#!/usr/bin/env bash
set -euo pipefail

gen-init ()
{
	echo "COPY common /build/common"
}

gen-cleanup ()
{
	echo "RUN rm -rf /build /data"
}

gen-docker-file ()
{
	if [ -f $src/Dockerfile.top ] ; then
		cat $src/Dockerfile.top
		gen-init
	fi

	for stage in $(cd $src && echo [0-9]*.[a-z]*) ; do
		case $stage in
			*.docker)
				cat $src/$stage
				if grep -wq '^FROM' $src/$stage ; then
					gen-init
				fi
				;;
			*.d|*.sh)
				echo "COPY $src/$stage /build/$stage"
				echo "RUN /build/common/run $stage"
				;;
			*)
				echo >&2 "ERROR: Unrecognized build stage name $stage"
				exit 1
				;;
		esac
	done

	if [ -f $src/Dockerfile.bottom ] ; then
		cat $src/Dockerfile.bottom
	fi

	gen-cleanup
}

if [ $# = 0 ] ; then
	echo >&2 "Usage: $0 <src-directory> [<podman build options>]"
	exit 1
fi

src=$1
shift

if [ ! -v http_proxy ] ; then
	PROXY=
	eval "$(apt-config shell PROXY Acquire::http::proxy)"
	if [ -n "$PROXY" ] ; then
		export http_proxy=$PROXY
	fi
fi

if [ -v http_proxy -a ! -v https_proxy ] ; then
	export https_proxy=$http_proxy
fi

CACHE_DIR=${XDG_CACHE_HOME:-$HOME/.cache}/container-build
if [ -d $CACHE_DIR ] ; then
	echo "Using cache $CACHE_DIR"
else
	echo "Creating cache $CACHE_DIR"
	mkdir -p $CACHE_DIR
fi
mkdir -p $CACHE_DIR/download

gen-docker-file | podman build \
	--file - \
	--http-proxy \
	--volume=$CACHE_DIR:/root/.cache \
	"$@" \
	.

echo -n "Cache usage: "
du -sh $CACHE_DIR | cut -d '	' -f1