From c383a291e1f05fc505539a431dbffccec7884e04 Mon Sep 17 00:00:00 2001
From: flfeders <f.federspiel@federspiel.tech>
Date: Wed, 9 Sep 2026 13:34:14 +0200
Subject: [PATCH] Kundeninventar-Nummern kollisionsfrei vergeben

---
 backend/src/routes/resources/main.ts          | 20 +++++++-
 backend/src/utils/functions.ts                | 34 ++++++++++---
 backend/tests/numberRangeAvailability.test.ts | 50 +++++++++++++++++++
 3 files changed, 97 insertions(+), 7 deletions(-)
 create mode 100644 backend/tests/numberRangeAvailability.test.ts

diff --git a/backend/src/routes/resources/main.ts b/backend/src/routes/resources/main.ts
index 9cefe5c..cffac5d 100644
--- a/backend/src/routes/resources/main.ts
+++ b/backend/src/routes/resources/main.ts
@@ -1035,7 +1035,25 @@ export default async function resourceRoutes(server: FastifyInstance) {
 
             if (config.numberRangeHolder && !body[config.numberRangeHolder]) {
                 const numberRangeResource = resource === "members" ? "customers" : resource
-                const result = await useNextNumberRangeNumber(server, req.user.tenant_id, numberRangeResource)
+                const numberRangeColumn = table[config.numberRangeHolder]
+                const tenantColumn = getTenantColumn(resource, table)
+                const result = await useNextNumberRangeNumber(
+                    server,
+                    req.user.tenant_id,
+                    numberRangeResource,
+                    async (candidate, tx) => {
+                        const existing = await tx
+                            .select({ id: table.id })
+                            .from(table)
+                            .where(and(
+                                eq(tenantColumn, req.user!.tenant_id),
+                                eq(numberRangeColumn, candidate)
+                            ))
+                            .limit(1)
+
+                        return existing.length === 0
+                    }
+                )
                 createData[config.numberRangeHolder] = result.usedNumber
             }
 
diff --git a/backend/src/utils/functions.ts b/backend/src/utils/functions.ts
index 764fa48..5742aa2 100644
--- a/backend/src/utils/functions.ts
+++ b/backend/src/utils/functions.ts
@@ -10,7 +10,8 @@ import { eq, sql } from "drizzle-orm"
 export const useNextNumberRangeNumber = async (
     server: FastifyInstance,
     tenantId: number,
-    numberRange: string
+    numberRange: string,
+    isAvailable: (candidate: string, tx: any) => Promise<boolean> = async () => true
 ) => {
     const numberRangeFallbacks: Record<string, string> = {
         costEstimates: "quotes",
@@ -44,18 +45,39 @@ export const useNextNumberRangeNumber = async (
         }
 
         const current = numberRanges[resolvedNumberRange]
+        let nextNumber = Number(current.nextNumber)
 
-        const usedNumber =
-            (current.prefix || "") +
-            current.nextNumber +
-            (current.suffix || "")
+        if (!Number.isFinite(nextNumber)) {
+            throw new Error(`Number range '${resolvedNumberRange}' has an invalid nextNumber`)
+        }
+
+        let usedNumber = ""
+        const maxAttempts = 10000
+
+        for (let attempt = 0; attempt < maxAttempts; attempt++) {
+            const candidate =
+                (current.prefix || "") +
+                nextNumber +
+                (current.suffix || "")
+
+            if (await isAvailable(candidate, tx)) {
+                usedNumber = candidate
+                break
+            }
+
+            nextNumber++
+        }
+
+        if (!usedNumber) {
+            throw new Error(`Could not find an available number in range '${resolvedNumberRange}'`)
+        }
 
         const updatedRanges = {
             // @ts-ignore
             ...numberRanges,
             [resolvedNumberRange]: {
                 ...current,
-                nextNumber: current.nextNumber + 1,
+                nextNumber: nextNumber + 1,
             },
         }
 
diff --git a/backend/tests/numberRangeAvailability.test.ts b/backend/tests/numberRangeAvailability.test.ts
new file mode 100644
index 0000000..1e4319a
--- /dev/null
+++ b/backend/tests/numberRangeAvailability.test.ts
@@ -0,0 +1,50 @@
+import assert from "node:assert/strict"
+import test from "node:test"
+
+import { useNextNumberRangeNumber } from "../src/utils/functions"
+
+test("number range skips identifiers that are already in use", async () => {
+    const tenant = {
+        id: 7,
+        numberRanges: {
+            customerinventoryitems: {
+                prefix: "KIA-",
+                suffix: "",
+                nextNumber: 1000,
+            },
+        },
+    }
+    let savedNumberRanges: any = null
+
+    const tx = {
+        execute: async () => undefined,
+        select: () => ({
+            from: () => ({
+                where: async () => [tenant],
+            }),
+        }),
+        update: () => ({
+            set: (data: any) => ({
+                where: async () => {
+                    savedNumberRanges = data.numberRanges
+                },
+            }),
+        }),
+    }
+    const server = {
+        db: {
+            transaction: async (callback: (transaction: typeof tx) => Promise<any>) => callback(tx),
+        },
+    } as any
+    const occupied = new Set(["KIA-1000", "KIA-1001"])
+
+    const result = await useNextNumberRangeNumber(
+        server,
+        tenant.id,
+        "customerinventoryitems",
+        async (candidate) => !occupied.has(candidate)
+    )
+
+    assert.equal(result.usedNumber, "KIA-1002")
+    assert.equal(savedNumberRanges.customerinventoryitems.nextNumber, 1003)
+})