exif-rename

#!/bin/bash
#
# exif-rename
#

[ -n "$MYDIR" ] || {
	declare MYDIR=
	MYDIR="$(dirname "$(readlink -f "$0")")"
}

[ -n "$MYLIB" ] || {
	declare MYLIB=
	MYLIB="$MYDIR"/lib
}

[ "$ui_loaded" ] || source "$MYLIB"/ui.source

declare optcount=0
declare srcdir=
declare destdir=
declare prefix=
declare suffix=
declare tag="-CreateDate"
declare b_execute=false

declare usagestr=
usagestr=$(
cat <<EOF

$(basename "$0") [options] srcdir

This utility renames the photos or videos based on their creation or modify
dates, as selected by the user. Default is Create Date.

The utility prints the derived newnames to the screen without actually
renaming the files by default.

To actually rename the files, you must select the x (exexute) option.

Example:

exif-rename \\\

   -x \\\

   -m \\\

   -p "TC-" \\\

   -s "-mountains" \\\

   -d "~/renamed-photos" \\\

   /Pictures/Photos/2023

The files in /Pictures/Photos/2023 will be renamed (-x) based on their
File Modify Date (-m) with a prefix of "TC-" (-p) and a suffix of
"-mountains" (-s) and placed in directory "~/renamed-photos"

Arguments
---------
   srcdir : location of the mp4 files to be renamed

Options
-------
   p:prefix  : prefix to be prepended to the name
   s:suffix  : suffix to be appended to the name
   d:destdir : destination directory, if different from srcdir
   c         : use file creation date (default)
   m         : use file modify date
   x         : execute the rename (default is to just show the new names)
   h         : this help screen

\0
EOF
)

# control_c: run if user hits control-c
#
# Global
#   CTLC_EXIT - bash environment variable
#
control_c() {
	echo -e "\nCtrl-c detected\nCleaning up and exiting."
	exit $CTLC_EXIT
}

# init
#
# GLOBALS
#
init() {
	local -i bgtemp

	ui_setbg bgtemp

	which exiftool || \
		ui_exit ui_err_missing_exec \
		"\n$INF You must install$MNU exiftool$INF to run this script.$OFF\n"
}

# parseopts
#
# Globals
#
parseopts() {
	local arg=
	local opt=

	for arg in $@; do

	    if [ "${arg:0:1}" == "-" ]; then
		opt="${arg:1}"
		shift
		((optcount++))

		case "$opt" in
		p ) prefix=$1
		    shift
		    ((optcount++))
		    ;;
		s ) suffix=$1
		    shift
		    ((optcount++))
		    ;;
		d ) destdir=$1
		    shift
		    ((optcount++))
		    ;;
		c ) tag="-CreateDate" # Default
		    ;;
		m ) tag="-FileModifyDate"
		    ;;
		x ) b_execute=true
		    ;;
		h ) echo -e "$usagestr"
		    exit 0
		esac
	    fi
	done
}

main() {
	local -a mp4jpgary=()
	local -A nameary	# associate name with a bump number
	local newname=
	local b_destdir=false
	local ext=
	local path=

	init

	(($# >= 1)) || ui_exit ui_err_invargc "$usagestr"

	parseopts "$@"

	shift "$optcount"
	srcdir="$1"

	# Check the directories
	[ -n "$srcdir" ] || ui_exit ui_err_missing_arg "Must provide src directory argument"
	[ -d "$srcdir" ] || ui_exit ui_err_invdir "$srcdir"

	if [ -n "$destdir" ]; then
		[ -d "$destdir" ] || i_exit ui_err_invdir "$destdir"
		b_destdir=true
		path="$destdir"
	else
		path="$srcdir"
	fi

	path="$(realpath "$path")"

	# Assure that there is one and only one trailing slash at the end
	# of the directory path.
	path="${path%/}"
	path="$path/"

	# Create an array of mp4 and jpg file names.
	mapfile -t mp4jpgary < <(find "$srcdir" -type f \( -iname "*.mp4" -o -iname "*.jpg" \))

	# Loop through the array of mp4 and jpg filenames to rename them
	# according to exif tag for CreateDate (default) or FileModifyDate,
	# as specified by user.
	for mp4jpg in ${mp4jpgary[@]}; do
		# Get the filename extension
		ext="${mp4jpg##*.}"
		# Get the exif date according to user preference
		# CreateDate or FileModifyDate contained in $tag
		newname=$(exiftool "$tag" "$mp4jpg")
		# Isolate the date and time
		newname=$(echo "$newname" | cut -d':' -f2-)
		# Remove leading and trailing spaces
		newname=$(echo $newname)
		# Replace colons with dashes
		newname=${newname//:/-}
		# Replace spaces with double dashes
		newname=${newname// /--}
		# Get the full name of the file and its path
		newname="$path$prefix$newname$suffix"

		# Assure that each file has a unique filename, even if the
		# time stamps are identical.
		# If this newname already exists in the nameary, then bump its
		# value by one.
		# Else, if it's a NEW newname, then set its value to zero.
		if [[ -v nameary["$newname"] ]]; then
			nameary["$newname"]=$((${nameary["$newname"]} + 1))
		else
			nameary["$newname"]=0
		fi

		# Set the new name accordint to its bump value in the nameary.
		# If it's greater than 0, then append the bump value.
		(( ${nameary["$newname"]} != 0)) && newname="$newname-${nameary["$newname"]}"

		# Add the file extension to the new name.
		newname="$newname.$ext"

		if $b_execute; then
			mv -n -u -v "$mp4jpg" "$newname"
		else
			echo "$mp4jpg --> $newname"
		fi
	done

	$b_execute || echo -e \
		"\n${MNU}You must use the -x option to actually rename the files.\n$OFF"
}

main "$@"