#!/bin/sh

# Purpose {{{
##	This script will check if Ceph is available on the system.
##	And download all deb files of all Ceph related packages installed on the system
##		(eg. ceph, rbd, rados,…).
#
##	You can use this script in a cron (for periodic backup of Ceph packages) or directly.
# }}}

# Vars {{{
PROGNAME=$(basename "${0}"); readonly PROGNAME
PROGDIR=$(readlink -m $(dirname "${0}")); readonly PROGDIR
ARGS="${*}"; readonly ARGS
readonly NBARGS="${#}"
[ -z "${DEBUG}" ] && DEBUG=1

# Default values for some vars
CEPH_VERSION_DEFAULT=$(ceph version | cut -d" " -f3)
BKP_DIR_DEFAULT="/srv/ceph"

## Colors
readonly PURPLE='\033[1;35m'
readonly RED='\033[0;31m'
readonly RESET='\033[0m'
readonly COLOR_DEBUG="${PURPLE}"
# }}}
usage() {                                                       # {{{

	cat <<- EOF
usage: $PROGNAME [-d]

Try to download all deb files of all Ceph related packages installed
on the system (eg. ceph, rbd, rados,…) and create one tar file.

EXAMPLES :
    - Backup Ceph related packages to default directory (${BKP_DIR_DEFAULT})
        ${PROGNAME}

    - Store tar files to a different location
        ${PROGNAME} --dir /opt/backup/ceph

OPTIONS :
    -d,--dir,--directory
        Path to store tar files
        (default: ${BKP_DIR_DEFAULT})

    --debug
        Enable debug messages.

    --help
        Print this help message.
EOF

}
# }}}
debug_message() {                                               # {{{

	local_message="${1}"

	## Print message if DEBUG is enable (=0)
	[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6b\e[m\n' "DEBUG − ${PROGNAME} : ${local_message}"

	return 0
}
# }}}
error_message() {                                               # {{{

	local_error_message="${1}"
	local_error_code="${2}"

	## Print error message
	printf '%b\n' "ERROR − ${PROGNAME} : ${RED}${local_error_message}${RESET}"

	exit "${local_error_code:=66}"
}
# }}}
define_vars() {                                                 # {{{

	# If BKP_DIR wasn't defined (argument) {{{
	if [ -z "${BKP_DIR}" ]; then
		## Use default value
		BKP_DIR="${BKP_DIR_DEFAULT}"
	fi
	# }}}
	# If CEPH_VERSION wasn't defined (argument) {{{
	if [ -z "${CEPH_VERSION}" ]; then
		## Use default value
		CEPH_VERSION="${CEPH_VERSION_DEFAULT}"
	fi
	# }}}
	# If CEPH_VERSION remains empty {{{
	if [ -z "${CEPH_VERSION}" ]; then
		error_message "Can't get ceph version. \
Ensure you have enought permissions to run \`ceph\` command." 01
	fi
	# }}}

	BKP_TAR_PATH="${BKP_DIR}/ceph-deb_${CEPH_VERSION}-$(date +%Y%m%d).tar"

	EXISTENT_BACKUP_TAR="$(find "${BKP_DIR}" -type f -iname "ceph-deb_${CEPH_VERSION}*")"
	CEPH_DEB_PKG_PATTERN="ceph|Ceph|rados|RADOS|rbd|rgw"

	## Temp file vars {{{
	CEPH_DEB_PKG_DIR=$(mktemp --directory --tmpdir="/tmp" -- ceph-deb-files-XXXXXX.tmp)
	## }}}

}
# }}}

main() {                                                        # {{{

	## If Ceph is not available on the system {{{
	### AND Exit with error
	! command -v ceph >/dev/null \
		&& error_message "Ceph doesn't seems to be available on this host. Please take a look to \`ceph version\` command." 11
	## }}}

	## Define all vars
	define_vars

	## If a backup already exists {{{
	### AND Print debug message
	### AND Delete temp directory
	### AND Exit
	test -f "${EXISTENT_BACKUP_TAR}" \
		&& debug_message "A backup of this version already exists : ${EXISTENT_BACKUP_TAR}" \
		&& rmdir -- "${CEPH_DEB_PKG_DIR}" \
		&& exit 0
	## }}}

	## Ensure backup directory exists
	mkdir --parents -- "${BKP_DIR}"

	## Go to temp directory
	cd -- "${CEPH_DEB_PKG_DIR}" > /dev/null \
		|| error_message "Can't cd to ${CEPH_DEB_PKG_DIR}" 12

	## Download deb files of all ceph related packages installed on the system
	debug_message "Download (with apt) deb files of all ceph related packages installed on the system."
	apt download -- $(dpkg -l | awk -v pattern="${CEPH_DEB_PKG_PATTERN}" '$0~pattern {print $2"="$3}') 2>/dev/null \
		|| error_message "Can't download Ceph related packages (pattern: ${CEPH_DEB_PKG_PATTERN})." 13

	debug_message "Backup Ceph deb files in version : ${CEPH_VERSION}"
	tar cf "${BKP_TAR_PATH}" ./*.deb > /dev/null 2>&1 \
		|| error_message "Error with creation of ${BKP_TAR_PATH} archive file." 14

	## Remove deb files
	rm --force -- *.deb \
		|| error_message "Can't delete temp deb files." 15

	cd - > /dev/null \
		|| error_message "Can't cd to previous directory (before ${CEPH_DEB_PKG_DIR})" 16

	## Remove temp directory
	rmdir -- "${CEPH_DEB_PKG_DIR}" \
		|| error_message "Can't delete temp directory (${CEPH_DEB_PKG_DIR})" 17

}
# }}}

# Manage arguments                                                # {{{
# This code can't be in a function due to argument management

if [ ! "${NBARGS}" -eq "0" ]; then

	manage_arg="0"

	## If the first argument is not an option
	if ! printf -- '%s' "${1}" | grep -q -E -- "^-+";
	then
		## Print help message and exit
		printf '%b\n' "${RED}Invalid option: ${1}${RESET}"
		printf '%b\n' "---"
		usage

		exit 1
	fi

	# Parse all options (start with a "-") one by one
	while printf -- '%s' "${1}" | grep -q -E -- "^-+"; do

	case "${1}" in
		-d|--dir|--directory|--backup-dir )   ## Define BKP_DIR
			## Move to the next argument
			shift
			## Define var
			readonly BKP_DIR="${1}"
			;;
		--debug )                             ## debug
			DEBUG=0
			;;
		--help )                              ## help
			usage
			## Exit after help informations
			exit 0
			;;
		* )                                   ## unknow option
			printf '%b\n' "${RED}Invalid option: ${1}${RESET}"
			printf '%b\n' "---"
			usage
			exit 1
			;;
	esac

	debug_message "Arguments management − \
${RED}${1}${COLOR_DEBUG} option managed."

	## Move to the next argument
	shift
	manage_arg=$((manage_arg+1))

	done

	debug_message "Arguments management − \
${RED}${manage_arg}${COLOR_DEBUG} argument(s) successfully managed."
else
	debug_message "Arguments management − \
No arguments/options to manage."
fi

# }}}

main

exit 0