#!/bin/bash -u
#############################################################################
# FILE-MV-ALL, a function that expands the shell 'mv' command to accept to
# rename multiple files with similar names.
# Usage:
#   file-mv-all TAG NEWTAG [-exclude=<EXTAG1> -exclude=<EXTAG2> ] [ -passive ]
# Selects all files that match regex *TAG* and rename them to *NEWTAG*
# Additional tags can be provided to exclude files from being renamed.
# Optional input flag defines the interactive nature of the function,
# By default FILE-MV-ALL displays list of files and changes that will be made
# If the '-passive' or '-p' flag is provided then no output is given and 
# changes are immediately executed
#
#@ Created by Pedro Inacio <P.M.G.Inacio@tudelft.nl>
#############################################################################

HELP="FILE-MV-ALL, a function that expands the shell 'mv' command to accept to \n
rename multiple files with similar names.\n
Usage:\n
	\tfile-mv-all TAG NEWTAG [-exclude=<EXTAG1> -exclude=<EXTAG2> ] [ -passive ]\n\n
Selects all files that match regex *TAG* and rename them to *NEWTAG*\n
Additional tags can be provided to exclude files from being renamed. 
Optional input flag defines the interactive nature of the function,\n
By default FILE-MV-ALL displays list of files and changes that will be made\n
If the '-passive' or '-p' flag is provided then no output is given and \n
changes are immediately executed."

# TODO: Add support for subfolder renaming.
# TODO: Add support for excluding patterns.

# Parameters
CMD='mv'
#CMD='echo mv'	#DEBUG mode

#Verify inputs
case $# in
	0)	echo -e ERROR: Invalid number of arguments.
		echo -e $HELP
		exit 3
		;;

	1)	if [ $1 == "--help" ]
		then
			echo -e $HELP
			exit 0
		else
			echo -e ERROR: Invalid argument, $1
			echo -e $HELP
			exit 3
		fi
		;;

	*)	#Two or more input arguments
		TAG=$1;
		NEWTAG=$2;
		MODE=active
		#Iterate through rest of inputs
		i=2
		ARGLIST=($@)
		EXCLIST=
		while [ $i -lt $# ]
		do
			ARG=${ARGLIST[$i]}
			#check for exclude inputs
			if [ ${ARG#-exclude=*} != $ARG ]
			then
				#echo Found exclude pattern, ${ARG#-exclude=*}
				EXCLIST=( ${EXCLIST[*]} ${ARG#-exclude=*} )
			#check for passive mode flag
			elif [ $ARG == -passive -o $ARG == -p ]
			then
				#echo Found mode, passive
				MODE=passive
			#fail on unknown input
			else
			echo -e ERROR: Invalid argument, $ARG.
			echo -e $HELP
			exit 3
			fi
			((i++))
		done
		;;
esac

#check that any files in folder match TAG
ls *$TAG* 1>/dev/null 2>&1
if [ $? == 0 ] 
then 
	FILES=(*$TAG*)
else 
	echo No files in current folder matching expression: $TAG 
	exit 0
fi

# remove files that match any of the exclude tags
EXCLFILES=
for EXCLTAG in ${EXCLIST[*]}
do
	IMAX=${#FILES[*]}
	for (( i=0 ; i < $IMAX ; i++ ))
	do	
		FILE=${FILES[$i]}
		if [ ${FILE/$EXCLTAG/} != $FILE ]
		then
			EXCLFILES=(${EXCLFILES[*]} $FILE)
			unset FILES[$i]
		fi
	done
	#Refresh FILES array removing empty positions
	FILES=( ${FILES[*]} )
done
#echo Excluded: ${EXCLFILES[*]}
#echo Included: ${FILES[*]}

if [ $MODE == active ]
then
	#Test if EXCLFILES is empty
	if [ ${#EXCLFILES} -gt 0 ]
	then
		echo "List of excluded files,"
		for f in ${EXCLFILES[*]}
		do
			echo -e "\t$f"
		done
	fi

	echo "The following files will be renamed,"
	for f in ${FILES[*]}
	do
		echo -e "\t$f -> ${f/$TAG/$NEWTAG}"
	done
	
	#Get user reply
	echo ""
	ANSWER=EMPTY
	while [ $ANSWER != Y -a $ANSWER != y -a $ANSWER != yes ]
	do
		echo -e "Do you wish to continue and rename files? [Y]es or [N]o?"
		read ANSWER
		if [ $ANSWER == N -o $ANSWER == n -o $ANSWER == no ]
		then
			exit 0
		fi
	done
fi

#rename files
for f in ${FILES[*]}
do
	$CMD $f ${f/$TAG/$NEWTAG}
done

exit