var BufferCursor = require('buffercursor');
var BufferBuilder = require('./bufferbuilder');

BinaryPack = {
  unpack: function(data){
    var unpacker = new BinaryPack.Unpacker(data);
    return unpacker.unpack();
  },
  pack: function(data){
    var packer = new BinaryPack.Packer();
    var buffer = packer.pack(data);
    return buffer;
  }
};

BinaryPack.Unpacker = function(buffer){
  this.cursor = new BufferCursor(buffer);
  this.length = buffer.length;
}

BinaryPack.Unpacker.prototype.unpack = function(){
  var type = this.cursor.readUInt8();
  if (type < 0x80){
    var positive_fixnum = type;
    return positive_fixnum;
  } else if ((type ^ 0xe0) < 0x20){
    var negative_fixnum = (type ^ 0xe0) - 0x20;
    return negative_fixnum;
  }
  var size;
  if ((size = type ^ 0xa0) <= 0x0f){
    return this.readraw(size);
  } else if ((size = type ^ 0xb0) <= 0x0f){
    return this.readstring(size);
  } else if ((size = type ^ 0x90) <= 0x0f){
    return this.readarray(size);
  } else if ((size = type ^ 0x80) <= 0x0f){
    return this.readmap(size);
  }
  switch(type){
    case 0xc0:
      return null;
    case 0xc1:
      return undefined;
    case 0xc2:
      return false;
    case 0xc3:
      return true;
    case 0xca:
      return this.cursor.readFloatBE();
    case 0xcb:
      return this.cursor.readDoubleBE();
    case 0xcc:
      return this.cursor.readUInt8();
    case 0xcd:
      return this.cursor.readUInt16BE();
    case 0xce:
      return this.cursor.readUInt32BE();
    case 0xcf:
      return this.readUInt64();
    case 0xd0:
      return this.cursor.readInt8();
    case 0xd1:
      return this.cursor.readInt16BE();
    case 0xd2:
      return this.cursor.readInt32BE();
    case 0xd3:
      return this.readInt64();
    case 0xd4:
      return undefined;
    case 0xd5:
      return undefined;
    case 0xd6:
      return undefined;
    case 0xd7:
      return undefined;
    case 0xd8:
      size = this.cursor.readUInt16BE();
      return this.readstring(size);
    case 0xd9:
      size = this.cursor.readUInt32BE();
      return this.readstring(size);
    case 0xda:
      size = this.cursor.readUInt16BE();
      return this.readraw(size);
    case 0xdb:
      size = this.cursor.readUInt32BE();
      return this.readraw(size);
    case 0xdc:
      size = this.cursor.readUInt16BE();
      return this.readarray(size);
    case 0xdd:
      size = this.cursor.readUInt32BE();
      return this.readarray(size);
    case 0xde:
      size = this.cursor.readUInt16BE();
      return this.readmap(size);
    case 0xdf:
      size = this.cursor.readUInt32BE();
      return this.readmap(size);
  }
}
BinaryPack.Unpacker.prototype.readUInt64 = function(){
  var bytes = this.cursor.slice(8);
  return ((((((bytes[0]  * 256 +
               bytes[1]) * 256 +
               bytes[2]) * 256 +
               bytes[3]) * 256 +
               bytes[4]) * 256 +
               bytes[5]) * 256 +
               bytes[6]) * 256 +
               bytes[7];
}

BinaryPack.Unpacker.prototype.readInt64 = function(){
  var uint64 = this.readInt64();
  return (uint64 < Math.pow(2, 63) ) ? uint64 : uint64 - Math.pow(2, 64);
}

BinaryPack.Unpacker.prototype.readraw = function(size){
  return this.cursor.slice(size).buffer;
}

BinaryPack.Unpacker.prototype.readstring = function(size){
  return this.cursor.toString('utf8', size);
}

BinaryPack.Unpacker.prototype.readarray = function(size){
  var objects = new Array(size);
  for(var i = 0; i < size ; i++){
    objects[i] = this.unpack();
  }
  return objects;
}

BinaryPack.Unpacker.prototype.readmap = function(size){
  var map = {};
  for(var i = 0; i < size ; i++){
    var key  = this.unpack();
    var value = this.unpack();
    map[key] = value;
  }
  return map;
}




BinaryPack.Packer = function(){
  this.bufferBuilder = new BufferBuilder();
}

BinaryPack.Packer.prototype.pack = function(value){
  var type = typeof(value);
  if (type == 'string'){
    this.pack_string(value);
  } else if (type == 'number'){
    if (Math.floor(value) === value){
      this.pack_integer(value);
    } else{
      this.pack_double(value);
    }
  } else if (type == 'boolean'){
    if (value === true){
      this.bufferBuilder.append(0xc3, 2);
    } else if (value === false){
      this.bufferBuilder.append(0xc2, 2);
    }
  } else if (type == 'undefined'){
    this.bufferBuilder.append(0xc0, 2);
  } else if (type == 'object'){
    if (value === null){
      this.bufferBuilder.append(0xc0, 2);
    } else {
      var constructor = value.constructor;
      if (constructor == Array){
        this.pack_array(value);
      } else if (Buffer.isBuffer(value)) {
        this.pack_bin(value);
      } else if (constructor == Object){
        this.pack_object(value);
      } else if (constructor == Date){
        this.pack_string(value.toString());
      } else if (typeof value.toBinaryPack == 'function'){
        this.bufferBuilder.append(value.toBinaryPack(), 1);
      } else {
        throw new Error('Type "' + constructor.toString() + '" not yet supported');
      }
    }
  } else {
    throw new Error('Type "' + type + '" not yet supported');
  }
  return this.bufferBuilder.getBuffer();
}


BinaryPack.Packer.prototype.pack_bin = function(blob){
  var length = blob.length || blob.byteLength || blob.size;
  if (length <= 0x0f){
    this.bufferBuilder.append(0xa0 + length, 2);
  } else if (length <= 0xffff){
    this.bufferBuilder.append(0xda, 2) ;
    this.bufferBuilder.append(length, 3);
  } else if (length <= 0xffffffff){
    this.bufferBuilder.append(0xdb, 2);
    this.bufferBuilder.append(length, 4);
  } else{
    throw new Error('Invalid length');
    return;
  }
  this.bufferBuilder.append(blob, 1);
}

BinaryPack.Packer.prototype.pack_string = function(str){
  var length = Buffer.byteLength(str);
  if (length <= 0x0f){
    this.bufferBuilder.append(0xb0 + length, 2);
  } else if (length <= 0xffff){
    this.bufferBuilder.append(0xd8, 2) ;
    this.bufferBuilder.append(length, 3);
  } else if (length <= 0xffffffff){
    this.bufferBuilder.append(0xd9, 2);
    this.bufferBuilder.append(length, 4);
  } else{
    throw new Error('Invalid length');
    return;
  }
  this.bufferBuilder.append(str, 0);
}

BinaryPack.Packer.prototype.pack_array = function(ary){
  var length = ary.length;
  if (length <= 0x0f){
    this.bufferBuilder.append(0x90 + length, 2);
  } else if (length <= 0xffff){
    this.bufferBuilder.append(0xdc, 2)
    this.bufferBuilder.append(length, 3);
  } else if (length <= 0xffffffff){
    this.bufferBuilder.append(0xdd, 2);
    this.bufferBuilder.append(length, 4);
  } else{
    throw new Error('Invalid length');
  }
  for(var i = 0; i < length ; i++){
    this.pack(ary[i]);
  }
}

BinaryPack.Packer.prototype.pack_integer = function(num){
  if ( -0x20 <= num && num <= 0x7f){
    this.bufferBuilder.append(num & 0xff, 2);
  } else if (0x00 <= num && num <= 0xff){
    this.bufferBuilder.append(0xcc, 2);
    this.bufferBuilder.append(num, 2);
  } else if (-0x80 <= num && num <= 0x7f){
    this.bufferBuilder.append(0xd0, 2);
    this.bufferBuilder.append(num, 5);
  } else if ( 0x0000 <= num && num <= 0xffff){
    this.bufferBuilder.append(0xcd, 2);
    this.bufferBuilder.append(num, 3);
  } else if (-0x8000 <= num && num <= 0x7fff){
    this.bufferBuilder.append(0xd1, 2);
    this.bufferBuilder.append(num, 6);
  } else if ( 0x00000000 <= num && num <= 0xffffffff){
    this.bufferBuilder.append(0xce, 2);
    this.bufferBuilder.append(num, 4);
  } else if (-0x80000000 <= num && num <= 0x7fffffff){
    this.bufferBuilder.append(0xd2, 2);
    this.bufferBuilder.append(num, 7);
  } else if (-0x8000000000000000 <= num && num <= 0x7FFFFFFFFFFFFFFF){
    this.bufferBuilder.append(0xd3, 2);
    this.pack_int64(num);
  } else if (0x0000000000000000 <= num && num <= 0xFFFFFFFFFFFFFFFF){
    this.bufferBuilder.append(0xcf);
    this.pack_uint64(num);
  } else{
    throw new Error('Invalid integer');
  }
}

BinaryPack.Packer.prototype.pack_double = function(num){
  this.bufferBuilder.append(0xcb, 2);
  this.bufferBuilder.append(num, 9);
}

BinaryPack.Packer.prototype.pack_object = function(obj){
  var keys = Object.keys(obj);
  var length = keys.length;
  if (length <= 0x0f){
    this.bufferBuilder.append(0x80 + length, 2);
  } else if (length <= 0xffff){
    this.bufferBuilder.append(0xde, 2);
    this.bufferBuilder.append(length, 3);
  } else if (length <= 0xffffffff){
    this.bufferBuilder.append(0xdf, 2);
    this.bufferBuilder.append(length, 4);
  } else{
    throw new Error('Invalid length');
  }
  for(var prop in obj){
    if (obj.hasOwnProperty(prop)){
      this.pack(prop);
      this.pack(obj[prop]);
    }
  }
}

BinaryPack.Packer.prototype.pack_int64 = function(num){
  var high = Math.floor(num / Math.pow(2, 32));
  var low  = num % Math.pow(2, 32);
  this.bufferBuilder.append((high & 0xff000000) >>> 24, 2);
  this.bufferBuilder.append((high & 0x00ff0000) >>> 16, 2);
  this.bufferBuilder.append((high & 0x0000ff00) >>>  8, 2);
  this.bufferBuilder.append((high & 0x000000ff), 2);
  this.bufferBuilder.append((low  & 0xff000000) >>> 24, 2);
  this.bufferBuilder.append((low  & 0x00ff0000) >>> 16, 2);
  this.bufferBuilder.append((low  & 0x0000ff00) >>>  8, 2);
  this.bufferBuilder.append((low  & 0x000000ff), 2);
}

BinaryPack.Packer.prototype.pack_uint64 = function(num){
  var high = num / Math.pow(2, 32);
  var low  = num % Math.pow(2, 32);
  this.bufferBuilder.append((high & 0xff000000) >>> 24, 2);
  this.bufferBuilder.append((high & 0x00ff0000) >>> 16, 2);
  this.bufferBuilder.append((high & 0x0000ff00) >>>  8, 2);
  this.bufferBuilder.append((high & 0x000000ff), 2);
  this.bufferBuilder.append((low  & 0xff000000) >>> 24, 2);
  this.bufferBuilder.append((low  & 0x00ff0000) >>> 16, 2);
  this.bufferBuilder.append((low  & 0x0000ff00) >>>  8, 2);
  this.bufferBuilder.append((low  & 0x000000ff), 2);
}

module.exports = BinaryPack;