nimbus-eth2/beacon_chain/eth2_network.nim

import
  options, chronos, json_serialization, strutils,
  spec/digest, version, conf

const
  clientId = "Nimbus beacon node v" & fullVersionStr()

when useRLPx:
  import
    os,
    eth/[rlp, p2p, keys], gossipsub_protocol,
    eth/p2p/peer_pool # for log on connected peers

  export
    p2p, rlp, gossipsub_protocol

  const
    netBackendName* = "rlpx"

  type
    Eth2Node* = EthereumNode
    BootstrapAddr* = ENode

  template libp2pProtocol*(name, version: string) {.pragma.}

  func parseNat(nat: string): IpAddress =
    # TODO we should try to discover the actual external IP, in case we're
    #      behind a nat / upnp / etc..
    if nat.startsWith("extip:"):
      parseIpAddress(nat[6..^1])
    else:
      parseIpAddress("127.0.0.1")

  proc ensureNetworkKeys*(conf: BeaconNodeConf): KeyPair =
    let privateKeyFile = conf.dataDir / "network.privkey"
    var privKey: PrivateKey
    if not fileExists(privateKeyFile):
      privKey = newPrivateKey()
      createDir conf.dataDir.string
      writeFile(privateKeyFile, $privKey)
    else:
      privKey = initPrivateKey(readFile(privateKeyFile).string)

    KeyPair(seckey: privKey, pubkey: privKey.getPublicKey())

  proc getPersistenBootstrapAddr*(conf: BeaconNodeConf,
                                  ip: IpAddress, port: Port): BootstrapAddr =
    let
      keys = ensureNetworkKeys(conf)
      address = Address(ip: ip, tcpPort: port, udpPort: port)

    initENode(keys.pubKey, address)

  proc writeValue*(writer: var JsonWriter, value: BootstrapAddr) {.inline.} =
    writer.writeValue $value

  proc readValue*(reader: var JsonReader, value: var BootstrapAddr) {.inline.} =
    value = initENode reader.readValue(string)

  proc createEth2Node*(conf: BeaconNodeConf): Future[EthereumNode] {.async.} =
    let
      keys = ensureNetworkKeys(conf)
      address = Address(ip: parseNat(conf.nat),
                        tcpPort: Port conf.tcpPort,
                        udpPort: Port conf.udpPort)

    # TODO there are more networking options to add here: local bind ip, ipv6
    #      etc.
    return newEthereumNode(keys, address, 0,
                           nil, clientId, minPeers = 1)

  proc saveConnectionAddressFile*(node: Eth2Node, filename: string) =
    writeFile(filename, $node.listeningAddress)

  proc init*(T: type BootstrapAddr, str: string): T =
    initENode(str)

  func connectedPeers*(enode: EthereumNode): int = 
    enode.peerPool.len

else:
  import
    libp2p/daemon/daemonapi, chronicles,
    libp2p_backend

  export
    libp2p_backend

  type
    BootstrapAddr* = PeerInfo

  const
    netBackendName* = "libp2p"

  proc writeValue*(writer: var JsonWriter, value: PeerID) {.inline.} =
    writer.writeValue value.pretty

  proc readValue*(reader: var JsonReader, value: var PeerID) {.inline.} =
    value = PeerID.init reader.readValue(string)

  proc writeValue*(writer: var JsonWriter, value: MultiAddress) {.inline.} =
    writer.writeValue $value

  proc readValue*(reader: var JsonReader, value: var MultiAddress) {.inline.} =
    value = MultiAddress.init reader.readValue(string)

  proc init*(T: type BootstrapAddr, str: string): T =
    Json.decode(str, PeerInfo)

  proc createEth2Node*(conf: BeaconNodeConf): Future[Eth2Node] {.async.} =
    var node = new Eth2Node
    await node.init()
    return node

  proc connectToNetwork*(node: Eth2Node, bootstrapNodes: seq[PeerInfo]) {.async.} =
    # TODO: perhaps we should do these in parallel
    for bootstrapNode in bootstrapNodes:
      try:
        await node.daemon.connect(bootstrapNode.peer, bootstrapNode.addresses)
        let peer = node.getPeer(bootstrapNode.peer)
        await peer.performProtocolHandshakes()
      except PeerDisconnected:
        error "Failed to connect to bootstrap node", node = bootstrapNode

  proc saveConnectionAddressFile*(node: Eth2Node, filename: string) =
    let id = waitFor node.daemon.identity()
    Json.saveFile(filename, id, pretty = false)

  proc loadConnectionAddressFile*(filename: string): PeerInfo =
    Json.loadFile(filename, PeerInfo)