feat: add last_refreshed timestamp to leaderboard response

Author: factorydroid

bounty_challenge.wasm

@@ -78,10 +78,13 @@ fn get_param<'a>(request: &'a WasmRouteRequest, name: &str) -> Option<&'a str> {
 }
 
 pub fn handle_leaderboard(_request: &WasmRouteRequest) -> WasmRouteResponse {
-    // Rebuild leaderboard dynamically and use the returned entries directly
-    // (P2P storage write may not have landed yet).
     let entries = scoring::rebuild_leaderboard();
-    json_response(&entries)
+    let last_refreshed = crate::storage::get_last_refreshed();
+    let response = crate::types::LeaderboardResponse {
+        last_refreshed,
+        entries,
+    };
+    json_response(&response)
 }
 
 pub fn handle_stats(_request: &WasmRouteRequest) -> WasmRouteResponse {

src/api/handlers.rs

@@ -217,6 +217,9 @@ pub fn background_tick() {
 
     storage::recount_all_balances();
     rebuild_leaderboard();
+
+    let now = platform_challenge_sdk_wasm::host_functions::host_get_timestamp();
+    storage::store_last_refreshed(now);
 }
 
 /// Perform a full sync: rebuild leaderboard and return sync result for consensus

src/scoring.rs

@@ -719,6 +719,25 @@ pub fn get_validator_count() -> u64 {
         .unwrap_or(0)
 }
 
+pub fn store_last_refreshed(ts: i64) {
+    let _ = host_storage_set(b"last_refreshed", &ts.to_le_bytes());
+}
+
+pub fn get_last_refreshed() -> i64 {
+    host_storage_get(b"last_refreshed")
+        .ok()
+        .and_then(|d| {
+            if d.len() >= 8 {
+                let mut buf = [0u8; 8];
+                buf.copy_from_slice(&d[..8]);
+                Some(i64::from_le_bytes(buf))
+            } else {
+                None
+            }
+        })
+        .unwrap_or(0)
+}
+
 pub fn ensure_hotkey_tracked(hotkey: &str) {
     add_registered_hotkey(hotkey);
 }

src/storage/bounty_storage.rs

@@ -97,6 +97,12 @@ pub struct LeaderboardEntry {
     pub malicious_issues: u32,
 }
 
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct LeaderboardResponse {
+    pub last_refreshed: i64,
+    pub entries: Vec<LeaderboardEntry>,
+}
+
 #[derive(Clone, Debug, Serialize, Deserialize)]
 pub struct StatsResponse {
     pub total_bounties: u64,