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)

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>
+  )
+}
+