nwaku/waku/node/jsonrpc/relay/handlers.nim

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

import
  std/sequtils,
  chronicles,
  json_rpc/rpcserver,
  eth/keys,
  nimcrypto/sysrand
import
  ../../../common/base64,
  ../../../waku_core,
  ../../../waku_relay,
  ../../waku_node,
  ../../message_cache,
  ../message

from std/times import getTime
from std/times import toUnix

when defined(rln):
  import
    ../../../waku_rln_relay,
    ../../../waku_rln_relay/rln/wrappers

logScope:
  topics = "waku node jsonrpc relay_api"


const futTimeout* = 5.seconds # Max time to wait for futures

type
  MessageCache* = message_cache.MessageCache[PubsubTopic]


## Waku Relay JSON-RPC API

proc installRelayApiHandlers*(node: WakuNode, server: RpcServer, cache: MessageCache) =
  if node.wakuRelay.isNil():
    debug "waku relay protocol is nil. skipping json rpc api handlers installation"
    return

  let topicHandler = proc(topic: PubsubTopic, message: WakuMessage) {.async.} =
      cache.addMessage(topic, message)

  # The node may already be subscribed to some topics when Relay API handlers
  # are installed
  for topic in node.wakuRelay.subscribedTopics:
    node.subscribe(topic, topicHandler)
    cache.subscribe(topic)


  server.rpc("post_waku_v2_relay_v1_subscriptions") do (topics: seq[PubsubTopic]) -> bool:
    ## Subscribes a node to a list of PubSub topics
    debug "post_waku_v2_relay_v1_subscriptions"

    # Subscribe to all requested topics
    let newTopics = topics.filterIt(not cache.isSubscribed(it))

    for topic in newTopics:
      cache.subscribe(topic)
      node.subscribe(topic, topicHandler)

    return true

  server.rpc("delete_waku_v2_relay_v1_subscriptions") do (topics: seq[PubsubTopic]) -> bool:
    ## Unsubscribes a node from a list of PubSub topics
    debug "delete_waku_v2_relay_v1_subscriptions"

    # Unsubscribe all handlers from requested topics
    let subscribedTopics = topics.filterIt(cache.isSubscribed(it))

    for topic in subscribedTopics:
      node.unsubscribe(topic)
      cache.unsubscribe(topic)

    return true

  server.rpc("post_waku_v2_relay_v1_message") do (pubsubTopic: PubsubTopic, msg: WakuMessageRPC) -> bool:
    ## Publishes a WakuMessage to a PubSub topic
    debug "post_waku_v2_relay_v1_message", pubsubTopic=pubsubTopic

    let payloadRes = base64.decode(msg.payload)
    if payloadRes.isErr():
      raise newException(ValueError, "invalid payload format: " & payloadRes.error)

    var message = WakuMessage(
        payload: payloadRes.value,
        # TODO: Fail if the message doesn't have a content topic
        contentTopic: msg.contentTopic.get(DefaultContentTopic),
        version: msg.version.get(0'u32),
        timestamp: msg.timestamp.get(Timestamp(0)),
        ephemeral: msg.ephemeral.get(false)
      )

    # ensure the node is subscribed to the pubsubTopic. otherwise it risks publishing
    # to a topic with no connected peers
    if pubsubTopic notin node.wakuRelay.subscribedTopics():
      raise newException(ValueError, "Failed to publish: Node not subscribed to pubsubTopic: " & pubsubTopic)

    # if RLN is mounted, append the proof to the message
    when defined(rln):
      if not node.wakuRlnRelay.isNil():
        # append the proof to the message
        let success = node.wakuRlnRelay.appendRLNProof(message,
                                                      float64(getTime().toUnix()))
        if not success:
          raise newException(ValueError, "Failed to publish: error appending RLN proof to message")
        # validate the message before sending it
        let result = node.wakuRlnRelay.validateMessage(message)
        if result == MessageValidationResult.Invalid:
          raise newException(ValueError, "Failed to publish: invalid RLN proof")
        elif result == MessageValidationResult.Spam:
          raise newException(ValueError, "Failed to publish: limit exceeded, try again later")
        elif result == MessageValidationResult.Valid:
          debug "RLN proof validated successfully", pubSubTopic=pubSubTopic
        else:
          raise newException(ValueError, "Failed to publish: unknown RLN proof validation result")
      else:
        raise newException(ValueError, "Failed to publish: RLN enabled but not mounted")

    # if we reach here its either a non-RLN message or a RLN message with a valid proof
    debug "Publishing message", pubSubTopic=pubSubTopic, rln=defined(rln)
    let publishFut = node.publish(pubsubTopic, message)
    if not await publishFut.withTimeout(futTimeout):
      raise newException(ValueError, "Failed to publish: timed out")

    return true

  server.rpc("get_waku_v2_relay_v1_messages") do (topic: PubsubTopic) -> seq[WakuMessageRPC]:
    ## Returns all WakuMessages received on a PubSub topic since the
    ## last time this method was called
    debug "get_waku_v2_relay_v1_messages", topic=topic

    if not cache.isSubscribed(topic):
      raise newException(ValueError, "Not subscribed to topic: " & topic)

    let msgRes = cache.getMessages(topic, clear=true)
    if msgRes.isErr():
      raise newException(ValueError, "Not subscribed to topic: " & topic)

    return msgRes.value.map(toWakuMessageRPC)


## Waku Relay Private JSON-RPC API (Whisper/Waku v1 compatibility)
## Support for the Relay Private API has been deprecated.
## This API existed for compatibility with the Waku v1/Whisper spec and encryption schemes.
## It is recommended to use the Relay API instead.