gettags() {
  ffprobe -v error -show_entries format_tags -print_format json "$1" |
    $JQ -r --compact-output '.format.tags | {
      trackid: (."MusicBrainz Release Track Id" // ."MUSICBRAINZ_RELEASETRACKID" // ."MusicBrainz/Release Track Id" // ""),
      releaseid: (."MusicBrainz Album Id" // ."MUSICBRAINZ_ALBUMID" // ."MusicBrainz/Album Id" // "")
    }'
}

# Read music files in specified directory and create json file that points to
# all relevant MusicBrainz IDs.
# @input $1: Path to directory with album
decorate() {
  if [ -f "$1/$DECORATION_FILENAME" ]; then
    info "Directory $1 has already been decorated (skipping)"
    return 0
  fi
  decoration=$($JQ -n '.tracks = {}')
  tmpf=$(mktemp)
  (cd "$1" && find . -type f -iname '*.mp3' -o -iname '*.mp4' -o -iname '*.flac' -o -iname '*.m4a') >"$tmpf"
  while IFS= read -r f; do
    mbid=$(gettags "$1/$f")
    rid=$(echo "$mbid" | $JQ -r '.releaseid')
    tid=$(echo "$mbid" | $JQ -r '.trackid')
    if [ ! "$rid" ] || [ ! "$tid" ]; then
      err "File $f: Seems not tagged"
      releaseid=""
      break
    fi
    if [ "${releaseid:-}" ]; then
      if [ "$releaseid" != "$rid" ]; then
        err "Directory $1 contains files of different releases"
        releaseid=""
        break
      fi
    else
      info "Decorating $1 as release $rid"
      releaseid="$rid"
    fi
    decoration=$(echo "$decoration" | $JQ ".tracks += {\"$tid\": \"$f\"}")
  done <"$tmpf"
  rm -f "$tmpf"
  if [ "$releaseid" ]; then
    echo "$decoration" | $JQ --compact-output ".releaseid = \"$releaseid\"" >"$1/$DECORATION_FILENAME"
  else
    return 1
  fi
}

# Load missing cache entries (batch mode)
# argument $1: type
# argument $2: File with one ID per line
__batch_load_missing() {
  tmpf=$(mktemp)
  while IFS= read -r mbid; do
    if ! in_cache "$1" "$mbid"; then
      echo "$mbid" >>"$tmpf"
    fi
  done <"$2"
  if [ -s "$tmpf" ]; then
    lines=$(wc -l "$tmpf" | cut -d ' ' -f 1)
    if [ "$lines" -gt 0 ]; then
      case "$1" in
      "$TYPE_ARTIST")
        tt="artists"
        ;;
      "$TYPE_RELEASEGROUP")
        tt="release groups"
        ;;
      "$TYPE_RELEASE")
        tt="releases"
        ;;
      esac
      info "Fetching $lines missing $tt"
      cnt=0
      while IFS= read -r mbid; do
        case "$1" in
        "$TYPE_ARTIST")
          mb_artist "$mbid" >/dev/null
          ;;
        "$TYPE_RELEASEGROUP")
          mb_releasegroup "$mbid" >/dev/null
          ;;
        "$TYPE_RELEASE")
          mb_release "$mbid" >/dev/null
          ;;
        esac
        cnt=$((cnt + 1))
        printf "\033[K\r%d/%d (%s: %s)" "$cnt" "$lines" "$mbid" "$($JQ -r ".name // .title")"
        sleep 1
      done <"$tmpf"
      printf "\n"
    fi
  fi
  rm -f "$tmpf"
}

LOCALDATADIR="$HOME/.cache/$APP_NAME/local"
LOCALDATA_ARTISTS="$LOCALDATADIR/artists"
LOCALDATA_RELEASEGROUPS="$LOCALDATADIR/releasegroups"
LOCALDATA_RELEASES="$LOCALDATADIR/releases"

# Load local music
load_local() {
  [ -d "$LOCALDATADIR" ] || mkdir -p "$LOCALDATADIR"
  tmpreleases=$(mktemp)
  [ -f "$tmpreleases" ] || exit 1
  find "$MUSICDIR" -type f -name "$DECORATION_FILENAME" -print0 |
    xargs -0 -P 4 $JQ -r '.releaseid+"\t"+input_filename' |
    tee "$LOCALDATA_RELEASES" |
    cut -d "$(printf '\t')" -f 1 >"$tmpreleases"
  __batch_load_missing "$TYPE_RELEASE" "$tmpreleases"
  # Get release groups and album artists
  while IFS= read -r rid; do
    mb=$(mb_release "$rid")
    echo "$mb" | $JQ -r '."release-group".id' >>"$LOCALDATA_RELEASEGROUPS"
    echo "$mb" | $JQ -r '."release-group"."artist-credit" | map(.artist.id) | join("\n")' >>"$LOCALDATA_ARTISTS"
  done <"$tmpreleases"
  tf=$(mktemp)
  sort "$LOCALDATA_RELEASEGROUPS" | uniq >"$tf" && mv "$tf" "$LOCALDATA_RELEASEGROUPS"
  sort "$LOCALDATA_ARTISTS" | uniq >"$tf" && mv "$tf" "$LOCALDATA_ARTISTS"
  # Populate cache with missing data
  __batch_load_missing "$TYPE_RELEASEGROUP" "$LOCALDATA_RELEASEGROUPS"
  __batch_load_missing "$TYPE_ARTIST" "$LOCALDATA_ARTISTS"
  rm -f "$tmpreleases"
}

# List all releases
list_releases() {
  cut -d "$(printf '\t')" -f 1 "$LOCALDATA_RELEASES"
}

# List all release groups
list_releasegroups() {
  cat "$LOCALDATA_RELEASEGROUPS"
}

# List all album artists
list_artists() {
  cat "$LOCALDATA_ARTISTS"
}