From 5d3af6d3c36f669a3cc74fe261652c96bb17b5ac Mon Sep 17 00:00:00 2001
From: Sergei Tikhomirov <sergey.s.tikhomirov@gmail.com>
Date: Thu, 5 Jun 2025 10:22:30 +0200
Subject: [PATCH] [WIP] eligibility check with hard-coded parameters

---
 waku/factory/builder.nim                  |  2 ++
 waku/factory/external_config.nim          |  2 ++
 waku/factory/node_factory.nim             |  8 +++++++
 waku/node/waku_node.nim                   | 29 +++++++++++++++++++++--
 waku/waku_api/rest/lightpush/handlers.nim |  2 +-
 5 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/waku/factory/builder.nim b/waku/factory/builder.nim
index d1cede969..4af6fc658 100644
--- a/waku/factory/builder.nim
+++ b/waku/factory/builder.nim
@@ -206,6 +206,8 @@ proc build*(builder: WakuNodeBuilder): Result[WakuNode, string] =
     colocationLimit = builder.colocationLimit,
     shardedPeerManagement = builder.shardAware,
     dnsNameServers = netConfig.dnsNameServers,
+    eligibilityEnabled = true, # FIXME: i13n: read config or something instead
+    #reputationEnabled = true, # FIXME: i13n: read config or something instead
   )
 
   var node: WakuNode
diff --git a/waku/factory/external_config.nim b/waku/factory/external_config.nim
index ce0eec97f..075b132ab 100644
--- a/waku/factory/external_config.nim
+++ b/waku/factory/external_config.nim
@@ -487,6 +487,7 @@ hence would have reachability issues.""",
     .}: bool
 
     ## Eligibility config
+    ## Is eligibility check enabled or not
     eligibilityEnabled* {.
       desc:
         "Enable server-side eligibility (proof-of-payment) check for light protocols: true|false",
@@ -494,6 +495,7 @@ hence would have reachability issues.""",
       name: "eligibility"
     .}: bool
 
+
     ## Reliability config
     reliabilityEnabled* {.
       desc:
diff --git a/waku/factory/node_factory.nim b/waku/factory/node_factory.nim
index 7df5c2567..fc53ea81f 100644
--- a/waku/factory/node_factory.nim
+++ b/waku/factory/node_factory.nim
@@ -430,6 +430,14 @@ proc setupProtocols(
       return
         err("failed to set node waku peer-exchange peer: " & peerExchangeNode.error)
 
+  # set up eligibility check (i13n POC)
+  # check that: rlnRelay is mounted; Lightpush is mounted
+  # FIXME: conf items are not propagated here; where are they parsed?
+  #if conf.eligibilityEnabled:
+  #  debug "i13n: eligibility enabled!"
+  #  debug "eligibilityReceiverAddress:", conf.eligibilityReceiverAddress
+  #  debug "eligibilityPaymentAmountWei:", conf.eligibilityPaymentAmountWei
+
   return ok()
 
 ## Start node
diff --git a/waku/node/waku_node.nim b/waku/node/waku_node.nim
index 127f34941..04bf54c79 100644
--- a/waku/node/waku_node.nim
+++ b/waku/node/waku_node.nim
@@ -1213,9 +1213,34 @@ proc lightpushPublish*(
       error "lightpush publish error", error = msg
       return lighpushErrorResult(INTERNAL_SERVER_ERROR, msg)
   
-  # TODO: check eligibilityProof here
+  # Checking eligibility proof of Lightpush request
+  debug "in lightpushPublish"
+  debug "eligibilityProof: ", eligibilityProof
+  if node.peerManager.eligibilityManager.isNone():
+    # the service node doesn't want to check eligibility
+    debug "eligibilityManager is disabled - skipping eligibility check"
+  else:
+    debug "eligibilityManager is enabled"
+    var em = node.peerManager.eligibilityManager.get()
+    # FIXME: where should I init eligibilityManager?
+    # FIXME: how to reuse EthClient from CLI arguments?
+    debug "initializing eligibilityManager..."
+    let ethClient = "https://sepolia.infura.io/v3/470c2e9a16f24057aee6660081729fb9"
+    em = await EligibilityManager.init(ethClient)
+    debug "checking eligibilityProof..."
+    let txNonExistent = TxHash.fromHex("0x0000000000000000000000000000000000000000000000000000000000000000")
+    let expectedToAddress = Address.fromHex("0xe8284Af9A5F3b0CD1334DBFaf512F09BeDA805a3")
+    let expectedValueWei = 30000000000000.u256
+    
+    let isEligible = await em.isEligibleTxId(
+      eligibilityProof.get(), expectedToAddress, expectedValueWei
+    )
+    if isEligible.isErr():
+      let msg = "Eligibility check failed!"
+      #debug msg
+      return lighpushErrorResult(PAYMENT_REQUIRED, msg)
 
-  # TODO: eligibilityProof must be already checked if present
+  debug "Eligibility check passed!"
   return await lightpushPublishHandler(node, pubsubForPublish, message, toPeer)
 
 ## Waku RLN Relay
diff --git a/waku/waku_api/rest/lightpush/handlers.nim b/waku/waku_api/rest/lightpush/handlers.nim
index 454d1c807..daa8a5571 100644
--- a/waku/waku_api/rest/lightpush/handlers.nim
+++ b/waku/waku_api/rest/lightpush/handlers.nim
@@ -94,7 +94,7 @@ proc installLightPushRequestHandler*(
             makeRestResponse(lightpushResultServiceUnavailable(NoPeerNoneFoundError))
       toPeer = some(aPeer)
 
-    let subFut = node.lightpushPublish(req.pubsubTopic, msg, none(EligibilityProof), toPeer)
+    let subFut = node.lightpushPublish(req.pubsubTopic, msg, req.eligibilityProof, toPeer)
 
     if not await subFut.withTimeout(FutTimeoutForPushRequestProcessing):
       error "Failed to request a message push due to timeout!"