#!/bin/sh

conv() {
	while [ $# -gt 0 ]; do
		if printf "%s" "$1" | grep -qE '^[0-9]+$'; then
			if [ "$m" -eq 0 ]; then	
				printf "Decimal %s → Hex: " "$1"
			fi
			printf "%s" "$p"
			printf "%X\n" "$1"

		elif printf "%s" "$1" | grep -qE '^0b[0-1]+$'; then
			if [ "$m" -eq 0 ]; then
				printf "Binary %s → Hex: " "$1"
			fi
			printf "%s" "$p"
			printf "%X\n" "$1"

		else
			printf "Error: '%s' is not a valid binary or decimal number\n" "$1" >&2
			stat=1

		fi
		shift
	done
	return "$stat"
}


main() {
	USAGE="usage: tohex [-lmnp] ..."
	if ! [ "$1" = "x" ] && ! [ -t 0 ]; then
		cat | tr '\n' ' ' | xargs tohex "x" "$@"
		return "$?"

	elif [ "$1" = "x" ]; then
		shift

	fi
	
	if [ $# -eq 0 ]; then
		printf "Error: No arguments provided\n%s\n" "$USAGE" >&2
		return 2

	fi
	
	stat=0	
	l=0; m=0; n=0; p=""
	while getopts "lmnp" flag; do
		case "$flag" in
			l) l=1; ;;
			m) m=1; ;;
		       	n) n=1; ;;
			p) p="0x" ;;
			*) printf "%s\n" "$USAGE" >&2 ; return 2 ;;
		esac
	done

	shift $(( OPTIND - 1 ))
	
	t=$(conv "$@")
	stat=$?

	if [ "$n" -eq 1 ] && [ "$m" -eq 1 ]; then
		t=$(printf "%s" "$t" | tr '\n' ' ')

	elif [ "$n" -eq 1 ] && [ "$m" -eq 0 ]; then
		t=$(printf "%s" "$t" | tr '\n' ';')

	else
		t=$(printf "%s" "$t")

	fi
	
	if [ "$l" -eq 1 ]; then
		t=$(printf "%s" "$t" | tr '[:upper:]' '[:lower:]')
	fi
	printf "%s\n" "$t"	
	return "$stat"
}

main "$@"