#!/usr/bin/env bash
#
# Author: Georg Voell - georg.voell@standby.cloud
# Version: @(#)convert-number 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.
#
#@  Convert Number String e.g. 2,3,5-7,9 into a sequential number string e.g. 002 003 005 006 007 009
#@
#@Usage: convert-number numberstr
#@  Options:
#@    -h, --help            : Displays helptext.
#@    -v, --version         : Displays the version of the script.
#@    -p, --padding <number>: Numbers are sorted and left padded with 0 (default padding is 3).
#@    -x, --max <number>    : Maximal <number> - useful if one calls script with e.g. "5-".
#@  NumberStr: Can be a numer or a string e.g. "2,3,5-7,9"
#@
#@Examples:
#@  convert-number --max 8 2,5-
#@    Displays "002 005 006 007 008"
#
# Exit codes:
#  01: Unknown or wrong parameter.
#  02: Invalid number
#  03: Minimum is 1.
#  04: Number is greater than max number.
#  99: User interrupt.
#
# Update history:
#
# V 2.0.0 05.07.2019 New version
# V 3.0.0 02.05.2020 Minor changes
# V 3.0.1 11.06.2020 Using library
# V 3.1.0 05.06.2023 New copyright
# V 3.1.1 28.07.2024 Trapping ctrl-c
# V 3.2.0 12.08.2024 New minor version
# V 3.2.1 13.10.2024 Converted from tcsh to bash
# 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 [[ =~ ]]; UUOC removed; bash parameter expansion for tr
#

# 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

# Preset
numberstr=""
maxnumber=""
padding="3"

# 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
			;;
		-p | --padding)
			shift
			if [[ -n "$1" ]]; then
				padding="${1}"
				if [[ ! "$padding" =~ ^[0-9]+$ ]]; then
					errstr="Not a number: '$padding'."
				fi
				shift
			else
				errstr="Please specify a number after parameter '$pname'."
			fi
			;;
		-x | --max)
			shift
			if [[ -n "$1" ]]; then
				maxnumber="${1}"
				if [[ ! "$maxnumber" =~ ^[0-9]+$ ]]; then
					errstr="Not a number: '$maxnumber'."
				fi
				shift
			else
				errstr="Please specify a number after parameter '$pname'."
			fi
			;;
		*)
			shift
			if [[ "$pname" == -* ]]; then
				errstr="Unknown option '$pname'."
			else
				if [[ -z "$errstr" ]]; then
					if [[ -z "$numberstr" ]]; then
						# Remove spaces with bash built-in (no tr subshell)
						numberstr="${pname// /}"
					else
						errstr="Number string was already specified '$numberstr'. Unknown additional parameter: '$pname'."
					fi
				fi
			fi
			;;
	esac
done

# Plausibility checks
if [[ -z "$errstr" && -z "$numberstr" ]]; then
	errstr="Please give a number string like '2,3,5-7,9'."
fi

# Display help or error message
DisplayHelp

### Main

# Create empty scratchfile
printf "" > "$scratchfile"

# Replace commas with spaces using bash built-in (no sed subshell)
numbers="${numberstr//,/ }"

# Iterate over each number/range token
for num in $numbers; do
	# Use bash regex to detect range pattern (no echo|grep subshell)
	if [[ "$num" =~ ^([0-9]*)[-]([0-9]*)$ ]]; then
		rstr1="${BASH_REMATCH[1]}"
		rstr2="${BASH_REMATCH[2]}"
		if [[ -n "$rstr2" ]]; then
			if [[ -z "$rstr1" ]]; then
				rstr1=1
			fi
			seq -f "%0${padding}g" "$rstr1" 1 "$rstr2" >> "$scratchfile"
		else
			if [[ -n "$rstr1" && -n "$maxnumber" ]]; then
				seq -f "%0${padding}g" "$rstr1" 1 "$maxnumber" >> "$scratchfile"
			else
				exitcode=2
				errormsg $exitcode "($progstr) String '$num' is not a valid number or expression."
				Cleanup
				exit $exitcode
			fi
		fi
	elif [[ "$num" =~ ^[0-9]+$ ]]; then
		printf "%0${padding}g\n" "$num" >> "$scratchfile"
	else
		exitcode=2
		errormsg $exitcode "($progstr) String '$num' is not a valid number or expression."
		Cleanup
		exit $exitcode
	fi
done

# Avoid UUOC: redirect file directly into sort
filemin=$(sort -u < "$scratchfile" | head -n 1)
if (( 10#$filemin < 1 )); then
	exitcode=3
	errormsg $exitcode "($progstr) Selection is less then min '1'."
fi

if [[ $exitcode -eq 0 ]]; then
	if [[ -n "$maxnumber" ]]; then
		filemax=$(sort -u < "$scratchfile" | taillastline)
		if (( 10#$filemax > 10#$maxnumber )); then
			exitcode=4
			errormsg $exitcode "($progstr) Selection is greater then max '$maxnumber'."
		fi
	fi

	# Display result
	if [[ $exitcode -eq 0 ]]; then
		sort -u < "$scratchfile"
	fi
fi

# Cleanup and exit
Cleanup
exit $exitcode