Add logical distribution board feed links

src/db/repositories/distribution-board-subtree-project-command.repository.ts

@@ -300,6 +300,69 @@ export class DistributionBoardSubtreeProjectCommandRepository
         );
       }
     }
+    const feedingDistributionBoardId =
+      snapshot.distributionBoard.feedingDistributionBoardId;
+    const feedingCircuitId = snapshot.distributionBoard.feedingCircuitId;
+    if (feedingDistributionBoardId === null) {
+      if (feedingCircuitId !== null) {
+        throw new Error(
+          "Ein speisender Stromkreis erfordert eine speisende Verteilung."
+        );
+      }
+    } else {
+      if (feedingDistributionBoardId === snapshot.distributionBoard.id) {
+        throw new Error("Eine Verteilung kann sich nicht selbst speisen.");
+      }
+      const projectBoards = database
+        .select({
+          id: distributionBoards.id,
+          feedingDistributionBoardId:
+            distributionBoards.feedingDistributionBoardId,
+        })
+        .from(distributionBoards)
+        .where(eq(distributionBoards.projectId, projectId))
+        .all();
+      const boardById = new Map(projectBoards.map((board) => [board.id, board]));
+      if (!boardById.has(feedingDistributionBoardId)) {
+        throw new Error(
+          "Die speisende Verteilung gehört nicht zum Projekt."
+        );
+      }
+      const visited = new Set<string>([snapshot.distributionBoard.id]);
+      let currentId: string | null = feedingDistributionBoardId;
+      while (currentId !== null) {
+        if (visited.has(currentId)) {
+          throw new Error(
+            "Die Einspeisungsverknüpfung würde einen Zyklus erzeugen."
+          );
+        }
+        visited.add(currentId);
+        currentId = boardById.get(currentId)?.feedingDistributionBoardId ?? null;
+      }
+      if (feedingCircuitId !== null) {
+        const feedingCircuit = database
+          .select({
+            projectId: circuitLists.projectId,
+            distributionBoardId: circuitLists.distributionBoardId,
+          })
+          .from(circuits)
+          .innerJoin(
+            circuitLists,
+            eq(circuitLists.id, circuits.circuitListId)
+          )
+          .where(eq(circuits.id, feedingCircuitId))
+          .get();
+        if (
+          !feedingCircuit ||
+          feedingCircuit.projectId !== projectId ||
+          feedingCircuit.distributionBoardId !== feedingDistributionBoardId
+        ) {
+          throw new Error(
+            "Der speisende Stromkreis gehört nicht zur gewählten Verteilung."
+          );
+        }
+      }
+    }
     const linkedProjectDeviceIds = uniqueStrings(
       snapshot.circuits.flatMap((circuit) =>
         circuit.deviceRows.flatMap((row) =>