var aes = require('./aes')
var Transform = require('cipher-base')
var inherits = require('inherits')
var modes = require('./modes')
var ebtk = require('evp_bytestokey')
var StreamCipher = require('./streamCipher')
var AuthCipher = require('./authCipher')
inherits(Cipher, Transform)
function Cipher (mode, key, iv) {
  if (!(this instanceof Cipher)) {
    return new Cipher(mode, key, iv)
  }
  Transform.call(this)
  this._cache = new Splitter()
  this._cipher = new aes.AES(key)
  this._prev = new Buffer(iv.length)
  iv.copy(this._prev)
  this._mode = mode
  this._autopadding = true
}
Cipher.prototype._update = function (data) {
  this._cache.add(data)
  var chunk
  var thing
  var out = []
  while ((chunk = this._cache.get())) {
    thing = this._mode.encrypt(this, chunk)
    out.push(thing)
  }
  return Buffer.concat(out)
}
Cipher.prototype._final = function () {
  var chunk = this._cache.flush()
  if (this._autopadding) {
    chunk = this._mode.encrypt(this, chunk)
    this._cipher.scrub()
    return chunk
  } else if (chunk.toString('hex') !== '10101010101010101010101010101010') {
    this._cipher.scrub()
    throw new Error('data not multiple of block length')
  }
}
Cipher.prototype.setAutoPadding = function (setTo) {
  this._autopadding = !!setTo
}

function Splitter () {
  if (!(this instanceof Splitter)) {
    return new Splitter()
  }
  this.cache = new Buffer('')
}
Splitter.prototype.add = function (data) {
  this.cache = Buffer.concat([this.cache, data])
}

Splitter.prototype.get = function () {
  if (this.cache.length > 15) {
    var out = this.cache.slice(0, 16)
    this.cache = this.cache.slice(16)
    return out
  }
  return null
}
Splitter.prototype.flush = function () {
  var len = 16 - this.cache.length
  var padBuff = new Buffer(len)

  var i = -1
  while (++i < len) {
    padBuff.writeUInt8(len, i)
  }
  var out = Buffer.concat([this.cache, padBuff])
  return out
}
var modelist = {
  ECB: require('./modes/ecb'),
  CBC: require('./modes/cbc'),
  CFB: require('./modes/cfb'),
  CFB8: require('./modes/cfb8'),
  CFB1: require('./modes/cfb1'),
  OFB: require('./modes/ofb'),
  CTR: require('./modes/ctr'),
  GCM: require('./modes/ctr')
}

function createCipheriv (suite, password, iv) {
  var config = modes[suite.toLowerCase()]
  if (!config) {
    throw new TypeError('invalid suite type')
  }
  if (typeof iv === 'string') {
    iv = new Buffer(iv)
  }
  if (typeof password === 'string') {
    password = new Buffer(password)
  }
  if (password.length !== config.key / 8) {
    throw new TypeError('invalid key length ' + password.length)
  }
  if (iv.length !== config.iv) {
    throw new TypeError('invalid iv length ' + iv.length)
  }
  if (config.type === 'stream') {
    return new StreamCipher(modelist[config.mode], password, iv)
  } else if (config.type === 'auth') {
    return new AuthCipher(modelist[config.mode], password, iv)
  }
  return new Cipher(modelist[config.mode], password, iv)
}
function createCipher (suite, password) {
  var config = modes[suite.toLowerCase()]
  if (!config) {
    throw new TypeError('invalid suite type')
  }
  var keys = ebtk(password, false, config.key, config.iv)
  return createCipheriv(suite, keys.key, keys.iv)
}

exports.createCipheriv = createCipheriv
exports.createCipher = createCipher
