#!/bin/sh
set -eu

cflags() {
	echo "CFLAGS += $*"
}
ldlibs() {
	echo "LDLIBS ${o:-}= $*"
	o=+
}
config() {
	pkg-config --print-errors "$@"
	cflags $(pkg-config --cflags "$@")
	ldlibs $(pkg-config --libs "$@")
}
defstr() {
	cflags "-D'$1=\"$2\"'"
}
defvar() {
	defstr "$1" "$(pkg-config --variable=$3 $2)${4:-}"
}

exec >config.mk

for opt; do
	case "${opt}" in
		(--prefix=*) echo "PREFIX = ${opt#*=}" ;;
		(--mandir=*) echo "MANDIR = ${opt#*=}" ;;
		(*) echo "warning: unsupported option ${opt}" >&2 ;;
	esac
done

case "$(uname)" in
	(FreeBSD)
		ldlibs -lcrypt
		config libcrypto libtls
		defvar OPENSSL_BIN openssl exec_prefix /bin/openssl
		defstr CERTBOT_PATH /usr/local/etc/letsencrypt
		echo 'INSTALLS = install-rcs install-dirs'
		;;
	(Linux)
		cflags -D_GNU_SOURCE
		ldlibs -lcrypt
		config libcrypto libtls
		defvar OPENSSL_BIN openssl exec_prefix /bin/openssl
		;;
	(Darwin)
		config libcrypto libtls
		defvar OPENSSL_BIN openssl exec_prefix /bin/openssl
		;;
	(*)
		ldlibs -lcrypt
		config libcrypto libtls
		defvar OPENSSL_BIN openssl exec_prefix /bin/openssl
		;;
esac