#!/usr/bin/env bash
#
# Author: Georg Voell - georg.voell@standby.cloud
# Version: @(#)compare-version 3.3.1 16.03.2026 (c)2026 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
# V 3.3.0 19.01.2026 Revised with support of Claude Code
# V 3.3.1 16.03.2026 Optimized: replaced backticks with $(); [ ] with [[ ]];
#                    echo|grep with bash regex [[ =~ ]]; echo with printf
#

# Find executable bash library and source it
lib=$(command -v lib.bash 2>/dev/null)
if [[ -n "$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() {
	local a="${1}"
	local b="${2}"

	# Use bash regex instead of echo|grep subshell
	if [[ ! "$a" =~ ^[0-9]+$ ]]; then
		exitcode=2
		errormsg $quietstr $exitcode "($progstr) Not a number: '$a'."
		return $exitcode
	fi

	if [[ ! "$b" =~ ^[0-9]+$ ]]; then
		exitcode=2
		errormsg $quietstr $exitcode "($progstr) Not a number: '$b'."
		return $exitcode
	fi

	if (( a == b )); then
		printf 'same\n'
	elif (( a > b )); then
		printf 'older\n'
	else
		printf 'newer\n'
	fi
}

function split() {
	local a="${1}"
	# Use bash parameter expansion instead of grep+cut subshells
	if [[ "$a" == *.* ]]; then
		printf '%s\n' "${a%%.*}"
	else
		printf '%s\n' "$a"
	fi
}

function check() {
	local par1
	local par2
	local res

	par1=$(split "$param1")
	par2=$(split "$param2")

	res=$(compare "$par1" "$par2")
	local stat=$?

	if [[ $stat -eq 0 ]]; then
		if [[ "$res" == "same" ]]; then
			# Strip leading segment (bash built-in, no sed subshell)
			param1="${param1#${par1}.}"
			param2="${param2#${par2}.}"

			if [[ -n "$param1" && -n "$param2" ]]; then
				res=$(check)
				stat=$?

				if [[ $stat -eq 0 ]]; then
					printf '%s\n' "$res"
				fi
			else
				printf 'same\n'
			fi
		else
			printf '%s\n' "$res"
		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
			# Use bash pattern match instead of echo|grep subshell
			if [[ "$pname" == -* ]]; then
				errstr="Unknown option '$pname'."
			else
				if [[ -z "$param1" ]]; then
					# Append dot and squeeze duplicates with bash built-in
					tmp="${pname}."
					param1="${tmp//../.}"
				elif [[ -z "$param2" ]]; then
					tmp="${pname}."
					param2="${tmp//../.}"
				else
					errstr="Versions were already specified '$param1 $param2'. Unknown additional parameter: '$pname'."
				fi
			fi
			;;
	esac
done

# Plausibility check
if [[ -z "$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
	printf 'same\n'
else
	result=$(check)
	exitcode=$?

	if [[ $exitcode -eq 0 ]]; then
		printf '%s\n' "$result"
	fi
fi

exit $exitcode