Delete invoice feature (#64)

* I mplement delete API for draft invoices with ownership verification

* Color change dark mode

app/(dashboard)/invoices/[id]/page.tsx

@@ -32,6 +32,14 @@ import {
   Trash2,
 } from 'lucide-react'
 import PaymentBookingDialog from '@/components/invoices/PaymentBookingDialog'
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle,
+} from '@/components/ui/dialog'
 import type { Invoice, InvoiceItem, Customer, InvoiceStatus, InvoiceReminder, InvoiceDocumentType } from '@/types'
 
 const statusConfig: Record<InvoiceStatus, { label: string; variant: 'default' | 'secondary' | 'success' | 'warning' | 'destructive'; icon: React.ElementType }> = {
@@ -72,6 +80,8 @@ export default function InvoiceDetailPage({ params }: { params: Promise<{ id: st
   const [isUpdating, setIsUpdating] = useState(false)
   const [isDownloading, setIsDownloading] = useState(false)
   const [isSendingEmail, setIsSendingEmail] = useState(false)
+  const [showDeleteDialog, setShowDeleteDialog] = useState(false)
+  const [isDeleting, setIsDeleting] = useState(false)
 
   useEffect(() => {
     fetchInvoice()
@@ -326,6 +336,39 @@ export default function InvoiceDetailPage({ params }: { params: Promise<{ id: st
     setIsDownloading(false)
   }
 
+  async function deleteInvoice() {
+    if (!invoice) return
+
+    setIsDeleting(true)
+
+    try {
+      const response = await fetch(`/api/invoices/${invoice.id}`, {
+        method: 'DELETE',
+      })
+
+      if (!response.ok) {
+        const data = await response.json()
+        throw new Error(data.error || 'Kunde inte ta bort fakturan')
+      }
+
+      toast({
+        title: 'Faktura borttagen',
+        description: `Utkast ${invoice.invoice_number} har tagits bort`,
+      })
+
+      router.push('/invoices')
+    } catch (error) {
+      toast({
+        title: 'Kunde inte ta bort fakturan',
+        description: error instanceof Error ? error.message : 'Försök igen.',
+        variant: 'destructive',
+      })
+    }
+
+    setIsDeleting(false)
+    setShowDeleteDialog(false)
+  }
+
   if (isLoading) {
     return (
       <div className="flex items-center justify-center h-64">
@@ -885,8 +928,8 @@ export default function InvoiceDetailPage({ params }: { params: Promise<{ id: st
                     <Button
                       variant="outline"
                       className="w-full text-destructive hover:text-destructive"
-                      onClick={() => updateStatus('cancelled')}
-                      disabled={isUpdating}
+                      onClick={() => setShowDeleteDialog(true)}
+                      disabled={isDeleting}
                     >
                       <Trash2 className="mr-2 h-4 w-4" />
                       Ta bort utkast
@@ -925,6 +968,27 @@ export default function InvoiceDetailPage({ params }: { params: Promise<{ id: st
         </div>
       </div>
 
+      {/* Delete confirmation dialog */}
+      <Dialog open={showDeleteDialog} onOpenChange={setShowDeleteDialog}>
+        <DialogContent>
+          <DialogHeader>
+            <DialogTitle>Ta bort fakturautkast</DialogTitle>
+            <DialogDescription>
+              Är du säker på att du vill ta bort utkast {invoice.invoice_number}? Detta kan inte ångras.
+            </DialogDescription>
+          </DialogHeader>
+          <DialogFooter>
+            <Button variant="outline" onClick={() => setShowDeleteDialog(false)} disabled={isDeleting}>
+              Avbryt
+            </Button>
+            <Button variant="destructive" onClick={deleteInvoice} disabled={isDeleting}>
+              {isDeleting && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
+              Ta bort
+            </Button>
+          </DialogFooter>
+        </DialogContent>
+      </Dialog>
+
       <PaymentBookingDialog
         open={showPaymentDialog}
         onOpenChange={setShowPaymentDialog}

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

@@ -0,0 +1,64 @@
+import { createClient } from '@/lib/supabase/server'
+import { NextResponse } from 'next/server'
+
+/**
+ * DELETE /api/invoices/[id]
+ *
+ * Permanently deletes a draft invoice and its items.
+ * Only invoices with status 'draft' can be deleted — committed invoices
+ * are immutable per BFL and must be reversed via credit note instead.
+ */
+export async function DELETE(
+  request: Request,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  const { id } = await params
+  const supabase = await createClient()
+
+  const { data: { user } } = await supabase.auth.getUser()
+
+  if (!user) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+  }
+
+  // Fetch invoice to verify ownership and status
+  const { data: invoice, error: fetchError } = await supabase
+    .from('invoices')
+    .select('id, status, user_id')
+    .eq('id', id)
+    .eq('user_id', user.id)
+    .single()
+
+  if (fetchError || !invoice) {
+    return NextResponse.json({ error: 'Invoice not found' }, { status: 404 })
+  }
+
+  if (invoice.status !== 'draft') {
+    return NextResponse.json(
+      { error: 'Endast utkast kan tas bort. Bokförda fakturor måste krediteras istället.' },
+      { status: 400 }
+    )
+  }
+
+  // Delete items first (FK constraint), then the invoice
+  const { error: itemsError } = await supabase
+    .from('invoice_items')
+    .delete()
+    .eq('invoice_id', id)
+
+  if (itemsError) {
+    return NextResponse.json({ error: itemsError.message }, { status: 500 })
+  }
+
+  const { error: deleteError } = await supabase
+    .from('invoices')
+    .delete()
+    .eq('id', id)
+    .eq('user_id', user.id)
+
+  if (deleteError) {
+    return NextResponse.json({ error: deleteError.message }, { status: 500 })
+  }
+
+  return NextResponse.json({ data: { deleted: true } })
+}

app/globals.css

@@ -105,7 +105,7 @@
   --success-foreground: 0 0% 100%;
 
   --warning: 38 50% 55%;
-  --warning-foreground: 0 0% 9%;
+  --warning-foreground: 38 50% 90%;
 
   --warm-accent: 38 42% 58%;