update

backend/src/services/events.service.ts

@@ -614,6 +614,48 @@ class EventsService {
     }));
   }
 
+  // -------------------------------------------------------------------------
+  // CONFLICT CHECK
+  // -------------------------------------------------------------------------
+
+  /**
+   * Returns events that overlap with the given time range.
+   * Used to warn users about scheduling conflicts before creating/updating events.
+   */
+  async checkConflicts(
+    datumVon: Date,
+    datumBis: Date,
+    excludeId?: string
+  ): Promise<Array<{ id: string; titel: string; datum_von: Date; datum_bis: Date; kategorie_name: string | null }>> {
+    const params: any[] = [datumVon, datumBis];
+    let excludeClause = '';
+    if (excludeId) {
+      excludeClause = ' AND v.id != $3';
+      params.push(excludeId);
+    }
+
+    const result = await pool.query(
+      `SELECT v.id, v.titel, v.datum_von, v.datum_bis,
+              k.name AS kategorie_name
+       FROM veranstaltungen v
+       LEFT JOIN veranstaltung_kategorien k ON k.id = v.kategorie_id
+       WHERE v.abgesagt = FALSE
+         AND ($1::timestamptz, $2::timestamptz) OVERLAPS (v.datum_von, v.datum_bis)
+         ${excludeClause}
+       ORDER BY v.datum_von ASC
+       LIMIT 10`,
+      params
+    );
+
+    return result.rows.map((row) => ({
+      id: row.id,
+      titel: row.titel,
+      datum_von: new Date(row.datum_von),
+      datum_bis: new Date(row.datum_bis),
+      kategorie_name: row.kategorie_name ?? null,
+    }));
+  }
+
   // -------------------------------------------------------------------------
   // ICAL EXPORT
   // -------------------------------------------------------------------------