#!/bin/sh
#
# configure
#
# A simple script to configure Makefiles
# (i.e. read Makefile.in, replace strings and write Makefile).
#
# heinzel <heinzel@heinzelwelt.de>
#
# $Id: configure,v 1.1 2008/02/19 14:12:59 heinzel Exp $
#
VERSION='configure Version 0.1 $Revision: 1.1 $ ($Date: 2008/02/19 14:12:59 $ $Author: heinzel $)'

### config ###
FILES=""
FILES_DEF="configure.files"

TEMPLATE_SUFFIX=".in"
MACROS_DEF="configure.macros"

MACROS="CTEMPLATE"
MACRO_CTEMPLATE="@CFILE@ (created by configure script)"

### functions ###
function print_help() {
	cat <<EOH
configure create files by processing templates and replace macros.
For now macros are simple name-value pairs. Use strings like @NAME@ within
the template files and configure will replace those strings by the named
value while creating the resulting files.

Usage: ./configure [OPTIONS]

Options:
  -h, --help
  -V, --version

Generic Options (and default values):
EOH
	for m in $MACROS ; do
		case "$m" in
		CFILE|CTEMPLATE)
			continue
			;;
		esac

		name="`echo $m | tr [[:upper:]] [[:lower:]]`"
		text="`eval_macro $m`"
		case "$text" in
		0)
			output="  --without-${name}"
			;;
		1)
			output="  --with-${name}"
			;;
		*)
			output="  --${name} $text"
			;;
		esac
		echo "$output"
	done
	echo ""
	cat <<EOH
Files:
  This script will create following files: $FILES
  or read file names to create from '$FILES_DEF'
  The templates have to end with '$TEMPLATE_SUFFIX'
  The macros can be defined in '$MACROS_DEF'
EOH
}

function print_version() {
	echo "$VERSION"
}

function set_macro() {
	case "$1" in
	'')
		return 1
		;;
	--with-*|--enable-*)
		name="`echo $1 | cut -f1 -d= | cut -f4- -d- | tr [[:lower:]] [[:upper:]]`"
		text="1"
		;;
	--without-*|--disable-*)
		name="`echo $1 | cut -f1 -d= | cut -f4- -d- | tr [[:lower:]] [[:upper:]]`"
		text="0"
		;;
	--*=*)
		name="`echo $1 | cut -f1 -d= | cut -c3- | tr [[:lower:]] [[:upper:]]`"
		text="`echo $1 | cut -f2- -d=`"
		;;
	--*)
		name="`echo $1 | cut -c3- | tr [[:lower:]] [[:upper:]]`"
		text="$2"
		;;
	*=*)
		name="`echo $1 | cut -f1 -d= | tr [[:lower:]] [[:upper:]]`"
		text="`echo $1 | cut -f2- -d=`"
		;;
	*)
		name="`echo $1 | tr [[:lower:]] [[:upper:]]`"
		text=""
		;;
	esac
	eval MACRO_${name}=${text}
	if ! expr " $MACROS " : ".* $name .*" >/dev/null ; then
		MACROS="$MACROS ${name}"
	fi
}

function eval_macro() {
	local name="$1"
	local text=""
	local return=""

	eval text="\$MACRO_${name}"
	while : ; do
		# Test if text contains more macros.
		echo "$text" | grep -E "@[A-Z][A-Z0-9]*@" >/dev/null
		r=$?
		if test "1${r}" != "10" ; then
			# Text is macro free.
			return="$text"
			break
		else
			# Get the last macro name from text...
			sm_name="`echo $text | sed -e 's=^.*@\([A-Z][A-Z0-9]*\)@.*$=\1='`"
			# Resolve it...
			sm_text="`eval_macro $sm_name`"
			# Substitute macro...
			text="`echo $text | sed -e 's=@'${sm_name}'@='${sm_text}'=g'`"
		fi
	done

	echo "$return"
}

function load_defaults() {
	local inc="${MACROS_DEF:-configure.macros}"
	local i=0
	local line=""

	if test "X${inc}" = "X" ; then
		return 1
	fi
	if test ! -r "$inc" -o -d "$inc" ; then
		echo "${inc}: not a readable file." >&2
		return 1
	fi

	while read line ; do
		i="`expr $i + 1`"
		case "$line" in
		\#*|\ *|'')
			continue
			;;
		*=*)
			set_macro "$line"
			;;
		*)
			echo "Warning: $inc: unexpected line ($i)." >&2
			;;
		esac
	done < "$inc"
}

function configure() {
	local file="$1"
	local ext="${TEMPLATE_SUFFIX:-.in}"
	local template=""

	local static_file=""

	local expr=""
	local name=""
	local text=""

	if test "X${file}" = "X" ; then
		echo "No filename given." >&2
		return 1
	fi
	template="${file}${ext}"
	if test ! -r "$template" -o -d "$template" ; then
		echo "$file: cannot read template ($template)."
		return 1
	fi

	set_macro CFILE="$file"
	ctext="`eval_macro CTEMPLATE`"
	cexpr="s=@${template}@=${ctext}=g"

	if test "X${CONFIGURE_STATIC_FILE}" != "X" ; then
		static_file="$CONFIGURE_STATIC_FILE"
		read expr < "$static_file"
	else
		static_file="`mktemp configure.tmp.XXXXXX`"
		if test "1$?" -ne "10" -o "X${static_file}" = "X" \
			-o ! -w "$static_file" ; then
			echo "Cannot create temp file." >&2
			return 1
		fi
		CONFIGURE_STATIC_FILE="$static_file"

		expr=""
		for name in $MACROS ; do
			case "$name" in
			CFILE|CTEMPLATE)
				continue
				;;
			esac
			text="`eval_macro $name`"
			expr="s=@$name@=$text=g
$expr"
		done

		echo "$expr" > "$static_file"
	fi

	sed -e "$cexpr" -e "$expr" "$template" > "$file"
}

function clean_up() {
	if test "X${CONFIGURE_STATIC_FILE}" != "X" -a -f "$CONFIGURE_STATIC_FILE" ; then
		rm "$CONFIGURE_STATIC_FILE"
	fi
}

### set options ###
load_defaults

while test "1$#" -gt "10" ; do
case "$1" in
-h|--help)
	print_help
	exit 0
	;;
-V|--version)
	print_version
	exit 0
	;;
--with-*|--without-*)
	set_macro "$1"
	shift
	;;
--enable-*|--disable-*)
	set_macro "$1"
	shift
	;;
--*=*)
	set_macro "$1"
	shift
	;;
--*)
	case "$2" in
	''|-*)
		set_macro "${1}=1"
		shift
		;;
	*)
		set_macro "$1" "$2"
		shift
		shift
		;;
	esac
	;;
esac
done

### action ###

files="$FILES"
if test "X${FILES_DEF}" != "X" -a -f "$FILES_DEF" ; then
	read buf < "$FILES_DEF"
	files="$files $buf"
fi


if test "X${files}" = "X" ; then
	echo "No files to configure." >&2
	echo " Make sure '$FILES_DEF' is there and readable." >&2
	exit 1
fi

for f in $files ; do
	echo "Creating file $f..."
	configure $f
done

clean_up
### end ###