Add optimized read_tag functions for id3v2 and flac

music_tagmove_lib

@@ -39,13 +39,79 @@ function error {
 	>&2 printf "%s\n" "$current_error_line"
 }
 
-function clr_errf { local_errf=
+function clr_errf {
+	local_errf=
 }
 
-function read_tag {
-	clr_errf
+function get_file_extension {
+	echo "${1##*.}"
+}
+
+function read_tag_flac {
+	local tag=${1^^}
+	local file="$2"
+
+	if [[ $tag == "TRACK" ]]; then
+		tag="TRACKNUMBER"
+	fi
+
+	local comment_line
+	comment_line=$(metaflac --list "$file" --block-type=VORBIS_COMMENT | grep -F "$tag=")
+	if [[ $? -ne 0 ]]; then
+		error "Reading tag \"$1\" from \"$file\" failed: metaflac error"
+		return
+	fi
+	local result=${comment_line#*=}
+	if [[ -z $result ]]; then
+		error "Reading tag "$1" from \"$file\" failed: empty value"
+		return
+	fi
+	echo "$result"
+}
+
+function read_tag_id3 {
 	local tag="$1"
 	local file="$2"
+
+	declare -A id3v2_map=( [artist]=TPE1 \
+		               [album]=TALB \
+			       [title]=TIT2 \
+			       [date]=TYER \
+			       [track]=TRCK )
+
+	local id3v2_content_rfc822
+	id3v2_content_rfc822=$(id3v2 -R "$file")
+	if [[ $? -ne 0 ]]; then
+		error "Reading tag \"$1\" from \"$file\" failed: id3v2 error"
+		return
+	fi
+	local no_id3tag_fmt='*No ID3 tag'
+
+	if [[ $id3v2_content_rfc822 == $no_id3tag_fmt ]]; then
+		read_tag_fallback "$tag" "$file"
+		return
+	else
+		local rfc822tag=${id3v2_map[$tag]}
+		if [[ -z $rfc822tag ]]; then
+			error "Unknown tag \"$tag\" requested for file \"$file\""
+			return
+		fi
+		local line=$(grep -E "^$rfc822tag:\s" <<<"$id3v2_content_rfc822")
+		local result=${line:6}
+
+		if [[ -z $result ]]; then
+			error "Reading tag \"$tag\" from \"$file\" failed: empty value"
+			return
+		fi
+
+		echo "$result"
+	fi
+}
+
+function read_tag_fallback {
+	local tag="$1"
+	local file="$2"
+
 	local result=$(ffprobe -loglevel error -show_entries format_tags="$tag" -of default=noprint_wrappers=1:nokey=1 "$file")
 	if [[ $? -ne 0 ]]; then
 		error "Reading tag \"$tag\" from \"$file\" failed (ffprobe failed)"
@@ -53,10 +119,31 @@ function read_tag {
 	fi
 	if [[ -z $result ]]; then
 		error "Reading tag \"$tag\" from \"$file\" failed (result empty)"
+		return
 	fi
 	echo "$result"
 }
 
+function read_tag {
+	clr_errf
+	local tag="$1"
+	local file="$2"
+	local ext=$(get_file_extension "$file")
+
+	shopt -s nocasematch
+	case "$ext" in
+		flac)
+			read_tag_flac "$tag" "$file"
+			;;
+		mp3)
+			read_tag_id3 "$tag" "$file"
+			;;
+		*)
+			read_tag_fallback "$tag" "$file"
+			;;
+	esac
+}
+
 function cuesplit_single {
 	clr_errf
 
@@ -119,7 +206,7 @@ function cuesplit_single {
 	if	cuebreakpoints "$cue" | shnsplit -o flac "$flac" || \
 		cuebreakpoints "$cue" | sed 's/$/0/' | shnsplit -o flac "$flac"; then
 		info "Tagging target \"$image_dir\""
-		if cuetag "$cue" split-*.flac; then
+		if cuetag.sh "$cue" split-*.flac; then
 			info "Renaming source files"
 			mv "$cue" "$cue.ignore"
 			mv "$flac" "$flac.ignore"
@@ -178,7 +265,27 @@ function tagmove_single {
 	eval "dest_file=\"$FILE_FORMAT\""
 
 	mkdir -p "$dest_root/$dest_directory"
-	mv_wrap "$file_name" "$dest_root/$dest_directory/$dest_file.${file_name##*.}"
+	mv_wrap "$file_name" "$dest_root/$dest_directory/$dest_file.$(get_file_extension "$file_name")"
+}
+
+function tagmove_get_media_type {
+	file="$1"
+	ext=$(get_file_extension "$file")
+
+	shopt -s nocasematch
+
+	case $ext in
+		flac|alac|aac|m4a|mp3|ogg|oga|opus|wav|wma)
+			echo "audio"
+			;;
+		jpg|jpeg|png)
+			echo "image"
+			;;
+		*)
+			file -b --mime-type "$file" | cut -d'/' -f1
+			;;
+	esac
+	
 }
 	
 
@@ -189,9 +296,18 @@ function tagmove {
 	fi
 
 	while read -r file; do
-		if [[ $(file -b --mime-type "$file") =~ ^audio/ ]]; then
-			tagmove_single "$file"
-		fi
+		media_type=$(tagmove_get_media_type "$file")
+		
+		case "$media_type" in
+			audio)
+				tagmove_single "$file"
+				;;
+			image)
+				# TODO: cover move
+				echo "potential cover: $file"
+				;;
+		esac
+
 	done < <(find "$source_dir" -type f -not -name "*.ignore")
 }