#!/bin/sh

prefix=/usr/local

usage() {
	echo "supported arguments"
	echo "--prefix=/path 		default: $prefix"
	echo "--exec_prefix=/path	default: $prefix/bin"
	echo "--bindir=/path		default: $prefix/bin"
	echo "--libdir=/path		default: $prefix/lib"
	echo "--includedir=/path	default: $prefix/include"
	echo "--sysconfdir=/path	default: $prefix/etc"
	echo "--help : show this text"
	exit 1
}

spliteq() {
	arg=$1
	echo "${arg#*=}"
	#alternatives echo "$arg" | cut -d= -f2-
	# or echo "$arg" | sed 's/[^=]*=//'
}

parsearg() {
	case "$1" in
	--prefix=*) prefix=`spliteq $1`;;
	--exec_prefix=*) exec_prefix=`spliteq $1`;;
	--bindir=*) bindir=`spliteq $1`;;
	--libdir=*) libdir=`spliteq $1`;;
	--includedir=*) includedir=`spliteq $1`;;
	--sysconfdir=*) sysconfdir=`spliteq $1`;;
	--help) usage;;
	esac
}

ismac() {
	uname -s | grep Darwin >/dev/null
}

isbsd() {
	uname -s | grep BSD >/dev/null
}

while true ; do
	case $1 in
	-*) parsearg "$1"; shift;;
	*) break ;;
	esac
done

if [ -z "$exec_prefix" ] ; then
	exec_prefix=$prefix
fi

if [ -z "$libdir" ] ; then
	libdir=$prefix/lib
fi

if [ -z "$includedir" ] ; then
	includedir=$prefix/include
fi

if [ -z "$sysconfdir" ] ; then
	sysconfdir=$prefix/etc
fi

if [ -z "$bindir" ] ; then
	bindir=$exec_prefix/bin
fi

if [ -z "$CC" ] ; then
	CC=cc
fi

echo CC?=$CC>config.mak
[ -z "$CPPFLAGS" ] || echo CPPFLAGS?=$CPPFLAGS>>config.mak
[ -z "$CFLAGS" ] || echo USER_CFLAGS?=$CFLAGS>>config.mak
echo prefix=$prefix>>config.mak
echo exec_prefix=$exec_prefix>>config.mak
echo bindir=$bindir>>config.mak
echo libdir=$libdir>>config.mak
echo includedir=$includedir>>config.mak
echo sysconfdir=$sysconfdir>>config.mak
if ismac ; then
	echo NO_AS_NEEDED=>>config.mak
	echo LDSO_SUFFIX=dylib>>config.mak
	echo MAC_CFLAGS+=-DIS_MAC=1>>config.mak
	echo LD_SET_SONAME=-Wl,-install_name,>>config.mak
	echo INSTALL_FLAGS=-m>>config.mak
elif isbsd ; then
	echo LIBDL=>>config.mak
	echo "CFLAGS+=-DIS_BSD">>config.mak
fi

echo done, now run make \&\& make install