#!/bin/bash
# Distributed under the terms of the GNU General Public License v2
# $Header: $

ATOM=
CAT=
PN=

ACTION=
PRETEND=

CMD="emerge -Cav"
WEBAPP_DIR="/usr/share/webapps"
WEBAPP_CONFIG=

[[ -z ${RC_GOT_FUNCTIONS} ]] && source /lib/gentoo/functions.sh

function help() {
	echo "Remove obsolete and unused versions of web applications"
	echo
	echo "Usage:"
	echo "   $0 [options] [action] app_name"
	echo
	echo "Options:"
	echo "   -p, --pretend"
	echo "       Instead of cleaning, simply show the commands to be executed"
	echo
	echo "Actions:"
	echo "   -P, --prune"
	echo "       Removes all but the latest version of a package. Similar to"
	echo "       emerge --prune"
	echo
	echo "   -C, --clean-unused"
	echo "       Removes all versions of a web application that have not been"
	echo "       installed into a virtual host"
	echo
	echo "   -h, --help"
	echo "       Displays this help message"
	echo
	echo "If multiple actions are given, only the action specified last will"
	echo "be executed"
}

function sanity_checks() {
	WEBAPP_CONFIG=$(which webapp-config)
	if [ "${WEBAPP_CONFIG}x" == "x" ]; then
		eerror "webapp-config not found"
		exit 1
	fi

	if [[ -z "${ACTION}" ]]; then
		eerror "Please specify a valid action"
		exit 1
	fi

	if [[ -z ${PN} && ${ACTION} != "help" ]]; then
		eerror "Please specify a web application to be cleaned"
		exit 1
	fi

	if [[ "${CAT}x" == "x" || "${PN}x" == "x" ]]; then
		eerror "Package name must be in the form CATEGORY/PN"
		exit 1
	fi

	if [[ ! -d "${WEBAPP_DIR}/${CAT}/${PN}" && ! -d  "${WEBAPP_DIR}/${PN}" ]]; then
		eerror "${PN} not found"
		exit 1
	fi
}


function prune() {

	if [[ $(ls -1 "${WEBAPP_DIR}/${PN}" | wc -l) == "1" ]]; then
		einfo "Nothing to clean"
		return
	else
		local BEST_VERSION=$(ls ${WEBAPP_DIR}/${PN} | sort -nr | head -n 1)
		for x in $(ls ${WEBAPP_DIR}/${PN}); do
			if [[ ${BEST_VERSION} != ${x} ]]; then
				CMD="${CMD} =${PN}-${x}"
			fi
		done

		einfo "Multiple versions of ${PN} detected."
		if [[ -z ${PRETEND} ]]; then
			einfo "Running ${CMD}"
			${CMD}
		else
			einfo "To prune, run the following command:"
			einfo "${CMD}"
		fi
	fi
}

function clean_unused() {
	local output=$(${WEBAPP_CONFIG} --lui ${PN})

	if [[ -z ${output} ]] ; then
		einfo "Nothing to clean"
		return
	else
		CMD="${CMD} =${output}"
		einfo "Unused versions of ${PN} detected."
		if [[ -z ${PRETEND} ]]; then
			einfo "Running ${CMD}"
			${CMD}
		else
			einfo "To clean, run the following command:"
			einfo "${CMD}"
		fi
	fi
}

function process_opts() {

	if [[ -z $1 ]]; then
		help
		exit 0
	fi

	while [ "$1+" != "+" ]; do
		case "$1" in
			-p|--pretend)
				PRETEND="yes"
				;;
			-P|--prune)
				ACTION="prune"
				;;
			-C|--clean-unused)
				ACTION="clean_unused"
				;;
			-h|--help)
				ACTION="help"
				;;
			*)
				ATOM="${1}"
				parse_atom
				;;
		esac

		shift
	done
}

parse_atom() {
	local pos=$(expr index "${ATOM}" "/")
	CAT=${ATOM:0:$pos - 1}
	PN=${ATOM:$pos}
}

process_opts $@

sanity_checks

${ACTION}