{Number:NumberT} = require './Number'
utils = require './utils'

class ArrayT
  constructor: (@type, @length, @lengthType = 'count') ->

  decode: (stream, parent) ->
    pos = stream.pos

    res = []
    ctx = parent
    
    if @length?
      length = utils.resolveLength @length, stream, parent

    if @length instanceof NumberT
      # define hidden properties
      Object.defineProperties res,
        parent:         { value: parent }
        _startOffset:   { value: pos }
        _currentOffset: { value: 0, writable: true }
        _length:        { value: length }

      ctx = res

    if not length? or @lengthType == 'bytes'
      target = if length?
        stream.pos + length
      else if parent?._length
        parent._startOffset + parent._length
      else
        stream.length

      while stream.pos < target
        res.push @type.decode(stream, ctx)

    else
      for i in [0...length] by 1
        res.push @type.decode(stream, ctx)

    return res

  size: (array, ctx) ->
    unless array
      return @type.size(null, ctx) * utils.resolveLength(@length, null, ctx)

    size = 0
    if @length instanceof NumberT
      size += @length.size()
      ctx = parent: ctx

    for item in array
      size += @type.size(item, ctx)

    return size

  encode: (stream, array, parent) ->
    ctx = parent
    if @length instanceof NumberT
      ctx =
        pointers: []
        startOffset: stream.pos
        parent: parent

      ctx.pointerOffset = stream.pos + @size(array, ctx)
      @length.encode(stream, array.length)

    for item in array
      @type.encode(stream, item, ctx)

    if @length instanceof NumberT
      i = 0
      while i < ctx.pointers.length
        ptr = ctx.pointers[i++]
        ptr.type.encode(stream, ptr.val)

    return

module.exports = ArrayT