#!/bin/bash
# Copyright 2011 Magellan-Linux
# Distributed under the terms of the GNU General Public License v2
# $Id$
# Author: Niels Rogalla <niro@magellan-linux.de>
# based on opengl-update from Gentoo-Linux
#

hasq()
{
	local x

	local me=${1}
	shift

	for x in $@
	do
		[[ ${x} = ${me} ]] && return 0
	done

	return 1
}

check_user()
{
	if [[ $(id -u) -ne 0 ]]
	then
		echo "${0}: Must be run as root."
		exit 1
	fi
}

get_current_implem()
{
	local implem

	if [[ -f ${ENV_D} ]]
	then
		source ${ENV_D}
		if [[ -n ${DRI_PROFILE} ]]
		then
			implem="${DRI_PROFILE}"
		fi
		unset DRI_PROFILE
	fi

	echo ${implem}
}

get_implementations()
{
	local implems

	for dir in ${PREFIX}/lib{,32,64}/mesa/*
	do
		if [[ -d ${dir} ]] &&
			! hasq ${dir##*/} ${implems}
		then
			implems=${implems:+${implems} }${dir##*/}
		fi
	done

	echo ${implems}
}

print_version()
{
	echo "dri-update ${VERSION}"
}

print_usage()
{
	# Get grammar right in message
	local IS_ARE IMPLEM_PLURAL

	if [[ $(echo ${AVAIL_IMPLEMS} | wc -w) -eq 1 ]]
	then
		IS_ARE="is"
		IMPLEM_PLURAL=""
	else
		IS_ARE="are"
		IMPLEM_PLURAL="s"
	fi

	print_version

	cat << FOO
Usage: ${0##*/} [<options>] <DRI implementation>
       Set the dri implementation.
       Valid options:
       --help|-h|-?:       Prints this help.
       --version:          Shows the version of this utility.
       --use-old:          If an implementation is already set, use that one.
       --prefix=<val>:     Set the source prefix (default: /usr)
       --dst-prefix=<val>: Set the destination prefix (default: /usr)

Usage: ${0##*/} --get-implementation
       Print the current implementaion

       This utility switches between DRI implementations.  There ${IS_ARE}
       $(echo ${AVAIL_IMPLEMS} | wc -w) available implementation${IMPLEM_PLURAL}: ${AVAIL_IMPLEMS}

Examples:
       ${0##*/} classic
       This will setup things to use the classic DRI drivers.

       ${0##*/} gallium
       This will setup things to use the gallium DRI drivers.

FOO
	exit 1
}

parse_options()
{
	local opt

	while [[ ${#} -gt 0 ]]
	do
		opt=${1}
		shift
		case ${opt} in
			--use-old)
				if [[ -n ${ACTION} ]]
				then
					ACTION="error"
					echo "Invalid usage."
				else
					if [[ -n "${CURRENT_DRI_IMPLEM}" ]] &&
						hasq ${CURRENT_DRI_IMPLEM} ${AVAIL_IMPLEMS}
					then
						ACTION="old-implementation"
					fi
				fi
				;;

			--get-implementation)
				if [[ -n ${ACTION} ]]
				then
					ACTION="error"
					echo "Invalid usage."
				else
					ACTION="get-implementation"
				fi
				;;

			--prefix=*)
				PREFIX=${opt#*=}
				AVAIL_IMPLEMS=$(get_implementations)
				;;

			--dst-prefix=*) DST_PREFIX=${opt#*=} ;;

			--help|-h|-?) ACTION="usage" ;;

			--version) ACTION="version" ;;

			*)
				if hasq ${opt} ${AVAIL_IMPLEMS}
				then
					if [[ ${ACTION} != old-implementation ]]
					then
						if [[ -n ${ACTION} ]]
						then
							ACTION="error"
							echo "Invalid usage."
						else
							ACTION="set-implementation"
							NEW_DRI_IMPLEM="${opt}"
						fi
					fi
				else
					echo "Unrecognized option: ${opt}"
					ACTION="error"
				fi
				;;
		esac
	done
}

set_new_implementation()
{
	local DRI_IMPLEM=${1}
	local DRI_LOCAL

	check_user

	# Set a sane umask... bug #83115
	umask 022

	if ! hasq ${DRI_IMPLEM} ${AVAIL_IMPLEMS}
	then
		echo "Invalid profile selected."
		exit 1
	fi

	echo "Switching to ${DRI_IMPLEM} DRI drivers"

	rm -f ${ENV_D} &> /dev/null

	LIBDIRS="lib32 lib lib64"
	for LIBDIR in ${LIBDIRS}
	do
		# Special case handling of lib32 because it can be a symlink to
		# emul libs
		if [[ ${LIBDIR} = lib32 ]]
		then
			[[ -d ${PREFIX}/${LIBDIR}/mesa ]] || continue
		else
			[[ -d ${PREFIX}/${LIBDIR}/mesa ]] &&
				[[ ! -h ${PREFIX}/${LIBDIR} ]] || continue
		fi

		# Fallback on classic if we don't have this implementation for this LIBDIR.
		if [[ ! -d ${PREFIX}/${LIBDIR}/mesa/${DRI_IMPLEM} ]]
		then
			DRI_LOCAL="classic"
		else
			DRI_LOCAL="${DRI_IMPLEM}"
		fi

		mkdir -p ${DST_PREFIX}/${LIBDIR}/dri
		pushd ${DST_PREFIX}/${LIBDIR}/dri &> /dev/null
			# First remove old symlinks
			for file in *_dri.so
			do
				[[ -h ${file} ]] && rm -f ${file}
			done

			for file in ${PREFIX}/${LIBDIR}/mesa/${DRI_LOCAL}/*_dri.so
			do
				[[ -f ${file} ]] || continue
				[[ -f ${file##*/} ]] && rm -f ${file##*/}

				ln -s ${file}
			done
		popd &> /dev/null
	done

	echo "DRI_PROFILE=\"${DRI_IMPLEM}\"" >> ${ENV_D}

	env-rebuild

	return 0
}

## START PROGRAM ##

ENV_D="/etc/env.d/03dri"
NEW_DRI_IMPLEM=""
ACTION=""
PREFIX="/usr"
DST_PREFIX="/usr"
AVAIL_IMPLEMS=$(get_implementations)
CURRENT_DRI_IMPLEM=$(get_current_implem)
VERSION="@@VERSION@@"

parse_options ${@}

case ${ACTION} in
	get-implementation)
		if [[ -n ${CURRENT_DRI_IMPLEM} ]]
		then
			echo ${CURRENT_DRI_IMPLEM}
			exit 0
		else
			exit 2
		fi
		;;

	old-implementation)
		set_new_implementation ${CURRENT_DRI_IMPLEM}
		exit $?
		;;

	set-implementation)
		if [[ -n ${NEW_DRI_IMPLEM} ]]
		then
			set_new_implementation ${NEW_DRI_IMPLEM}
			exit $?
		else
			print_usage
			exit 1
		fi
		;;

	version)
		print_version
		exit 0
		;;

	usage)
		print_usage
		exit 0
		;;

	error)
		print_usage
		exit 1
		;;

	*)
		print_usage
		exit 1
		;;
esac