don't allow to join as user if already cox

src/model/usertrip.rs

@@ -1,17 +1,45 @@
 use sqlx::SqlitePool;
 
+use super::planned_event::PlannedEvent;
+
 pub struct UserTrip {}
 
 impl UserTrip {
-    pub async fn create(db: &SqlitePool, user_id: i64, trip_details_id: i64) -> bool {
-        sqlx::query!(
+    pub async fn create(
+        db: &SqlitePool,
+        user_id: i64,
+        trip_details_id: i64,
+    ) -> Result<(), UserTripError> {
+        if PlannedEvent::is_full(db, trip_details_id).await {
+            return Err(UserTripError::EventAlreadyFull);
+        }
+
+        let is_cox = sqlx::query!(
+            "SELECT count(*) as amount
+            FROM trip 
+            WHERE trip_details_id = ? 
+            AND cox_id = ?",
+            trip_details_id,
+            user_id
+        )
+        .fetch_one(db)
+        .await
+        .unwrap();
+        if is_cox.amount > 0 {
+            return Err(UserTripError::AlreadyRegisteredAsCox);
+        }
+
+        match sqlx::query!(
             "INSERT INTO user_trip (user_id, trip_details_id) VALUES(?, ?)",
             user_id,
             trip_details_id
         )
         .execute(db)
         .await
-        .is_ok()
+        {
+            Ok(_) => Ok(()),
+            Err(_) => Err(UserTripError::AlreadyRegistered),
+        }
     }
 
     pub async fn delete(db: &SqlitePool, user_id: i64, trip_details_id: i64) {
@@ -25,3 +53,9 @@ impl UserTrip {
         .is_ok();
     }
 }
+
+pub enum UserTripError {
+    AlreadyRegistered,
+    AlreadyRegisteredAsCox,
+    EventAlreadyFull,
+}