# Nim-LibP2P
# Copyright (c) 2022 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.

when (NimMajor, NimMinor) < (1, 4):
  {.push raises: [Defect].}
else:
  {.push raises: [].}

import std/[options, sequtils, strutils]
import pkg/[chronos, chronicles, metrics]

import ../stream/connection,
       ../protocols/secure/secure,
       ../protocols/identify,
       ../multistream,
       ../peerstore,
       ../connmanager,
       ../errors,
       ../utility

export connmanager, connection, identify, secure, multistream

declarePublicCounter(libp2p_failed_upgrade, "peers failed upgrade")

logScope:
  topics = "libp2p upgrade"

type
  UpgradeFailedError* = object of LPError

  Upgrade* = ref object of RootObj
    ms*: MultistreamSelect
    identity*: Identify
    connManager*: ConnManager
    secureManagers*: seq[Secure]

method upgradeIncoming*(
  self: Upgrade,
  conn: Connection): Future[void] {.base.} =
  doAssert(false, "Not implemented!")

method upgradeOutgoing*(
  self: Upgrade,
  conn: Connection,
  peerId: Opt[PeerId]): Future[Connection] {.base.} =
  doAssert(false, "Not implemented!")

proc secure*(
  self: Upgrade,
  conn: Connection,
  peerId: Opt[PeerId]): Future[Connection] {.async, gcsafe.} =
  if self.secureManagers.len <= 0:
    raise newException(UpgradeFailedError, "No secure managers registered!")

  let codec = await self.ms.select(conn, self.secureManagers.mapIt(it.codec))
  if codec.len == 0:
    raise newException(UpgradeFailedError, "Unable to negotiate a secure channel!")

  trace "Securing connection", conn, codec
  let secureProtocol = self.secureManagers.filterIt(it.codec == codec)

  # ms.select should deal with the correctness of this
  # let's avoid duplicating checks but detect if it fails to do it properly
  doAssert(secureProtocol.len > 0)

  return await secureProtocol[0].secure(conn, true, peerId)

proc identify*(
  self: Upgrade,
  conn: Connection) {.async, gcsafe.} =
  ## identify the connection

  if (await self.ms.select(conn, self.identity.codec)):
    let
      info = await self.identity.identify(conn, conn.peerId)
      peerStore = self.connManager.peerStore

    if info.pubkey.isNone and isNil(conn):
      raise newException(UpgradeFailedError,
        "no public key provided and no existing peer identity found")

    conn.peerId = info.peerId

    when defined(libp2p_agents_metrics):
      conn.shortAgent = "unknown"
      if info.agentVersion.isSome and info.agentVersion.get().len > 0:
        let shortAgent = info.agentVersion.get().split("/")[0].safeToLowerAscii()
        if shortAgent.isOk() and KnownLibP2PAgentsSeq.contains(shortAgent.get()):
          conn.shortAgent = shortAgent.get()

    peerStore.updatePeerInfo(info)
    trace "identified remote peer", conn, peerId = shortLog(conn.peerId)