#!/bin/sh
# vim:ft=sh:ts=4:sw=4:expandtab

# Configured variables #####################################################
# Described in following format:
# name:initial value:type:if exported to makefile:if exported to C header
# Where type can be just a string (in C in "") or plain. None implies plain.
CNFS="GEML_VERSION:0.1:string:F:T
GEML_CONTACT:cynerd@email.cz:string:F:T
PREFIX:/usr/local:string:T:F
MOD_LUA:yes::T:F
MOD_PYTHON:yes::T:F
DEBUG:no::T:F
CFLAGS:::T:F
LFLAGS:::T:F"
############################################################################

print_help() {
	echo "Usage: ./configure [OPTION]..."
	echo "GEML configuration script. Execute this script to configure project"
	echo "and prepare it for building."
	echo
	echo "  --help, -h              Give this help list"
	echo "  --prefix=PATH           Set PATH as installation prefix."
	echo "                          In default /usr/local"
	echo "  --debug, -d             Enable development features."
	echo "  --release, -r           Disable development features for project."
	echo "  --dep-check             Force depencency check for this machine."
	echo 
	echo "  --mod-lua-enable, --mod-lua-disable"
	echo "	Set if Lua module should be compiled. In default is enabled."
	echo "  --mod-python-enable, --mod-python-disable"
	echo "	Set if Python module should be compiled. In default is enabled."
	echo
	echo "Environment variables:"
	echo "  CROSS_COMPILE           Prefix for compilation tools."
	echo
	echo "GEML version $GEML_VERSION"
	echo "Report bugs to <$GEML_CONTACT>."
}

CONFIG_FILE=.config
CONFIGURED_FILE=.configured # TODO

# TODO support for values with escaped colons
# Load default configuration
eval `echo "$CNFS" | grep -o -E '^[^:]*:[^:]*' | sed 's/:/=/'`

# Load existing configuration
if [ -f "$CONFIG_FILE" ]; then
	source ./"$CONFIG_FILE"
fi

# Requested operation.
# c - Configure, default configuration behavior
# m - Prints output for Makefile
# h - Prints C header file (machine validation is skipped)
OP=c

# Parse arguments
while [ "$#" -gt 0 ]; do
	case $1 in
		-h|--help)
			print_help
			exit 0
			;;
		--prefix=*)
			# TODO
			;;
		-d|--debug)
			DEBUG=yes
			;;
		-r|--release)
			DEBUG=no
			;;
		--mod-lua-enable)
			MOD_LUA=yes
			;;
		--mod-lua-disable)
			MOD_LUA=no
			;;
		--mod-python-enable)
			MOD_PYTHON=yes
			;;
		--mod-python-disable)
			MOD_PYTHON=no
			;;
		--op-makefile)
			OP=m
			;;
		--op-h)
			OP=h
			;;
		*)
			echo Unknown option $1 1>&2
			exit 2
			;;
	esac
	shift
done

# Basically save configuration to file
configure() {
	echo "# GEML configuration file" > "$CONFIG_FILE"
	echo "# Please do not edit this file directly." >> "$CONFIG_FILE"
	echo "$CNFS" | while read L; do
		NAME=`echo "$L" | grep -o -E '^[^:]*'`
		eval "VALUE=\$$NAME"
		echo "$NAME=$VALUE" >> "$CONFIG_FILE"
	done
	echo "Configuration written to \"$CONFIG_FILE\""
}

# Generate Makefile and configure them if they doesn't exists in PWD
doext() {
	if [ -f "Makefile" ] || [ -f configure ]; then
		return
	fi
	GEMLDIR=`dirname "$0"`

	echo "# This is external Makefile for GEML." > Makefile
	echo "export CROSS_COMPILE=$CROSS_COMPILE" >> Makefile
	echo >> Makefile
	echo "GEML_PATH = $GEMLDIR" >> Makefile
	echo >> Makefile
	echo "MAKEARGS := -C \"\$(GEML_PATH)\"" >> Makefile
	echo "MAKEARGS += O=\"\$(shell pwd)\"" >> Makefile
	echo >> Makefile
	echo "MAKEFLAGS += --no-print-directory" >> Makefile
	echo >> Makefile
	echo "Q = @" >> Makefile
	echo ".PHONY: all \$(MAKECMDGOALS)" >> Makefile
	echo "all \$(MAKECMDGOALS):" >> Makefile
	echo "	\$(Q)\$(MAKE) \$(MAKEARGS) \$@" >> Makefile

	echo Created local Makefile

	echo "# This is external configure script for GEML." > configure
	echo "GEML_PATH=$GEMLDIR" >> configure
	echo "\$GEML_PATH/configure \$@" >> configure
	chmod +x configure

	echo Created local configure script
}

makefile() {
	echo "$CNFS" | while read L; do
		if [ `echo $L | awk -F ':' '{ print $4 }'` != "T" ]; then
			continue
		fi
		NAME=`echo "$L" | grep -o -E '^[^:]*'`
		eval "VALUE=\$$NAME"
		echo "$NAME = $VALUE"
	done
}

cheader() {
	echo "$CNFS" | while read L; do
		if [ `echo $L | awk -F ':' '{ print $5 }'` != "T" ]; then
			continue
		fi
		NAME=`echo "$L" | grep -o -E '^[^:]*'`
		eval "VALUE=\$$NAME"
		if [ "`echo $L | awk -F ':' '{ print $3 }'`" = "string" ]; then
			echo "#define $NAME \"$VALUE\""
		else
			echo "#define $NAME $VALUE"
		fi
	done
}

validate() {
	echo -n
	# TODO check dependencies and programs
}

case $OP in
	c)
		validate
		doext
		configure
		;;
	m)
		validate
		makefile
		;;
	h)
		cheader
		;;
esac