#!/bin/bash

# change filename using command 'tr'
# Usage: fn-tr -p <tr parameters> -fdr <file/directory> <file/directory> ...
# -p parameters will transfered to command 'tr'
# -d change directory
# -f change normal file
# -r recursive
# known issues:
# can not change filename case under MS-Windows

trParams='';
changedir=0;
changefile=0;
recurse=0;
while getopts ':p:dfr' opt; do
	case $opt in
		p)
			trParams=$OPTARG;
			;;
		d)
			changedir=1;
			;;
		f)
			changefile=1;
			;;
		r)
			recurse=1;
			;;
	esac;
done;
shift $(($OPTIND-1));

function trFile()
{
	oldpathname="$1";
	oldname=$(basename "$oldpathname");
	path=$(dirname "$oldpathname");

	newname=$(eval "echo '$oldname' | tr $trParams");
	newpathname=$path'/'$newname;

	oldpathname=$(echo "$oldpathname" | tr -s '/');
	oldpathname=${oldpathname#./};
	oldpathname=${oldpathname%/};
	newpathname=$(echo "$newpathname" | tr -s '/');
	newpathname=${newpathname#./};
	newpathname=${newpathname%/};

	if [ "$oldname" != "$newname" -a -n "$newname" ]; then
		if [ ! -e "$newname" ]; then
			mv -Tn "$oldpathname" "$newpathname" &&
			echo "$oldpathname --> $newpathname [OK]" ||
			echo "$oldpathname --> $newpathname [Failed]" >&2
		else
			echo "$oldpathname --> $newpathname [Skipped, target exists]" >&2
		fi;
	fi;
}

function iterateFile()
{
	local file;
	for file in "$@"; do
		if [ -n "$file" -a -e "$file" ]; then
			if [ -d "$file" ]; then
				if [ $recurse -eq 1 ]; then
					eval "iterateFile '${file%/}'/*"
				fi;
				if [ $changedir -eq 1 ]; then trFile "$file"; fi;
			else
				if [ $changefile -eq 1 ]; then trFile "$file"; fi;
			fi;
		fi;
	done;
}

startFiles=$@;
if [ -z "$startFiles" -o -z "$trParams" ]; then
	echo "Usage: $(basename $0) -p <tr parameters> -fdr <file/directory> <file/directory> ..." >&2
fi;
iterateFile "$@";