#!/usr/bin/env bash

# A script to upgrade a RHEL derivative (Fedora, CentOS, ...). If you have ansible or puppet:
# this is way more simple with an automation framework. This script works with the paradigm
# that you only have a bash available and you want to see what happens without being murdered
# by gazillions of output lines.

# This script avoids combining options, e.g. dnf -C -q instead of dnf -Cq, since
# dnf is perfectly capable of POSIX standards, but yum fails at combined parameters.
# So we'll leave it this way in case of conversion of this script to yum or extension
# to be capable of both. (tl;dr no combined options because yum sucks at POSIX standards)

ROK="\033[666D[ \033[32mOK\033[0m ]\033[u\033[K"
RWRN="\033[666D[\033[33mWARN\033[0m]\033[u\033[K"
RERR="\033[666D[\033[31mFAIL\033[0m]\033[u\033[K"
RINF="\033[666D[\033[37mINFO\033[0m]\033[u\033[K"

UPDAVAIL=1
SCMD="$(command -v snap 2>/dev/null)"
UCMD="$(command -v dnf 2>/dev/null)"
[ "$?" -ne 0 ]&&UCMD="$(command -v yum 2>/dev/null)"
[ -z "$UCMD" ]&&printf "Neither yum nor dnf found!\n" >&2&&exit 1
RETVAL=0

function radd {
	[ -z "$1" ]&&return 1
	printf "\033[666D\033[u\033[K \033[37m(%b)\033[0m" "$1"
}
function rbeg {
	[ -z "$1" ]&&return 1
	printf "[....] %b.\033[s.." "$1"
}
function rok {
	case "$1" in
		"") printf "%b\n" "$ROK";;
		*)
			printf "%b" "$ROK"
			radd "$1"
			printf "\n"
		;;
	esac
}
function rwrn {
	case "$1" in
		"") printf "%b\n" "$RWRN";;
		*)
			printf "%b" "$RWRN"
			radd "$1"
			printf "\n"
		;;
	esac
}
function rerr {
	case "$1" in
		"") printf "%b\n" "$RERR";;
		*)
			printf "%b" "$RERR"
			radd "$1"
			printf "\n"
		;;
	esac
}
function rinf {
	case "$1" in
		"") printf "%b\n" "$RINF";;
		*)
			printf "%b" "$RINF"
			radd "$1"
			printf "\n"
		;;
	esac
}
function supgrade {
	printf "Listing updates...:\n"
	sudo "${UCMD}" -C -q check-upgrade
	case "$?" in
		0|100) ;;
		*) RETVAL=1;return 1;;
	esac
	rbeg "Upgrading system packages"
	sudo "${UCMD}" -q -y upgrade
	case "$?" in
		0) rok;;
		1)
			rwrn "error occurred but was handled by dnf"
			case "RETVAL" in
				0) RETVAL=255;;
			esac
		;;
		255)
			rwrn "Upgrade done but updates remaining"
			case "$RETVAL" in
				0) RETVAL=255;;
			esac
		;;
		*)
			rerr
			RETVAL=1;return 1
		;;
	esac
	printf "Checking for outdated running services or necessity to reboot...:\n"
	sudo "${UCMD}" needs-restarting
}
function snrefresh {
	rbeg "Refreshing snapd snaps"
	sudo "${SCMD}" refresh >/dev/null 2>&1
	case "$?" in
		0) rok;;
		*) rerr;RETVAL=1;return 1;;
	esac
}

rbeg "Updating dnf cache"
sudo "${UCMD}" -q makecache
case "$?" in
	0) rok;;
	100) rwrn;;
	*) rerr;exit 1;;
esac
rbeg "Checking for upgrades"
sudo "${UCMD}" -C -q check-upgrade
case "$?" in
	0)
		rinf "No updates"
	;;
	100)
		rok "Updates found"
		UPDAVAIL=0
	;;
esac

if [ "$UPDAVAIL" -eq 0 ];then
	supgrade
fi

if [ ! -z "$SCMD" ];then
	snrefresh
fi