'use strict';

var cli = require('cli');
var dns = require('dns');
var dgram = require('dgram');
var dnsjs = require('dns-suite');
var hexdump = require('../hexdump');
var crypto = require('crypto');
var common = require('../common');
var defaultNameservers = require('dns').getServers();

cli.parse({
//  'b': [ false, 'set source IP address (defaults to 0.0.0.0)', 'string' ]
  'class': [ 'c', 'class (defaults to IN)', 'string', 'IN' ]
, '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 ]
, 'timeout': [ false, "How long, in milliseconds, to wait for a response. Alias of +time=", 'int', false ]
, 'output': [ 'o', 'output prefix to use for writing query and response(s) to disk', 'file' ]
, 'address': [ false, 'ip address(es) to listen on (defaults to 0.0.0.0,::0)', 'string' ]
, 'port': [ 'p', 'port (defaults to 53 for dns and 5353 for mdns)', 'int' ]
, 'nameserver': [ false, 'the nameserver(s) to use for recursive lookups (defaults to ' + defaultNameservers.join(',') + ')', 'string' ]
//, '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' ]
});

cli.main(function (args, cli) {
  args.forEach(function (arg) {
    if (arg === '+norecurse') {
      if (cli.norecurse) {
        console.error("'+norecurse' was specified more than once");
        process.exit(1);
        return;
      }
      cli.norecurse = true;
      return;
    }
  });

  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 (!('timeout' in cli)) {
      cli.timeout = 3000;
    }
  } else {
    if (!cli.port) {
      cli.port = cli.p = 53;
    }
  }

  var handlers = {};
  var server = dgram.createSocket({
    type: cli.udp6 ? 'udp6' : 'udp4'
  //, reuseAddr: true
  });
  server.bind({
    port: cli.port
  , address: cli.address
  });

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

    if (cli.debug) {
      console.log('');
      console.log('DNS Question:');
      console.log('');
      console.log(query);
      console.log('');
      console.log(hexdump(queryAb));
      console.log('');
    }

    console.log(';; Got question:');
    console.log(';; ->>HEADER<<-');
    console.log(JSON.stringify(query.header));
    console.log('');
    console.log(';; QUESTION SECTION:');
    query.question.forEach(function (q) {
      console.log(';' + q.name + '.', ' ', q.className, q.typeName);
    });

    function print(q) {
      var printer = common.printers[q.typeName] || common.printers.ANY;
      printer(q);
    }
    if (query.answer.length) {
      console.error('[ERROR] Query contains an answer section:');
      console.log(';; ANSWER SECTION:');
      query.answer.forEach(print);
    }
    if (query.authority.length) {
      console.log('');
      console.error('[ERROR] Query contains an authority section:');
      console.log(';; AUTHORITY SECTION:');
      query.authority.forEach(print);
    }
    if (query.additional.length) {
      console.log('');
      console.error('[ERROR] Query contains an additional section:');
      console.log(';; ADDITIONAL SECTION:');
      query.additional.forEach(print);
    }
    console.log('');
    console.log(';; MSG SIZE  rcvd: ' + nb.byteLength);
    console.log('');

    if (cli.output) {
      console.log('');
      common.writeQuery(cli, query, queryAb);
      //common.writeResponse(opts, query, nb, packet);
    }

    if (!cli.norecurse) {
      // ANY, A, AAAA, CNAME, MX, NAPTR, NS, PTR, SOA, SRV, TXT
      var count = query.question.length;
      query.question.forEach(function (q) {
        dns.resolve(q.name, q.typeName, function () {
          count -= 1;
          if (!count) {
          }
        });
        console.log(';' + q.name + '.', ' ', q.className, q.typeName);
      });
    }
  };
  handlers.onListening = function () {
    /*jshint validthis:true*/
    var server = this;
    var nameserver = cli.nameserver;
    var index;

    if (!nameserver) {
      index = crypto.randomBytes(2).readUInt16BE(0) % defaultNameservers.length;
      nameserver = defaultNameservers[index];
      if (cli.debug) {
        console.log(index, defaultNameservers);
      }
    }

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

    console.log('');
    console.log('Bound and Listening:');
    console.log(server.address().address + '#' + server.address().port);
  };

  console.log('');
  if (!cli.nocmd) {
    console.log('; <<>> dig.js ' + 'v0.0.0' + ' <<>> ' + process.argv.slice(2));
    console.log(';; global options: +cmd');
  }

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