Add optional room areas

src/app/projects/[projectId]/struktur/page.tsx

@@ -48,13 +48,17 @@ import {
   filterRooms,
   groupFloorsByBuilding,
   hasFloorsWithoutBuilding,
+  hasRoomsWithoutFloor,
   normalizeBuildingSelection,
   normalizeFloorSelection,
   showsRoomsWithoutFloorEntry,
+  summarizeRoomAreas,
+  type RoomAreaSummary,
   type StructureSelection,
 } from "../../../../frontend/utils/building-structure";
 import { FormModal } from "../../../../frontend/components/form-modal";
 import { RoomModal } from "../../../../frontend/components/room-modal";
+import { formatRoomArea } from "../../../../frontend/utils/room-area";
 
 const BUILDING_HAS_FLOORS_MESSAGE =
   "Das Gebäude kann nicht gelöscht werden, solange Etagen zugeordnet sind.";
@@ -68,6 +72,23 @@ function formatCount(count: number, singular: string, plural: string) {
   return `${count} ${count === 1 ? singular : plural}`;
 }
 
+function formatAreaSummary(summary: RoomAreaSummary) {
+  return `${formatRoomArea(summary.areaM2)} m² · ${formatCount(
+    summary.missingAreaCount,
+    "Raum ohne Fläche",
+    "Räume ohne Fläche"
+  )}`;
+}
+
+function formatStructureMeta(
+  count: number,
+  singular: string,
+  plural: string,
+  summary: RoomAreaSummary
+) {
+  return `${formatCount(count, singular, plural)} · ${formatAreaSummary(summary)}`;
+}
+
 function compareRooms(left: RoomDto, right: RoomDto) {
   return (
     left.roomNumber.localeCompare(right.roomNumber, "de", { numeric: true }) ||
@@ -307,7 +328,25 @@ export default function BuildingStructurePage() {
     () => countRoomsByFloor(rooms, floors),
     [floors, rooms]
   );
-  const showUnassignedBuilding = hasFloorsWithoutBuilding(floors, buildings);
+  const areaSummaries = useMemo(
+    () => summarizeRoomAreas(rooms, floors, buildings),
+    [buildings, floors, rooms]
+  );
+  const emptyAreaSummary: RoomAreaSummary = {
+    areaM2: 0,
+    roomCount: 0,
+    missingAreaCount: 0,
+  };
+  const selectedBuildingAreaSummary =
+    effectiveBuildingSelection === ALL_SELECTION
+      ? areaSummaries.total
+      : areaSummaries.byBuilding.get(
+          effectiveBuildingSelection === UNASSIGNED_SELECTION
+            ? null
+            : effectiveBuildingSelection
+        ) ?? emptyAreaSummary;
+  const showUnassignedBuilding =
+    hasFloorsWithoutBuilding(floors, buildings) || hasRoomsWithoutFloor(rooms, floors);
   const showUnassignedFloor = showsRoomsWithoutFloorEntry(
     rooms,
     floors,
@@ -435,7 +474,8 @@ export default function BuildingStructurePage() {
       editingRoom &&
       editingRoom.roomNumber === input.roomNumber.trim() &&
       editingRoom.roomName === input.roomName.trim() &&
-      editingRoom.floorId === (input.floorId || null)
+      editingRoom.floorId === (input.floorId || null) &&
+      editingRoom.areaM2 === input.areaM2
     ) {
       setDialog(null);
       return;
@@ -536,7 +576,12 @@ export default function BuildingStructurePage() {
           <StructureEntry
             isSelected={effectiveBuildingSelection === ALL_SELECTION}
             label="Alle"
-            meta={formatCount(floors.length, "Etage", "Etagen")}
+            meta={formatStructureMeta(
+              floors.length,
+              "Etage",
+              "Etagen",
+              areaSummaries.total
+            )}
             onSelect={() => selectBuilding(ALL_SELECTION)}
           />
           {buildings.map((building) => (
@@ -553,10 +598,11 @@ export default function BuildingStructurePage() {
               isSelected={effectiveBuildingSelection === building.id}
               key={building.id}
               label={building.name}
-              meta={formatCount(
+              meta={formatStructureMeta(
                 floorCountByBuilding.get(building.id) ?? 0,
                 "Etage",
-                "Etagen"
+                "Etagen",
+                areaSummaries.byBuilding.get(building.id) ?? emptyAreaSummary
               )}
               onSelect={() => selectBuilding(building.id)}
             />
@@ -565,10 +611,11 @@ export default function BuildingStructurePage() {
             <StructureEntry
               isSelected={effectiveBuildingSelection === UNASSIGNED_SELECTION}
               label={<em>{UNASSIGNED_BUILDING_LABEL}</em>}
-              meta={formatCount(
+              meta={formatStructureMeta(
                 floorCountByBuilding.get(null) ?? 0,
                 "Etage",
-                "Etagen"
+                "Etagen",
+                areaSummaries.byBuilding.get(null) ?? emptyAreaSummary
               )}
               onSelect={() => selectBuilding(UNASSIGNED_SELECTION)}
             />
@@ -591,7 +638,12 @@ export default function BuildingStructurePage() {
           <StructureEntry
             isSelected={effectiveFloorSelection === ALL_SELECTION}
             label="Alle"
-            meta={formatCount(roomsInBuildingSelection, "Raum", "Räume")}
+            meta={formatStructureMeta(
+              roomsInBuildingSelection,
+              "Raum",
+              "Räume",
+              selectedBuildingAreaSummary
+            )}
             onSelect={() => setFloorSelection(ALL_SELECTION)}
           />
           {visibleFloorGroups.map((group) => (
@@ -613,10 +665,11 @@ export default function BuildingStructurePage() {
                   isSelected={effectiveFloorSelection === floor.id}
                   key={floor.id}
                   label={floor.name}
-                  meta={formatCount(
+                  meta={formatStructureMeta(
                     roomCountByFloor.get(floor.id) ?? 0,
                     "Raum",
-                    "Räume"
+                    "Räume",
+                    areaSummaries.byFloor.get(floor.id) ?? emptyAreaSummary
                   )}
                   onSelect={() => setFloorSelection(floor.id)}
                 />
@@ -627,7 +680,12 @@ export default function BuildingStructurePage() {
             <StructureEntry
               isSelected={effectiveFloorSelection === UNASSIGNED_SELECTION}
               label={<em>{UNASSIGNED_FLOOR_LABEL}</em>}
-              meta={formatCount(roomCountByFloor.get(null) ?? 0, "Raum", "Räume")}
+              meta={formatStructureMeta(
+                roomCountByFloor.get(null) ?? 0,
+                "Raum",
+                "Räume",
+                areaSummaries.byFloor.get(null) ?? emptyAreaSummary
+              )}
               onSelect={() => setFloorSelection(UNASSIGNED_SELECTION)}
             />
           ) : null}
@@ -671,6 +729,11 @@ export default function BuildingStructurePage() {
                   {room.roomName}
                 </>
               }
+              meta={
+                room.areaM2 === null
+                  ? "Fläche fehlt"
+                  : `${formatRoomArea(room.areaM2)} m²`
+              }
             />
           ))}
           {!visibleRooms.length && !isLoading ? (