matchsubtitles

#!/bin/bash
#
# Rename subtitles (.srt files) to match the given video files
#
# Copyright (C) 2011 Rodrigo Silva (MestreLion) <linux@rodrigosilva.com>
# License: GPLv3 or later, at your choice. See <http://www.gnu.org/licenses/gpl>
#
# For updated versions, see https://github.com/MestreLion/scripts/
#
# For an example on how to use it via GUI/File Manager, see the Nautilus action
# wrapper in `nautilus-scripts/Match subtitles`
#
# TODO: Support for multiple language subtitles ( *.xx.srt )
# FIXME: undo file should handle chained renames of the same file

self="${0##*/}"

run=0
verbose=0
undo=

fatal() {
	local msg="$1"
	if [[ "$msg" ]]; then
		printf "%s: %s\nTry '%s --help' for more information\n" \
		       "$self" "$msg" "$self" >&2
	fi
	exit 1
}
usage() {
cat << USAGEDOC
Rename subtitles (.srt files) to match the given video files

Usage: $self [--undo FILE] [--verbose] [--run] [--] [FILE|DIR]...

Options:
--undo FILE - Create an undo script to revert the renaming. Run ./FILE to revert
--run       - If not used, will not actually rename subtitles, only show what will be done

Video files are *.avi, *.mkv, *.mpg, *.mpeg and *.ogv. All other files are ignored
Files that already have a matching subtitle and subtitles that already have a matching video will be ignored
For desired results, files in same dir must be given in alphabetical order (use globs for that).

Example:
	$self --run ~/Videos/Lost /shared/csi/miami_s1* '/movies/star wars'

Copyright (C) 2011 Rodrigo Silva (MestreLion) <linux@rodrigosilva.com>
License: GPLv3 or later, at your choice. See <http://www.gnu.org/licenses/gpl>
USAGEDOC
exit
}

printundo() {

	local header="$1"
	local oldfile="$2"
	local newfile="$3"

	if [[ -z "$header" ]]; then
		printf '#Automatically generated by %s at %s\n' "$self" "$(date +'%F %T')"
		printf '#arguments:'
		printf ' %q' "${args[@]}"
		printf '\ncd %q\n' "$PWD"
	fi

	printf "mv -- %q %q\n" "$oldfile" "$newfile"
}

addfiles() {
	local arg="$1"
	if [[ -f "$arg" ]]; then files+=( "$arg"       ); return; fi  # add file
	if [[ -d "$arg" ]]; then files+=( "${arg%/}/"* ); return; fi  # add files in dir
	fatal "$(printf '%q' "$arg"): not a file or directory"
}

#save for log
args=( "$@" )

# command line parsing
while [[ $# -gt 0 ]]; do
	arg="$1"; shift
	case "$arg" in
	-h|--help   ) usage           ;;
	-t|--run    ) run=1           ;;
	-v|--verbose) verbose=1       ;;
	-u|--undo   ) undo="$1";shift ;;
	--          ) break           ;;
	*           ) addfiles "$arg" ;;
	esac
done
for arg; do addfiles "$arg"; done  # add remaining files after --
if [[ "${#files[@]}" -eq 0 ]]; then addfiles "$PWD"; fi  # no files given: add current dir

# set the verbose -v option for mv
v=()
if ((verbose)); then v=("-v"); fi

# loop the files
prevdir=""
match=0
for video in "${files[@]}"; do

	# File exists? (can be an umatched glob or empty dir)
	if ! [[ -f "$video" ]]; then continue; fi

	# Split full filename in file, title, ext and dir (with trailing '/')
	file="${video##*/}"
	title="${file%.*}"
	ext="${file#"$title"}"
	ext="${ext#.}"
	dir="${video%"$file"}"
	dir="${dir:-./}"

	# Is it a video?
	shopt -s nocasematch
	case "${ext}" in avi|mpg|mpeg|mkv|mp4|ogv) ;; *) continue ;; esac
	shopt -u nocasematch

	# Has a matching subtitle already?
	subtitle="${video%."$ext"}.srt"
	if [[ -f "$subtitle" ]]; then continue; fi

	# Populate the unmatched subtitles array for this dir
	if [[ "$dir" != "$prevdir" ]]; then
		prevdir="$dir"
		allsubs=( "${dir%/}"/*.[Ss][Rr][Tt] )
		subtitles=()
		s=0
		for sub in "${allsubs[@]}"; do
			if [[ -f "$sub" ]]; then
				matchsub=""
				for f in "${sub%.[Ss][Rr][Tt]}".{avi,mpg,mpeg,mkv,mp4,ogv}; do
					if [[ -f "$f" ]]; then matchsub=1; break; fi
				done
				if [[ -z "$matchsub" ]]; then subtitles+=( "$sub" ); fi
			fi
		done
	fi

	# Are there any avaliable, unmatched subtitles left in this dir?
	if ! (( s < ${#subtitles[@]} )); then continue; fi

	# Rename the first subtitle
	if ((run)); then
		mv "${v[@]}" -- "${subtitles[s]}" "${subtitle}" ||
		fatal "could not rename ${subtitles[s]}"
		if [[ "$undo" ]]; then
			printundo "$match" "${subtitle}" "${subtitles[s]}" >> "$undo" ||
			fatal "could not write to undo file $undo"
		fi
	elif ((verbose)); then
		printf '# mv -- %q %q\n' "${subtitles[s]}" "${subtitle}"
	fi
	match=1
	(( s++ ))

done

if ((verbose && match && ! run)); then
	echo "Dry run, no rename was executed. Use --run to apply"
fi

if [[ "$undo" ]] && ((match && run)); then
	printf '\n' >> "$undo" || fatal "could not write to undo file $undo"
	chmod +x "$undo" || fatal "could not set to executable undo script $undo"
	if ((verbose)); then echo "undo file created: $undo"; fi
fi