# Waku Switch utils.
{.push raises: [].}

import
  std/options,
  chronos,
  chronicles,
  eth/keys,
  libp2p/crypto/crypto,
  libp2p/protocols/pubsub/gossipsub,
  libp2p/protocols/rendezvous,
  libp2p/nameresolving/nameresolver,
  libp2p/builders,
  libp2p/switch,
  libp2p/transports/[transport, tcptransport, wstransport]

# override nim-libp2p default value (which is also 1)
const MaxConnectionsPerPeer* = 1

proc withWsTransport*(b: SwitchBuilder): SwitchBuilder =
  b.withTransport(
    proc(upgr: Upgrade): Transport =
      WsTransport.new(upgr)
  )

proc getSecureKey(path: string): TLSPrivateKey {.raises: [Defect, IOError].} =
  trace "Key path is.", path = path
  let stringkey: string = readFile(path)
  try:
    let key = TLSPrivateKey.init(stringkey)
    return key
  except TLSStreamProtocolError as exc:
    debug "exception raised from getSecureKey", err = exc.msg

proc getSecureCert(path: string): TLSCertificate {.raises: [Defect, IOError].} =
  trace "Certificate path is.", path = path
  let stringCert: string = readFile(path)
  try:
    let cert = TLSCertificate.init(stringCert)
    return cert
  except TLSStreamProtocolError as exc:
    debug "exception raised from getSecureCert", err = exc.msg

proc withWssTransport*(
    b: SwitchBuilder, secureKeyPath: string, secureCertPath: string
): SwitchBuilder {.raises: [Defect, IOError].} =
  let key: TLSPrivateKey = getSecureKey(secureKeyPath)
  let cert: TLSCertificate = getSecureCert(secureCertPath)
  b.withTransport(
    proc(upgr: Upgrade): Transport =
      WsTransport.new(
        upgr,
        tlsPrivateKey = key,
        tlsCertificate = cert,
        {TLSFlags.NoVerifyHost, TLSFlags.NoVerifyServerName},
      )
  )

proc newWakuSwitch*(
    privKey = none(crypto.PrivateKey),
    address = MultiAddress.init("/ip4/127.0.0.1/tcp/0").tryGet(),
    wsAddress = none(MultiAddress),
    secureManagers: openarray[SecureProtocol] = [SecureProtocol.Noise],
    transportFlags: set[ServerFlags] = {},
    rng: ref HmacDrbgContext,
    inTimeout: Duration = 5.minutes,
    outTimeout: Duration = 5.minutes,
    maxConnections = MaxConnections,
    maxIn = -1,
    maxOut = -1,
    maxConnsPerPeer = MaxConnectionsPerPeer,
    nameResolver: NameResolver = nil,
    sendSignedPeerRecord = false,
    wssEnabled: bool = false,
    secureKeyPath: string = "",
    secureCertPath: string = "",
    agentString = none(string), # defaults to nim-libp2p version
    peerStoreCapacity = none(int), # defaults to 1.25 maxConnections
    services: seq[switch.Service] = @[],
    rendezvous: RendezVous = nil,
): Switch {.raises: [Defect, IOError, LPError].} =
  var b = SwitchBuilder
    .new()
    .withRng(rng)
    .withMaxConnections(maxConnections)
    .withMaxIn(maxIn)
    .withMaxOut(maxOut)
    .withMaxConnsPerPeer(maxConnsPerPeer)
    .withYamux()
    .withMplex(inTimeout, outTimeout)
    .withNoise()
    .withTcpTransport(transportFlags)
    .withNameResolver(nameResolver)
    .withSignedPeerRecord(sendSignedPeerRecord)
    .withCircuitRelay()
    .withAutonat()

  if peerStoreCapacity.isSome():
    b = b.withPeerStore(peerStoreCapacity.get())
  else:
    let defaultPeerStoreCapacity = int(maxConnections) * 5
    b = b.withPeerStore(defaultPeerStoreCapacity)
  if agentString.isSome():
    b = b.withAgentVersion(agentString.get())
  if privKey.isSome():
    b = b.withPrivateKey(privKey.get())
  if wsAddress.isSome():
    b = b.withAddresses(@[wsAddress.get(), address])

    if wssEnabled:
      b = b.withWssTransport(secureKeyPath, secureCertPath)
    else:
      b = b.withWsTransport()
  else:
    b = b.withAddress(address)

  if services.len > 0:
    b = b.withServices(services)

  if not rendezvous.isNil():
    b = b.withRendezVous(rendezvous)

  b.build()