cvccommit

#!/bin/bash
################################################################################
# Loading configuration
################################################################################

CVCINTERNAL_SCRIPTROOT=$(dirname "$0")
source "${CVCINTERNAL_SCRIPTROOT}/config"

################################################################################
# Documentation
################################################################################

# Return code reference
# 1     Syntax error in invocation
# 2     Missing argument
# 3     Target CVC file does not exist
# 4     Related audio file does not exist
# 5     Error during CVC expansion: cvcexpand returned an error
# 6     metaflac couldn't remove current tags from the audio file
# 7     metaflac couldn't import new tags to the audio file
# 8     metaflac couldn't remove embedded pictures from the audio file
# 9     metaflac couldn't embed a picture into an audio file
# 16    Internal error

# Show usage
function usage {
    echo "This command updates Vorbis Comments within FLAC files. It expands a CVC file"
    echo "to Vorbis Comments using cvcexpand, stores the resulting tags to a companion"
    echo "file with the .tags extension, then updates the actual audio file using"
    echo "metaflac. On-disk updates are only performed when needed."
    echo ""
    echo "Usage: cvccommit [-f] [-h] [-l <lang>] [-v] <file>"
    echo ""
    echo "Options:"
    echo "-f            Force the script to perform on-disk updates, even if it seems"
    echo "              not necessary".
    echo "-h            Show this message."
    echo "-l <lang>     Specify a language filter (cvcexpand -l option)."
    echo "-v            Verbose mode."
    echo ""
    echo "Arguments:"
    echo "<file>        A text file with CVC content."
}

################################################################################
# Option and argument parsing
################################################################################

# Default values
cvcexpandExtraArgs=""

# Calling option parser
while getopts ":fhl:v" option; do
    case "${option}" in
        # -f: Force mode
        f)
            OPT_Force=1
            ;;

        # -h: Help
        h)
            usage
            exit
            ;;

        # -l: Language filter
        l)
            cvcexpandExtraArgs+="-l ${OPTARG}"
            ;;

        # -v: Verbose mode
        v)
            OPT_Verbose=1
            ;;

        # Syntax error
        \?)
            >&2 echo "ERROR: Invalid option: -${OPTARG}"
            usage
            [[ "${BASH_SOURCE[0]}" != "${0}" ]] && return 1 || exit 1
            ;;

        # Syntax error
        :)
            >&2 echo "ERROR: Option -${OPTARG} requires an argument."
            usage
            [[ "${BASH_SOURCE[0]}" != "${0}" ]] && return 1 || exit 1
            ;;

        # Any other value is an internal error
        *)
            >&2 echo "ERROR: Internal getopts error."
            [[ "${BASH_SOURCE[0]}" != "${0}" ]] && return 16 || exit 16
            ;;
    esac
done

shift $((OPTIND-1))

# Checking whether a CVC file was supplied as an argument.
if [ -z "$1" ]
then
    >&2 echo "ERROR: No CVC file was specified."
    usage
    [[ "${BASH_SOURCE[0]}" != "${0}" ]] && return 2 || exit 2
fi

################################################################################
# Additional checks
################################################################################

# Abstracting supplied arguments
targetCVCFile="$1"

# Checking whether the supplied CVC file does exist
if [ ! -f "${targetCVCFile}" ]
then
    >&2 echo "ERROR: The CVC file ${targetCVCFile} does not exist!"
    [[ "${BASH_SOURCE[0]}" != "${0}" ]] && return 3 || exit 3
fi

# Generating related filenames
targetFileBasename=$(basename "$1" .${CFG_FileExtensions_CVC})
targetFileBasedir=$(dirname "${targetCVCFile}")
targetAudioFile="${targetFileBasedir}/${targetFileBasename}.${CFG_FileExtensions_Audio}"
targetTagsFile="${targetFileBasedir}/${targetFileBasename}.${CFG_FileExtensions_Tags}"

# If the supplied CVC filename is in the ignore list, we escape here.
for ignoredFilename in "${CFG_CVCCommit_IgnoredFilenames[@]}"; do
    if [ "${targetFileBasename}" == "${ignoredFilename}" ]
    then
        [[ "${BASH_SOURCE[0]}" != "${0}" ]] && return 0 || exit 0
    fi
done

# Checking whether the related audio file does exist
if [ ! -f "${targetAudioFile}" ]
then
    >&2 echo "ERROR: The related audio file ${targetAudioFile} does not exist!"
    [[ "${BASH_SOURCE[0]}" != "${0}" ]] && return 4 || exit 4
fi

################################################################################
# Performing CVC expansion
################################################################################

[ "${OPT_Verbose}" ] && echo "Performing CVC expansion on file ${targetCVCFile}..."
expansionOutput=$("${CFG_CVCTools_CVCExpand}" ${cvcexpandExtraArgs} "${targetCVCFile}")

if [ ! "$?" -eq 0 ]
then
    >&2 echo "ERROR: Error in CVC expansion. Operation halted."
    [[ "${BASH_SOURCE[0]}" != "${0}" ]] && return 5 || exit 5
fi

################################################################################
# Data comparison and tags file update
################################################################################

# We only compare Vorbis Comments if a .tags file already exists.
if [ -f "${targetTagsFile}" ]
then
    echo "${expansionOutput}" | diff -q "${targetTagsFile}" - > /dev/null

    if [ "$?" -gt 0 ] || [ "${OPT_Force}" ]
    then
        [ "${OPT_Verbose}" ] && echo "Updating tag file ${targetTagsFile}..."
        echo "${expansionOutput}" > "${targetTagsFile}"
    else
        [ "${OPT_Verbose}" ] && echo "Tag file is already up to date."
    fi

# If not tags file exists, we write a new one now
else
    [ "${OPT_Verbose}" ] && echo "Creating tag file '${targetTagsFile}'..."
    echo "${expansionOutput}" > "${targetTagsFile}"
fi

################################################################################
# Updating tags
################################################################################

if [[ "${targetTagsFile}" -nt "${targetAudioFile}" ]] || [ "${OPT_Force}" ]
then
    [ "${OPT_Verbose}" ] && echo "Updating metadata in audio file ${targetAudioFile}..."

    # Deleting current FLAC tags
    "${CFG_ExtTools_Metaflac}" --remove-all-tags "${targetAudioFile}" > /dev/null
    if [ ! "$?" -eq 0 ]
    then
        >&2 echo "ERROR: Unable to erase current FLAC tags. Operation halted."
        [[ "${BASH_SOURCE[0]}" != "${0}" ]] && return 6 || exit 6
    fi

    # Adding the new tags
    "${CFG_CVCTools_CVCExpand}" "${targetCVCFile}" | \
        "${CFG_ExtTools_Metaflac}" --import-tags-from=- "${targetAudioFile}"
    if [ ! "$?" -eq 0 ]
    then
        >&2 echo "ERROR: Unable to add the new FLAC tags. Operation halted."
        [[ "${BASH_SOURCE[0]}" != "${0}" ]] && return 7 || exit 7
    fi

else
    [ "${OPT_Verbose}" ] && echo "Audio file metadata are already up to date."
fi

################################################################################
# Updating embedded pictures
################################################################################

# Initializing variables
updateEmbeddedPictures=0
declare -a frontPictures
declare -a backPictures

# Searching for picture files
for pictureBasename in "${CFG_CVCCommit_AlbumArt_Front[@]}" "${CFG_CVCCommit_AlbumArt_Back[@]}"
do
    # Enumerating valid picture file extensions
    for pictureExtension in "${CFG_CVCCommit_PictureExtensions[@]}"
    do
        # Expected picture filename
        pictureFile="${targetFileBasedir}/${pictureBasename}.${pictureExtension}"

        # If a picture file with the expected file name is found, it must be
        # embedded into the audio file.
        if [ -f "${pictureFile}" ]
        then
            # Front picture
            if [[ " ${CFG_CVCCommit_AlbumArt_Front[*]} " == *" ${pictureBasename} "*  ]]
            then
                # We add the picture file to the list of found picture files.
                [ "${OPT_Verbose}" ] && echo "Album picture found (front): ${pictureBasename}.${pictureExtension}"
                frontPictures+=("${pictureFile}")

            # Back picture
            elif [[ " ${CFG_CVCCommit_AlbumArt_Back[*]} " == *" ${pictureBasename} "*  ]]
            then
                # We add the picture file to the list of found picture files.
                [ "${OPT_Verbose}" ] && echo "Album picture found (back): ${pictureBasename}.${pictureExtension}"
                backPictures+=("${pictureFile}")

            else
                >&2 echo "ERROR: Unable to deduce the type of an album picture."
                [[ "${BASH_SOURCE[0]}" != "${0}" ]] && return 16 || exit 16
            fi

            # If at least one picture file is newer than the last modification
            # time of the audio file, the audio file needs to be updated. Since
            # that update requires removing all embedded pictures from the file
            # first, all available pictures will have to be reembedded. A single
            # newer picture file is thus enough to trigger the update process.
            if [[ "${pictureFile}" -nt "${targetAudioFile}" ]] || [ "${OPT_Force}" ]
            then
                updateEmbeddedPictures=1
            fi
        fi
    done
done

# If the audio file needs to be updated, we do it here
if [ "${updateEmbeddedPictures}" -eq 1 ]
then

    # Deleting previous embedded pictures
    [ "${OPT_Verbose}" ] && echo "Removing all embedded pictures from the audio file ${targetAudioFile}..."
    "${CFG_ExtTools_Metaflac}" --remove --block-type=PICTURE "${targetAudioFile}" > /dev/null

    # Checking removal result
    if [ ! "$?" -eq 0 ]
    then
        >&2 echo "ERROR: Unable to remove embedded pictures from a FLAC file."
        [[ "${BASH_SOURCE[0]}" != "${0}" ]] && return 8 || exit 8
    fi

    # Embedding front pictures
    for pictureFile in "${frontPictures[@]}"
    do
        [ "${OPT_Verbose}" ] && echo "Embedding front picture ${pictureFile} into file ${targetAudioFile}..."

        "${CFG_ExtTools_Metaflac}" --import-picture-from="3||||${pictureFile}" "${targetAudioFile}" > /dev/null
        if [ ! "$?" -eq 0 ]
        then
            >&2 echo "ERROR: Unable to embed a picture into a FLAC file. Operation halted."
            [[ "${BASH_SOURCE[0]}" != "${0}" ]] && return 9 || exit 9
        fi
    done

    # Embedding back pictures
    for pictureFile in "${backPictures[@]}"
    do
        [ "${OPT_Verbose}" ] && echo "Embedding back picture ${pictureFile} into file ${targetAudioFile}..."

        "${CFG_ExtTools_Metaflac}" --import-picture-from="4||||${pictureFile}" "${targetAudioFile}" > /dev/null
        if [ ! "$?" -eq 0 ]
        then
            >&2 echo "ERROR: Unable to embed a picture into a FLAC file. Operation halted."
            [[ "${BASH_SOURCE[0]}" != "${0}" ]] && return 9 || exit 9
        fi
    done
else
    [ "${OPT_Verbose}" ] && echo "Embedded pictures are up to date."
fi