#!/usr/bin/bash
#   pacdiff : a simple pacnew/pacsave updater
#
#   Copyright (c) 2007 Aaron Griffin <aaronmgriffin@gmail.com>
#   Copyright (c) 2013-2016 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

declare -r myname='pacdiff'
declare -r myver='1.0.0'

diffprog=${DIFFPROG:-'vim -d'}
diffsearchpath=${DIFFSEARCHPATH:-/etc}
USE_COLOR='y'
declare -a oldsaves
declare -i USE_FIND=0 USE_LOCATE=0 USE_PACDB=0 OUTPUTONLY=0

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
}


usage() {
	cat <<EOF
${myname} v${myver}

A simple program to merge or remove pacnew/pacsave files.

Usage: $myname [-l | -f | -p] [--nocolor]

Search Options:     select one (default: --pacmandb)
  -l/--locate       scan using locate
  -f/--find         scan using find
  -p/--pacmandb     scan active config files from pacman database

General Options:
  -o/--output       print files instead of merging them
  --nocolor         remove colors from output

Environment Variables:
  DIFFPROG          override the merge program: (default: 'vim -d')
  DIFFSEARCHPATH    override the search path. (only when using find)
                    (default: /etc)

Example: DIFFPROG=meld DIFFSEARCHPATH="/boot /etc /usr" $myname
Example: $myname --output --locate

EOF
}

version() {
	printf "%s %s\n" "$myname" "$myver"
	echo 'Copyright (C) 2007 Aaron Griffin <aaronmgriffin@gmail.com>'
	echo 'Copyright (C) 2013-2016 Pacman Development Team <pacman-dev@archlinux.org>'
}

print_existing() {
	[[ -f "$1" ]] && printf '%s\0' "$1"
}

print_existing_pacsave(){
	for f in "${1}"?(.+([0-9])); do
		[[ -f $f ]] && printf '%s\0' "$f"
	done
}

cmd() {
	if (( USE_LOCATE )); then
		locate -0 -e -b \*.pacnew \*.pacorig \*.pacsave '*.pacsave.[0-9]*'
	elif (( USE_FIND )); then
		find $diffsearchpath \( -name \*.pacnew -o -name \*.pacorig -o -name \*.pacsave -o -name '*.pacsave.[0-9]*' \) -print0
	elif (( USE_PACDB )); then
		awk '/^%BACKUP%$/ {
		while (getline) {
			if (/^$/) { nextfile }
				print $1
			}
		}' "${pac_db}"/*/files | while read -r bkup; do
			print_existing "/$bkup.pacnew"
			print_existing "/$bkup.pacorig"
			print_existing_pacsave "/$bkup.pacsave"
		done
	fi
}

while [[ -n "$1" ]]; do
	case "$1" in
		-l|--locate)
			USE_LOCATE=1;;
		-f|--find)
			USE_FIND=1;;
		-p|--pacmandb)
			USE_PACDB=1;;
		-o|--output)
			OUTPUTONLY=1;;
		--nocolor)
			USE_COLOR='n';;
		-V|--version)
			version; exit 0;;
		-h|--help)
			usage; exit 0;;
		*)
			usage; exit 1;;
	esac
	shift
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 ! type -p ${diffprog%% *} >/dev/null && (( ! OUTPUTONLY )); then
	error "Cannot find the $diffprog binary required for viewing differences."
	exit 1
fi

case $(( USE_FIND + USE_LOCATE + USE_PACDB )) in
	0) USE_PACDB=1;; # set the default search option
	[^1]) error "Only one search option may be used at a time"
	 	usage; exit 1;;
esac

if (( USE_PACDB )); then
	if ! DBPath="$(pacman-conf DBPath)"; then
		error "unable to read /etc/pacman.conf"
		usage; exit 1
	fi
	pac_db="${DBPath:-/var/lib/pacman/}local"
	if [[ ! -d "${pac_db}" ]]; then
		error "unable to read pacman database %s". "${pac_db}"
		usage; exit 1
	fi
fi

# see http://mywiki.wooledge.org/BashFAQ/020
while IFS= read -u 3 -r -d '' pacfile; do
	file="${pacfile%.pac*}"
	file_type="pac${pacfile##*.pac}"

	if (( OUTPUTONLY )); then
		echo "$pacfile"
		continue
	fi

	# add matches for pacsave.N to oldsaves array, do not prompt
	if [[ $file_type = pacsave.+([0-9]) ]]; then
		oldsaves+=("$pacfile")
		continue
	fi

	msg "%s file found for %s" "$file_type" "$file"
	if [ ! -f "$file" ]; then
		warning "$file does not exist"
		rm -iv "$pacfile"
		continue
	fi

	if cmp -s "$pacfile" "$file"; then
		msg2 "Files are identical, removing..."
		rm -v "$pacfile"
	else
		ask "(V)iew, (S)kip, (R)emove %s, (O)verwrite with %s, (Q)uit: [v/s/r/o/q] " "$file_type" "$file_type"
		while read c; do
			case $c in
				q|Q) exit 0;;
				r|R) rm -v "$pacfile"; break ;;
				o|O) mv -v "$pacfile" "$file"; break ;;
				v|V)
					$diffprog "$pacfile" "$file"
					ask "(V)iew, (S)kip, (R)emove %s, (O)verwrite with %s, (Q)uit: [v/s/r/o/q] " "$file_type" "$file_type";
					continue ;;
				s|S) break ;;
				*) ask "Invalid answer. Try again: [v/s/r/o/q] "; continue ;;
			esac
		done
	fi
done 3< <(cmd)

(( ${#oldsaves[@]} )) && warning "Ignoring %s" "${oldsaves[@]}"

exit 0

# vim: set noet: