fix(model): skip stale unload command

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/routes/model.rs

@@ -88,7 +88,12 @@ pub async fn model_load(State(state): State<AppState>) -> impl IntoResponse {
     )
 )]
 pub async fn model_unload(State(state): State<AppState>) -> impl IntoResponse {
-    let _ = state.cmd_tx.try_send(WorkerCmd::Unload);
+    if !matches!(
+        *state.model_state.read().await,
+        crate::models::ModelState::Unloaded
+    ) {
+        let _ = state.cmd_tx.try_send(WorkerCmd::Unload);
+    }
     (
         StatusCode::OK,
         Json(serde_json::json!({"status": "unload_requested"})),
@@ -164,3 +169,76 @@ fn vram_stats(gpu_device: u32) -> (Option<u64>, Option<u64>) {
         None => (None, None),
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::sync::{atomic::AtomicUsize, Arc, Mutex};
+
+    use axum::response::IntoResponse;
+    use chrono::Utc;
+    use tempfile::tempdir;
+    use tokio::sync::{broadcast, mpsc, RwLock};
+
+    use crate::{models::ModelState, storage::Storage, worker::ProgressRegistry, AppState};
+
+    async fn test_state(
+        model_state: ModelState,
+    ) -> (
+        AppState,
+        tempfile::TempDir,
+        std::sync::mpsc::Receiver<WorkerCmd>,
+    ) {
+        let tmp = tempdir().expect("tempdir");
+        let storage = Arc::new(Storage::new(tmp.path()).await.expect("storage"));
+        let (job_tx, _job_rx) = mpsc::unbounded_channel();
+        let (cmd_tx, cmd_rx) = std::sync::mpsc::sync_channel(8);
+        let progress: ProgressRegistry = Arc::new(dashmap::DashMap::new());
+        let (model_event_tx, _) = broadcast::channel(8);
+
+        (
+            AppState {
+                job_tx,
+                cmd_tx,
+                storage,
+                progress,
+                model_name: "test".into(),
+                queue_depth: Arc::new(AtomicUsize::new(0)),
+                gpu_device: 0,
+                model_state: Arc::new(RwLock::new(model_state)),
+                model_event_tx,
+                webhook_registry: Arc::new(Mutex::new(Default::default())),
+                idle_timeout: std::time::Duration::from_secs(300),
+                gpu_poll_interval: std::time::Duration::from_secs(30),
+            },
+            tmp,
+            cmd_rx,
+        )
+    }
+
+    #[tokio::test]
+    async fn test_model_unload_skips_command_when_already_unloaded() {
+        let (state, _tmp, cmd_rx) = test_state(ModelState::Unloaded).await;
+
+        let response = model_unload(State(state)).await.into_response();
+
+        assert_eq!(response.status(), StatusCode::OK);
+        assert!(
+            cmd_rx.try_recv().is_err(),
+            "unexpected unload command queued"
+        );
+    }
+
+    #[tokio::test]
+    async fn test_model_unload_queues_command_when_ready() {
+        let (state, _tmp, cmd_rx) = test_state(ModelState::Ready {
+            loaded_at: Utc::now(),
+        })
+        .await;
+
+        let response = model_unload(State(state)).await.into_response();
+
+        assert_eq!(response.status(), StatusCode::OK);
+        assert!(matches!(cmd_rx.try_recv(), Ok(WorkerCmd::Unload)));
+    }
+}