#!/bin/sh

#{{{ printhelp
printhelp () {
  printf "amg: Auto Music Grabber; script to download, format, and tag music.\n"
  printf "  -h) prints this help message.\n"
  printf "  -u X) uses X for the URL to download from.\n"
  printf "  -s) processes the url as a single track as a single song.\n"
  printf "  -l) processes the url as a single track as an album.\n"
  printf "  -p) processes the yrk as a playlist as an album.\n"
  printf "  -a X) sets the artist name to X.\n"
  printf "  -A X) sets the album name to X.\n"
  printf "  -t X) sets the track name to X (only for a single song).\n"
  printf "  -T X) sets the track number to X (only for a single song).\n"
  printf "  -y X) sets the date to X.\n"
  exit
}
#}}}

#{{{ getopts
unset ALBUM ARTIST MODE TITLE TRACKNUM YEAR
while getopts "hslpu:a:A:t:T:y:" arg; do case "${arg}" in
  s) MODE='single' ;;
  l) MODE='split' ;;
  p) MODE='album' ;;
  u) URL="$OPTARG" ;;
  a) ARTIST="$OPTARG" ;;
  A) ALBUM="$OPTARG" ;;
  t) TITLE="$OPTARG" ;;
  T) TRACKNUM="$OPTARG" ;;
  y) YEAR="$OPTARG" ;;
  *) printhelp ;;
esac done
#}}}

#{{{ print given args
printf "Received Tags:
Artist: %s
Album: %s
Song: %s
Number: %s
Year: %s\n\n" "$ARTIST" "$ALBUM" "$TITLE" "$TRACKNUM" "$YEAR"
#}}}

#{{{ fill in missing variables
# prompt to determine later tagging
if [ -z "$MODE" ]; then
  printf "Will the link be for a [p]laylist, a[l]bum video, or [s]ong video? "
  read -r RESPONSE
  case "$RESPONSE" in
    p) MODE='album' ;;
    l) MODE='split' ;;
    s) MODE='single' ;;
    *) printhelp ;;
  esac
  printf "\n"
fi

# prompt to get the URL
if [ -z "$URL" ]; then
  printf "Enter the link: "
  read -r URL
  printf "\n"
fi
#}}}

#{{{ base logic for certain modes
# if song, don't download playlist
case "$MODE" in
  s)
    NO_PLAYLIST="yes"
    ;;
  l)
    NO_PLAYLIST="yes"
    unset TITLE TRACKNUM
    ;;
  p)
    unset TITLE TRACKNUM
    ;;
esac
#}}}

#{{{ download the video(s)
printf "Starting download...\n\n"
if [ "$(find . | wc -l)" -gt 0 ]; then
  printf "Already downloaded\n"
else
  yt-dlp ${NO_PLAYLIST:+"--no-playlist"} --format bestaudio --restrict-filenames "$URL"
fi
printf "Download stopped.\n\n"
#}}}

#{{{ while loop to remove files from list
printf "\n\nDo you want to remove any tracks?\n\n"
while true; do
  find . | nl
  printf "Enter the line number of the file to remove:\n"
  read -r WHILE_RESPONSE
  [ -z "$WHILE_RESPONSE" ] && break
  rm -rf "$(find . | head -n "$WHILE_RESPONSE" | tail -1)"
done
#}}}

#{{{ convert the downloaded files to mp3
printf "\n\nStarting to convert files..."
for i in *.m4a *.webm; do
  imp3=$(echo "$i" | sed 's/\.m4a$/.mp3/;s/\.webm$/.mp3/')
  [ ! -f "$imp3" ] && ffmpeg -i "$i" -acodec mp3 "$imp3" || echo "File not converted"
done
printf "Finished converting files.\n\n"
#}}}

#{{{ tag files
printf "\n\n"
for file in *.mp3; do
  printf "%s\n" "$file"
  if [ -z "$ARTIST" ]; then
    printf "\nWho is the artist? "
    read -r ARTIST
  fi
  if [ -z "$ALBUM" ]; then
    printf "\nWhat is the album? "
    read -r ALBUM
  fi
  if [ -z "$TITLE" ]; then
    printf "\nWhat is the title? "
    read -r TITLE
  fi
  if [ -z "$TRACKNUM" ]; then
    printf "\nWhat is the track number? "
    read -r TRACKNUM_
    TRACKNUM="$(printf "%02d" "$TRACKNUM_")"
    unset TRACKNUM_
  fi
  if [ -z "$YEAR" ]; then
    printf "\nWhat is the release date? "
    read -r YEAR
  fi
  case "$TRACKNUM" in
    [!0-9]*)
      unset TRACKNUM
      printf "\n%s doesn't look like a track number!\n" "$TRACKNUM" 1>&2
      ;;
  esac
  FMT_ARTIST="$(echo "$ARTIST" | sed "s/[^[:alnum:].-]/_/g")"
  FMT_ALBUM="$(echo "$ALBUM" | sed "s/[^[:alnum:].-]/_/g")"
  FMT_TITLE="$(echo "$TITLE" | sed "s/[^[:alnum:].-]/_/g")"
  [ -n "$ARTIST" ] && kid3-cli -c "set \"Artist\" \"$ARTIST\"" "$file"
  [ -n "$ALBUM" ]  && kid3-cli -c "set \"Album\" \"$ALBUM\"" "$file"
  [ -n "$TITLE" ] && kid3-cli -c "set \"Title\" \"$TITLE\"" "$file"
  [ -n "$TRACKNUM" ] && kid3-cli -c "set \"Track Number\" \"$TRACKNUM\"" "$file"
  [ -n "$YEAR" ] && kid3-cli -c "set \"Date\" \"$YEAR\"" "$file"
  printf "\n\n%s\n" "$file"
  kid3-cli -c get "$file"
  NEWFILENAME="${FMT_ARTIST}_-_${FMT_ALBUM}_-_${TRACKNUM:-00}_${FMT_TITLE}.mp3"
  #NEWFILENAME="$(printf "%s" "$NEWFILENAME" | sed 's/ /_/g;s/[!@#$%^&*()-_=+{}\|;:,.<>/?`~'"\[\]\'\""']//g')"
  [ -n "${ARTIST}" ] && [ -n "${ALBUM}" ] && [ -n "${TITLE}" ] && mv "$file" "$NEWFILENAME"
  unset TITLE TRACKNUM
  printf "%s\n\n\n" "$NEWFILENAME"
done

printf "\n\nDone.\n"
#}}}