# Nim-LibP2P
# Copyright (c) 2023 Status Research & Development GmbH
# Licensed under either of
#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
# at your option.
# This file may not be copied, modified, or distributed except according to
# those terms.

## `Perf <https://github.com/libp2p/specs/blob/master/perf/perf.md>`_ protocol specification

{.push raises: [].}

import chronos, chronicles
import stew/endians2
import ./core,
       ../protocol,
       ../../stream/connection,
       ../../utility

export chronicles, connection

logScope:
  topics = "libp2p perf"

type Perf* = ref object of LPProtocol

proc new*(T: typedesc[Perf]): T {.public.} =
  var p = T()
  proc handle(conn: Connection, proto: string) {.async.} =
    var bytesRead = 0
    try:
      trace "Received benchmark performance check", conn
      var
        sizeBuffer: array[8, byte]
        size: uint64
      await conn.readExactly(addr sizeBuffer[0], 8)
      size = uint64.fromBytesBE(sizeBuffer)

      var toReadBuffer: array[PerfSize, byte]
      try:
        while true:
          bytesRead += await conn.readOnce(addr toReadBuffer[0], PerfSize)
      except CatchableError as exc:
        discard

      var buf: array[PerfSize, byte]
      while size > 0:
        let toWrite = min(size, PerfSize)
        await conn.write(buf[0..<toWrite])
        size -= toWrite
    except CancelledError as exc:
      raise exc
    except CatchableError as exc:
      trace "exception in perf handler", exc = exc.msg, conn
    await conn.close()

  p.handler = handle
  p.codec = PerfCodec
  return p