#!/bin/bash
#
# Author: Georg Voell - georg.voell@standby.cloud
# Version: @(#)compare-version 3.2.0 11.09.2024 (c)2024 Standby.cloud
# Licensed under the Universal Permissive License v 1.0 as shown at https://oss.oracle.com/licenses/upl/
#
# This script can be used free of charge. Use it as is or customize as needed. It is not guaranteed to be
# error free and you will not be reimbursed for any damage it may cause.
#
#@  Compare two version numbers e.g. 1.6.7 1.7.0
#@  Returns "older" if version in second parameter is older than version in first parameter.
#@  Returns "newer" if version in second parameter is newer than version in first parameter.
#@  Returns "same" if both versions are the same.
#@
#@Usage: compare-version [options] versionnumber versionnumber
#@  Options:
#@    -h, --help    : Displays helptext.
#@    -v, --version : Displays the version of the script.
#@    -q, --quiet   : Don't display any error messages.
#@  VersionNumber: e.g. 1.2.5
#@
#@Examples:
#@  compare-version 1.2.4 1.2.5
#@    Returns "newer"
#@  compare-version 1.2 1.2.5
#@    Returns "same" - only first two letters will be compared.
#
# Exit codes:
#  01: Unknown or wrong parameter.
#  02: Not a number.
#
# Update history:
#
# V 3.0.0 18.04.2020 New version
# V 3.0.1 11.06.2020 Using library
# V 3.0.2 10.11.2022 Silent mode
# V 3.1.0 05.06.2023 New copyright
# V 3.2.0 11.09.2024 New minor version
#

# Find executable bash library and source it
lib=`which lib.bash 2>/dev/null | sed 's|^no 'lib.bash' in .*||'`
if [ "$lib" != "" ]; then
	source "$lib"
else
	progdir=`dirname "$0"`
	if [ -r "${progdir}/lib.bash" ]; then
		source "${progdir}/lib.bash"
	else
		echo "Unexpected error: Unable to locate bash library 'lib.bash'."
		exit 1
	fi
fi

function compare() {
	a=${1}
	b=${2}
	
	numstr=`echo "$a" | grep '^[0123456789]*$'`
	if [ "$numstr" = "" ]; then
		exitcode=2
		errormsg $quietstr $exitcode "($progstr) Not a number: '$a'."
		return $exitcode
	fi
	
	numstr=`echo "$b" | grep '^[0123456789]*$'`
	if [ "$numstr" = "" ]; then
		exitcode=2
		errormsg $quietstr $exitcode "($progstr) Not a number: '$b'."
		return $exitcode
	fi
	
	if [ $a -eq $b ]; then
		echo "same"
	else
		if [ $a -gt $b ]; then
			echo "older"
		else
			echo "newer"
		fi
	fi
}

function split() {
	a=${1}
	grepres=`echo $a | grep '\.'`
	if [ "$grepres" = "" ]; then
		echo $a
	else
		result=`echo $a | cut -d'.' -f1`
		echo $result
	fi
}

function check() {
	par1=`split $param1`
	par2=`split $param2`
	
	result=`compare $par1 $par2`
	stat=$?
	
	if [ $stat -eq 0 ]; then
		if [ "$result" = "same" ]; then
			param1=`echo $param1 | sed 's|^'$par1'.||'`
			param2=`echo $param2 | sed 's|^'$par2'.||'`
			
			if [ "$param1" != "" -a "$param2" != "" ]; then
				result=`check`
				stat=$?
				
				if [ $stat -eq 0 ]; then
					echo $result
				fi
			else
				echo "same"
			fi
		else
			echo $result
		fi
	fi
	
	return $stat
}

# Preset
param1=""
param2=""
quietstr=""

# Check parameters: Loop until all parameters are used up
while [ $# -gt 0 ]; do
	pname=${1}
	case "$pname" in
		-v | --version)
			shift
			showversion=true
			;;
		-h | --help)
			shift
			showhelp=true
			;;
		-q | --quiet)
			shift
			quietstr="$pname"
			;;
		*)
			shift
			paramck=`echo "$pname" | grep '^-'` # Types don't begin with '-'
			if [ "$paramck" != "" ]; then
				errstr="Unknown option '$pname'."
			else
				if [ "$param1" = "" ]; then
					param1=`echo "${pname}." | tr -s '.'`
				else
					if [ "$param2" = "" -a "$paramck" = "" ]; then
						param2=`echo "${pname}." | tr -s '.'`
					else
						errstr="Versions were already specified '$param1 $param2'. Unknown additional parameter: '$pname'."
					fi
				fi
			fi
	esac
done

# Plausibility check
if [ "$param2" = "" ]; then
	errstr="You have to compare two version numbers (e.g. 1.2.5) to get a result."
fi

# Display help or error message
DisplayHelp

# Compare
if [ "$param1" = "$param2" ]; then
	echo "same"
else
	result=`check`
	exitcode=$?
	
	if [ $exitcode -eq 0 ]; then
		echo $result
	fi
fi

exit $exitcode