add the ability to make props non-droppable

crates/chattyness-db/src/queries/inventory.rs

@@ -20,6 +20,7 @@ pub async fn list_user_inventory<'e>(
             layer,
             is_transferable,
             is_portable,
+            is_droppable,
             origin,
             acquired_at
         FROM props.inventory
@@ -35,16 +36,30 @@ pub async fn list_user_inventory<'e>(
 }
 
 /// Drop a prop (remove from inventory).
+/// Returns an error if the prop is non-droppable (essential prop).
 pub async fn drop_inventory_item<'e>(
     executor: impl PgExecutor<'e>,
     user_id: Uuid,
     item_id: Uuid,
 ) -> Result<(), AppError> {
-    let result = sqlx::query(
+    // Use a CTE to check existence/droppability and delete in a single query
+    // Returns: (existed, was_droppable, was_deleted)
+    let result: Option<(bool, bool, bool)> = sqlx::query_as(
         r#"
-        DELETE FROM props.inventory
-        WHERE id = $1 AND user_id = $2
-        RETURNING id
+        WITH item_info AS (
+            SELECT id, is_droppable
+            FROM props.inventory
+            WHERE id = $1 AND user_id = $2
+        ),
+        deleted AS (
+            DELETE FROM props.inventory
+            WHERE id = $1 AND user_id = $2 AND is_droppable = true
+            RETURNING id
+        )
+        SELECT
+            EXISTS(SELECT 1 FROM item_info) AS existed,
+            COALESCE((SELECT is_droppable FROM item_info), false) AS was_droppable,
+            EXISTS(SELECT 1 FROM deleted) AS was_deleted
         "#,
     )
     .bind(item_id)
@@ -52,10 +67,26 @@ pub async fn drop_inventory_item<'e>(
     .fetch_optional(executor)
     .await?;
 
-    if result.is_none() {
-        return Err(AppError::NotFound(
-            "Inventory item not found or not owned by user".to_string(),
-        ));
+    match result {
+        Some((false, _, _)) | None => {
+            return Err(AppError::NotFound(
+                "Inventory item not found or not owned by user".to_string(),
+            ));
+        }
+        Some((true, false, _)) => {
+            return Err(AppError::Forbidden(
+                "This prop cannot be dropped - it is an essential prop".to_string(),
+            ));
+        }
+        Some((true, true, true)) => {
+            // Successfully deleted
+        }
+        Some((true, true, false)) => {
+            // Should not happen - item existed, was droppable, but wasn't deleted
+            return Err(AppError::Internal(
+                "Unexpected error dropping inventory item".to_string(),
+            ));
+        }
     }
 
     Ok(())