#!/usr/bin/env node
'use strict';

var dnsjs = require('dns-suite');
var cli = require('cli');
var hexdump = require('../hexdump');
var crypto = require('crypto');
cli.parse({
//  'b': [ false, 'set source IP address (defaults to 0.0.0.0)', 'string' ]
  'debug': [ false, 'more verbose output', 'boolean', false ]
//, 'insecure': [ false, 'turn off RaNDOm cAPS required for securing queries']
//, 'ipv4': [ '4', 'use ipv4 exclusively (defaults to false)', 'boolean', false ]
//, 'ipv6': [ '6', 'use ipv6 exclusively (defaults to false)', 'boolean', false ]
//, 'json': [ false, 'output results as json', 'string' ]
//, 'lint': [ false, 'attack (in the metaphorical sense) a nameserver with all sorts of queries to test for correct responses', 'string', false ]
, 'mdns': [ false, "Alias for setting defaults to -p 5353 @224.0.0.251 -t PTR -q _services._dns-sd._udp.local and waiting for multiple responses", 'boolean', false ]
, 'output': [ 'o', 'output prefix to use for writing query and response(s) to disk', 'file' ]
, 'port': [ 'p', 'port (defaults to 53 for dns and 5353 for mdns)', 'int' ]
//, 'serve': [ 's', 'path to json file with array of responses to issue for given queries', 'string' ]
, 'type': [ 't', 'type (defaults to ANY for dns and PTR for mdns)', 'string' ]
, 'query': [ 'q', 'a superfluous explicit option to set the query as a command line flag' ]
});

var fs = require('fs');
var dgram = require('dgram');
var commonTypes = [ 'A', 'AAAA', 'CNAME', 'MX', 'NS', 'PTR', 'SOA', 'SRV', 'TXT' ];
var commonPrinters = {
  'ANY': function (q) {
    console.log(';' + q.name + '.', q.ttl, q.className, q.typeName, q.data || q.rdata || 'unknown record type');
  }

, 'A': function (q) {
    console.log(';' + q.name + '.', q.ttl, q.className, q.typeName, q.address);
  }
, 'AAAA': function (q) {
    console.log(';' + q.name + '.', q.ttl, q.className, q.typeName, q.address);
  }
, 'CNAME': function (q) {
    console.log(';' + q.name + '.', q.ttl, q.className, q.typeName, q.data + '.');
  }
, 'MX': function (q) {
    console.log(';' + q.name + '.', q.ttl, q.className, q.typeName, q.priority + ' ' + q.exchange + '.');
  }
, 'NS': function (q) {
    console.log(';' + q.name + '.', q.ttl, q.className, q.typeName, q.data);
  }
, 'PTR': function (q) {
    console.log(';' + q.name + '.', q.ttl, q.className, q.typeName, q.data);
  }
/*
, 'SOA': function (q) {
    console.log(';' + q.name + '.', q.ttl, q.className, q.typeName, q.data);
  }
*/
, 'SRV': function (q) {
    console.log(';' + q.name + '.', q.ttl, q.className, q.typeName, q.priority + ' ' + q.weight + ' ' + q.port + ' ' + q.target);
  }
, 'TXT': function (q) {
    console.log(';' + q.name + '.', q.ttl, q.className, q.typeName, '"' + q.data.join('" "') + '"');
  }
};

function writeQuery(opts, query, queryAb) {
  var path = require('path');
  var binname = query.question[0].name + '.' + query.question[0].typeName.toLowerCase() + '.query.bin';
  var jsonname = query.question[0].name + '.' + query.question[0].typeName.toLowerCase() + '.query.json';
  var binpath = opts.output + '.' + binname;
  var jsonpath = opts.output + '.' + jsonname;
  var json = JSON.stringify(query, null, 2);
  if (-1 !== ['.', '/', '\\' ].indexOf(opts.output[opts.output.length -1])) {
    binpath = path.join(opts.output, binname);
    jsonpath = path.join(opts.output, jsonname);
  }

  fs.writeFile(binpath, Buffer.from(queryAb), null, function () {
    console.log('wrote ' + queryAb.byteLength + ' bytes to ' + binpath);
  });
  fs.writeFile(jsonpath, json, null, function () {
    console.log('wrote ' + json.length + ' bytes to ' + jsonpath);
  });
}

var count = 0;
function writeResponse(opts, query, nb, packet) {
  var path = require('path');
  var binname = query.question[0].name + '.' + query.question[0].typeName.toLowerCase() + '.' + count + '.bin';
  var jsonname = query.question[0].name + '.' + query.question[0].typeName.toLowerCase() + '.' + count + '.json';
  var binpath = opts.output + '.' + binname;
  var jsonpath = opts.output + '.' + jsonname;
  var json = JSON.stringify(packet, null, 2);
  if (-1 !== ['.', '/', '\\' ].indexOf(opts.output[opts.output.length -1])) {
    binpath = path.join(opts.output, binname);
    jsonpath = path.join(opts.output, jsonname);
  }

  count += 1;

  fs.writeFile(binpath, nb, null, function () {
    console.log('wrote ' + nb.byteLength + ' bytes to ' + binpath);
  });
  fs.writeFile(jsonpath, json, null, function () {
    console.log('wrote ' + json.length + ' bytes to ' + jsonpath);
  });
}

function request(query, opts) {
  var queryAb = dnsjs.DNSPacket.write(query);

  if (opts.debug) {
    console.log('');
    console.log('DNS Question:');
    console.log('');
    console.log(query);
    console.log('');
    console.log(hexdump(queryAb));
    console.log('');
    console.log(dnsjs.DNSPacket.parse(queryAb));
    console.log('');
  }

  var handlers = {};
  var server = dgram.createSocket({
    type: 'udp4'
  , reuseAddr: true
  });

  handlers.onError = function (err) {
    console.error("error:", err.stack);
    server.close();
  };
  handlers.onMessage = function (nb) {
    console.log("YOYOYO GOT MESSAGE");
    var packet = dnsjs.DNSPacket.parse(nb.buffer.slice(nb.byteOffset, nb.byteOffset + nb.byteLength));

    if (opts.debug) {
      console.log('');
      console.log('DNS Request:');
      console.log(packet);
    }

    console.log('');
    console.log('; <<>> dig.js ' + 'v0.0.0' + ' <<>> ' + query.question[0].name);
    console.log(';; Got answer:');
    console.log(';; ->>HEADER<<-');
    console.log(JSON.stringify(packet.header));
    console.log('');
    console.log(';; QUESTION SECTION:');
    packet.question.forEach(function (q) {
      console.log(';' + q.name + '.', ' ', q.className, q.typeName);
    });
    /*
    function print(q) {
      var printer = commonPrinters[q.typeName] || commonPrinters.ANY;
      printer(q);
    }
    if (packet.answer.length) {
      console.log('');
      console.log(';; ANSWER SECTION:');
      packet.answer.forEach(print);
    }
    if (packet.authority.length) {
      console.log('');
      console.log(';; AUTHORITY SECTION:');
      packet.authority.forEach(print);
    }
    if (packet.additional.length) {
      console.log('');
      console.log(';; ADDITIONAL SECTION:');
      packet.additional.forEach(print);
    }
    console.log('');
    console.log(';; MSG SIZE  rcvd: ' + nb.byteLength);
    console.log('');
    */

    if (opts.output) {
      console.log('');
      writeQuery(opts, query, queryAb);
      //writeResponse(opts, query, nb, packet);
    }
  };
  handlers.onListening = function () {
    console.log("YOYOYO ON LISTENING");
    /*jshint validthis:true*/
    var server = this;
    var nameserver = opts.nameserver;
    var nameservers;
    var index;

    if (!nameserver) {
      nameservers = require('dns').getServers();
      index = crypto.randomBytes(2).readUInt16BE(0) % nameservers.length;
      nameserver = nameservers[index];
      if (opts.debug) {
        console.log(index, nameservers);
      }
    }

    if (opts.mdns || '224.0.0.251' === opts.nameserver) {
      server.setBroadcast(true);
      server.addMembership(opts.nameserver);
    }

    if (opts.debug) {
      console.log('');
      console.log('Bound and Listening:');
      console.log(server.address());
    }

    if (opts.debug) {
      console.log('querying ' + nameserver + ':' + opts.port);
    }
  };


  server.on('error', handlers.onError);
  server.on('message', handlers.onMessage);
  server.on('listening', handlers.onListening);

  // 53 dns server
  // 5353 mdns
  console.log("YOYOYO BINDING ON", opts.port);
  server.bind(opts.port);
}

cli.main(function (args, cli) {
  args.forEach(function (arg) {
    if (-1 !== commonTypes.indexOf(arg.toUpperCase())) {
      if (cli.type) {
        console.error("'type' was specified more than once");
        process.exit(1);
        return;
      }
      cli.type = cli.t = arg.toUpperCase();
      return;
    }

    if (/^\+time=/.test(arg)) {
      if (cli.timeout) {
        console.error("'+time=' was specified more than once");
        process.exit(1);
        return;
      }
      cli.timeout = Math.round(parseInt(arg.replace(/\+time=/, ''), 10) * 1000);
      return;
    }

    if (/^@/.test(arg)) {
      if (cli.nameserver) {
        console.error("'@server' was specified more than once");
        process.exit(1);
        return;
      }
      cli.nameserver = cli.n = arg.substr(1);
      return;
    }

    if (cli.query) {
      console.error("'query' was specified more than once");
      process.exit(1);
      return;
    }
    cli.query = cli.q = arg;

  });

  if (cli.mdns) {
    if (!cli.type) {
      cli.type = cli.t = 'PTR';
    }
    if (!cli.port) {
      cli.port = cli.p = 5353;
    }
    if (!cli.nameserver) {
      cli.nameserver = '224.0.0.251';
    }
    if (!cli.query) {
      cli.query = '_services._dns-sd._udp.local';
    }
    if (!cli.timeout) {
      cli.timeout = 3000;
    }
  }

  if (!cli.type) {
    cli.type = cli.t = 'A';
  }
  if (!cli.port) {
    cli.port = cli.p = 53;
  }
  if (!cli.class) {
    cli.class = cli.c = 'IN';
  }
  if (!cli.query) {
    cli.query = 'example.com';
    /*
    console.error('');
    console.error('Usage:');
    console.error('digd.js [@server] [TYPE] [domain]');
    console.error('');
    console.error('Example:');
    console.error('digd.js daplie.com');
    console.error('');
    process.exit(1);
    */
  }

  var query = {
    header: {
      id: crypto.randomBytes(2).readUInt16BE(0)
    , qr: 0
    , opcode: 0
    , aa: 0     // NA
    , tc: 0     // NA
    , rd: 1
    , ra: 0     // NA
    , rcode: 0  // NA
    }
  , question: [
      { name: cli.query
      , typeName: cli.type
      , className: cli.class
      }
    ]
  };

  if (!cli.daemon) {
    request(query, cli);
    return;
  }
});