var tape = require('tape')
var concat = require('.')
var pull = require('pull-stream')
var crypto = require('crypto')

var emptyPack = new Buffer([0x50, 0x41, 0x43, 0x4b, 0, 0, 0, 2, 0, 0, 0, 0,
  0xda, 0x39, 0xa3, 0xee, 0x5e, 0x6b, 0x4b, 0x0d, 0x32, 0x55,
  0xbf, 0xef, 0x95, 0x60, 0x18, 0x90, 0xaf, 0xd8, 0x07, 0x09])

function readPack(numObjects, payload) {
  var header = new Buffer([0x50, 0x41, 0x43, 0x4b, 0, 0, 0, 2, 0, 0, 0, 0])
  if (numObjects) header.writeUInt32BE(numObjects, 8)
  var checksum = crypto.createHash('sha1')
  if (!payload) payload = new Buffer([])
  checksum.update(payload)
  return pull.values([header, payload, checksum.digest()])
}

function pack(n, p, numObjects) {
  return {read: readPack(n, p), numObjects: numObjects}
}

function pullEquals(a, b) {
  return function (t) {
    pull(a, pull.collect(function (err, bufsA) {
      t.error(err, 'collect 1')
      pull(b, pull.collect(function (err, bufsB) {
        t.error(err, 'collect 2')
        t.deepEquals(Buffer.concat(bufsA), Buffer.concat(bufsB), 'bufs')
        t.end()
      }))
    }))
  }
}

tape('empty 0', pullEquals(concat([]), readPack()))
tape('empty 1', pullEquals(concat([pack()]), readPack()))
tape('empty 2', pullEquals(concat([pack(), pack()]), readPack()))

tape('sum num objs', pullEquals(concat([pack(1), pack(3)]), readPack(4)))

tape('sum num objs with property',
  pullEquals(concat([pack(1, null, 1), pack(3)]), readPack(4)))

tape('concat data', pullEquals(
  concat([
    pack(0, new Buffer([5,4,3])),
    pack(1, new Buffer([7,9]))
  ]),
  readPack(1, new Buffer([5,4,3,7,9]))
))