Make domain configurable with default and interactive prompt

- Replace hardcoded domain in template.cfg with DOMAIN_NAME placeholder
- Add DEFAULT_DOMAIN constant and prompt in unattended.sh
- Support DOMAIN_NAME env var with fallback to default/interactive input
- Apply DOMAIN_NAME substitution to preseed.cfg

template.cfg

@@ -67,7 +67,7 @@ d-i netcfg/dhcpv6_timeout string 1
 # values set here. However, setting the values still prevents the questions
 # from being shown, even if values come from dhcp.
 d-i netcfg/get_hostname string debian
-d-i netcfg/get_domain string home.bjphoster.cloud
+d-i netcfg/get_domain string DOMAIN_NAME
 
 # If you want to force a hostname, regardless of what either the DHCP
 # server returns or what the reverse DNS entry for the IP is, uncomment

unattended.sh

@@ -1,11 +1,22 @@
 #!/usr/bin/env bash
 
-# Get password from user prompt and set it in preseed
+DEFAULT_ROOT_PASSWORD='IamGr00t!'
+DEFAULT_DOMAIN="home.bjphoster.cloud"
+
+# Get password from user prompt (empty input keeps the default) and set it in preseed
 if [ -z "$ROOT_PASSWORD" ]; then
-  read -sp "Enter the root password: " ROOT_PASSWORD
+  read -sp "Enter the root password [${DEFAULT_ROOT_PASSWORD}]: " ROOT_PASSWORD
+  echo
 fi
+ROOT_PASSWORD="${ROOT_PASSWORD:-${DEFAULT_ROOT_PASSWORD}}"
+# Get the domain from user prompt (empty input keeps the default) and set it in preseed
+if [ -z "$DOMAIN_NAME" ]; then
+  read -p "Enter the domain [${DEFAULT_DOMAIN}]: " DOMAIN_NAME
+fi
+DOMAIN_NAME="${DOMAIN_NAME:-${DEFAULT_DOMAIN}}"
 cp -f template.cfg preseed.cfg
 sed -i "s/ROOT_PASSWORD/${ROOT_PASSWORD}/" preseed.cfg
+sed -i "s/DOMAIN_NAME/${DOMAIN_NAME}/" preseed.cfg
 
 # Get the file name
 ISONAME=$(ls | grep "netinst.iso" | sort | tail -n1)