prelogin-payload.coffee

sprintf = require('sprintf').sprintf
WritableTrackingBuffer = require('./tracking-buffer/tracking-buffer').WritableTrackingBuffer

optionBufferSize = 20

VERSION = 0x000000001
SUBBUILD = 0x0001

TOKEN =
  VERSION: 0x00,
  ENCRYPTION: 0x01,
  INSTOPT: 0x02,
  THREADID: 0x03,
  MARS: 0x04,
  TERMINATOR: 0xFF

ENCRYPT =
  OFF: 0x00,
  ON: 0x01,
  NOT_SUP: 0x02,
  REQ: 0x03

encryptByValue = {}
for name, value of ENCRYPT
  encryptByValue[value] = name

MARS =
  OFF: 0x00,
  ON: 0x01

marsByValue = {}
for name, value of MARS
  marsByValue[value] = name

###
  s2.2.6.4
###
class PreloginPayload
  constructor: (bufferOrOptions) ->
    if bufferOrOptions instanceof Buffer
      @data = bufferOrOptions
    else
      @options = bufferOrOptions || {}
      @createOptions()

    @extractOptions()

  createOptions: ->
    options = [
      @createVersionOption(),
      @createEncryptionOption(),
      @createInstanceOption(),
      @createThreadIdOption(),
      @createMarsOption()
    ]

    length = 0
    for option in options
      length += 5 + option.data.length
    length++ # terminator

    @data = new Buffer(length)
    optionOffset = 0
    optionDataOffset = 5 * options.length + 1
    for option in options
      @data.writeUInt8(option.token, optionOffset + 0)
      @data.writeUInt16BE(optionDataOffset, optionOffset + 1)
      @data.writeUInt16BE(option.data.length, optionOffset + 3)
      optionOffset += 5

      option.data.copy(@data, optionDataOffset)
      optionDataOffset += option.data.length

    @data.writeUInt8(TOKEN.TERMINATOR, optionOffset)

  createVersionOption: () ->
    buffer = new WritableTrackingBuffer(optionBufferSize)
    buffer.writeUInt32BE(VERSION)
    buffer.writeUInt16BE(SUBBUILD)

    token: TOKEN.VERSION
    data: buffer.data

  createEncryptionOption: () ->
    buffer = new WritableTrackingBuffer(optionBufferSize)
    if @options.encrypt
      buffer.writeUInt8(ENCRYPT.ON)
    else
      buffer.writeUInt8(ENCRYPT.NOT_SUP)

    token: TOKEN.ENCRYPTION
    data: buffer.data

  createInstanceOption: () ->
    buffer = new WritableTrackingBuffer(optionBufferSize)
    buffer.writeUInt8(0x00)

    token: TOKEN.INSTOPT
    data: buffer.data

  createThreadIdOption: () ->
    buffer = new WritableTrackingBuffer(optionBufferSize)
    buffer.writeUInt32BE(0x00)

    token: TOKEN.THREADID
    data: buffer.data

  createMarsOption: () ->
    buffer = new WritableTrackingBuffer(optionBufferSize)
    buffer.writeUInt8(MARS.OFF)

    token: TOKEN.MARS
    data: buffer.data

  extractOptions: ->
    offset = 0;
    while @data[offset] != TOKEN.TERMINATOR
      dataOffset = @data.readUInt16BE(offset + 1)
      dataLength = @data.readUInt16BE(offset + 3)

      switch @data[offset]
        when TOKEN.VERSION
          @extractVersion(dataOffset)
        when TOKEN.ENCRYPTION
          @extractEncryption(dataOffset)
        when TOKEN.INSTOPT
          @extractInstance(dataOffset)
        when TOKEN.THREADID
          if (dataLength > 0)
            @extractThreadId(dataOffset)
        when TOKEN.MARS
          @extractMars(dataOffset)

      offset += 5
      dataOffset += dataLength

  extractVersion: (offset) ->
    @version =
      major: @data.readUInt8(offset + 0),
      minor: @data.readUInt8(offset + 1),
      patch: @data.readUInt8(offset + 2),
      trivial: @data.readUInt8(offset + 3),
      subbuild: @data.readUInt16BE(offset + 4)

  extractEncryption: (offset) ->
    @encryption = @data.readUInt8(offset)
    @encryptionString = encryptByValue[@encryption]

  extractInstance: (offset) ->
    @instance = @data.readUInt8(offset)

  extractThreadId: (offset) ->
    @threadId = @data.readUInt32BE(offset)

  extractMars: (offset) ->
    @mars = @data.readUInt8(offset)
    @marsString = marsByValue[@mars]

  toString: (indent) ->
    indent ||= ''

    indent + 'PreLogin - ' +
      sprintf('version:%d.%d.%d.%d %d, encryption:0x%02X(%s), instopt:0x%02X, threadId:0x%08X, mars:0x%02X(%s)',
          @version.major,
          @version.minor,
          @version.patch,
          @version.trivial,
          @version.subbuild,
          if @encryption then @encryption else 0,
          if @encryptionString then @encryptionString else 0,
          if @instance then @instance else 0,
          if @threadId then @threadId else 0,
          if @mars then @mars else 0,
          if @marsString then @marsString else 0
      )

module.exports = PreloginPayload