From 8e77151c4d410d1303380838686dec134c8c2c0f Mon Sep 17 00:00:00 2001
From: Tanut Lertwarachai <tanutlertwarachai@Tanuts-MacBook-Pro.local>
Date: Wed, 8 Apr 2026 15:09:12 +0700
Subject: [PATCH] add contract address field

---
 proto/fkms/v1/signer.proto |  2 +-
 src/codec/flow.rs          | 26 ++++++++++++++++++++++++++
 src/server/service.rs      |  3 ++-
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/proto/fkms/v1/signer.proto b/proto/fkms/v1/signer.proto
index 9897ef2..ce3bd73 100644
--- a/proto/fkms/v1/signer.proto
+++ b/proto/fkms/v1/signer.proto
@@ -83,7 +83,7 @@ message FlowSignerPayload {
   string block_id = 3;
   uint32 key_index = 4;
   uint64 sequence = 5;
-  bytes script = 6;
+  string contract_address = 6;
 }
 
 message SorobanSignerPayload {
diff --git a/src/codec/flow.rs b/src/codec/flow.rs
index 630863f..55c43cb 100644
--- a/src/codec/flow.rs
+++ b/src/codec/flow.rs
@@ -7,6 +7,32 @@ use sha3::{Digest, Sha3_256};
 const FLOW_TRANSACTION_DOMAIN_TAG: &[u8] =
     b"FLOW-V0.0-transaction\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00";
 
+const RELAY_SCRIPT_TEMPLATE: &str = r#"
+    import BandOracle from {contract}
+
+    transaction (symbolsRates: {String: UInt64}, resolveTime: UInt64, requestID: UInt64) {
+        let relayRef: &BandOracle.Relay
+
+        prepare (acct: auth(BorrowValue)&Account){
+            // Get a reference to the relayer resource from storage
+            self.relayRef = acct.storage.borrow<&BandOracle.Relay>(from: BandOracle.RelayStoragePath) ??
+                panic("Cannot borrow reference to relay resource")
+        }
+
+        execute {
+            // Call the relayRates function exposed by the relayer resource
+            self.relayRef.relayRates(symbolsRates: symbolsRates, resolveTime: resolveTime, requestID: requestID)
+        }
+    }
+"#;
+
+/// Builds the Cadence relay script with the given contract address substituted in.
+pub fn build_script(contract_address: &str) -> Vec<u8> {
+    RELAY_SCRIPT_TEMPLATE
+        .replace("{contract}", contract_address)
+        .into_bytes()
+}
+
 // Builds the RLP-encoded transaction payload used for signing.
 #[allow(clippy::too_many_arguments)]
 pub fn build_payload_rlp(
diff --git a/src/server/service.rs b/src/server/service.rs
index 76e13a3..3c0bff0 100644
--- a/src/server/service.rs
+++ b/src/server/service.rs
@@ -305,6 +305,7 @@ impl FkmsService for Server {
                     .map_err(|_| Status::invalid_argument("Timestamp must be non-negative"))?;
                 let request_id = tunnel_packet.sequence;
 
+                let script = flow::build_script(&signer_payload.contract_address);
                 let payload_rlp = flow::build_payload_rlp(
                     &signals,
                     &signer_payload.address,
@@ -312,7 +313,7 @@ impl FkmsService for Server {
                     &signer_payload.block_id,
                     signer_payload.key_index,
                     signer_payload.sequence,
-                    &signer_payload.script,
+                    &script,
                     resolve_time,
                     request_id,
                 )