#!/bin/bash
#
#   pkgdelta - create delta files for use with pacman and repo-add
#   @configure_input@
#
#   Copyright (c) 2009 Xavier Chantry <shiningxc@gmail.com>
#
#   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 errexit

# gettext initialization
export TEXTDOMAIN='pacman-scripts'
export TEXTDOMAINDIR='@localedir@'

declare -r myver='@PACKAGE_VERSION@'

QUIET=0

# ensure we have a sane umask set
umask 0022

m4_include(library/output_format.sh)

# print usage instructions
usage() {
	printf "pkgdelta (pacman) %s\n\n" "$myver"
	printf "$(gettext "Usage: pkgdelta [-q] <package1> <package2>\n")"
	printf "$(gettext "\
	pkgdelta will create a delta file between two packages.\n\
This delta file can then be added to a database using repo-add.\n\n")"
	echo "$(gettext "Example:  pkgdelta pacman-3.0.0.pkg.tar.gz pacman-3.0.1.pkg.tar.gz")"
}

version() {
	printf "pkgdelta (pacman) %s\n\n" "$myver"
	printf "$(gettext "\
Copyright (c) 2009 Xavier Chantry <shiningxc@gmail.com>.\n\n\
This is free software; see the source for copying conditions.\n\
There is NO WARRANTY, to the extent permitted by law.\n")"
}

read_pkginfo()
{
	pkgname= pkgver= arch=
	local OLDIFS=$IFS
	# IFS (field separator) is only the newline character
	IFS="
"
	local line var val
	for line in $(bsdtar -xOf "$1" .PKGINFO 2>/dev/null |
		grep -v "^#" | sed 's|\(\w*\)\s*=\s*\(.*\)|\1="\2"|'); do
		eval "$line"
		if [[ -n $pkgname && -n $pkgver && -n $arch ]]; then
			IFS=$OLDIFS
			return 0
		fi
	done
	IFS=$OLDIFS
	error "$(gettext "Invalid package file '%s'.")" "$1"
	return 1
}

# $oldfile $oldmd5 $newfile $newmd5 $deltafile $deltamd5 $deltasize
create_xdelta()
{
	local oldfile=$1
	local newfile=$2
	local \
	oldname oldver oldarch \
	newname newver newarch \
	deltafile

	read_pkginfo "$oldfile" || return 1
	oldname="$pkgname"
	oldver="$pkgver"
	oldarch="$arch"
	read_pkginfo "$newfile" || return 1
	newname="$pkgname"
	newver="$pkgver"
	newarch="$arch"

	if [[ $oldname != "$newname" ]]; then
		error "$(gettext "The package names don't match : '%s' and '%s'")" "$oldname" "$newname"
		return 1
	fi

	if [[ $oldarch != "$newarch" ]]; then
		error "$(gettext "The package architectures don't match : '%s' and '%s'")" "$oldarch" "$newarch"
		return 1
	fi

	if [[ $oldver == "$newver" ]]; then
		error "$(gettext "Both packages have the same version : '%s'")" "$newver"
		return 1
	fi

	msg "$(gettext "Generating delta from version %s to version %s")" "$oldver" "$newver"
	deltafile="$(dirname $newfile)/$pkgname-${oldver}_to_${newver}-$arch.delta"
	local ret=0

	xdelta3 -q -f -s "$oldfile" "$newfile" "$deltafile" || ret=$?
	if (( ret )); then
		error "$(gettext "Delta could not be created.")"
		return 1
	else
		msg "$(gettext "Generated delta : '%s'")" "$deltafile"
		(( QUIET )) && echo "$deltafile"
	fi
	return 0
}

case "$1" in
	-h|--help)    usage; exit 0 ;;
	-V|--version) version; exit 0 ;;
	-q|--quiet)   QUIET=1; shift ;;
esac

if (( $# != 2 )); then
	usage
	exit 1
fi

if [[ ! -f $1 ]]; then
	error "$(gettext "File '%s' does not exist")" "$1"
	exit 0
fi

if [[ ! -f $2 ]]; then
	error "$(gettext "File '%s' does not exist")" "$2"
	exit 0
fi

if ! type xdelta3 &>/dev/null; then
	error "$(gettext "Cannot find the xdelta3 binary! Is xdelta3 installed?")"
	exit 1
fi

create_xdelta "$1" "$2"

# vim: set ts=2 sw=2 noet: