--[[

Copyright 2014 The Luvit Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS-IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

--]]
local utils = require('utils')
local Readable = require('./stream_readable').Readable
local Writable = require('./stream_writable').Writable

local Duplex = Readable:extend()

local onend

for k,v in pairs(Writable) do
  if not Duplex[k] and k ~= 'meta' then
    Duplex[k] = v
  end
end

function Duplex:initialize(options)
  --[[
  if (!(this instanceof Duplex))
    return new Duplex(options);
  --]]

  Readable.initialize(self, options)
  Writable.initialize(self, options)

  if options and options.readable == false then
    self.readable = false
  end

  if options and options.writable == false then
    self.writable = false
  end

  self.allowHalfOpen = true
  if options and options.allowHalfOpen == false then
    self.allowHalfOpen = false
  end

  self:once('end', utils.bind(onend, self))
end

--[[
// the no-half-open enforcer
--]]
function onend(self)
  --[[
  // if we allow half-open state, or if the writable side ended,
  // then we're ok.
  --]]
  if self.allowHalfOpen or self._writableState.ended then
    return
  end

  --[[
  // no more data can be written.
  // But allow more writes to happen in this tick.
  --]]
  process.nextTick(utils.bind(self._end, self))
end

return { Duplex = Duplex }