{.used.}

import
  testutils/unittests,

  # FastStreams modules:
  ../faststreams/[pipelines, multisync]

when fsAsyncSupport:
  import
    # Std lib:
    std/[strutils, random, base64, terminal],
    # FastStreams modules:
    ../faststreams/[pipelines, multisync],
    # Testing modules:
    ./base64 as fsBase64

  include system/timers

  type
    TestTimes = object
      fsPipeline: Nanos
      fsAsyncPipeline: Nanos
      stdFunctionCalls: Nanos

  proc upcaseAllCharacters(i: InputStream, o: OutputStream) {.fsMultiSync.} =
    let inputLen = i.len
    if inputLen.isSome:
      o.ensureRunway inputLen.get

    while i.readable:
      o.write toUpperAscii(i.read.char)

    close o

  proc printTimes(t: TestTimes) =
    styledEcho "  cpu time [FS Sync  ]: ", styleBright, $t.fsPipeline, "ms"
    styledEcho "  cpu time [FS Async ]: ", styleBright, $t.fsAsyncPipeline, "ms"
    styledEcho "  cpu time [Std Lib  ]: ", styleBright, $t.stdFunctionCalls, "ms"

  template timeit(timerVar: var Nanos, code: untyped) =
    let t0 = getTicks()
    code
    timerVar = int64(getTicks() - t0) div 1000000

  proc getOutput(sp: AsyncInputStream, T: type string): Future[string] {.async.} =
    # this proc is a quick hack to let the test pass
    # do not use it in production code
    let size = sp.totalUnconsumedBytes()
    if size > 0:
      var data = newSeq[byte](size)
      discard sp.readInto(data)
      result = cast[string](data)

  suite "pipelines":
    const loremIpsum = """
      Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod
      tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim
      veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex
      ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate
      velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat
      cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id
      est laborum.

    """

    test "upper-case/base64 pipeline benchmark":
      var
        times: TestTimes
        stdRes: string
        fsRes: string
        fsAsyncRes: string

      let inputText = loremIpsum.repeat(5000)

      timeit times.stdFunctionCalls:
        stdRes = base64.decode(base64.encode(toUpperAscii(inputText)))

      timeit times.fsPipeline:
        fsRes = executePipeline(unsafeMemoryInput(inputText),
                                upcaseAllCharacters,
                                base64encode,
                                base64decode,
                                getOutput string)

      timeit times.fsAsyncPipeline:
        fsAsyncRes = waitFor executePipeline(Async unsafeMemoryInput(inputText),
                                            upcaseAllCharacters,
                                            base64encode,
                                            base64decode,
                                            getOutput string)

      check fsAsyncRes == stdRes
      check fsRes == stdRes

      printTimes times

    asyncTest "upper-case/base64 async pipeline":
      let pipe = asyncPipe()
      let inputText = repeat(loremIpsum, 100)

      proc pipeFeeder(s: AsyncOutputStream) {.gcsafe, async.} =
        randomize 1234
        var pos = 0

        while pos != inputText.len:
          let bytesToWrite = rand(15)

          if bytesToWrite == 0:
            s.write inputText[pos]
            inc pos
          else:
            let endPos = min(pos + bytesToWrite, inputText.len)
            s.writeAndWait inputText[pos ..< endPos]
            pos = endPos

          let sleep = rand(50) - 45
          if sleep > 0:
            await sleepAsync(sleep.milliseconds)

        close s

      asyncCheck pipeFeeder(pipe.initWriter)

      let f = executePipeline(pipe.initReader,
                              upcaseAllCharacters,
                              base64encode,
                              base64decode,
                              getOutput string)

      let fsAsyncres = await f

      check fsAsyncres == toUpperAscii(inputText)
else:
  test "pipelines":
    skip