"use strict";

var crypto = require('crypto');
var stream = require('stream');

var Readable = stream.Readable;
require('util').inherits(RandomChunkStream, Readable);

module.exports = RandomChunkStream;

function RandomChunkStream(options) {
  this.maxchunksize = options.maxchunksize>>>0;
  this.size = options.size>>>0;
  this.buffer = Buffer.allocUnsafe(this.size);
  this.cursor = 0;
  Readable.call(this, options);
}

RandomChunkStream.prototype._read = function() {
  var buffer = this.buffer;
  var slicelen = (Math.random()*this.maxchunksize|0) + 1;
  slicelen = Math.min(slicelen, this.size - this.cursor);
  crypto.randomBytes(slicelen).copy(buffer, this.cursor);
  var n = this.cursor + slicelen;
  this.push(buffer.slice(this.cursor, n));
  this.cursor = n;
  if (n >= this.size)
    this.push(null);
};