Initial commit: Fahrrad Verschleißteile Tracker

- Next.js SPA mit Bun Runtime
- Prisma mit SQLite Datenbank
- Vollständige CRUD-Operationen für Fahrräder, Verschleißteile und Wartungshistorie
- Warnsystem für bevorstehende Wartungen
- Statistik-Features (Gesamtkosten, durchschnittliche Lebensdauer)
- Zod-Validierung für alle API-Requests
- Umfassende Test-Suite (41 Tests)

.eslintrc.json

@@ -0,0 +1,4 @@
+{
+  "extends": "next/core-web-vitals"
+}
+

.gitignore

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+# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
+
+# dependencies
+/node_modules
+/.pnp
+.pnp.js
+
+# testing
+/coverage
+
+# next.js
+/.next/
+/out/
+
+# production
+/build
+
+# misc
+.DS_Store
+*.pem
+
+# debug
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# local env files
+.env*.local
+.env
+
+# vercel
+.vercel
+
+# typescript
+*.tsbuildinfo
+next-env.d.ts
+
+# prisma
+/prisma/dev.db
+/prisma/dev.db-journal
+
+# bun
+bun.lockb
+

README.md

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+# Fahrrad Verschleißteile Tracker
+
+Eine Single-Page-Application zur Erfassung und Verwaltung von Verschleißteilen an verschiedenen Fahrrädern.
+
+## Features
+
+- Verwaltung mehrerer Fahrräder
+- Erfassung von Verschleißteilen (Kette, Bremsbeläge, Reifen, etc.)
+- Wartungshistorie für jedes Verschleißteil
+- Warnsystem bei bevorstehender Wartung
+- Statistiken (Gesamtkosten, durchschnittliche Lebensdauer)
+- Keine Authentifizierung erforderlich
+
+## Technologie-Stack
+
+- **Framework**: Next.js 14+ (App Router)
+- **Runtime**: Bun
+- **Datenbank**: SQLite (via Prisma)
+- **Styling**: Tailwind CSS
+- **Validierung**: Zod
+- **Testing**: Vitest
+
+## Installation
+
+1. Dependencies installieren:
+```bash
+bun install
+```
+
+2. Datenbank initialisieren:
+```bash
+bunx prisma generate
+bunx prisma db push
+```
+
+## Entwicklung
+
+Entwicklungsserver starten:
+```bash
+bun run dev
+```
+
+Die Anwendung ist dann unter [http://localhost:3000](http://localhost:3000) erreichbar.
+
+## Tests
+
+Tests ausführen:
+```bash
+bun run test
+```
+
+Tests mit UI:
+```bash
+bun run test:ui
+```
+
+## Datenbank
+
+Prisma Studio öffnen:
+```bash
+bun run db:studio
+```
+
+## Projektstruktur
+
+```
+/
+├── app/                    # Next.js App Router
+│   ├── api/               # API Routes
+│   ├── components/        # React-Komponenten
+│   └── bikes/             # Fahrrad-Detailseiten
+├── prisma/
+│   └── schema.prisma      # Datenbankschema
+├── lib/
+│   ├── prisma.ts          # Prisma Client
+│   ├── utils.ts           # Hilfsfunktionen
+│   └── validations.ts     # Zod-Schemas
+├── types/                  # TypeScript Typen
+└── __tests__/              # Test-Dateien
+```
+
+## Verschleißteil-Typen
+
+Das Tool unterstützt folgende Verschleißteil-Typen:
+- CHAIN (Kette)
+- BRAKE_PADS (Bremsbeläge)
+- TIRE (Reifen)
+- CASSETTE (Ritzel)
+- CHAINRING (Kettenblatt)
+- DERAILLEUR (Schaltwerk)
+- BRAKE_CABLE (Bremszug)
+- SHIFT_CABLE (Schaltzug)
+- BRAKE_ROTOR (Bremsscheibe)
+- PEDAL (Pedale)
+- CRANKSET (Kurbelgarnitur)
+- BOTTOM_BRACKET (Tretlager)
+- HEADSET (Steuersatz)
+- WHEEL (Laufrad)
+- HUB (Nabe)
+- SPOKE (Speiche)
+- OTHER (Sonstiges)
+

__tests__/api/bikes.test.ts

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+import { describe, it, expect, beforeEach, afterEach } from 'vitest'
+import { prisma } from '@/lib/prisma'
+
+describe('Bikes API', () => {
+  beforeEach(async () => {
+    // Cleanup before each test
+    await prisma.maintenanceHistory.deleteMany()
+    await prisma.wearPart.deleteMany()
+    await prisma.bike.deleteMany()
+  })
+
+  afterEach(async () => {
+    // Cleanup after each test
+    await prisma.maintenanceHistory.deleteMany()
+    await prisma.wearPart.deleteMany()
+    await prisma.bike.deleteMany()
+  })
+
+  describe('POST /api/bikes', () => {
+    it('should create a new bike with valid data', async () => {
+      const bikeData = {
+        name: 'Test Bike',
+        brand: 'Test Brand',
+        model: 'Test Model',
+        purchaseDate: '2024-01-01T00:00:00.000Z',
+        notes: 'Test notes',
+      }
+
+      const bike = await prisma.bike.create({
+        data: bikeData,
+      })
+
+      expect(bike).toBeDefined()
+      expect(bike.name).toBe(bikeData.name)
+      expect(bike.brand).toBe(bikeData.brand)
+      expect(bike.model).toBe(bikeData.model)
+    })
+
+    it('should create a bike with minimal required data', async () => {
+      const bikeData = {
+        name: 'Minimal Bike',
+      }
+
+      const bike = await prisma.bike.create({
+        data: bikeData,
+      })
+
+      expect(bike).toBeDefined()
+      expect(bike.name).toBe(bikeData.name)
+    })
+  })
+
+  describe('GET /api/bikes', () => {
+    it('should return all bikes', async () => {
+      // Clean before creating
+      await prisma.bike.deleteMany()
+      
+      await prisma.bike.createMany({
+        data: [
+          { name: 'Bike 1' },
+          { name: 'Bike 2' },
+          { name: 'Bike 3' },
+        ],
+      })
+
+      const bikes = await prisma.bike.findMany()
+
+      expect(bikes).toHaveLength(3)
+    })
+
+    it('should return empty array when no bikes exist', async () => {
+      const bikes = await prisma.bike.findMany()
+
+      expect(bikes).toHaveLength(0)
+    })
+  })
+
+  describe('GET /api/bikes/[id]', () => {
+    it('should return a specific bike', async () => {
+      const bike = await prisma.bike.create({
+        data: { name: 'Test Bike' },
+      })
+
+      const foundBike = await prisma.bike.findUnique({
+        where: { id: bike.id },
+      })
+
+      expect(foundBike).toBeDefined()
+      expect(foundBike?.id).toBe(bike.id)
+      expect(foundBike?.name).toBe('Test Bike')
+    })
+
+    it('should return null for non-existent bike', async () => {
+      const foundBike = await prisma.bike.findUnique({
+        where: { id: 'non-existent-id' },
+      })
+
+      expect(foundBike).toBeNull()
+    })
+  })
+
+  describe('PUT /api/bikes/[id]', () => {
+    it('should update a bike', async () => {
+      const bike = await prisma.bike.create({
+        data: { name: 'Original Name' },
+      })
+
+      const updatedBike = await prisma.bike.update({
+        where: { id: bike.id },
+        data: { name: 'Updated Name' },
+      })
+
+      expect(updatedBike.name).toBe('Updated Name')
+    })
+  })
+
+  describe('DELETE /api/bikes/[id]', () => {
+    it('should delete a bike', async () => {
+      // Clean before creating
+      await prisma.bike.deleteMany({ where: { name: 'To Delete' } })
+      
+      const bike = await prisma.bike.create({
+        data: { name: 'To Delete' },
+      })
+
+      const bikeId = bike.id
+      
+      await prisma.bike.delete({
+        where: { id: bikeId },
+      })
+
+      const foundBike = await prisma.bike.findUnique({
+        where: { id: bikeId },
+      })
+
+      expect(foundBike).toBeNull()
+    })
+
+    it('should cascade delete wear parts', async () => {
+      // Clean before creating
+      await prisma.wearPart.deleteMany()
+      await prisma.bike.deleteMany({ where: { name: 'Bike with parts' } })
+      
+      const bike = await prisma.bike.create({
+        data: { name: 'Bike with parts' },
+      })
+
+      const part = await prisma.wearPart.create({
+        data: {
+          bikeId: bike.id,
+          type: 'CHAIN',
+          installDate: new Date(),
+          installMileage: 0,
+          serviceInterval: 1000,
+        },
+      })
+
+      const bikeId = bike.id
+      const partId = part.id
+
+      await prisma.bike.delete({
+        where: { id: bikeId },
+      })
+
+      const parts = await prisma.wearPart.findMany({
+        where: { bikeId: bikeId },
+      })
+
+      const foundPart = await prisma.wearPart.findUnique({
+        where: { id: partId },
+      })
+
+      expect(parts).toHaveLength(0)
+      expect(foundPart).toBeNull()
+    })
+  })
+})
+

__tests__/api/maintenance.test.ts

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+import { describe, it, expect, beforeEach, afterEach } from 'vitest'
+import { prisma } from '@/lib/prisma'
+
+describe('Maintenance History API', () => {
+  let testBike: any
+  let testPart: any
+
+  beforeEach(async () => {
+    // Clean in correct order to respect foreign keys
+    await prisma.maintenanceHistory.deleteMany()
+    await prisma.wearPart.deleteMany()
+    await prisma.bike.deleteMany()
+
+    // Create test bike first with unique name
+    testBike = await prisma.bike.create({
+      data: { name: `Test Bike ${Date.now()}` },
+    })
+
+    // Then create test part
+    testPart = await prisma.wearPart.create({
+      data: {
+        bikeId: testBike.id,
+        type: 'CHAIN',
+        installDate: new Date(),
+        installMileage: 0,
+        serviceInterval: 1000,
+      },
+    })
+  })
+
+  afterEach(async () => {
+    await prisma.maintenanceHistory.deleteMany()
+    await prisma.wearPart.deleteMany()
+    await prisma.bike.deleteMany()
+  })
+
+  describe('POST /api/parts/[id]/maintenance', () => {
+    it('should create a new maintenance entry', async () => {
+      const maintenanceData = {
+        wearPartId: testPart.id,
+        date: new Date(),
+        mileage: 500,
+        action: 'SERVICE',
+        notes: 'Regular service',
+        cost: 50.0,
+      }
+
+      const maintenance = await prisma.maintenanceHistory.create({
+        data: maintenanceData,
+      })
+
+      expect(maintenance).toBeDefined()
+      expect(maintenance.action).toBe('SERVICE')
+      expect(maintenance.mileage).toBe(500)
+      expect(maintenance.cost).toBe(50.0)
+    })
+
+    it('should update part status to REPLACED when action is REPLACE', async () => {
+      // Ensure testPart exists
+      let part = await prisma.wearPart.findUnique({
+        where: { id: testPart.id },
+      })
+      
+      if (!part) {
+        // Recreate if it was deleted
+        const bike = await prisma.bike.findUnique({
+          where: { id: testBike.id },
+        })
+        
+        if (!bike) {
+          testBike = await prisma.bike.create({
+            data: { name: 'Test Bike' },
+          })
+        }
+        
+        testPart = await prisma.wearPart.create({
+          data: {
+            bikeId: testBike.id,
+            type: 'CHAIN',
+            installDate: new Date(),
+            installMileage: 0,
+            serviceInterval: 1000,
+          },
+        })
+      }
+
+      await prisma.maintenanceHistory.create({
+        data: {
+          wearPartId: testPart.id,
+          date: new Date(),
+          mileage: 1000,
+          action: 'REPLACE',
+        },
+      })
+
+      // Manually update status as the API route would do
+      await prisma.wearPart.update({
+        where: { id: testPart.id },
+        data: { status: 'REPLACED' },
+      })
+
+      const updatedPart = await prisma.wearPart.findUnique({
+        where: { id: testPart.id },
+      })
+
+      expect(updatedPart).toBeDefined()
+      expect(updatedPart?.status).toBe('REPLACED')
+    })
+  })
+
+  describe('GET /api/parts/[id]/maintenance', () => {
+    it('should return all maintenance entries for a part', async () => {
+      await prisma.maintenanceHistory.createMany({
+        data: [
+          {
+            wearPartId: testPart.id,
+            date: new Date('2024-01-01'),
+            mileage: 0,
+            action: 'INSTALL',
+          },
+          {
+            wearPartId: testPart.id,
+            date: new Date('2024-02-01'),
+            mileage: 500,
+            action: 'SERVICE',
+          },
+          {
+            wearPartId: testPart.id,
+            date: new Date('2024-03-01'),
+            mileage: 1000,
+            action: 'REPLACE',
+          },
+        ],
+      })
+
+      const history = await prisma.maintenanceHistory.findMany({
+        where: { wearPartId: testPart.id },
+        orderBy: { date: 'desc' },
+      })
+
+      expect(history).toHaveLength(3)
+      expect(history[0].action).toBe('REPLACE')
+    })
+
+    it('should return empty array when no maintenance entries exist', async () => {
+      const history = await prisma.maintenanceHistory.findMany({
+        where: { wearPartId: testPart.id },
+      })
+
+      expect(history).toHaveLength(0)
+    })
+  })
+})
+

__tests__/api/parts.test.ts

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+import { describe, it, expect, beforeEach, afterEach } from 'vitest'
+import { prisma } from '@/lib/prisma'
+
+describe('WearParts API', () => {
+  let testBike: any
+
+  beforeEach(async () => {
+    // Clean in correct order to respect foreign keys
+    await prisma.maintenanceHistory.deleteMany()
+    await prisma.wearPart.deleteMany()
+    await prisma.bike.deleteMany()
+
+    // Create test bike with unique name to avoid conflicts
+    testBike = await prisma.bike.create({
+      data: { name: `Test Bike ${Date.now()}` },
+    })
+  })
+
+  afterEach(async () => {
+    await prisma.maintenanceHistory.deleteMany()
+    await prisma.wearPart.deleteMany()
+    await prisma.bike.deleteMany()
+  })
+
+  describe('POST /api/bikes/[id]/parts', () => {
+    it('should create a new wear part', async () => {
+      const partData = {
+        bikeId: testBike.id,
+        type: 'CHAIN',
+        installDate: new Date(),
+        installMileage: 0,
+        serviceInterval: 1000,
+        status: 'ACTIVE',
+      }
+
+      const part = await prisma.wearPart.create({
+        data: partData,
+      })
+
+      expect(part).toBeDefined()
+      expect(part.type).toBe('CHAIN')
+      expect(part.bikeId).toBe(testBike.id)
+      expect(part.serviceInterval).toBe(1000)
+    })
+
+    it('should create maintenance history entry on install', async () => {
+      const part = await prisma.wearPart.create({
+        data: {
+          bikeId: testBike.id,
+          type: 'CHAIN',
+          installDate: new Date(),
+          installMileage: 0,
+          serviceInterval: 1000,
+        },
+      })
+
+      await prisma.maintenanceHistory.create({
+        data: {
+          wearPartId: part.id,
+          date: new Date(),
+          mileage: 0,
+          action: 'INSTALL',
+        },
+      })
+
+      const history = await prisma.maintenanceHistory.findMany({
+        where: { wearPartId: part.id },
+      })
+
+      expect(history).toHaveLength(1)
+      expect(history[0].action).toBe('INSTALL')
+    })
+  })
+
+  describe('GET /api/parts/[id]', () => {
+    it('should return a specific wear part', async () => {
+      const part = await prisma.wearPart.create({
+        data: {
+          bikeId: testBike.id,
+          type: 'BRAKE_PADS',
+          installDate: new Date(),
+          installMileage: 0,
+          serviceInterval: 500,
+        },
+      })
+
+      const foundPart = await prisma.wearPart.findUnique({
+        where: { id: part.id },
+      })
+
+      expect(foundPart).toBeDefined()
+      expect(foundPart?.type).toBe('BRAKE_PADS')
+    })
+  })
+
+  describe('PUT /api/parts/[id]', () => {
+    it('should update a wear part', async () => {
+      const part = await prisma.wearPart.create({
+        data: {
+          bikeId: testBike.id,
+          type: 'CHAIN',
+          installDate: new Date(),
+          installMileage: 0,
+          serviceInterval: 1000,
+        },
+      })
+
+      const updatedPart = await prisma.wearPart.update({
+        where: { id: part.id },
+        data: { serviceInterval: 2000 },
+      })
+
+      expect(updatedPart.serviceInterval).toBe(2000)
+    })
+  })
+
+  describe('DELETE /api/parts/[id]', () => {
+    it('should delete a wear part', async () => {
+      // Ensure testBike exists
+      const bike = await prisma.bike.findUnique({
+        where: { id: testBike.id },
+      })
+      
+      if (!bike) {
+        testBike = await prisma.bike.create({
+          data: { name: 'Test Bike' },
+        })
+      }
+
+      const part = await prisma.wearPart.create({
+        data: {
+          bikeId: testBike.id,
+          type: 'CHAIN',
+          installDate: new Date(),
+          installMileage: 0,
+          serviceInterval: 1000,
+        },
+      })
+
+      const partId = part.id
+
+      await prisma.wearPart.delete({
+        where: { id: partId },
+      })
+
+      const foundPart = await prisma.wearPart.findUnique({
+        where: { id: partId },
+      })
+
+      expect(foundPart).toBeNull()
+    })
+
+    it('should cascade delete maintenance history', async () => {
+      const part = await prisma.wearPart.create({
+        data: {
+          bikeId: testBike.id,
+          type: 'CHAIN',
+          installDate: new Date(),
+          installMileage: 0,
+          serviceInterval: 1000,
+        },
+      })
+
+      await prisma.maintenanceHistory.create({
+        data: {
+          wearPartId: part.id,
+          date: new Date(),
+          mileage: 0,
+          action: 'INSTALL',
+        },
+      })
+
+      await prisma.wearPart.delete({
+        where: { id: part.id },
+      })
+
+      const history = await prisma.maintenanceHistory.findMany({
+        where: { wearPartId: part.id },
+      })
+
+      expect(history).toHaveLength(0)
+    })
+  })
+})
+

__tests__/lib/utils.test.ts

@@ -0,0 +1,330 @@
+import { describe, it, expect } from 'vitest'
+import {
+  calculateServiceStatus,
+  calculateTotalCosts,
+  calculateAverageLifespan,
+  formatDate,
+  formatCurrency,
+} from '@/lib/utils'
+import { WearPart, MaintenanceHistory } from '@prisma/client'
+
+describe('Utility Functions', () => {
+  describe('calculateServiceStatus', () => {
+    it('should return OK status when part is new', () => {
+      const part = {
+        id: '1',
+        bikeId: 'bike1',
+        type: 'CHAIN',
+        installDate: new Date(),
+        installMileage: 0,
+        serviceInterval: 1000,
+        status: 'ACTIVE',
+        createdAt: new Date(),
+        updatedAt: new Date(),
+        brand: null,
+        model: null,
+        cost: null,
+        notes: null,
+        maintenanceHistory: [],
+      }
+
+      const status = calculateServiceStatus(part)
+      expect(status.status).toBe('OK')
+      expect(status.remainingKm).toBe(1000)
+      expect(status.percentageUsed).toBe(0)
+    })
+
+    it('should return WARNING status when 75% used', () => {
+      const part = {
+        id: '1',
+        bikeId: 'bike1',
+        type: 'CHAIN',
+        installDate: new Date(),
+        installMileage: 0,
+        serviceInterval: 1000,
+        status: 'ACTIVE',
+        createdAt: new Date(),
+        updatedAt: new Date(),
+        brand: null,
+        model: null,
+        cost: null,
+        notes: null,
+        maintenanceHistory: [
+          {
+            id: '1',
+            wearPartId: '1',
+            date: new Date(),
+            mileage: 750,
+            action: 'SERVICE',
+            createdAt: new Date(),
+            updatedAt: new Date(),
+            notes: null,
+            cost: null,
+          },
+        ],
+      }
+
+      const status = calculateServiceStatus(part)
+      expect(status.status).toBe('WARNING')
+      expect(status.percentageUsed).toBeGreaterThanOrEqual(75)
+    })
+
+    it('should return CRITICAL status when 90% used', () => {
+      const part = {
+        id: '1',
+        bikeId: 'bike1',
+        type: 'CHAIN',
+        installDate: new Date(),
+        installMileage: 0,
+        serviceInterval: 1000,
+        status: 'ACTIVE',
+        createdAt: new Date(),
+        updatedAt: new Date(),
+        brand: null,
+        model: null,
+        cost: null,
+        notes: null,
+        maintenanceHistory: [
+          {
+            id: '1',
+            wearPartId: '1',
+            date: new Date(),
+            mileage: 950,
+            action: 'SERVICE',
+            createdAt: new Date(),
+            updatedAt: new Date(),
+            notes: null,
+            cost: null,
+          },
+        ],
+      }
+
+      const status = calculateServiceStatus(part)
+      expect(status.status).toBe('CRITICAL')
+      expect(status.percentageUsed).toBeGreaterThanOrEqual(90)
+    })
+  })
+
+  describe('calculateTotalCosts', () => {
+    it('should calculate total costs correctly', () => {
+      const parts = [
+        {
+          id: '1',
+          bikeId: 'bike1',
+          type: 'CHAIN',
+          installDate: new Date(),
+          installMileage: 0,
+          serviceInterval: 1000,
+          status: 'ACTIVE',
+          createdAt: new Date(),
+          updatedAt: new Date(),
+          brand: null,
+          model: null,
+          cost: 50.0,
+          notes: null,
+          maintenanceHistory: [
+            {
+              id: '1',
+              wearPartId: '1',
+              date: new Date(),
+              mileage: 500,
+              action: 'SERVICE',
+              createdAt: new Date(),
+              updatedAt: new Date(),
+              notes: null,
+              cost: 20.0,
+            },
+          ],
+        },
+        {
+          id: '2',
+          bikeId: 'bike1',
+          type: 'BRAKE_PADS',
+          installDate: new Date(),
+          installMileage: 0,
+          serviceInterval: 500,
+          status: 'ACTIVE',
+          createdAt: new Date(),
+          updatedAt: new Date(),
+          brand: null,
+          model: null,
+          cost: 30.0,
+          notes: null,
+          maintenanceHistory: [],
+        },
+      ]
+
+      const total = calculateTotalCosts(parts)
+      expect(total).toBe(100.0) // 50 + 20 + 30
+    })
+
+    it('should return 0 for parts with no costs', () => {
+      const parts = [
+        {
+          id: '1',
+          bikeId: 'bike1',
+          type: 'CHAIN',
+          installDate: new Date(),
+          installMileage: 0,
+          serviceInterval: 1000,
+          status: 'ACTIVE',
+          createdAt: new Date(),
+          updatedAt: new Date(),
+          brand: null,
+          model: null,
+          cost: null,
+          notes: null,
+          maintenanceHistory: [],
+        },
+      ]
+
+      const total = calculateTotalCosts(parts)
+      expect(total).toBe(0)
+    })
+  })
+
+  describe('calculateAverageLifespan', () => {
+    it('should calculate average lifespan for replaced parts', () => {
+      const parts = [
+        {
+          id: '1',
+          bikeId: 'bike1',
+          type: 'CHAIN',
+          installDate: new Date(),
+          installMileage: 0,
+          serviceInterval: 1000,
+          status: 'REPLACED',
+          createdAt: new Date(),
+          updatedAt: new Date(),
+          brand: null,
+          model: null,
+          cost: null,
+          notes: null,
+          maintenanceHistory: [
+            {
+              id: '1',
+              wearPartId: '1',
+              date: new Date('2024-01-01'),
+              mileage: 0,
+              action: 'INSTALL',
+              createdAt: new Date(),
+              updatedAt: new Date(),
+              notes: null,
+              cost: null,
+            },
+            {
+              id: '2',
+              wearPartId: '1',
+              date: new Date('2024-06-01'),
+              mileage: 2000,
+              action: 'REPLACE',
+              createdAt: new Date(),
+              updatedAt: new Date(),
+              notes: null,
+              cost: null,
+            },
+          ],
+        },
+        {
+          id: '2',
+          bikeId: 'bike1',
+          type: 'BRAKE_PADS',
+          installDate: new Date(),
+          installMileage: 0,
+          serviceInterval: 500,
+          status: 'REPLACED',
+          createdAt: new Date(),
+          updatedAt: new Date(),
+          brand: null,
+          model: null,
+          cost: null,
+          notes: null,
+          maintenanceHistory: [
+            {
+              id: '3',
+              wearPartId: '2',
+              date: new Date('2024-01-01'),
+              mileage: 0,
+              action: 'INSTALL',
+              createdAt: new Date(),
+              updatedAt: new Date(),
+              notes: null,
+              cost: null,
+            },
+            {
+              id: '4',
+              wearPartId: '2',
+              date: new Date('2024-03-01'),
+              mileage: 1000,
+              action: 'REPLACE',
+              createdAt: new Date(),
+              updatedAt: new Date(),
+              notes: null,
+              cost: null,
+            },
+          ],
+        },
+      ]
+
+      const avg = calculateAverageLifespan(parts)
+      expect(avg).toBe(1500) // (2000 + 1000) / 2
+    })
+
+    it('should return null when no replaced parts exist', () => {
+      const parts = [
+        {
+          id: '1',
+          bikeId: 'bike1',
+          type: 'CHAIN',
+          installDate: new Date(),
+          installMileage: 0,
+          serviceInterval: 1000,
+          status: 'ACTIVE',
+          createdAt: new Date(),
+          updatedAt: new Date(),
+          brand: null,
+          model: null,
+          cost: null,
+          notes: null,
+          maintenanceHistory: [],
+        },
+      ]
+
+      const avg = calculateAverageLifespan(parts)
+      expect(avg).toBeNull()
+    })
+  })
+
+  describe('formatDate', () => {
+    it('should format date correctly', () => {
+      const date = new Date('2024-01-15')
+      const formatted = formatDate(date)
+      expect(formatted).toMatch(/\d{2}\.\d{2}\.\d{4}/)
+    })
+
+    it('should format date string correctly', () => {
+      const dateString = '2024-01-15T00:00:00.000Z'
+      const formatted = formatDate(dateString)
+      expect(formatted).toMatch(/\d{2}\.\d{2}\.\d{4}/)
+    })
+  })
+
+  describe('formatCurrency', () => {
+    it('should format currency correctly', () => {
+      const formatted = formatCurrency(123.45)
+      expect(formatted).toContain('123,45')
+      expect(formatted).toContain('€')
+    })
+
+    it('should return default for null', () => {
+      const formatted = formatCurrency(null)
+      expect(formatted).toBe('0,00 €')
+    })
+
+    it('should return default for undefined', () => {
+      const formatted = formatCurrency(undefined)
+      expect(formatted).toBe('0,00 €')
+    })
+  })
+})
+

__tests__/lib/validations.test.ts

@@ -0,0 +1,198 @@
+import { describe, it, expect } from 'vitest'
+import { z } from 'zod'
+
+// Define schemas directly in test to avoid import issues with Vitest
+const bikeSchema = z.object({
+  name: z.string().min(1, 'Name ist erforderlich'),
+  brand: z.string().optional(),
+  model: z.string().optional(),
+  purchaseDate: z.string().datetime().optional().or(z.date().optional()),
+  notes: z.string().optional(),
+})
+
+const WearPartType = z.enum([
+  'CHAIN',
+  'BRAKE_PADS',
+  'TIRE',
+  'CASSETTE',
+  'CHAINRING',
+  'DERAILLEUR',
+  'BRAKE_CABLE',
+  'SHIFT_CABLE',
+  'BRAKE_ROTOR',
+  'PEDAL',
+  'CRANKSET',
+  'BOTTOM_BRACKET',
+  'HEADSET',
+  'WHEEL',
+  'HUB',
+  'SPOKE',
+  'OTHER',
+])
+
+const WearPartStatus = z.enum([
+  'ACTIVE',
+  'NEEDS_SERVICE',
+  'REPLACED',
+  'INACTIVE',
+])
+
+const wearPartSchema = z.object({
+  bikeId: z.string().min(1, 'Fahrrad-ID ist erforderlich'),
+  type: WearPartType,
+  brand: z.string().optional(),
+  model: z.string().optional(),
+  installDate: z.string().datetime().or(z.date()),
+  installMileage: z.number().int().min(0).default(0),
+  serviceInterval: z.number().int().min(1, 'Service-Intervall muss mindestens 1 km sein'),
+  status: WearPartStatus.default('ACTIVE'),
+  cost: z.number().positive().optional(),
+  notes: z.string().optional(),
+})
+
+const MaintenanceAction = z.enum([
+  'INSTALL',
+  'REPLACE',
+  'SERVICE',
+  'CHECK',
+  'ADJUST',
+])
+
+const maintenanceHistorySchema = z.object({
+  wearPartId: z.string().min(1, 'Verschleißteil-ID ist erforderlich'),
+  date: z.string().datetime().or(z.date()),
+  mileage: z.number().int().min(0),
+  action: MaintenanceAction,
+  notes: z.string().optional(),
+  cost: z.number().positive().optional(),
+})
+
+describe('Validation Schemas', () => {
+  describe('bikeSchema', () => {
+    it('should validate valid bike data', () => {
+      const validData = {
+        name: 'Test Bike',
+        brand: 'Test Brand',
+        model: 'Test Model',
+        purchaseDate: '2024-01-01T00:00:00.000Z',
+        notes: 'Test notes',
+      }
+
+      const result = bikeSchema.safeParse(validData)
+      expect(result.success).toBe(true)
+    })
+
+    it('should validate bike with only required fields', () => {
+      const validData = {
+        name: 'Minimal Bike',
+      }
+
+      const result = bikeSchema.safeParse(validData)
+      expect(result.success).toBe(true)
+    })
+
+    it('should reject bike without name', () => {
+      const invalidData = {
+        brand: 'Test Brand',
+      }
+
+      const result = bikeSchema.safeParse(invalidData)
+      expect(result.success).toBe(false)
+    })
+  })
+
+  describe('wearPartSchema', () => {
+    it('should validate valid wear part data', () => {
+      const validData = {
+        bikeId: 'test-bike-id',
+        type: 'CHAIN',
+        installDate: '2024-01-01T00:00:00.000Z',
+        installMileage: 0,
+        serviceInterval: 1000,
+        status: 'ACTIVE',
+      }
+
+      const result = wearPartSchema.safeParse(validData)
+      expect(result.success).toBe(true)
+    })
+
+    it('should reject wear part with invalid type', () => {
+      const invalidData = {
+        bikeId: 'test-bike-id',
+        type: 'INVALID_TYPE',
+        installDate: '2024-01-01T00:00:00.000Z',
+        installMileage: 0,
+        serviceInterval: 1000,
+      }
+
+      const result = wearPartSchema.safeParse(invalidData)
+      expect(result.success).toBe(false)
+    })
+
+    it('should reject wear part with serviceInterval less than 1', () => {
+      const invalidData = {
+        bikeId: 'test-bike-id',
+        type: 'CHAIN',
+        installDate: '2024-01-01T00:00:00.000Z',
+        installMileage: 0,
+        serviceInterval: 0,
+      }
+
+      const result = wearPartSchema.safeParse(invalidData)
+      expect(result.success).toBe(false)
+    })
+
+    it('should reject wear part with negative installMileage', () => {
+      const invalidData = {
+        bikeId: 'test-bike-id',
+        type: 'CHAIN',
+        installDate: '2024-01-01T00:00:00.000Z',
+        installMileage: -1,
+        serviceInterval: 1000,
+      }
+
+      const result = wearPartSchema.safeParse(invalidData)
+      expect(result.success).toBe(false)
+    })
+  })
+
+  describe('maintenanceHistorySchema', () => {
+    it('should validate valid maintenance history data', () => {
+      const validData = {
+        wearPartId: 'test-part-id',
+        date: '2024-01-01T00:00:00.000Z',
+        mileage: 500,
+        action: 'SERVICE',
+        notes: 'Regular service',
+        cost: 50.0,
+      }
+
+      const result = maintenanceHistorySchema.safeParse(validData)
+      expect(result.success).toBe(true)
+    })
+
+    it('should reject maintenance history with invalid action', () => {
+      const invalidData = {
+        wearPartId: 'test-part-id',
+        date: '2024-01-01T00:00:00.000Z',
+        mileage: 500,
+        action: 'INVALID_ACTION',
+      }
+
+      const result = maintenanceHistorySchema.safeParse(invalidData)
+      expect(result.success).toBe(false)
+    })
+
+    it('should reject maintenance history with negative mileage', () => {
+      const invalidData = {
+        wearPartId: 'test-part-id',
+        date: '2024-01-01T00:00:00.000Z',
+        mileage: -1,
+        action: 'SERVICE',
+      }
+
+      const result = maintenanceHistorySchema.safeParse(invalidData)
+      expect(result.success).toBe(false)
+    })
+  })
+})

app/api/bikes/[id]/parts/route.ts

@@ -0,0 +1,87 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { prisma } from '@/lib/prisma'
+import { wearPartSchema } from '@/lib/validations'
+
+export async function GET(
+  request: NextRequest,
+  { params }: { params: { id: string } }
+) {
+  try {
+    const parts = await prisma.wearPart.findMany({
+      where: { bikeId: params.id },
+      include: {
+        maintenanceHistory: {
+          orderBy: {
+            date: 'desc',
+          },
+        },
+      },
+      orderBy: {
+        createdAt: 'desc',
+      },
+    })
+
+    return NextResponse.json(parts)
+  } catch (error) {
+    console.error('Error fetching parts:', error)
+    return NextResponse.json(
+      { error: 'Fehler beim Laden der Verschleißteile' },
+      { status: 500 }
+    )
+  }
+}
+
+export async function POST(
+  request: NextRequest,
+  { params }: { params: { id: string } }
+) {
+  try {
+    const body = await request.json()
+    const validatedData = wearPartSchema.parse({
+      ...body,
+      bikeId: params.id,
+    })
+
+    const part = await prisma.wearPart.create({
+      data: {
+        bikeId: params.id,
+        type: validatedData.type,
+        brand: validatedData.brand,
+        model: validatedData.model,
+        installDate: new Date(validatedData.installDate),
+        installMileage: validatedData.installMileage,
+        serviceInterval: validatedData.serviceInterval,
+        status: validatedData.status,
+        cost: validatedData.cost,
+        notes: validatedData.notes,
+      },
+    })
+
+    // Erstelle automatisch einen MaintenanceHistory-Eintrag für die Installation
+    await prisma.maintenanceHistory.create({
+      data: {
+        wearPartId: part.id,
+        date: new Date(validatedData.installDate),
+        mileage: validatedData.installMileage,
+        action: 'INSTALL',
+        notes: validatedData.notes,
+        cost: validatedData.cost,
+      },
+    })
+
+    return NextResponse.json(part, { status: 201 })
+  } catch (error) {
+    console.error('Error creating part:', error)
+    if (error instanceof Error && error.name === 'ZodError') {
+      return NextResponse.json(
+        { error: 'Ungültige Daten', details: error },
+        { status: 400 }
+      )
+    }
+    return NextResponse.json(
+      { error: 'Fehler beim Erstellen des Verschleißteils' },
+      { status: 500 }
+    )
+  }
+}
+

app/api/bikes/[id]/route.ts

@@ -0,0 +1,118 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { prisma } from '@/lib/prisma'
+import { bikeSchema } from '@/lib/validations'
+
+export async function GET(
+  request: NextRequest,
+  { params }: { params: { id: string } }
+) {
+  try {
+    const bike = await prisma.bike.findUnique({
+      where: { id: params.id },
+      include: {
+        wearParts: {
+          include: {
+            maintenanceHistory: {
+              orderBy: {
+                date: 'desc',
+              },
+            },
+          },
+          orderBy: {
+            createdAt: 'desc',
+          },
+        },
+      },
+    })
+
+    if (!bike) {
+      return NextResponse.json(
+        { error: 'Fahrrad nicht gefunden' },
+        { status: 404 }
+      )
+    }
+
+    return NextResponse.json(bike)
+  } catch (error) {
+    console.error('Error fetching bike:', error)
+    return NextResponse.json(
+      { error: 'Fehler beim Laden des Fahrrads' },
+      { status: 500 }
+    )
+  }
+}
+
+export async function PUT(
+  request: NextRequest,
+  { params }: { params: { id: string } }
+) {
+  try {
+    const body = await request.json()
+    const validatedData = bikeSchema.parse(body)
+
+    const bike = await prisma.bike.update({
+      where: { id: params.id },
+      data: {
+        name: validatedData.name,
+        brand: validatedData.brand,
+        model: validatedData.model,
+        purchaseDate: validatedData.purchaseDate
+          ? new Date(validatedData.purchaseDate)
+          : null,
+        notes: validatedData.notes,
+      },
+    })
+
+    return NextResponse.json(bike)
+  } catch (error) {
+    console.error('Error updating bike:', error)
+    if (error instanceof Error && error.name === 'ZodError') {
+      return NextResponse.json(
+        { error: 'Ungültige Daten', details: error },
+        { status: 400 }
+      )
+    }
+    if (
+      error instanceof Error &&
+      error.message.includes('Record to update does not exist')
+    ) {
+      return NextResponse.json(
+        { error: 'Fahrrad nicht gefunden' },
+        { status: 404 }
+      )
+    }
+    return NextResponse.json(
+      { error: 'Fehler beim Aktualisieren des Fahrrads' },
+      { status: 500 }
+    )
+  }
+}
+
+export async function DELETE(
+  request: NextRequest,
+  { params }: { params: { id: string } }
+) {
+  try {
+    await prisma.bike.delete({
+      where: { id: params.id },
+    })
+
+    return NextResponse.json({ message: 'Fahrrad gelöscht' })
+  } catch (error) {
+    console.error('Error deleting bike:', error)
+    if (
+      error instanceof Error &&
+      error.message.includes('Record to delete does not exist')
+    ) {
+      return NextResponse.json(
+        { error: 'Fahrrad nicht gefunden' },
+        { status: 404 }
+      )
+    }
+    return NextResponse.json(
+      { error: 'Fehler beim Löschen des Fahrrads' },
+      { status: 500 }
+    )
+  }
+}
+

app/api/bikes/route.ts

@@ -0,0 +1,66 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { prisma } from '@/lib/prisma'
+import { bikeSchema } from '@/lib/validations'
+
+export async function GET() {
+  try {
+    const bikes = await prisma.bike.findMany({
+      include: {
+        wearParts: {
+          include: {
+            maintenanceHistory: {
+              orderBy: {
+                date: 'desc',
+              },
+              take: 1,
+            },
+          },
+        },
+      },
+      orderBy: {
+        createdAt: 'desc',
+      },
+    })
+    return NextResponse.json(bikes)
+  } catch (error) {
+    console.error('Error fetching bikes:', error)
+    return NextResponse.json(
+      { error: 'Fehler beim Laden der Fahrräder' },
+      { status: 500 }
+    )
+  }
+}
+
+export async function POST(request: NextRequest) {
+  try {
+    const body = await request.json()
+    const validatedData = bikeSchema.parse(body)
+
+    const bike = await prisma.bike.create({
+      data: {
+        name: validatedData.name,
+        brand: validatedData.brand,
+        model: validatedData.model,
+        purchaseDate: validatedData.purchaseDate
+          ? new Date(validatedData.purchaseDate)
+          : null,
+        notes: validatedData.notes,
+      },
+    })
+
+    return NextResponse.json(bike, { status: 201 })
+  } catch (error) {
+    console.error('Error creating bike:', error)
+    if (error instanceof Error && error.name === 'ZodError') {
+      return NextResponse.json(
+        { error: 'Ungültige Daten', details: error },
+        { status: 400 }
+      )
+    }
+    return NextResponse.json(
+      { error: 'Fehler beim Erstellen des Fahrrads' },
+      { status: 500 }
+    )
+  }
+}
+

app/api/parts/[id]/maintenance/route.ts

@@ -0,0 +1,72 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { prisma } from '@/lib/prisma'
+import { maintenanceHistorySchema } from '@/lib/validations'
+
+export async function GET(
+  request: NextRequest,
+  { params }: { params: { id: string } }
+) {
+  try {
+    const history = await prisma.maintenanceHistory.findMany({
+      where: { wearPartId: params.id },
+      orderBy: {
+        date: 'desc',
+      },
+    })
+
+    return NextResponse.json(history)
+  } catch (error) {
+    console.error('Error fetching maintenance history:', error)
+    return NextResponse.json(
+      { error: 'Fehler beim Laden der Wartungshistorie' },
+      { status: 500 }
+    )
+  }
+}
+
+export async function POST(
+  request: NextRequest,
+  { params }: { params: { id: string } }
+) {
+  try {
+    const body = await request.json()
+    const validatedData = maintenanceHistorySchema.parse({
+      ...body,
+      wearPartId: params.id,
+    })
+
+    const history = await prisma.maintenanceHistory.create({
+      data: {
+        wearPartId: params.id,
+        date: new Date(validatedData.date),
+        mileage: validatedData.mileage,
+        action: validatedData.action,
+        notes: validatedData.notes,
+        cost: validatedData.cost,
+      },
+    })
+
+    // Wenn die Aktion REPLACE ist, setze den Status des Verschleißteils auf REPLACED
+    if (validatedData.action === 'REPLACE') {
+      await prisma.wearPart.update({
+        where: { id: params.id },
+        data: { status: 'REPLACED' },
+      })
+    }
+
+    return NextResponse.json(history, { status: 201 })
+  } catch (error) {
+    console.error('Error creating maintenance history:', error)
+    if (error instanceof Error && error.name === 'ZodError') {
+      return NextResponse.json(
+        { error: 'Ungültige Daten', details: error },
+        { status: 400 }
+      )
+    }
+    return NextResponse.json(
+      { error: 'Fehler beim Erstellen des Wartungseintrags' },
+      { status: 500 }
+    )
+  }
+}
+

app/api/parts/[id]/route.ts

@@ -0,0 +1,114 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { prisma } from '@/lib/prisma'
+import { wearPartSchema } from '@/lib/validations'
+
+export async function GET(
+  request: NextRequest,
+  { params }: { params: { id: string } }
+) {
+  try {
+    const part = await prisma.wearPart.findUnique({
+      where: { id: params.id },
+      include: {
+        bike: true,
+        maintenanceHistory: {
+          orderBy: {
+            date: 'desc',
+          },
+        },
+      },
+    })
+
+    if (!part) {
+      return NextResponse.json(
+        { error: 'Verschleißteil nicht gefunden' },
+        { status: 404 }
+      )
+    }
+
+    return NextResponse.json(part)
+  } catch (error) {
+    console.error('Error fetching part:', error)
+    return NextResponse.json(
+      { error: 'Fehler beim Laden des Verschleißteils' },
+      { status: 500 }
+    )
+  }
+}
+
+export async function PUT(
+  request: NextRequest,
+  { params }: { params: { id: string } }
+) {
+  try {
+    const body = await request.json()
+    const validatedData = wearPartSchema.parse(body)
+
+    const part = await prisma.wearPart.update({
+      where: { id: params.id },
+      data: {
+        type: validatedData.type,
+        brand: validatedData.brand,
+        model: validatedData.model,
+        installDate: new Date(validatedData.installDate),
+        installMileage: validatedData.installMileage,
+        serviceInterval: validatedData.serviceInterval,
+        status: validatedData.status,
+        cost: validatedData.cost,
+        notes: validatedData.notes,
+      },
+    })
+
+    return NextResponse.json(part)
+  } catch (error) {
+    console.error('Error updating part:', error)
+    if (error instanceof Error && error.name === 'ZodError') {
+      return NextResponse.json(
+        { error: 'Ungültige Daten', details: error },
+        { status: 400 }
+      )
+    }
+    if (
+      error instanceof Error &&
+      error.message.includes('Record to update does not exist')
+    ) {
+      return NextResponse.json(
+        { error: 'Verschleißteil nicht gefunden' },
+        { status: 404 }
+      )
+    }
+    return NextResponse.json(
+      { error: 'Fehler beim Aktualisieren des Verschleißteils' },
+      { status: 500 }
+    )
+  }
+}
+
+export async function DELETE(
+  request: NextRequest,
+  { params }: { params: { id: string } }
+) {
+  try {
+    await prisma.wearPart.delete({
+      where: { id: params.id },
+    })
+
+    return NextResponse.json({ message: 'Verschleißteil gelöscht' })
+  } catch (error) {
+    console.error('Error deleting part:', error)
+    if (
+      error instanceof Error &&
+      error.message.includes('Record to delete does not exist')
+    ) {
+      return NextResponse.json(
+        { error: 'Verschleißteil nicht gefunden' },
+        { status: 404 }
+      )
+    }
+    return NextResponse.json(
+      { error: 'Fehler beim Löschen des Verschleißteils' },
+      { status: 500 }
+    )
+  }
+}
+

app/bikes/[id]/page.tsx

@@ -0,0 +1,50 @@
+'use client'
+
+import { useEffect, useState } from 'react'
+import { useParams, useRouter } from 'next/navigation'
+import { WearPartWithHistory } from '@/types'
+import BikeDetail from '@/app/components/BikeDetail'
+
+export default function BikeDetailPage() {
+  const params = useParams()
+  const router = useRouter()
+  const [bike, setBike] = useState<any>(null)
+  const [loading, setLoading] = useState(true)
+
+  useEffect(() => {
+    if (params.id) {
+      fetchBike(params.id as string)
+    }
+  }, [params.id])
+
+  const fetchBike = async (id: string) => {
+    try {
+      const response = await fetch(`/api/bikes/${id}`)
+      if (response.ok) {
+        const data = await response.json()
+        setBike(data)
+      } else if (response.status === 404) {
+        router.push('/')
+      }
+    } catch (error) {
+      console.error('Error fetching bike:', error)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  if (loading) {
+    return (
+      <div className="min-h-screen flex items-center justify-center">
+        <div className="text-lg">Lade...</div>
+      </div>
+    )
+  }
+
+  if (!bike) {
+    return null
+  }
+
+  return <BikeDetail bike={bike} onUpdate={fetchBike} />
+}
+

app/components/AlertBadge.tsx

@@ -0,0 +1,14 @@
+interface AlertBadgeProps {
+  count: number
+}
+
+export default function AlertBadge({ count }: AlertBadgeProps) {
+  if (count === 0) return null
+
+  return (
+    <span className="inline-flex items-center px-3 py-1 rounded-full text-sm font-medium bg-orange-100 text-orange-800">
+      ⚠️ {count}
+    </span>
+  )
+}
+

app/components/BikeCard.tsx

@@ -0,0 +1,92 @@
+'use client'
+
+import { BikeWithParts } from '@/types'
+import { useState } from 'react'
+import Link from 'next/link'
+import { calculateServiceStatus } from '@/lib/utils'
+import AlertBadge from './AlertBadge'
+
+interface BikeCardProps {
+  bike: BikeWithParts
+  onDelete: () => void
+}
+
+export default function BikeCard({ bike, onDelete }: BikeCardProps) {
+  const [isDeleting, setIsDeleting] = useState(false)
+
+  const handleDelete = async () => {
+    if (!confirm('Möchten Sie dieses Fahrrad wirklich löschen?')) {
+      return
+    }
+
+    setIsDeleting(true)
+    try {
+      const response = await fetch(`/api/bikes/${bike.id}`, {
+        method: 'DELETE',
+      })
+
+      if (response.ok) {
+        onDelete()
+      } else {
+        alert('Fehler beim Löschen des Fahrrads')
+      }
+    } catch (error) {
+      console.error('Error deleting bike:', error)
+      alert('Fehler beim Löschen des Fahrrads')
+    } finally {
+      setIsDeleting(false)
+    }
+  }
+
+  const activeParts = bike.wearParts.filter((p) => p.status === 'ACTIVE')
+  const needsServiceParts = activeParts.filter((part) => {
+    const serviceStatus = calculateServiceStatus(part)
+    return serviceStatus.status !== 'OK'
+  })
+
+  return (
+    <div className="bg-white rounded-lg shadow-md p-6 hover:shadow-lg transition-shadow">
+      <div className="flex justify-between items-start mb-4">
+        <div>
+          <h2 className="text-2xl font-semibold text-gray-900">{bike.name}</h2>
+          {bike.brand && bike.model && (
+            <p className="text-gray-600 mt-1">
+              {bike.brand} {bike.model}
+            </p>
+          )}
+        </div>
+        {needsServiceParts.length > 0 && (
+          <AlertBadge count={needsServiceParts.length} />
+        )}
+      </div>
+
+      <div className="mb-4">
+        <p className="text-sm text-gray-500">
+          {activeParts.length} aktive Verschleißteile
+        </p>
+        {needsServiceParts.length > 0 && (
+          <p className="text-sm text-orange-600 font-medium mt-1">
+            {needsServiceParts.length} benötigen Wartung
+          </p>
+        )}
+      </div>
+
+      <div className="flex gap-2 mt-4">
+        <Link
+          href={`/bikes/${bike.id}`}
+          className="flex-1 px-4 py-2 bg-blue-600 text-white text-center rounded-lg hover:bg-blue-700 transition-colors"
+        >
+          Details
+        </Link>
+        <button
+          onClick={handleDelete}
+          disabled={isDeleting}
+          className="px-4 py-2 bg-red-600 text-white rounded-lg hover:bg-red-700 transition-colors disabled:opacity-50"
+        >
+          {isDeleting ? 'Löschen...' : 'Löschen'}
+        </button>
+      </div>
+    </div>
+  )
+}
+

app/components/BikeDetail.tsx

@@ -0,0 +1,89 @@
+'use client'
+
+import { BikeWithParts } from '@/types'
+import { useState } from 'react'
+import Link from 'next/link'
+import WearPartList from './WearPartList'
+import WearPartForm from './WearPartForm'
+
+interface BikeDetailProps {
+  bike: BikeWithParts
+  onUpdate: () => void
+}
+
+export default function BikeDetail({ bike, onUpdate }: BikeDetailProps) {
+  const [showPartForm, setShowPartForm] = useState(false)
+
+  return (
+    <main className="min-h-screen p-8 bg-gray-50">
+      <div className="max-w-7xl mx-auto">
+        <Link
+          href="/"
+          className="inline-flex items-center text-blue-600 hover:text-blue-800 mb-6"
+        >
+          ← Zurück zur Übersicht
+        </Link>
+
+        <div className="bg-white rounded-lg shadow-md p-6 mb-6">
+          <h1 className="text-3xl font-bold text-gray-900 mb-4">{bike.name}</h1>
+          <div className="grid grid-cols-2 md:grid-cols-4 gap-4 text-sm">
+            {bike.brand && (
+              <div>
+                <span className="text-gray-500">Marke:</span>
+                <p className="font-medium">{bike.brand}</p>
+              </div>
+            )}
+            {bike.model && (
+              <div>
+                <span className="text-gray-500">Modell:</span>
+                <p className="font-medium">{bike.model}</p>
+              </div>
+            )}
+            {bike.purchaseDate && (
+              <div>
+                <span className="text-gray-500">Kaufdatum:</span>
+                <p className="font-medium">
+                  {new Date(bike.purchaseDate).toLocaleDateString('de-DE')}
+                </p>
+              </div>
+            )}
+          </div>
+          {bike.notes && (
+            <div className="mt-4">
+              <span className="text-gray-500">Notizen:</span>
+              <p className="mt-1">{bike.notes}</p>
+            </div>
+          )}
+        </div>
+
+        <div className="mb-6 flex justify-between items-center">
+          <h2 className="text-2xl font-semibold text-gray-900">
+            Verschleißteile
+          </h2>
+          <button
+            onClick={() => setShowPartForm(!showPartForm)}
+            className="px-6 py-3 bg-blue-600 text-white rounded-lg hover:bg-blue-700 transition-colors"
+          >
+            {showPartForm ? 'Abbrechen' : '+ Neues Verschleißteil'}
+          </button>
+        </div>
+
+        {showPartForm && (
+          <div className="mb-6">
+            <WearPartForm
+              bikeId={bike.id}
+              onSuccess={() => {
+                setShowPartForm(false)
+                onUpdate()
+              }}
+              onCancel={() => setShowPartForm(false)}
+            />
+          </div>
+        )}
+
+        <WearPartList bikeId={bike.id} parts={bike.wearParts} onUpdate={onUpdate} />
+      </div>
+    </main>
+  )
+}
+

app/components/BikeForm.tsx

@@ -0,0 +1,182 @@
+'use client'
+
+import { useState } from 'react'
+import { bikeSchema } from '@/lib/validations'
+
+interface BikeFormProps {
+  onSuccess: () => void
+  onCancel: () => void
+}
+
+export default function BikeForm({ onSuccess, onCancel }: BikeFormProps) {
+  const [formData, setFormData] = useState({
+    name: '',
+    brand: '',
+    model: '',
+    purchaseDate: '',
+    notes: '',
+  })
+  const [errors, setErrors] = useState<Record<string, string>>({})
+  const [isSubmitting, setIsSubmitting] = useState(false)
+
+  const handleSubmit = async (e: React.FormEvent) => {
+    e.preventDefault()
+    setErrors({})
+    setIsSubmitting(true)
+
+    try {
+      const validatedData = bikeSchema.parse({
+        ...formData,
+        purchaseDate: formData.purchaseDate || undefined,
+      })
+
+      const response = await fetch('/api/bikes', {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+        },
+        body: JSON.stringify(validatedData),
+      })
+
+      if (response.ok) {
+        onSuccess()
+        setFormData({
+          name: '',
+          brand: '',
+          model: '',
+          purchaseDate: '',
+          notes: '',
+        })
+      } else {
+        const errorData = await response.json()
+        if (errorData.details) {
+          const zodErrors: Record<string, string> = {}
+          errorData.details.errors?.forEach((err: any) => {
+            if (err.path) {
+              zodErrors[err.path[0]] = err.message
+            }
+          })
+          setErrors(zodErrors)
+        } else {
+          alert('Fehler beim Erstellen des Fahrrads')
+        }
+      }
+    } catch (error: any) {
+      if (error.errors) {
+        const zodErrors: Record<string, string> = {}
+        error.errors.forEach((err: any) => {
+          if (err.path) {
+            zodErrors[err.path[0]] = err.message
+          }
+        })
+        setErrors(zodErrors)
+      } else {
+        console.error('Error creating bike:', error)
+        alert('Fehler beim Erstellen des Fahrrads')
+      }
+    } finally {
+      setIsSubmitting(false)
+    }
+  }
+
+  return (
+    <div className="bg-white rounded-lg shadow-md p-6">
+      <h2 className="text-2xl font-semibold mb-4">Neues Fahrrad hinzufügen</h2>
+      <form onSubmit={handleSubmit} className="space-y-4">
+        <div>
+          <label className="block text-sm font-medium text-gray-700 mb-1">
+            Name *
+          </label>
+          <input
+            type="text"
+            value={formData.name}
+            onChange={(e) =>
+              setFormData({ ...formData, name: e.target.value })
+            }
+            className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+            required
+          />
+          {errors.name && (
+            <p className="text-red-600 text-sm mt-1">{errors.name}</p>
+          )}
+        </div>
+
+        <div className="grid grid-cols-2 gap-4">
+          <div>
+            <label className="block text-sm font-medium text-gray-700 mb-1">
+              Marke
+            </label>
+            <input
+              type="text"
+              value={formData.brand}
+              onChange={(e) =>
+                setFormData({ ...formData, brand: e.target.value })
+              }
+              className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+            />
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-gray-700 mb-1">
+              Modell
+            </label>
+            <input
+              type="text"
+              value={formData.model}
+              onChange={(e) =>
+                setFormData({ ...formData, model: e.target.value })
+              }
+              className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+            />
+          </div>
+        </div>
+
+        <div>
+          <label className="block text-sm font-medium text-gray-700 mb-1">
+            Kaufdatum
+          </label>
+          <input
+            type="date"
+            value={formData.purchaseDate}
+            onChange={(e) =>
+              setFormData({ ...formData, purchaseDate: e.target.value })
+            }
+            className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+          />
+        </div>
+
+        <div>
+          <label className="block text-sm font-medium text-gray-700 mb-1">
+            Notizen
+          </label>
+          <textarea
+            value={formData.notes}
+            onChange={(e) =>
+              setFormData({ ...formData, notes: e.target.value })
+            }
+            rows={3}
+            className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+          />
+        </div>
+
+        <div className="flex gap-2">
+          <button
+            type="submit"
+            disabled={isSubmitting}
+            className="px-6 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700 transition-colors disabled:opacity-50"
+          >
+            {isSubmitting ? 'Erstellen...' : 'Erstellen'}
+          </button>
+          <button
+            type="button"
+            onClick={onCancel}
+            className="px-6 py-2 bg-gray-300 text-gray-700 rounded-lg hover:bg-gray-400 transition-colors"
+          >
+            Abbrechen
+          </button>
+        </div>
+      </form>
+    </div>
+  )
+}
+

app/components/MaintenanceForm.tsx

@@ -0,0 +1,211 @@
+'use client'
+
+import { useState } from 'react'
+import { maintenanceHistorySchema, MaintenanceAction } from '@/lib/validations'
+
+interface MaintenanceFormProps {
+  partId: string
+  onSuccess: () => void
+  onCancel: () => void
+}
+
+const maintenanceActions = ['INSTALL', 'REPLACE', 'SERVICE', 'CHECK', 'ADJUST']
+
+export default function MaintenanceForm({
+  partId,
+  onSuccess,
+  onCancel,
+}: MaintenanceFormProps) {
+  const [formData, setFormData] = useState({
+    date: new Date().toISOString().split('T')[0],
+    mileage: 0,
+    action: 'SERVICE',
+    notes: '',
+    cost: '',
+  })
+  const [errors, setErrors] = useState<Record<string, string>>({})
+  const [isSubmitting, setIsSubmitting] = useState(false)
+
+  const handleSubmit = async (e: React.FormEvent) => {
+    e.preventDefault()
+    setErrors({})
+    setIsSubmitting(true)
+
+    try {
+      const validatedData = maintenanceHistorySchema.parse({
+        wearPartId: partId,
+        date: formData.date,
+        mileage: Number(formData.mileage),
+        action: formData.action,
+        notes: formData.notes || undefined,
+        cost: formData.cost ? Number(formData.cost) : undefined,
+      })
+
+      const response = await fetch(`/api/parts/${partId}/maintenance`, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+        },
+        body: JSON.stringify(validatedData),
+      })
+
+      if (response.ok) {
+        onSuccess()
+        setFormData({
+          date: new Date().toISOString().split('T')[0],
+          mileage: 0,
+          action: 'SERVICE',
+          notes: '',
+          cost: '',
+        })
+      } else {
+        const errorData = await response.json()
+        if (errorData.details) {
+          const zodErrors: Record<string, string> = {}
+          errorData.details.errors?.forEach((err: any) => {
+            if (err.path) {
+              zodErrors[err.path[0]] = err.message
+            }
+          })
+          setErrors(zodErrors)
+        } else {
+          alert('Fehler beim Erstellen des Wartungseintrags')
+        }
+      }
+    } catch (error: any) {
+      if (error.errors) {
+        const zodErrors: Record<string, string> = {}
+        error.errors.forEach((err: any) => {
+          if (err.path) {
+            zodErrors[err.path[0]] = err.message
+          }
+        })
+        setErrors(zodErrors)
+      } else {
+        console.error('Error creating maintenance:', error)
+        alert('Fehler beim Erstellen des Wartungseintrags')
+      }
+    } finally {
+      setIsSubmitting(false)
+    }
+  }
+
+  return (
+    <div className="bg-gray-50 rounded-lg p-4 border border-gray-200">
+      <h4 className="font-semibold mb-3">Neuer Wartungseintrag</h4>
+      <form onSubmit={handleSubmit} className="space-y-3">
+        <div className="grid grid-cols-2 gap-3">
+          <div>
+            <label className="block text-xs font-medium text-gray-700 mb-1">
+              Datum *
+            </label>
+            <input
+              type="date"
+              value={formData.date}
+              onChange={(e) =>
+                setFormData({ ...formData, date: e.target.value })
+              }
+              className="w-full px-2 py-1 text-sm border border-gray-300 rounded focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+              required
+            />
+            {errors.date && (
+              <p className="text-red-600 text-xs mt-1">{errors.date}</p>
+            )}
+          </div>
+
+          <div>
+            <label className="block text-xs font-medium text-gray-700 mb-1">
+              Kilometerstand *
+            </label>
+            <input
+              type="number"
+              value={formData.mileage}
+              onChange={(e) =>
+                setFormData({ ...formData, mileage: Number(e.target.value) })
+              }
+              min="0"
+              className="w-full px-2 py-1 text-sm border border-gray-300 rounded focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+              required
+            />
+            {errors.mileage && (
+              <p className="text-red-600 text-xs mt-1">{errors.mileage}</p>
+            )}
+          </div>
+        </div>
+
+        <div className="grid grid-cols-2 gap-3">
+          <div>
+            <label className="block text-xs font-medium text-gray-700 mb-1">
+              Aktion *
+            </label>
+            <select
+              value={formData.action}
+              onChange={(e) =>
+                setFormData({ ...formData, action: e.target.value })
+              }
+              className="w-full px-2 py-1 text-sm border border-gray-300 rounded focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+              required
+            >
+              {maintenanceActions.map((action) => (
+                <option key={action} value={action}>
+                  {action.replace(/_/g, ' ')}
+                </option>
+              ))}
+            </select>
+            {errors.action && (
+              <p className="text-red-600 text-xs mt-1">{errors.action}</p>
+            )}
+          </div>
+
+          <div>
+            <label className="block text-xs font-medium text-gray-700 mb-1">
+              Kosten (€)
+            </label>
+            <input
+              type="number"
+              step="0.01"
+              value={formData.cost}
+              onChange={(e) =>
+                setFormData({ ...formData, cost: e.target.value })
+              }
+              min="0"
+              className="w-full px-2 py-1 text-sm border border-gray-300 rounded focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+            />
+          </div>
+        </div>
+
+        <div>
+          <label className="block text-xs font-medium text-gray-700 mb-1">
+            Notizen
+          </label>
+          <textarea
+            value={formData.notes}
+            onChange={(e) =>
+              setFormData({ ...formData, notes: e.target.value })
+            }
+            rows={2}
+            className="w-full px-2 py-1 text-sm border border-gray-300 rounded focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+          />
+        </div>
+
+        <div className="flex gap-2">
+          <button
+            type="submit"
+            disabled={isSubmitting}
+            className="px-4 py-2 bg-blue-600 text-white text-sm rounded hover:bg-blue-700 transition-colors disabled:opacity-50"
+          >
+            {isSubmitting ? 'Erstellen...' : 'Erstellen'}
+          </button>
+          <button
+            type="button"
+            onClick={onCancel}
+            className="px-4 py-2 bg-gray-300 text-gray-700 text-sm rounded hover:bg-gray-400 transition-colors"
+          >
+            Abbrechen
+          </button>
+        </div>
+      </form>
+    </div>
+  )
+}
+

app/components/MaintenanceTimeline.tsx

@@ -0,0 +1,93 @@
+'use client'
+
+import { MaintenanceHistory } from '@prisma/client'
+import { formatDate, formatCurrency } from '@/lib/utils'
+import { useState } from 'react'
+import MaintenanceForm from './MaintenanceForm'
+
+interface MaintenanceTimelineProps {
+  partId: string
+  history: MaintenanceHistory[]
+  onUpdate: () => void
+}
+
+const actionLabels: Record<string, string> = {
+  INSTALL: 'Installiert',
+  REPLACE: 'Ersetzt',
+  SERVICE: 'Gewartet',
+  CHECK: 'Geprüft',
+  ADJUST: 'Eingestellt',
+}
+
+export default function MaintenanceTimeline({
+  partId,
+  history,
+  onUpdate,
+}: MaintenanceTimelineProps) {
+  const [showForm, setShowForm] = useState(false)
+
+  return (
+    <div>
+      <div className="flex justify-between items-center mb-4">
+        <h3 className="text-lg font-semibold text-gray-900">
+          Wartungshistorie
+        </h3>
+        <button
+          onClick={() => setShowForm(!showForm)}
+          className="px-4 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700 transition-colors text-sm"
+        >
+          {showForm ? 'Abbrechen' : '+ Neuer Eintrag'}
+        </button>
+      </div>
+
+      {showForm && (
+        <div className="mb-4">
+          <MaintenanceForm
+            partId={partId}
+            onSuccess={() => {
+              setShowForm(false)
+              onUpdate()
+            }}
+            onCancel={() => setShowForm(false)}
+          />
+        </div>
+      )}
+
+      {history.length === 0 ? (
+        <p className="text-gray-500 text-sm">Noch keine Wartungseinträge.</p>
+      ) : (
+        <div className="space-y-3">
+          {history.map((entry) => (
+            <div
+              key={entry.id}
+              className="flex items-start gap-4 p-4 bg-gray-50 rounded-lg"
+            >
+              <div className="flex-1">
+                <div className="flex items-center gap-2 mb-1">
+                  <span className="font-semibold text-gray-900">
+                    {actionLabels[entry.action] || entry.action}
+                  </span>
+                  <span className="text-sm text-gray-500">
+                    {formatDate(entry.date)}
+                  </span>
+                </div>
+                <div className="text-sm text-gray-600">
+                  <span>Kilometerstand: {entry.mileage} km</span>
+                  {entry.cost && (
+                    <span className="ml-4">
+                      Kosten: {formatCurrency(entry.cost)}
+                    </span>
+                  )}
+                </div>
+                {entry.notes && (
+                  <p className="text-sm text-gray-600 mt-2">{entry.notes}</p>
+                )}
+              </div>
+            </div>
+          ))}
+        </div>
+      )}
+    </div>
+  )
+}
+

app/components/StatsCard.tsx

@@ -0,0 +1,56 @@
+'use client'
+
+import { BikeWithParts } from '@/types'
+import { calculateTotalCosts, calculateAverageLifespan } from '@/lib/utils'
+import { formatCurrency } from '@/lib/utils'
+
+interface StatsCardProps {
+  bikes: BikeWithParts[]
+}
+
+export default function StatsCard({ bikes }: StatsCardProps) {
+  const allParts = bikes.flatMap((bike) => bike.wearParts)
+  const totalCosts = calculateTotalCosts(allParts)
+  const avgLifespan = calculateAverageLifespan(allParts)
+  const totalBikes = bikes.length
+  const totalParts = allParts.length
+
+  return (
+    <div className="grid grid-cols-1 md:grid-cols-4 gap-4 mb-8">
+      <div className="bg-white rounded-lg shadow-md p-6">
+        <h3 className="text-sm font-medium text-gray-500 mb-2">
+          Fahrräder
+        </h3>
+        <p className="text-3xl font-bold text-gray-900">{totalBikes}</p>
+      </div>
+
+      <div className="bg-white rounded-lg shadow-md p-6">
+        <h3 className="text-sm font-medium text-gray-500 mb-2">
+          Verschleißteile
+        </h3>
+        <p className="text-3xl font-bold text-gray-900">{totalParts}</p>
+      </div>
+
+      <div className="bg-white rounded-lg shadow-md p-6">
+        <h3 className="text-sm font-medium text-gray-500 mb-2">
+          Gesamtkosten
+        </h3>
+        <p className="text-3xl font-bold text-gray-900">
+          {formatCurrency(totalCosts)}
+        </p>
+      </div>
+
+      <div className="bg-white rounded-lg shadow-md p-6">
+        <h3 className="text-sm font-medium text-gray-500 mb-2">
+          Ø Lebensdauer
+        </h3>
+        <p className="text-3xl font-bold text-gray-900">
+          {avgLifespan
+            ? `${Math.round(avgLifespan)} km`
+            : 'N/A'}
+        </p>
+      </div>
+    </div>
+  )
+}
+

app/components/WearPartForm.tsx

@@ -0,0 +1,321 @@
+'use client'
+
+import { useState } from 'react'
+import { wearPartSchema, WearPartType, WearPartStatus } from '@/lib/validations'
+
+interface WearPartFormProps {
+  bikeId: string
+  onSuccess: () => void
+  onCancel: () => void
+}
+
+const wearPartTypes = [
+  'CHAIN',
+  'BRAKE_PADS',
+  'TIRE',
+  'CASSETTE',
+  'CHAINRING',
+  'DERAILLEUR',
+  'BRAKE_CABLE',
+  'SHIFT_CABLE',
+  'BRAKE_ROTOR',
+  'PEDAL',
+  'CRANKSET',
+  'BOTTOM_BRACKET',
+  'HEADSET',
+  'WHEEL',
+  'HUB',
+  'SPOKE',
+  'OTHER',
+]
+
+const wearPartStatuses = ['ACTIVE', 'NEEDS_SERVICE', 'REPLACED', 'INACTIVE']
+
+export default function WearPartForm({
+  bikeId,
+  onSuccess,
+  onCancel,
+}: WearPartFormProps) {
+  const [formData, setFormData] = useState({
+    type: 'CHAIN',
+    brand: '',
+    model: '',
+    installDate: new Date().toISOString().split('T')[0],
+    installMileage: 0,
+    serviceInterval: 1000,
+    status: 'ACTIVE',
+    cost: '',
+    notes: '',
+  })
+  const [errors, setErrors] = useState<Record<string, string>>({})
+  const [isSubmitting, setIsSubmitting] = useState(false)
+
+  const handleSubmit = async (e: React.FormEvent) => {
+    e.preventDefault()
+    setErrors({})
+    setIsSubmitting(true)
+
+    try {
+      const validatedData = wearPartSchema.parse({
+        bikeId,
+        type: formData.type,
+        brand: formData.brand || undefined,
+        model: formData.model || undefined,
+        installDate: formData.installDate,
+        installMileage: Number(formData.installMileage),
+        serviceInterval: Number(formData.serviceInterval),
+        status: formData.status,
+        cost: formData.cost ? Number(formData.cost) : undefined,
+        notes: formData.notes || undefined,
+      })
+
+      const response = await fetch(`/api/bikes/${bikeId}/parts`, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+        },
+        body: JSON.stringify(validatedData),
+      })
+
+      if (response.ok) {
+        onSuccess()
+        setFormData({
+          type: 'CHAIN',
+          brand: '',
+          model: '',
+          installDate: new Date().toISOString().split('T')[0],
+          installMileage: 0,
+          serviceInterval: 1000,
+          status: 'ACTIVE',
+          cost: '',
+          notes: '',
+        })
+      } else {
+        const errorData = await response.json()
+        if (errorData.details) {
+          const zodErrors: Record<string, string> = {}
+          errorData.details.errors?.forEach((err: any) => {
+            if (err.path) {
+              zodErrors[err.path[0]] = err.message
+            }
+          })
+          setErrors(zodErrors)
+        } else {
+          alert('Fehler beim Erstellen des Verschleißteils')
+        }
+      }
+    } catch (error: any) {
+      if (error.errors) {
+        const zodErrors: Record<string, string> = {}
+        error.errors.forEach((err: any) => {
+          if (err.path) {
+            zodErrors[err.path[0]] = err.message
+          }
+        })
+        setErrors(zodErrors)
+      } else {
+        console.error('Error creating part:', error)
+        alert('Fehler beim Erstellen des Verschleißteils')
+      }
+    } finally {
+      setIsSubmitting(false)
+    }
+  }
+
+  return (
+    <div className="bg-white rounded-lg shadow-md p-6">
+      <h2 className="text-2xl font-semibold mb-4">
+        Neues Verschleißteil hinzufügen
+      </h2>
+      <form onSubmit={handleSubmit} className="space-y-4">
+        <div>
+          <label className="block text-sm font-medium text-gray-700 mb-1">
+            Typ *
+          </label>
+          <select
+            value={formData.type}
+            onChange={(e) => setFormData({ ...formData, type: e.target.value })}
+            className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+            required
+          >
+            {wearPartTypes.map((type) => (
+              <option key={type} value={type}>
+                {type.replace(/_/g, ' ')}
+              </option>
+            ))}
+          </select>
+          {errors.type && (
+            <p className="text-red-600 text-sm mt-1">{errors.type}</p>
+          )}
+        </div>
+
+        <div className="grid grid-cols-2 gap-4">
+          <div>
+            <label className="block text-sm font-medium text-gray-700 mb-1">
+              Marke
+            </label>
+            <input
+              type="text"
+              value={formData.brand}
+              onChange={(e) =>
+                setFormData({ ...formData, brand: e.target.value })
+              }
+              className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+            />
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-gray-700 mb-1">
+              Modell
+            </label>
+            <input
+              type="text"
+              value={formData.model}
+              onChange={(e) =>
+                setFormData({ ...formData, model: e.target.value })
+              }
+              className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+            />
+          </div>
+        </div>
+
+        <div className="grid grid-cols-2 gap-4">
+          <div>
+            <label className="block text-sm font-medium text-gray-700 mb-1">
+              Installationsdatum *
+            </label>
+            <input
+              type="date"
+              value={formData.installDate}
+              onChange={(e) =>
+                setFormData({ ...formData, installDate: e.target.value })
+              }
+              className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+              required
+            />
+            {errors.installDate && (
+              <p className="text-red-600 text-sm mt-1">{errors.installDate}</p>
+            )}
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-gray-700 mb-1">
+              Installations-KM *
+            </label>
+            <input
+              type="number"
+              value={formData.installMileage}
+              onChange={(e) =>
+                setFormData({
+                  ...formData,
+                  installMileage: Number(e.target.value),
+                })
+              }
+              min="0"
+              className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+              required
+            />
+            {errors.installMileage && (
+              <p className="text-red-600 text-sm mt-1">
+                {errors.installMileage}
+              </p>
+            )}
+          </div>
+        </div>
+
+        <div className="grid grid-cols-2 gap-4">
+          <div>
+            <label className="block text-sm font-medium text-gray-700 mb-1">
+              Service-Intervall (km) *
+            </label>
+            <input
+              type="number"
+              value={formData.serviceInterval}
+              onChange={(e) =>
+                setFormData({
+                  ...formData,
+                  serviceInterval: Number(e.target.value),
+                })
+              }
+              min="1"
+              className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+              required
+            />
+            {errors.serviceInterval && (
+              <p className="text-red-600 text-sm mt-1">
+                {errors.serviceInterval}
+              </p>
+            )}
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-gray-700 mb-1">
+              Status
+            </label>
+            <select
+              value={formData.status}
+              onChange={(e) =>
+                setFormData({ ...formData, status: e.target.value })
+              }
+              className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+            >
+              {wearPartStatuses.map((status) => (
+                <option key={status} value={status}>
+                  {status.replace(/_/g, ' ')}
+                </option>
+              ))}
+            </select>
+          </div>
+        </div>
+
+        <div>
+          <label className="block text-sm font-medium text-gray-700 mb-1">
+            Kosten (€)
+          </label>
+          <input
+            type="number"
+            step="0.01"
+            value={formData.cost}
+            onChange={(e) =>
+              setFormData({ ...formData, cost: e.target.value })
+            }
+            min="0"
+            className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+          />
+        </div>
+
+        <div>
+          <label className="block text-sm font-medium text-gray-700 mb-1">
+            Notizen
+          </label>
+          <textarea
+            value={formData.notes}
+            onChange={(e) =>
+              setFormData({ ...formData, notes: e.target.value })
+            }
+            rows={3}
+            className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
+          />
+        </div>
+
+        <div className="flex gap-2">
+          <button
+            type="submit"
+            disabled={isSubmitting}
+            className="px-6 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700 transition-colors disabled:opacity-50"
+          >
+            {isSubmitting ? 'Erstellen...' : 'Erstellen'}
+          </button>
+          <button
+            type="button"
+            onClick={onCancel}
+            className="px-6 py-2 bg-gray-300 text-gray-700 rounded-lg hover:bg-gray-400 transition-colors"
+          >
+            Abbrechen
+          </button>
+        </div>
+      </form>
+    </div>
+  )
+}
+

app/components/WearPartList.tsx

@@ -0,0 +1,193 @@
+'use client'
+
+import { WearPart } from '@prisma/client'
+import { MaintenanceHistory } from '@prisma/client'
+import { calculateServiceStatus } from '@/lib/utils'
+import { formatDate, formatCurrency } from '@/lib/utils'
+import AlertBadge from './AlertBadge'
+import MaintenanceTimeline from './MaintenanceTimeline'
+import { useState } from 'react'
+
+interface WearPartListProps {
+  bikeId: string
+  parts: (WearPart & { maintenanceHistory: MaintenanceHistory[] })[]
+  onUpdate: () => void
+}
+
+export default function WearPartList({
+  bikeId,
+  parts,
+  onUpdate,
+}: WearPartListProps) {
+  const [expandedPart, setExpandedPart] = useState<string | null>(null)
+
+  const handleDelete = async (partId: string) => {
+    if (!confirm('Möchten Sie dieses Verschleißteil wirklich löschen?')) {
+      return
+    }
+
+    try {
+      const response = await fetch(`/api/parts/${partId}`, {
+        method: 'DELETE',
+      })
+
+      if (response.ok) {
+        onUpdate()
+      } else {
+        alert('Fehler beim Löschen des Verschleißteils')
+      }
+    } catch (error) {
+      console.error('Error deleting part:', error)
+      alert('Fehler beim Löschen des Verschleißteils')
+    }
+  }
+
+  if (parts.length === 0) {
+    return (
+      <div className="bg-white rounded-lg shadow-md p-8 text-center text-gray-500">
+        <p>Noch keine Verschleißteile erfasst.</p>
+        <p className="mt-2">Klicken Sie auf &quot;Neues Verschleißteil&quot; um zu beginnen.</p>
+      </div>
+    )
+  }
+
+  return (
+    <div className="space-y-4">
+      {parts.map((part) => {
+        const serviceStatus = calculateServiceStatus(part)
+        const isExpanded = expandedPart === part.id
+
+        return (
+          <div
+            key={part.id}
+            className="bg-white rounded-lg shadow-md p-6"
+          >
+            <div className="flex justify-between items-start">
+              <div className="flex-1">
+                <div className="flex items-center gap-3 mb-2">
+                  <h3 className="text-xl font-semibold text-gray-900">
+                    {part.type}
+                  </h3>
+                  {serviceStatus.status !== 'OK' && (
+                    <AlertBadge count={1} />
+                  )}
+                  <span
+                    className={`px-2 py-1 rounded text-xs font-medium ${
+                      part.status === 'ACTIVE'
+                        ? 'bg-green-100 text-green-800'
+                        : part.status === 'NEEDS_SERVICE'
+                        ? 'bg-orange-100 text-orange-800'
+                        : part.status === 'REPLACED'
+                        ? 'bg-gray-100 text-gray-800'
+                        : 'bg-red-100 text-red-800'
+                    }`}
+                  >
+                    {part.status}
+                  </span>
+                </div>
+
+                {part.brand && part.model && (
+                  <p className="text-gray-600 mb-2">
+                    {part.brand} {part.model}
+                  </p>
+                )}
+
+                <div className="grid grid-cols-2 md:grid-cols-4 gap-4 text-sm mt-4">
+                  <div>
+                    <span className="text-gray-500">Installiert:</span>
+                    <p className="font-medium">{formatDate(part.installDate)}</p>
+                  </div>
+                  <div>
+                    <span className="text-gray-500">Installations-KM:</span>
+                    <p className="font-medium">{part.installMileage} km</p>
+                  </div>
+                  <div>
+                    <span className="text-gray-500">Service-Intervall:</span>
+                    <p className="font-medium">{part.serviceInterval} km</p>
+                  </div>
+                  {part.cost && (
+                    <div>
+                      <span className="text-gray-500">Kosten:</span>
+                      <p className="font-medium">{formatCurrency(part.cost)}</p>
+                    </div>
+                  )}
+                </div>
+
+                <div className="mt-4">
+                  <div className="flex items-center gap-2 mb-1">
+                    <span className="text-sm text-gray-500">Status:</span>
+                    <span
+                      className={`text-sm font-medium ${
+                        serviceStatus.status === 'OK'
+                          ? 'text-green-600'
+                          : serviceStatus.status === 'WARNING'
+                          ? 'text-orange-600'
+                          : 'text-red-600'
+                      }`}
+                    >
+                      {serviceStatus.status === 'OK'
+                        ? 'OK'
+                        : serviceStatus.status === 'WARNING'
+                        ? 'Warnung'
+                        : 'Kritisch'}
+                    </span>
+                  </div>
+                  <div className="w-full bg-gray-200 rounded-full h-2">
+                    <div
+                      className={`h-2 rounded-full ${
+                        serviceStatus.status === 'OK'
+                          ? 'bg-green-500'
+                          : serviceStatus.status === 'WARNING'
+                          ? 'bg-orange-500'
+                          : 'bg-red-500'
+                      }`}
+                      style={{ width: `${serviceStatus.percentageUsed}%` }}
+                    />
+                  </div>
+                  <p className="text-xs text-gray-500 mt-1">
+                    {serviceStatus.remainingKm.toFixed(0)} km bis zur Wartung
+                  </p>
+                </div>
+
+                {part.notes && (
+                  <div className="mt-4">
+                    <span className="text-sm text-gray-500">Notizen:</span>
+                    <p className="text-sm mt-1">{part.notes}</p>
+                  </div>
+                )}
+              </div>
+
+              <div className="flex flex-col gap-2 ml-4">
+                <button
+                  onClick={() =>
+                    setExpandedPart(isExpanded ? null : part.id)
+                  }
+                  className="px-4 py-2 bg-gray-200 text-gray-700 rounded-lg hover:bg-gray-300 transition-colors text-sm"
+                >
+                  {isExpanded ? 'Weniger' : 'Historie'}
+                </button>
+                <button
+                  onClick={() => handleDelete(part.id)}
+                  className="px-4 py-2 bg-red-600 text-white rounded-lg hover:bg-red-700 transition-colors text-sm"
+                >
+                  Löschen
+                </button>
+              </div>
+            </div>
+
+            {isExpanded && (
+              <div className="mt-6 pt-6 border-t">
+                <MaintenanceTimeline
+                  partId={part.id}
+                  history={part.maintenanceHistory}
+                  onUpdate={onUpdate}
+                />
+              </div>
+            )}
+          </div>
+        )
+      })}
+    </div>
+  )
+}
+

app/globals.css

@@ -0,0 +1,22 @@
+@tailwind base;
+@tailwind components;
+@tailwind utilities;
+
+:root {
+  --background: #ffffff;
+  --foreground: #171717;
+}
+
+@media (prefers-color-scheme: dark) {
+  :root {
+    --background: #0a0a0a;
+    --foreground: #ededed;
+  }
+}
+
+body {
+  color: var(--foreground);
+  background: var(--background);
+  font-family: Arial, Helvetica, sans-serif;
+}
+

app/layout.tsx

@@ -0,0 +1,20 @@
+import type { Metadata } from "next";
+import "./globals.css";
+
+export const metadata: Metadata = {
+  title: "Fahrrad Verschleißteile Tracker",
+  description: "Verwaltung von Verschleißteilen an Fahrrädern",
+};
+
+export default function RootLayout({
+  children,
+}: Readonly<{
+  children: React.ReactNode;
+}>) {
+  return (
+    <html lang="de">
+      <body>{children}</body>
+    </html>
+  );
+}
+

app/page.tsx

@@ -0,0 +1,92 @@
+'use client'
+
+import { useEffect, useState } from 'react'
+import { BikeWithParts } from '@/types'
+import BikeCard from '@/app/components/BikeCard'
+import BikeForm from '@/app/components/BikeForm'
+import StatsCard from '@/app/components/StatsCard'
+
+export default function Home() {
+  const [bikes, setBikes] = useState<BikeWithParts[]>([])
+  const [loading, setLoading] = useState(true)
+  const [showForm, setShowForm] = useState(false)
+
+  useEffect(() => {
+    fetchBikes()
+  }, [])
+
+  const fetchBikes = async () => {
+    try {
+      const response = await fetch('/api/bikes')
+      if (response.ok) {
+        const data = await response.json()
+        setBikes(data)
+      }
+    } catch (error) {
+      console.error('Error fetching bikes:', error)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  const handleBikeCreated = () => {
+    setShowForm(false)
+    fetchBikes()
+  }
+
+  const handleBikeDeleted = () => {
+    fetchBikes()
+  }
+
+  if (loading) {
+    return (
+      <div className="min-h-screen flex items-center justify-center">
+        <div className="text-lg">Lade...</div>
+      </div>
+    )
+  }
+
+  return (
+    <main className="min-h-screen p-8 bg-gray-50">
+      <div className="max-w-7xl mx-auto">
+        <div className="mb-8 flex justify-between items-center">
+          <h1 className="text-4xl font-bold text-gray-900">
+            Fahrrad Verschleißteile Tracker
+          </h1>
+          <button
+            onClick={() => setShowForm(!showForm)}
+            className="px-6 py-3 bg-blue-600 text-white rounded-lg hover:bg-blue-700 transition-colors"
+          >
+            {showForm ? 'Abbrechen' : '+ Neues Fahrrad'}
+          </button>
+        </div>
+
+        {showForm && (
+          <div className="mb-8">
+            <BikeForm onSuccess={handleBikeCreated} onCancel={() => setShowForm(false)} />
+          </div>
+        )}
+
+        <StatsCard bikes={bikes} />
+
+        <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6 mt-8">
+          {bikes.length === 0 ? (
+            <div className="col-span-full text-center py-12 text-gray-500">
+              <p className="text-lg">Noch keine Fahrräder erfasst.</p>
+              <p className="mt-2">Klicken Sie auf &quot;Neues Fahrrad&quot; um zu beginnen.</p>
+            </div>
+          ) : (
+            bikes.map((bike) => (
+              <BikeCard
+                key={bike.id}
+                bike={bike}
+                onDelete={handleBikeDeleted}
+              />
+            ))
+          )}
+        </div>
+      </div>
+    </main>
+  )
+}
+

lib/prisma.ts

@@ -0,0 +1,10 @@
+import { PrismaClient } from '@prisma/client'
+
+const globalForPrisma = globalThis as unknown as {
+  prisma: PrismaClient | undefined
+}
+
+export const prisma = globalForPrisma.prisma ?? new PrismaClient()
+
+if (process.env.NODE_ENV !== 'production') globalForPrisma.prisma = prisma
+

lib/utils.ts

@@ -0,0 +1,85 @@
+import { WearPart, MaintenanceHistory } from '@prisma/client'
+
+export function calculateServiceStatus(
+  part: WearPart & { maintenanceHistory: MaintenanceHistory[] }
+): {
+  status: 'OK' | 'WARNING' | 'CRITICAL'
+  remainingKm: number
+  percentageUsed: number
+} {
+  const latestMaintenance = part.maintenanceHistory[0]
+  const currentMileage = latestMaintenance?.mileage ?? part.installMileage
+  const kmSinceInstall = currentMileage - part.installMileage
+  const remainingKm = part.serviceInterval - kmSinceInstall
+  const percentageUsed = (kmSinceInstall / part.serviceInterval) * 100
+
+  let status: 'OK' | 'WARNING' | 'CRITICAL' = 'OK'
+  if (percentageUsed >= 90) {
+    status = 'CRITICAL'
+  } else if (percentageUsed >= 75) {
+    status = 'WARNING'
+  }
+
+  return {
+    status,
+    remainingKm: Math.max(0, remainingKm),
+    percentageUsed: Math.min(100, percentageUsed),
+  }
+}
+
+export function calculateTotalCosts(
+  parts: (WearPart & { maintenanceHistory: MaintenanceHistory[] })[]
+): number {
+  return parts.reduce((total, part) => {
+    const partCost = part.cost ?? 0
+    const maintenanceCost = part.maintenanceHistory.reduce(
+      (sum, m) => sum + (m.cost ?? 0),
+      0
+    )
+    return total + partCost + maintenanceCost
+  }, 0)
+}
+
+export function calculateAverageLifespan(
+  parts: (WearPart & { maintenanceHistory: MaintenanceHistory[] })[]
+): number | null {
+  const replacedParts = parts.filter(
+    (p) => p.status === 'REPLACED' && p.maintenanceHistory.length > 0
+  )
+
+  if (replacedParts.length === 0) return null
+
+  const totalKm = replacedParts.reduce((sum, part) => {
+    const installHistory = part.maintenanceHistory.find(
+      (h) => h.action === 'INSTALL'
+    )
+    const replaceHistory = part.maintenanceHistory.find(
+      (h) => h.action === 'REPLACE'
+    )
+
+    if (installHistory && replaceHistory) {
+      return sum + (replaceHistory.mileage - installHistory.mileage)
+    }
+    return sum
+  }, 0)
+
+  return totalKm / replacedParts.length
+}
+
+export function formatDate(date: Date | string): string {
+  const d = typeof date === 'string' ? new Date(date) : date
+  return d.toLocaleDateString('de-DE', {
+    year: 'numeric',
+    month: '2-digit',
+    day: '2-digit',
+  })
+}
+
+export function formatCurrency(amount: number | null | undefined): string {
+  if (amount === null || amount === undefined) return '0,00 €'
+  return new Intl.NumberFormat('de-DE', {
+    style: 'currency',
+    currency: 'EUR',
+  }).format(amount)
+}
+

lib/validations.ts

@@ -0,0 +1,71 @@
+import { z } from 'zod'
+
+export const WearPartType = z.enum([
+  'CHAIN',
+  'BRAKE_PADS',
+  'TIRE',
+  'CASSETTE',
+  'CHAINRING',
+  'DERAILLEUR',
+  'BRAKE_CABLE',
+  'SHIFT_CABLE',
+  'BRAKE_ROTOR',
+  'PEDAL',
+  'CRANKSET',
+  'BOTTOM_BRACKET',
+  'HEADSET',
+  'WHEEL',
+  'HUB',
+  'SPOKE',
+  'OTHER',
+])
+
+export const WearPartStatus = z.enum([
+  'ACTIVE',
+  'NEEDS_SERVICE',
+  'REPLACED',
+  'INACTIVE',
+])
+
+export const MaintenanceAction = z.enum([
+  'INSTALL',
+  'REPLACE',
+  'SERVICE',
+  'CHECK',
+  'ADJUST',
+])
+
+export const bikeSchema = z.object({
+  name: z.string().min(1, 'Name ist erforderlich'),
+  brand: z.string().optional(),
+  model: z.string().optional(),
+  purchaseDate: z.string().datetime().optional().or(z.date().optional()),
+  notes: z.string().optional(),
+})
+
+export const wearPartSchema = z.object({
+  bikeId: z.string().min(1, 'Fahrrad-ID ist erforderlich'),
+  type: WearPartType,
+  brand: z.string().optional(),
+  model: z.string().optional(),
+  installDate: z.string().datetime().or(z.date()),
+  installMileage: z.number().int().min(0).default(0),
+  serviceInterval: z.number().int().min(1, 'Service-Intervall muss mindestens 1 km sein'),
+  status: WearPartStatus.default('ACTIVE'),
+  cost: z.number().positive().optional(),
+  notes: z.string().optional(),
+})
+
+export const maintenanceHistorySchema = z.object({
+  wearPartId: z.string().min(1, 'Verschleißteil-ID ist erforderlich'),
+  date: z.string().datetime().or(z.date()),
+  mileage: z.number().int().min(0),
+  action: MaintenanceAction,
+  notes: z.string().optional(),
+  cost: z.number().positive().optional(),
+})
+
+export type BikeInput = z.infer<typeof bikeSchema>
+export type WearPartInput = z.infer<typeof wearPartSchema>
+export type MaintenanceHistoryInput = z.infer<typeof maintenanceHistorySchema>
+

next.config.js

@@ -0,0 +1,5 @@
+/** @type {import('next').NextConfig} */
+const nextConfig = {}
+
+module.exports = nextConfig
+

package.json

@@ -0,0 +1,39 @@
+{
+  "name": "bike-wear-parts-tracker",
+  "version": "0.1.0",
+  "private": true,
+  "scripts": {
+    "dev": "next dev",
+    "build": "next build",
+    "start": "next start",
+    "lint": "next lint",
+    "db:push": "prisma db push",
+    "db:generate": "prisma generate",
+    "db:studio": "prisma studio",
+    "test": "vitest run --exclude '**/validations.test.ts' && bun test __tests__/lib/validations.test.ts",
+    "test:all": "vitest run",
+    "test:ui": "vitest --ui"
+  },
+  "dependencies": {
+    "react": "^18.3.1",
+    "react-dom": "^18.3.1",
+    "next": "^14.2.5",
+    "@prisma/client": "^5.19.1",
+    "zod": "^3.23.8"
+  },
+  "devDependencies": {
+    "typescript": "^5.5.4",
+    "@types/node": "^22.5.0",
+    "@types/react": "^18.3.5",
+    "@types/react-dom": "^18.3.0",
+    "prisma": "^5.19.1",
+    "tailwindcss": "^3.4.7",
+    "postcss": "^8.4.41",
+    "autoprefixer": "^10.4.20",
+    "eslint": "^8.57.1",
+    "eslint-config-next": "^14.2.5",
+    "vitest": "^2.0.3",
+    "@vitest/ui": "^2.0.3"
+  }
+}
+

postcss.config.js

@@ -0,0 +1,7 @@
+module.exports = {
+  plugins: {
+    tailwindcss: {},
+    autoprefixer: {},
+  },
+}
+

prisma/schema.prisma

@@ -0,0 +1,55 @@
+// This is your Prisma schema file,
+// learn more about it in the docs: https://pris.ly/d/prisma-schema
+
+generator client {
+  provider = "prisma-client-js"
+}
+
+datasource db {
+  provider = "sqlite"
+  url      = "file:./dev.db"
+}
+
+model Bike {
+  id           String     @id @default(cuid())
+  name         String
+  brand        String?
+  model        String?
+  purchaseDate DateTime?
+  notes        String?
+  wearParts    WearPart[]
+  createdAt    DateTime   @default(now())
+  updatedAt    DateTime   @updatedAt
+}
+
+model WearPart {
+  id                String              @id @default(cuid())
+  bikeId            String
+  bike              Bike                 @relation(fields: [bikeId], references: [id], onDelete: Cascade)
+  type              String               // CHAIN, BRAKE_PADS, TIRE, CASSETTE, CHAINRING, DERAILLEUR, etc.
+  brand             String?
+  model             String?
+  installDate       DateTime
+  installMileage    Int                  @default(0)
+  serviceInterval   Int                  // in km
+  status            String               @default("ACTIVE") // ACTIVE, NEEDS_SERVICE, REPLACED, INACTIVE
+  cost              Float?
+  notes             String?
+  maintenanceHistory MaintenanceHistory[]
+  createdAt         DateTime             @default(now())
+  updatedAt         DateTime             @updatedAt
+}
+
+model MaintenanceHistory {
+  id         String        @id @default(cuid())
+  wearPartId String
+  wearPart   WearPart      @relation(fields: [wearPartId], references: [id], onDelete: Cascade)
+  date       DateTime
+  mileage    Int
+  action     String        // INSTALL, REPLACE, SERVICE, CHECK, ADJUST
+  notes      String?
+  cost       Float?
+  createdAt  DateTime      @default(now())
+  updatedAt  DateTime      @updatedAt
+}
+

tailwind.config.ts

@@ -0,0 +1,20 @@
+import type { Config } from "tailwindcss";
+
+const config: Config = {
+  content: [
+    "./pages/**/*.{js,ts,jsx,tsx,mdx}",
+    "./components/**/*.{js,ts,jsx,tsx,mdx}",
+    "./app/**/*.{js,ts,jsx,tsx,mdx}",
+  ],
+  theme: {
+    extend: {
+      colors: {
+        background: "var(--background)",
+        foreground: "var(--foreground)",
+      },
+    },
+  },
+  plugins: [],
+};
+export default config;
+

tsconfig.json

@@ -0,0 +1,28 @@
+{
+  "compilerOptions": {
+    "target": "ES2017",
+    "lib": ["dom", "dom.iterable", "esnext"],
+    "allowJs": true,
+    "skipLibCheck": true,
+    "strict": true,
+    "noEmit": true,
+    "esModuleInterop": true,
+    "module": "esnext",
+    "moduleResolution": "bundler",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "jsx": "preserve",
+    "incremental": true,
+    "plugins": [
+      {
+        "name": "next"
+      }
+    ],
+    "paths": {
+      "@/*": ["./*"]
+    }
+  },
+  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx", ".next/types/**/*.ts"],
+  "exclude": ["node_modules"]
+}
+

types/index.ts

@@ -0,0 +1,15 @@
+import { Bike, WearPart, MaintenanceHistory } from '@prisma/client'
+
+export type BikeWithParts = Bike & {
+  wearParts: WearPart[]
+}
+
+export type WearPartWithHistory = WearPart & {
+  maintenanceHistory: MaintenanceHistory[]
+  bike: Bike
+}
+
+export type MaintenanceHistoryWithPart = MaintenanceHistory & {
+  wearPart: WearPart
+}
+

vitest.config.ts

@@ -0,0 +1,28 @@
+import { defineConfig } from 'vitest/config'
+import path from 'path'
+
+export default defineConfig({
+  test: {
+    globals: true,
+    environment: 'node',
+    pool: 'forks',
+    poolOptions: {
+      forks: {
+        singleFork: true,
+      },
+    },
+    sequence: {
+      shuffle: false,
+    },
+  },
+  resolve: {
+    alias: {
+      '@': path.resolve(__dirname, './'),
+    },
+  },
+  optimizeDeps: {
+    include: ['zod'],
+    exclude: [],
+  },
+})
+