'use strict';

var Packer = module.exports;

Packer.create = function (opts) {
  var machine;

  if (!opts.onMessage && !opts.onmessage) {
    machine = new (require('events').EventEmitter)();
  } else {
    machine = {};
  }

  machine.onmessage = opts.onmessage || opts.onMessage;
  machine.oncontrol = opts.oncontrol || opts.onControl;
  machine.onerror = opts.onerror || opts.onError;
  machine.onend = opts.onend || opts.onEnd;

  machine._version = 1;
  machine.fns = {};

  machine.chunkIndex = 0;
  machine.buf = null;
  machine.bufIndex = 0;
  machine.fns.collectData = function (chunk, size) {
    var chunkLeft = chunk.length - machine.chunkIndex;

    if (size <= 0) {
      return Buffer.alloc(0);
    }

    // First handle case where we don't have all the data we need yet. We need to save
    // what we have in a buffer, and increment the index for both the buffer and the chunk.
    if (machine.bufIndex + chunkLeft < size) {
      if (!machine.buf) {
        machine.buf = Buffer.alloc(size);
      }
      chunk.copy(machine.buf, machine.bufIndex, machine.chunkIndex);
      machine.bufIndex += chunkLeft;
      machine.chunkIndex += chunkLeft;

      return null;
    }

    // Read and mark as read however much data we need from the chunk to complete our buffer.
    var partLen = size - machine.bufIndex;
    var part = chunk.slice(machine.chunkIndex, machine.chunkIndex+partLen);
    machine.chunkIndex += partLen;

    // If we had nothing buffered than the part of the chunk we just read is all we need.
    if (!machine.buf) {
      return part;
    }

    // Otherwise we need to copy the new data into the buffer.
    part.copy(machine.buf, machine.bufIndex);
    // Before returning the buffer we need to clear our reference to it.
    var buf = machine.buf;
    machine.buf = null;
    machine.bufIndex = 0;
    return buf;
  };

  machine.fns.version = function (chunk) {
    //console.log('');
    //console.log('[version]');
    if ((255 - machine._version) !== chunk[machine.chunkIndex]) {
      console.error("not v" + machine._version + " (or data is corrupt)");
      // no idea how to fix this yet
    }
    machine.chunkIndex += 1;

    return true;
  };


  machine.headerLen = 0;
  machine.fns.headerLength = function (chunk) {
    //console.log('');
    //console.log('[headerLength]');
    machine.headerLen = chunk[machine.chunkIndex];
    machine.chunkIndex += 1;

    return true;
  };

  machine.fns.header = function (chunk) {
    //console.log('');
    //console.log('[header]');
    var header = machine.fns.collectData(chunk, machine.headerLen);

    // We don't have the entire header yet so return false.
    if (!header) {
      return false;
    }

    machine._headers = header.toString().split(/,/g);

    machine.family  = machine._headers[0];
    machine.address = machine._headers[1];
    machine.port    = machine._headers[2];
    machine.bodyLen = parseInt(machine._headers[3], 10) || 0;
    machine.service = machine._headers[4];
    //console.log('machine.service', machine.service);

    return true;
  };

  machine.fns.data = function (chunk) {
    //console.log('');
    //console.log('[data]');
    var data = machine.fns.collectData(chunk, machine.bodyLen);

    // We don't have the entire body yet so return false.
    if (!data) {
      return false;
    }

    //
    // data, end, error
    //
    var msg = {};
    if ('error' === machine.service) {
      try {
        msg = JSON.parse(data.toString());
      } catch(e) {
        msg.message = data.toString();
        msg.code = 'E_UNKNOWN_ERR';
      }
    }

    msg.family  = machine.family;
    msg.address = machine.address;
    msg.port    = machine.port;
    msg.service = machine.service;
    msg.data    = data;

    if ('end' === machine.service) {
      if (machine.emit) {
        machine.emit('tunnelEnd', msg);
      }
      else {
        (machine.onend||machine.onmessage)(msg);
      }
    }
    else if ('error' === machine.service) {
      if (machine.emit) {
        machine.emit('tunnelError', msg);
      }
      else {
        (machine.onerror||machine.onmessage)(msg);
      }
    }
    else if ('control' === machine.service) {
      if (machine.emit) {
        machine.emit('tunnelControl', msg);
      }
      else {
        (machine.oncontrol||machine.onmessage)(msg);
      }
    }
    else {
      if (machine.emit) {
        machine.emit('tunnelData', msg);
      }
      else {
        machine.onmessage(msg);
      }
    }

    return true;
  };

  machine.state = 0;
  machine.states = ['version', 'headerLength', 'header', 'data'];
  machine.fns.addChunk = function (chunk) {
    //console.log('');
    //console.log('[addChunk]');
    machine.chunkIndex = 0;
    while (machine.chunkIndex < chunk.length) {
      //console.log('chunkIndex:', machine.chunkIndex, 'state:', machine.state);

      if (true === machine.fns[machine.states[machine.state]](chunk)) {
        machine.state += 1;
        machine.state %= machine.states.length;
      }
    }
  };

  return machine;
};

Packer.pack = function (address, data, service) {
  data = data || Buffer.alloc(1);
  if (!Buffer.isBuffer(data)) {
    data = new Buffer(JSON.stringify(data));
  }
  if (!data.byteLength) {
    data = Buffer.alloc(1);
  }

  if ('error' === service) {
    address.service = 'error';
  }
  else if ('end' === service) {
    address.service = 'end';
  }

  var version = 1;
  var header;
  if (service === 'control') {
    header = Buffer.from(['', '', '', data.byteLength, service].join(','));
  }
  else {
    header = Buffer.from([
      address.family, address.address, address.port, data.byteLength, (address.service || '')
    ].join(','));
  }
  var meta = Buffer.from([ 255 - version, header.length ]);
  var buf = Buffer.alloc(meta.byteLength + header.byteLength + data.byteLength);

  meta.copy(buf, 0);
  header.copy(buf, 2);
  data.copy(buf, 2 + header.byteLength);

  return buf;
};

Packer.socketToAddr = function (socket) {
  // TODO BUG XXX
  // https://github.com/nodejs/node/issues/8854
  // tlsSocket.remoteAddress = remoteAddress; // causes core dump
  // console.log(tlsSocket.remoteAddress);

  function extractValue(name) {
    return socket[name]
      || socket['_'+name]
      || socket._handle._parentWrap[name]
      || socket._handle._parentWrap._handle.owner.stream[name]
      ;
  }

  return {
    family:  extractValue('remoteFamily')
  , address: extractValue('remoteAddress')
  , port:    extractValue('remotePort')
  };
};

Packer.addrToId = function (address) {
  return address.family + ',' + address.address + ',' + address.port;
};

Packer.socketToId = function (socket) {
  return Packer.addrToId(Packer.socketToAddr(socket));
};


/*
 *
 * Tunnel Packer
 *
 */

var Transform = require('stream').Transform;
var util = require('util');

function MyTransform(options) {
  if (!(this instanceof MyTransform)) {
    return new MyTransform(options);
  }
  this.__my_addr = options.address;
  this.__my_service = options.service;
  Transform.call(this, options);
}
util.inherits(MyTransform, Transform);
function transform(me, data, encoding, callback) {
  var address = me.__my_addr;

  address.service = address.service || me.__my_service;
  me.push(Packer.pack(address, data));
  callback();
}
MyTransform.prototype._transform = function (data, encoding, callback) {
  return transform(this, data, encoding, callback);
};

Packer.Stream = {};
var Dup = {
  write: function (chunk, encoding, cb) {
    //console.log('_write', chunk.byteLength);
    this.__my_socket.write(chunk, encoding);
    cb();
  }
, read: function (size) {
    //console.log('_read');
    var x = this.__my_socket.read(size);
    if (x) {
      console.log('_read', size);
      this.push(x);
    }
  }
};
Packer.Stream.create = function (socket) {
  // Workaround for
  // https://github.com/nodejs/node/issues/8854

  // https://www.google.com/#q=get+socket+address+from+file+descriptor
  // TODO try creating a new net.Socket({ handle: socket._handle, fd: socket._handle.fd })
  // from the old one and then adding back the data with
  // sock.push(firstChunk)
  var Duplex = require('stream').Duplex;
  var myDuplex = new Duplex();

  myDuplex.__my_socket = socket;
  myDuplex._write = Dup.write;
  myDuplex._read = Dup.read;
  //console.log('plainSocket.*Address');
  //console.log('remote:', socket.remoteAddress);
  //console.log('local:', socket.localAddress);
  //console.log('address():', socket.address());
  myDuplex.remoteFamily = socket.remoteFamily;
  myDuplex.remoteAddress = socket.remoteAddress;
  myDuplex.remotePort = socket.remotePort;
  myDuplex.localFamily = socket.localFamily;
  myDuplex.localAddress = socket.localAddress;
  myDuplex.localPort = socket.localPort;

  return myDuplex;
};

Packer.Transform = {};
Packer.Transform.create = function (opts) {
  // Note: service refers to the port that the incoming request was from,
  // if known (smtps, smtp, https, http, etc)
  // { address: '127.0.0.1', service: 'https' }
  return new MyTransform(opts);
};