#!/bin/bash
#######################################
# Inspiration from bug #34921
# Thanks to Paul Varner

# Distributed under the GPL v2
# Written by John Mylchreest (johnm@gentoo.org)
# Copyright Gentoo Linux

R_VERSION="0.1"
R_MODULES="${ROOT}/usr/share/module-rebuild/moduledb"
R_PORTAGEQ="`which portageq 2>/dev/null`"
[[ -n ${R_PORTAGEQ} ]] && R_PORTDIR=`${R_PORTAGEQ} portdir`

if [[ -z ${R_PORTDIR} ]]; then
	echo "** FATAL: Unable to find portdir."
	exit 1
fi

package_valid() {
	local package=${1}
	[[ -z ${package} ]] && return 1
	[[ -z ${package/*\/*} ]] && return 0 || return 1
}

package_valid_strict() {
	local package=${1}
	package_valid ${package} && [[ -z ${package//*-[0-9]*} ]] && return 0 || return 1
}

package_exists() {
	local package=${1}

	package=${package//-[0-9]*}
	if $(${R_PORTAGEQ} has_version / ${package}); then
		return 0
	else
		return 1
	fi
}

db_module_exists() {
	local line package=${1}

	for line in `<${R_MODULES}`; do
		[[ -z ${line/*${package}*} ]] && return 0
	done
	return 1
}

db_module_toggle() {
	local package=${1} toggleto=${2} togglefrom line
	
	if db_module_exists ${package}; then
		line=`grep ${package} ${R_MODULES}`
		togglefrom=${line#*:}
		togglefrom=${togglefrom/:*}
		[[ -z ${toggleto} ]] && [[ ${togglefrom} = 0 ]] && toggleto=1 || toggleto=0
		echo "** Setting ${package}; rebuild=${toggleto}."
		sed -ie "s:\(.\:\)\([01]\)\(\:${package}\):\1${toggleto}\3:g" ${R_MODULES}
	else
		echo "** ${package} not found in moduledb."
	fi
}

db_module_add() {
	local package=${1}

	if db_module_exists ${package}; then
		echo "** Module already exists in moduledb."
		db_module_toggle ${package} 1
		return 0
	else
		if package_exists ${package}; then
			echo "** Adding ${package} to moduledb."
			echo "m:1:${package}" >> ${R_MODULES}
			return 0
		else
			echo "** Unable to locate an available ebuild for ${package}."
			echo "** Please manually emerge ${package} first."
		fi
	fi
	return 1
}

db_module_del() {
	local package=${1}
	
	if db_module_exists ${package}; then
		echo "** Removing ${package} from moduledb."
		sed -ie "/.*${package/\//\\/}.*/d" ${R_MODULES}
		return 0
	else
		echo "** ${package} not found in moduledb."
		return 1
	fi
}

db_module_list() {
	local line autoload pkg a=0 b=0

	for line in `<${R_MODULES}`; do
		mode=${line:0:1}
		pkg=${line#*:}
		autoload=${pkg/:*}
		pkg=${pkg/*:}
		
		package_valid_strict ${pkg} && pkg="=${pkg}"
		if [[ ${autoload} = 1 ]]; then
			tomerge[${a}]=${pkg}
			a=$((${a} + 1))
		else
			toignore[${b}]=${pkg}
			b=$((${b} + 1))
		fi
	done

	pkg="${tomerge[@]}${toignore[@]}"
	if [[ -z ${pkg} ]]; then
		echo "** There are no known modules. Quitting."
		exit 1
	fi
	
	echo "** Packages which I will emerge are:"
	for pkg in ${tomerge[@]}; do
		echo -e "\t${pkg}"
	done

	echo "** Packages which I will ignore are:"
	for pkg in ${toignore[@]}; do
		echo -e "\t${pkg}"
	done
}

db_module_merge() {
	local i pad
	
	echo "** Preparing to merge modules:"
	db_module_list >/dev/null

	echo "** Packages which I will emerge are:"
	for pkg in ${tomerge[@]}; do
		echo -e "\t${pkg}"
	done
	
	for((i=1;i<6;i++)); do
		echo -n "$((6 - ${i})) "
		sleep 1
	done

	emerge ${tomerge[@]}
}

phelp() {
cat << EOF
module-rebuild action [category/package]
Version: ${R_VERSION}

Where action is one of:
	add 	- Add package to moduledb.
	del	- Delete a package from moduledb.
	toggle	- Toggle auto-rebuild of Package.
	list	- List packages to auto-rebuild.
	rebuild	- Rebuild packages.

EOF

}

if [[ `id -u` != 0 ]]; then
	echo "This application must be ran as root."
	exit 1
fi

if [[ ! -f ${ROOT}/usr/share/module-rebuild/moduledb ]]; then
	[[ ! -d ${ROOT}/usr/share/module-rebuild/ ]] && mkdir ${ROOT}/usr/share/module-rebuild/
	touch ${ROOT}/usr/share/module-rebuild/moduledb
fi

check_validity() {
	local package=${1} strict=${2:-0} ret=1

	[[ ${strict} = 0 ]] && package_valid ${package} && ret=0
	[[ ${strict} = 1 ]] && package_valid_strict ${package} && ret=0

	
	if [[ ${ret} != 0 ]]; then
		echo "** Please pass the fully qualified package. For example:"
		echo "** media-video/nvidia-kernel-1.0.7174"
		exit 1
	fi
}

method="${1}"
case ${method} in
	add)		check_validity ${2} 1; db_module_add ${2};;
	del)		check_validity ${2}; db_module_del ${2};;
	toggle)		check_validity ${2}; db_module_toggle ${2};;
	list)		db_module_list;;
	rebuild)	db_module_merge;;
	*)			phelp;;
esac