#!/usr/bin/bash
#
#   bacman: recreate a package from a running system
#   This script rebuilds an already installed package using metadata
#   stored into the pacman database and system files
#
#   Copyright (c) 2008 locci <carlocci_at_gmail_dot_com>
#   Copyright (c) 2008-2016 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/>.
#

shopt -s extglob
shopt -s nullglob

declare -r myname='bacman'
declare -r myver='5.0.1'
USE_COLOR='y'
INCLUDE_PACNEW='n'
# Required for fakeroot because options are shifted off the array.
ARGS=("$@")

plain() {
	(( QUIET )) && return
	local mesg=$1; shift
	printf "${BOLD}    ${mesg}${ALL_OFF}\n" "$@" >&1
}

msg() {
	(( QUIET )) && return
	local mesg=$1; shift
	printf "${GREEN}==>${ALL_OFF}${BOLD} ${mesg}${ALL_OFF}\n" "$@" >&1
}

msg2() {
	(( QUIET )) && return
	local mesg=$1; shift
	printf "${BLUE}  ->${ALL_OFF}${BOLD} ${mesg}${ALL_OFF}\n" "$@" >&1
}

ask() {
	local mesg=$1; shift
	printf "${BLUE}::${ALL_OFF}${BOLD} ${mesg}${ALL_OFF}" "$@" >&1
}

warning() {
	local mesg=$1; shift
	printf "${YELLOW}==> $(gettext "WARNING:")${ALL_OFF}${BOLD} ${mesg}${ALL_OFF}\n" "$@" >&2
}

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


#
# User Friendliness
#
usage() {
	echo "${myname} (pacman) v${myver}"
	echo
	echo "Recreate a package using pacman's database and system files"
	echo
	echo "Usage: ${myname} [--nocolor] [--pacnew] <installed package name>"
	echo
	echo "Example: ${myname} linux-headers"
}

version() {
	printf "%s %s\n" "$myname" "$myver"
	echo 'Copyright (C) 2008 locci <carlocci_at_gmail_dot_com>'
	echo 'Copyright (C) 2008-2016 Pacman Development Team <pacman-dev@archlinux.org>'
}

while [[ ! -z $1 ]]; do
	if [[ $1 == "--nocolor" ]]; then
		USE_COLOR='n'
		shift
	elif [[ $1 == "--pacnew" ]]; then
		INCLUDE_PACNEW='y'
		shift
	else
		break
	fi
done

# check if messages are to be printed using color
unset ALL_OFF BOLD BLUE GREEN RED YELLOW
if [[ -t 2 && ! $USE_COLOR = "n" ]]; then
	# prefer terminal safe colored and bold text when tput is supported
	if tput setaf 0 &>/dev/null; then
		ALL_OFF="$(tput sgr0)"
		BOLD="$(tput bold)"
		BLUE="${BOLD}$(tput setaf 4)"
		GREEN="${BOLD}$(tput setaf 2)"
		RED="${BOLD}$(tput setaf 1)"
		YELLOW="${BOLD}$(tput setaf 3)"
	else
		ALL_OFF="\e[1;0m"
		BOLD="\e[1;1m"
		BLUE="${BOLD}\e[1;34m"
		GREEN="${BOLD}\e[1;32m"
		RED="${BOLD}\e[1;31m"
		YELLOW="${BOLD}\e[1;33m"
	fi
fi
readonly ALL_OFF BOLD BLUE GREEN RED YELLOW


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

if [[ $1 = -@(h|-help) ]]; then
	usage
	exit 0
elif [[ $1 = -@(V|-version) ]]; then
	version
	exit 0
fi

#
# Setting environmental variables
#
if [[ ! -r /etc/pacman.conf ]]; then
	error "unable to read /etc/pacman.conf"
	exit 1
fi

eval $(awk '/DBPath/ {print $1$2$3}' /etc/pacman.conf)
pac_db="${DBPath:-/var/lib/pacman/}/local"

if [[ ! -r /etc/makepkg.conf ]]; then
	error "unable to read /etc/makepkg.conf"
	exit 1
fi

source "/etc/makepkg.conf"
if [[ -r ~/.makepkg.conf ]]; then
	source ~/.makepkg.conf
fi

pkg_dest="${PKGDEST:-$PWD}"
pkg_pkger=${PACKAGER:-'Unknown Packager'}

pkg_name="$1"
pkg_dir=("$pac_db/$pkg_name"-+([^-])-+([^-]))
pkg_namver=("${pkg_dir[@]##*/}")

#
# Checks everything is in place
#
if [[ ! -d $pac_db ]]; then
	error "pacman database directory ${pac_db} not found"
	exit 1
fi

if (( ${#pkg_dir[@]} != 1 )); then
	error "%d entries for package %s found in pacman database" \
		${#pkg_dir[@]} "${pkg_name}"
	msg2 "%s" "${pkg_dir[@]}"
	exit 1
fi

if [[ ! -d $pkg_dir ]]; then
	error "package %s is found in pacman database," "${pkg_name}"
	plain "       but '%s' is not a directory" "${pkg_dir}"
	exit 1
fi

#
# Begin
#
msg "Package: ${pkg_namver}"
work_dir=$(mktemp -d "${TMPDIR:-/tmp}/bacman.XXXXXXXXXX")
cd "$work_dir" || exit 1

#
# File copying
#
msg2 "Copying package files..."

while read i; do
	if [[ -z $i ]]; then
		continue
	fi

	if [[ $i == %+([A-Z])% ]]; then
		current=$i
		continue
	fi

	case "$current" in
		%FILES%)
			local_file="/$i"
			package_file="$work_dir/$i"

			if [[ ! -e $local_file ]]; then
				warning "package file $local_file is missing"
				continue
			fi
			;;

		%BACKUP%)
			# Get the MD5 checksum.
			original_md5="${i##*$'\t'}"
			# Strip the md5sum after the tab.
			i="${i%$'\t'*}"
			local_file="/$i.pacnew"
			package_file="$work_dir/$i"

			# Include unmodified .pacnew files.
			local_md5="$(md5sum "$local_file" | cut -d' ' -f1)"
			if [[ $INCLUDE_PACNEW == 'n' ]] \
			|| [[ ! -e $local_file ]] \
			|| [[ $local_md5 != $original_md5 ]]; then
				# Warn about modified files.
				local_md5="$(md5sum "/$i" | cut -d' ' -f1)"
				if [[ $local_md5 != $original_md5 ]]; then
					warning "package file /$i has been modified"
				fi
				# Let the normal file be included in the %FILES% list.
				continue
			fi
			;;

		*)
			continue
			;;
	esac

	ret=0
	/usr/bin/bsdtar -cnf - -s'/.pacnew$//' "$local_file" 2> /dev/null | /bin/bsdtar -xpf - 2> /dev/null

	# Workaround to bsdtar not reporting a missing file as an error
	if ! [[ -e $package_file || -L $package_file ]]; then
		error "unable to add $local_file to the package"
		plain "       If your user does not have permission to read this file, then"
		plain "       you will need to run $myname as root."
		rm -rf "$work_dir"
		exit 1
	fi
done < "$pkg_dir"/files

ret=$?
if (( ret )); then
	rm -rf "$work_dir"
	exit 1
fi

pkg_size=$(du -sk | awk '{print $1 * 1024}')

#
# .PKGINFO stuff
# TODO adopt makepkg's write_pkginfo() into this or scripts/library
#
msg2 "Generating .PKGINFO metadata..."
echo "# Generated by $myname $myver"    > .PKGINFO
echo "# $(LC_ALL=C date)"            >> .PKGINFO
echo "#"                    >> .PKGINFO

while read i; do
	if [[ -z $i ]]; then
		continue;
	fi

	if [[ $i == %+([A-Z])% ]]; then
		current=$i
		continue
	fi

	case "$current" in
		# desc
		%NAME%)
			echo "pkgname = $i"    >> .PKGINFO
			;;
		%VERSION%)
			echo "pkgver = $i"    >> .PKGINFO
			;;
		%DESC%)
			echo "pkgdesc = $i"    >> .PKGINFO
			;;
		%URL%)
			echo "url = $i"    >> .PKGINFO
			;;
		%LICENSE%)
			echo "license = $i"    >> .PKGINFO
			;;
		%ARCH%)
			echo "arch = $i"    >> .PKGINFO
			pkg_arch="$i"
			;;
		%BUILDDATE%)
			echo "builddate = $(date -u "+%s")"    >> .PKGINFO
			;;
		%PACKAGER%)
			echo "packager = $pkg_pkger"        >> .PKGINFO
			;;
		%SIZE%)
			echo "size = $pkg_size"        >> .PKGINFO
			;;
		%GROUPS%)
			echo "group = $i"    >> .PKGINFO
			;;
		%REPLACES%)
			echo "replaces = $i"    >> .PKGINFO
			;;
		%DEPENDS%)
			echo "depend = $i"   >> .PKGINFO
			;;
		%OPTDEPENDS%)
			echo "optdepend = $i" >> .PKGINFO
			;;
		%CONFLICTS%)
			echo "conflict = $i" >> .PKGINFO
			;;
		%PROVIDES%)
			echo "provides = $i"  >> .PKGINFO
			;;

		# files
		%BACKUP%)
			# Strip the md5sum after the tab
			echo "backup = ${i%%$'\t'*}"   >> .PKGINFO
			;;
	esac
done < <(cat "$pkg_dir"/{desc,files})

comp_files=".PKGINFO"

if [[ -f $pkg_dir/install ]]; then
	cp "$pkg_dir/install" "$work_dir/.INSTALL"
	comp_files+=" .INSTALL"
fi
if [[ -f $pkg_dir/changelog ]]; then
	cp "$pkg_dir/changelog" "$work_dir/.CHANGELOG"
	comp_files+=" .CHANGELOG"
fi

#
# Fixes owner:group and permissions for .PKGINFO, .CHANGELOG, .INSTALL
#
chown root:root "$work_dir"/{.PKGINFO,.CHANGELOG,.INSTALL} 2> /dev/null
chmod 644 "$work_dir"/{.PKGINFO,.CHANGELOG,.INSTALL} 2> /dev/null

#
# Generate the package
#
msg2 "Generating the package..."

pkg_file="$pkg_dest/$pkg_namver-$pkg_arch${PKGEXT}"
ret=0

# TODO: Maybe this can be set globally for robustness
shopt -s -o pipefail
/usr/bin/bsdtar -cf - $comp_files * |
case "$PKGEXT" in
	*tar.gz)  /bin/gzip -c -f -n ;;
	*tar.bz2) /bin/bzip2 -c -f ;;
	*tar.xz)  /bin/xz -c -z - ;;
	*tar.Z)   compress -c -f ;;
	*tar)     cat ;;
	*) warning "'%s' is not a valid archive extension." \
	"$PKGEXT"; cat ;;
esac > "${pkg_file}"; ret=$?

if (( ret )); then
	error "Unable to write package to $pkg_dest"
	plain "       Maybe the disk is full or you do not have write access"
	rm -rf "$work_dir"
	exit 1
fi

rm -rf "$work_dir"

msg "Done."

exit 0

# vim: set noet:
