#!/bin/bash

#  Includes
. $(miniade) || { echo "${0##*/}: ERROR: miniade failed (hint: run 'miniade' to see error)" >&2; exit 1; }

#  Configurable stuff
TUPLES=(
    '^Various - .* - ([0-9]{2,3}) - (.* \(.*\))\.mp3$' unpack_format_standard_various
    '^.* - .* - ([0-9]{2,3}) - (.*)\.mp3$'             unpack_format_standard
    '^(.*) \[[-A-Za-z0-9_]{11}\]\.mp3$'                unpack_format_ytdlp
    '^(.*)\.mp3$'                                      unpack_format_unknown
)

#  Other globals
TUPLE_LEN=2

main()
{
    local MY_ARGS
    local 

    #  Defaults for options

    #  Process options
    special_opts_handler()
    {
        case $1 in
        esac
    }
    miniade_process_options --help-handler=help --special-opts-handler=special_opts_handler MY_ARGS "$@" && set -- "${MY_ARGS[@]}"

    #  Process arguments
    [ $# -ge 1 ] || miniade_bad_usage
    THINGS=( "$@" )

    #  Sanity checks and derivations

    #  Guts
    for THING in "${THINGS[@]}"; do
        process "${THING%/}"
    done
}

process()
{
    local THING THING2 OLD_ABS_THING NEW_ABS_THING I MATCH MUSIC_DIR ARTIST_SUBDIR ALBUM_SUBDIR OLD_BASENAME
    local OLD_TRACKNO OLD_TRACK UNMUNGED_ARTIST_SUBDIR NEW_BASENAME

    #  Process arguments
    [ $# = 1 ] || miniade_internal "process: bad argument count ($#)"
    THING=$1
    miniade_debug 10 "process: THING=$THING"

    #  Sanity checks and derivations
    case $THING in
        /*) OLD_ABS_THING=$THING ;;
        *)  OLD_ABS_THING=$(pwd)/$THING ;;
    esac

    #  If artist recurse to do albums by artist.
    if [ -d "${OLD_ABS_THING%/*}/KLF" ]; then
        miniade_debug 10 "process: $THING: is an artist"
        for THING2 in "$THING"/*; do
            process "$THING2"
        done

    #  If album recurse to do tracks on album.
    elif [ -d "${OLD_ABS_THING%/*}/../KLF" ]; then
        miniade_debug 10 "process: $THING: is an album"
        for THING2 in "$THING"/*; do
            process "$THING2"
        done

    #  If track then process it.
    elif [ -d "${OLD_ABS_THING%/*}/../../KLF" ]; then
        if [[ $THING =~ .*\.jpg$ ]]; then
            miniade_debug 10 "process: $THING: is skippable; skipping ..."
            return
        fi
        miniade_debug 10 "process: $THING: is a track"
        #  Sanity checks and derivations
        [ -f "$OLD_ABS_THING" ] || miniade_error "$OLD_ABS_THING: not accessible"
        [[ $OLD_ABS_THING =~ (.*)/([^/]+)/([^/]+)/([^/]+)$ ]] || miniade_error "$OLD_ABS_THING: failed to disect"
        MUSIC_DIR=${BASH_REMATCH[1]}
        ARTIST_SUBDIR=${BASH_REMATCH[2]}
        ALBUM_SUBDIR=${BASH_REMATCH[3]}
        OLD_BASENAME=${BASH_REMATCH[4]}
        unmunge_artist_subdir "$ARTIST_SUBDIR" UNMUNGED_ARTIST_SUBDIR
        if [ "$ARTIST_SUBDIR" = Various -a "$ALBUM_SUBDIR" = Singles ]; then
            TRACKNO_WIDTH=3
        else
            TRACKNO_WIDTH=2
        fi
    
        #  Guts
        #  Match filename against templates in order to extract old track number and old
        #  track title, which will be used as defaults when prompting for new ones.
        for ((I=0; I<${#TUPLES[*]}; I+=TUPLE_LEN)); do
            MATCH=false
            if [[ $OLD_BASENAME =~ ${TUPLES[$I]} ]]; then
                MATCH=true
                break
            fi
        done
        $MATCH || miniade_internal "$OLD_BASENAME: failed to find match in TUPLES table"
        ${TUPLES[$((I+1))]} "${BASH_REMATCH[@]}"
        #  Enquire, validate, rationalise
        echo "$OLD_BASENAME"
        read -e -p "Track-No: " -i "$OLD_TRACKNO" NEW_TRACKNO
        read -e -p "Track: " -i "$OLD_TRACK" NEW_TRACK
        [[ $NEW_TRACKNO =~ ^[0-9]{1,3}$ ]] || miniade_error "$NEW_TRACKNO: badly formatted track number"
        #  strip leading zeroes in order that printf doesn't interpret '08' as invalid octal.
        [[ $NEW_TRACKNO =~ ^0*(.*) ]]
        NEW_TRACKNO=${BASH_REMATCH[1]}
        printf -v NEW_TRACKNO %0${TRACKNO_WIDTH}d $NEW_TRACKNO
        #  Combine fixed filesystem-derived fields and user-decided fields.
        NEW_BASENAME="$UNMUNGED_ARTIST_SUBDIR - $ALBUM_SUBDIR - $NEW_TRACKNO - $NEW_TRACK.mp3"
        miniade_debug 10 "process: NEW_BASENAME=[$NEW_BASENAME]"
        NEW_ABS_THING="$MUSIC_DIR/$ARTIST_SUBDIR/$ALBUM_SUBDIR/$NEW_BASENAME"
        if [ "X$OLD_ABS_THING" = "X$NEW_ABS_THING" ]; then
            miniade_debug 10 "process: no rename necessary"
        else
            miniade_debug 10 "process: moving ..."
            miniade_evaler "mv --no-clobber \"$OLD_ABS_THING\" \"$NEW_ABS_THING\""
        fi
        miniade_debug 10 "process: clearing ID3v2 tags ..."
        miniade_evaler "id3v2 -D \"$NEW_ABS_THING\" > /dev/null"
        miniade_debug 10 "process: setting ID3v2 tags ..."
        miniade_evaler "id3v2 -a \"$UNMUNGED_ARTIST_SUBDIR\" -A \"$ALBUM_SUBDIR\" -T $NEW_TRACKNO -t \"$NEW_TRACK\" \"$NEW_ABS_THING\""
        echo
    else
        miniade_internal "can't find KLF (KLF is reference for determining what you're trying to rename"
    fi
}

unmunge_artist_subdir()
{
    local ARTIST_SUBDIR REF LOCAL_UNMUNGED_ARTIST_SUBDIR

    ARTIST_SUBDIR=$1
    REF=$2

    #  Change 'X, The' to 'The X'
    if [[ $ARTIST_SUBDIR =~ (.*),\ (The)$ ]]; then
        LOCAL_UNMUNGED_ARTIST_SUBDIR="${BASH_REMATCH[2]} ${BASH_REMATCH[1]}"

    #  Change 'secondname, firstname' to 'firstname secondname'
    elif [[ $ARTIST_SUBDIR =~ ^([^, ]+),\ ([^, ]+)$ ]]; then
        LOCAL_UNMUNGED_ARTIST_SUBDIR="${BASH_REMATCH[2]} ${BASH_REMATCH[1]}"

    else
        LOCAL_UNMUNGED_ARTIST_SUBDIR=$ARTIST_SUBDIR
    fi

    eval "$REF=\"\$LOCAL_UNMUNGED_ARTIST_SUBDIR\""
}

unpack_format_ytdlp()
{
    OLD_TRACKNO=1
    OLD_TRACK=${BASH_REMATCH[1]}
}

unpack_format_standard_various()
{
    OLD_TRACKNO=${BASH_REMATCH[1]}
    OLD_TRACK=${BASH_REMATCH[2]}
}

unpack_format_standard()
{
    OLD_TRACKNO=${BASH_REMATCH[1]}
    OLD_TRACK=${BASH_REMATCH[2]}
}

unpack_format_unknown()
{
    OLD_TRACKNO=1
    OLD_TRACK=${BASH_REMATCH[1]}
}

help()
{
    local PROGNAME

    miniade_get_progname PROGNAME

    echo "$PROGNAME [ <standard-options> ] { <artist-dir> | <album-dir> | <track-file> } ..." >&2
    exit 1
}

main "$@"