add qr to invoice

rechnung.typ

@@ -1,5 +1,6 @@
 #import "templates/tmpl_letter.typ": tmpl_letter
 #import "templates/common.typ": colors, money
+#import "@preview/cades:0.3.0": qr-code
 #let config = yaml("rechnung.yml")
 
 #show: doc => tmpl_letter(
@@ -73,4 +74,25 @@
   #pad(x:1em)[
     *Gesamtbetrag: #money(config.entries.map(e => e.pieces * e.price - e.sale).sum())*
   ]
+]
+
+#if config.type == "invoice" [
+  #v(1em)
+  #align(right)[
+    #block(
+      stroke: 1pt,
+      inset: 1em,
+      radius: 1em
+    )[
+      #qr-code("BCD\n002\n1\nSCT\n\nswablab e.V.\nDE12642624080125634005\nEUR" + str(config.entries.map(e => e.pieces * e.price - e.sale).sum()) + "\nGDDS\n\nRechnung " + str(config.invoice_no) + "\nswablab Rechnung", width: 2cm)
+      
+      #place(center+bottom, dy: 1.1em)[
+        #block(width: 100%+0.75em, fill: white)[
+          #text(size: 8pt)[
+            Zahlen mit Code
+          ]
+        ]
+      ]
+    ]
+  ]
 ]