configure

#!/bin/sh

# We don't support out of tree builds
cd "$(dirname -- "$0")"

# Default values
prefix="${PREFIX:-/usr/local}"
pudev="${UDEVDIR:-/lib/udev/rules.d}"
udev="auto"
logind="disabled"
sdbus="auto"
mode="auto"

help() {
	cat <<EOF
Usage $0 [options]

Options: [defaults in brackets after description]

   --help			print this message
   --prefix=PREFIX		install in PREFIX [$prefix]
   --install-mode=MODE		brightnessctl installation mode [$mode]
   --udev-dir=PATH		installation path of the udev rules
				[$pudev]
   --dbus-provider=PROVIDER	DBus library for logind one of systemd,
				elogind, basu [$sdbus]

Optional features, enabled with --enable-FEATURE and disabled with
--disable-FEATURE: [default state in brackets after description]

   udev				Install udev rules [if logind is disabled]
   logind			Enable logind brighness API [$logind]
EOF
}

# Command line parsing, `getopt` is not used because long options are not in the
# posix interface
for opt do
	optarg=$(expr "x$opt" : 'x[^=]*=\(.*\)')
	case "$opt" in
	--help|-h)
		help
		exit 0
		;;
	--prefix=*) prefix="$optarg"
		;;
	--install-mode=*) mode="$optarg"
		;;
	--udev-dir=*) pudev="$optarg"
		;;
	--enable-udev) udev="enabled"
		;;
	--disable-udev) udev="disabled"
		;;
	--enable-logind) logind="enabled"
		;;
	--disable-logind) logind="disabled"
		;;
	--dbus-provider=*) sdbus="$optarg"
		;;
	*)
		echo "Unknown option $opt" >&2
		help >&2
		exit 1
		;;
	esac
done

# Specialize automatic options
if [ "$udev" = "auto" ]; then
	if [ "$logind" = "disabled" ]; then
		udev="enabled"
	else
		udev="disabled"
	fi
fi

if [ "$mode" = "auto" ]; then
	if [ "$udev" = "disabled" ] && [ "$logind" = "disabled" ]; then
		mode="4711"
	else
		mode="0755"
	fi
fi

# Generate `config.mk`
cat >config.mk <<EOF
# auto-generated by configure
PREFIX = $prefix
MODE = $mode
UDEVDIR = $pudev

EOF

if [ "$udev" = "enabled" ]; then
	echo 'INSTALL_UDEV_RULES = 1' >> config.mk
fi

if [ "$logind" = "enabled" ]; then
	case "$sdbus" in
	auto)
		for prov in basu libelogind libsystemd; do
			if pkg-config --exists "$prov"; then
				bus_provider="$prov"
				sdbus="$prov"
				break
			fi
		done
		if [ -z "$bus_provider" ]; then
			echo "Unable to find a workind dbus provider"
			exit 1
		fi
		;;
	systemd) bus_provider=libsystemd
		;;
	elogind) bus_provider=libelogind
		;;
	basu) bus_provider=basu
		;;
	*)
		echo "Unexpected dbus provider: $sdbus" >&2
		exit 1
		;;
	esac
	cat >> config.mk <<EOF
CFLAGS += $(pkg-config --cflags "$bus_provider")
LDLIBS += $(pkg-config --libs "$bus_provider")
CPPFLAGS += -DENABLE_LOGIND -DHAVE_$(echo "$bus_provider" | tr '[:lower:]' '[:upper:]')
EOF
fi

# Dump config to user
cat <<EOF
Build configuration:

   PREFIX:	$prefix
   MODE:	$mode
   UDEV_DIR:	$pudev

   udev:	$udev
   logind:	$logind [$sdbus]
EOF