From 72008ac59b2535c45b290918238b196dc0875b10 Mon Sep 17 00:00:00 2001
From: bernd <kontakt@digitalschmiede.tech>
Date: Thu, 13 Aug 2026 12:02:03 +0000
Subject: [PATCH] Auto-create a contract when a room-assigned invitation is
 accepted
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Accepting an invitation with a roomId previously only set User.roomId
— no Contract row was created. Since every tenant-facing feature
(Miet-Ampel, Vertragsdokumente, Kündigungsfristen, ...) is driven by
Contract, not User.roomId, the tenant would silently show up nowhere
despite "having" a room. Now the accept transaction also creates an
active Contract (rent/deposit defaulted from the room's baseRent/
utilityPauschal, same defaults already used by the "Wieder aufnehmen"
flow) and marks the room OCCUPIED, unless the room already has an
active contract (guards against a stale/duplicate invite race).
---
 backend/src/routes/invitations.ts | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/backend/src/routes/invitations.ts b/backend/src/routes/invitations.ts
index 76aba7c..7fc82a2 100644
--- a/backend/src/routes/invitations.ts
+++ b/backend/src/routes/invitations.ts
@@ -220,6 +220,34 @@ invitationsRouter.post('/invitations/:token/accept', async (req: Request, res: R
       where: { id: invitation.id },
       data: { status: 'ACCEPTED', acceptedAt: new Date() },
     });
+
+    // War der Einladung ein Zimmer zugeordnet, entsteht daraus jetzt auch ein
+    // Mietvertrag — sonst taucht der Mieter zwar mit roomId beim User auf,
+    // aber nirgendwo in Miet-Ampel/Vertragsdokumenten/Kündigungsfristen, da
+    // die überall an Contract hängen, nicht an User.roomId. Warmmiete/Kaution
+    // werden aus den bereits am Zimmer hinterlegten Werten übernommen (wie
+    // beim „Wieder aufnehmen“-Formular) — der Vermieter kann sie danach über
+    // den Vertragsdokumente-Bereich jederzeit anpassen.
+    if (invitation.roomId && invitation.role === UserRole.TENANT) {
+      const room = await tx.room.findUnique({ where: { id: invitation.roomId } });
+      const activeContract = room
+        ? await tx.contract.findFirst({ where: { roomId: room.id, isActive: true } })
+        : null;
+      if (room && !activeContract) {
+        await tx.contract.create({
+          data: {
+            userId: created.id,
+            roomId: room.id,
+            startDate: new Date(),
+            totalWarmRent: Number(room.baseRent) + Number(room.utilityPauschal),
+            depositAmount: Number(room.baseRent) * 3,
+            isActive: true,
+          },
+        });
+        await tx.room.update({ where: { id: room.id }, data: { status: 'OCCUPIED' } });
+      }
+    }
+
     return created;
   });