/* global FileReader */
var from2 = require('from2')
var toBuffer = require('typedarray-to-buffer')

module.exports = function (file, options) {
  options = options || {}
  var offset = options.offset || 0
  var chunkSize = options.chunkSize || 1024 * 1024 // default 1MB chunk has tolerable perf on large files
  var fileReader = new FileReader(file)

  var from = from2(function (size, cb) {
    if (offset >= file.size) return cb(null, null)
    fileReader.onloadend = function loaded (event) {
      var data = event.target.result
      if (data instanceof ArrayBuffer) data = toBuffer(new Uint8Array(event.target.result))
      cb(null, data)
    }
    var end = offset + chunkSize
    var slice = file.slice(offset, end)
    fileReader.readAsArrayBuffer(slice)
    offset = end
  })

  from.name = file.name
  from.size = file.size
  from.type = file.type
  from.lastModifiedDate = file.lastModifiedDate

  fileReader.onerror = function (err) {
    from.destroy(err)
  }

  return from
}

@@ -874,20 +874,16 @@
 Modified
-Date
  = file.
@@ -898,12 +898,8 @@
 fied
-Date
 %0A%0A  

replace lastModifiedDate with lastModified