verify, that boat is not on water on adding log entry; Fixes #625 (#697)

Reviewed-on: #697

src/model/boat.rs

@@ -1,5 +1,6 @@
 use std::ops::DerefMut;
 
+use chrono::NaiveDateTime;
 use itertools::Itertools;
 use rocket::serde::{Deserialize, Serialize};
 use rocket::FromForm;
@@ -391,6 +392,39 @@ ORDER BY amount_seats DESC
         .await
         .ok()
     }
+
+    pub async fn on_water_between(
+        &self,
+        db: &mut Transaction<'_, Sqlite>,
+        dep: NaiveDateTime,
+        arr: NaiveDateTime,
+    ) -> bool {
+        let dep = dep.format("%Y-%m-%dT%H:%M").to_string();
+        let arr = arr.format("%Y-%m-%dT%H:%M").to_string();
+
+        sqlx::query!(
+            "SELECT COUNT(*) AS overlap_count
+FROM logbook
+WHERE boat_id = ?
+  AND (
+    (departure <= ? AND arrival >= ?)  -- Existing entry covers the entire new period
+    OR (departure >= ? AND departure < ?)  -- Existing entry starts during the new period
+    OR (arrival > ? AND arrival <= ?)  -- Existing entry ends during the new period
+  );",
+            self.id,
+            arr,
+            arr,
+            dep,
+            dep,
+            dep,
+            arr
+        )
+        .fetch_one(db.deref_mut())
+        .await
+        .unwrap()
+        .overlap_count
+            > 0
+    }
 }
 
 #[cfg(test)]