#!/bin/sh
set -eu

usage() {
	cat <<-'EOF'
		Usage:
		  gc [TYPE]
		  gc -h
	EOF
}

help() {
	cat <<-'EOF'


		Options:
		  -h, --help    show this message

		  TYPE          what to do GC on (default: all):
		                - guix
		                - deploy
		                - trash
		                - tmpdir
		                - logs


		GC the server, deleting old, unusable data, in order to free
		disk space system-wide.


		Examples:

		  Just run it, for all:

		    $ gc


		  Cleanup tmpdir:

		    $ gc tmpdir
	EOF
}


for flag in "$@"; do
	case "$flag" in
		--)
			break
			;;
		--help)
			usage
			help
			exit
			;;
		*)
			;;
	esac
done

while getopts 'h' flag; do
	case "$flag" in
		h)
			usage
			help
			exit
			;;
		*)
			usage >&2
			exit 2
			;;
	esac
done
shift $((OPTIND - 1))


if [ "$(id -un)" != 'root' ]; then
	printf 'This script must be run as root.\n\n' >&2
	usage >&2
	exit 2
fi


disk() {
	df -h / /mnt/backup/ |
		tail -n +2 |
		awk '{ printf "%s\t%s/%s\t%s\n", $4, $3, $2, $6 }'
}

today() {
	date '+%Y-%m-%d'
}

gc_guix() {
	sudo -i guix system delete-generations 1m
	sudo -i guix gc -d 1m
}

gc_deploy() {
	find /opt/deploy \
		! -path /opt/deploy -prune \
		-type d \
		-not -name "$(today)*" \
		-exec rm -rvf "{}" ';'
}

gc_trash() {
	yes | sudo -i trash-empty
}

gc_tmpdir() {
	find "${TMPDIR:-/tmp}"    -atime +10 -exec rm -vf "{}" ';'
}

gc_logs() {
	find /var/log/ci/ -atime +10 -exec rm -vf "{}" ';'
}


gc_all() {
	gc_guix
	gc_deploy
	gc_trash
	gc_tmpdir
	gc_logs
}


TYPE="${1:-all}"
CMD=gc_"$TYPE"
if ! command -v "$CMD" >/dev/null; then
	printf 'Invalid TYPE: "%s".\n\n' "$TYPE" >&2
	usage >&2
	exit 2
fi

BEFORE="$(disk)"
set -x
"$CMD"
set +x
AFTER="$(disk)"

cat <<-EOF
	Disk space:
	  before: $BEFORE
	  after:  $AFTER
EOF