x87\x91\x6f\xd6\xcd\xd4\xad\x4a\x29\xdd\x7d\x59'+
    '\xbd\x15\x34\x53\xb1\xd8\x50\x11\x83\x79\x66\x21\x9e\x87\x5b\x24'+
    '\x2f\x4f\xd7\x73\x34\xa2\xf7\x09\xd5\xd9\x42\x9d\xf8\x15\xdf\x0e'+
    '\x10\xcc\x05\x04\x35\x81\xb2\xd5\x7a\xd2\xa0\xa5\x7b\xb8\x75\xd2'+
    '\x35\x0b\x39\x8f\x1b\x44\x0e\xce\x66\x87\x1b\x64\xac\xe1\xca\x67'+
    '\xb4\xce\x33\xdb\x89\xfe\xd8\x8e\xcd\x58\x92\x41\x50\x40\xcb\x08'+
    '\xe1\x15\xee\xf4\x64\xfe\x1c\xee\x25\xe7\x21\xe6\x6c\xc6\xa6\x2e'+
    '\x52\x23\xa7\x20\xd2\xd7\x28\x07\x23\x14\x24\x3d\x45\xa5\xc7\x90'+
    '\xdb\x77\xdd\xea\x38\x59\x89\x32\xbc\x00\x3a\x6d\x61\x4e\xdb\x29';

const crc_table = [
    0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
    0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
    0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
    0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
    0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
    0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
    0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
    0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
    0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
    0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
    0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
    0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
    0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
    0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
    0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
    0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
    0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
    0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
    0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
    0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
    0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
    0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
    0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
    0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
    0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
    0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
    0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
    0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
    0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
    0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
    0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
    0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
];

module.exports = Ventrilo;
