#!/bin/bash
#
#   pacscripts : tries to print out the {pre,post}_{install,remove,upgrade}
#   scripts of a given package
#
#   Copyright (c) 2009 Xavier Chantry <shiningxc@gmail.com>
#   Copyright (c) 2009-2016 Pacman Development Team <pacman-dev@archlinux.org>
#
#   This program is free software; you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation; either version 2 of the License, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

# bash options
set -o nounset
set -o errexit

declare -r myname='pacscripts'
declare -r myver='@PACKAGE_VERSION@'

conf="@sysconfdir@/pacman.conf"

if [ ! -r "$conf" ]; then
	echo "ERROR: unable to read $conf"
	exit 1
fi

eval $(awk '/DBPath/ {print $1$2$3}' "$conf")
eval $(awk '/CacheDir/ {print $1$2$3}' "$conf")
pac_db="${DBPath:-@localstatedir@/lib/pacman}/local"
pac_cache="${CacheDir:-@localstatedir@/cache/pacman/pkg}"

error() {
	local mesg=$1; shift
	printf "==> $(gettext "ERROR:") ${mesg}\n" "$@" >&2
}

usage() {
	echo "${myname} (pacman) v${myver}"
	echo
	echo "Prints the {pre,post}_{install,remove,upgrade} scripts of a given package."
	echo
	echo "Usage: ${myname} <pkgname|pkgfile>"
	echo
	echo " Options:"
	echo "  -h, --help                 Print this help message"
	echo "  -v, --version              Print program name and version"
	echo
	echo "Example: ${myname} gconf-editor"
	echo "Example: ${myname} gconf-editor-3.0.1-3-x86_64.pkg.tar.xz"
}

version() {
	printf "%s %s\n" "$myname" "$myver"
	echo 'Copyright (c) 2009 Giulio "giulivo" Fidente <giulivo.navigante@gmail.com>'
	echo 'Copyright (c) 2009 Xavier Chantry <shiningxc@gmail.com>'
}

spacman() {
	if [ $EUID -eq 0 ]; then
		pacman "$@"
	else
		if ! type -p sudo; then
			error "Cannot find the sudo binary!"
			error "${myname} requires root privileges. Either install \"sudo\" or run as root."
			exit 1
		else
			sudo pacman "$@"
		fi
	fi
}

print_db() {
	pkg=$(pacman -Q "$1")
	pkg=${pkg/ /-}
	if [ -f $pac_db/$pkg*/install ]; then
		cat $pac_db/$pkg*/install
		echo
		return 0
	else
		error "Package $1 does not include any .INSTALL script"
		return 1
	fi
}

print_pkg() {
	if ! bsdtar -xqOf "$1" .INSTALL 2>/dev/null; then
		error "Package $1 does not include any .INSTALL script"
		return 1
	fi
	echo
}

print_scriptlet() {
	if [ -f "$1" ]; then
		if bsdtar tf "$1" .PKGINFO &>/dev/null; then
			print_pkg "$1"
			return
		fi
	fi
	if pacman -Q "$1" &>/dev/null; then
		print_db "$1"
		return
	fi
	if ! pacman -Si $1 &>/dev/null; then
		error "Package $1 not found"
		return 1
	fi
	url=$(pacman -Sddp $1)
	filename=$(basename $url)
	if [ ! -f "$pac_cache/$filename" ]; then
		if ! spacman -Sddw --noconfirm $1 >&2; then
			error "Failed to download $1"
			return 1
		fi
		echo >&2
	fi
	print_pkg "$pac_cache/$filename"
	return
}

if [ $# -ne 1 ] ; then
	usage
	exit 1
fi

case "$1" in
	--help|-h) usage; exit 0 ;;
	--version|-V) version; exit 0 ;;
	*) print_scriptlet $1 ;;
esac