Add some hand-holding

build.sh

@@ -3,8 +3,32 @@
 set -euo pipefail
 
 HERE=$(dirname "$(realpath "${0}")")
+ANDROID_TARGETS="mainline optimized legacy"
+LINUX_TARGETS="native amd64 steamdeck zen2 allyx rog-ally zen4 legacy aarch64 armv9"
+
+if [[ "${#}" != 2 ]]; then
+    echo "${0} <android|linux> <${ANDROID_TARGETS// /|}|${LINUX_TARGETS// /|}>"
+    exit 1
+fi
+
+# Now we know ${1} isn't unbound
 IMAGE="eden-${1}-builder"
 
+if [[ "${1}" == "android" ]]; then
+    if [[ "$(grep " ${2} " <<< " ${ANDROID_TARGETS} ")" == "" ]]; then
+        echo "Android target must be one of: ${ANDROID_TARGETS}"
+        exit 1
+    fi
+elif [[ "${1}" == "linux" ]]; then
+    if [[ "$(grep " ${2} " <<< " ${LINUX_TARGETS} ")" == "" ]]; then
+        echo "Linux target must be one of: ${LINUX_TARGETS}"
+        exit 1
+    fi
+else
+    echo "Platform must be one of: android linux"
+    exit 1
+fi
+
 if [[ "$(docker images | grep "^${IMAGE} ")" == "" ]]; then
     docker pull ubuntu
     docker build --no-cache -t "${IMAGE}" -f "${HERE}/Dockerfile.${1}" "${HERE}"