+edit_invoice(){
+ id="$1"
+ if [ -f "invoices/$id" ]; then
+ read -r sender client date number vat<<-EOF
+ $(sed q "invoices/$id")
+ EOF
+ fi
+
+ [ "${date#date=}" -ge 0 ] 2>&- \
+ && date="$(date -d "@${date#date=}" +%F)" \
+ || date="$(date +%F)"
+ [ "${number#number=}" ] || number="number=$(date +%s)"
+ [ "${vat%=*}" = vat -a "${vat#vat=}" -ge 0 ] 2>&- \
+ && vatrate="${vat#vat=}" \
+ || vatrate=19
+
+ cat <<-EOF
+ [form method="POST" action="/update_invoice"
+ [hidden "id" "$(HTML "$id")"]
+
+ [label Sender:]
+ [select name=sender
+ $(sender_list "${sender#sender=}")
+ ]
+
+ [label Client:]
+ [select name=client
+ $(client_list "${client#client=}")
+ ]
+
+ [label for=number Invoice Number:]
+ [input #number name=number value="$(UNSTRING "${number#number=}" |HTML)"]
+
+ [label for=date Date:]
+ [input #date name=date value="${date}" placeholder="YYYY-MM-TT"]
+
+ [radio "vat" "smallbusiness" #vatsb $([ "$vat" = smallbusiness ] && printf checked) ]
+ [label for=vatsb Small business exemption from VAT]
+ [radio "vat" "allgross" #vatgross $([ "$vat" = allgross ] && printf checked)]
+ [label for=vatgross All amounts are gross]
+ [radio "vat" "rate" #vatrate $([ "${vat%=*}" = vat ] && printf checked) ]
+ [label for=vatrate VAT Rate: [input type=number name="vatrate" value="${vatrate}"]% ]
+
+ [submit "update" "update" Update]
+ ]
+ EOF
+}
+