#!/usr/bin/env bash
# Craig Jennings <c@cjennings.net>
# Basically just a bash wrapper around a find/grep/awk command pipe
# to generate m3u playlists from video or audio files in a directory.

# One m3u playlist will be placed in the MUSIC_DIR, and another
# will be placed inside each playlist directory.
# It also converts .opus and .ogg files to .m4a for Android playback.

# Note:
# This script requires the following utilities to be on the path:
# mid3v2 (aur package: python-mutagen)
# tageditor (aur package: tageditor)
# metaflac (aur package: flac)

set -e

MUSIC_DIR="$HOME/music"
# REQUIRED_TOOLS=("mid3v2" "tageditor")
REQUIRED_TOOLS=("mid3v2" "metaflac" "tageditor")

#  ---------------------------- Functions ----------------------------

usage () {
    printf "\nUsage: mkplaylist <playlist_name>\n\n"
    printf "mkplaylist - creates an m3u playlist in the $MUSIC_DIR directory\n"
    printf "based the music and video files in directory which m3uplaylist is called.\n\n"
    printf " - this script should be run in the directory containing the music or video files\n"
    printf " - <playlist_name> is mandatory and shouldn't end with '.m3u' extension\n"
    printf " - change the destination ($MUSIC_DIR) by editing this script\n\n"
}

tag_music_file() {
  while IFS= read -r file; do
    filename=$(basename "$file")
    extension="${filename##*.}"
    artist=$(basename "$file" | cut -d '-' -f 1)
    title=$(basename "$file" | cut -d '-' -f 2- | cut -d '.' -f 1)
    outputfile="$(dirname "$file")/$title.flac"

    # If file is not already flac, convert it
    if [ "$extension" != "flac" ]; then

      # Delete all tags using mid3v2
      mid3v2 --delete-all "$file"
      ffmpeg -i "$file" -vn -c:a flac "$outputfile"
      file="$outputfile"  # Now we're working with the new FLAC file

    fi

    # Set artist and song title tags using metaflac
    metaflac --set-tag="ARTIST=$artist" --set-tag="TITLE=$title" "$file"

   done
}

# tag_music_file() {
#     while IFS= read -r file; do
#         filename=$(basename "$file")
#         extension="${filename##*.}"
#         artist=$(basename "$file" | cut -d '-' -f 1)
#         title=$(basename "$file" | cut -d '-' -f 2- | cut -d '.' -f 1)
#         outputfile="$(dirname "$file")/$title.flac"

#         # Delete all tags using mid3v2
#         mid3v2 --delete-all "$file"

#         # If file is not already flac, convert it
#         if [ "$extension" != "flac" ]; then
#             ffmpeg -i "$file" -vn -c:a flac "$outputfile"
#             file="$outputfile"  # Now we're working with the new FLAC file
#         fi

#         # Set artist and song title tags using metaflac
#         metaflac --set-tag="ARTIST=$artist" --set-tag="TITLE=$title" "$file"
#     done
# }

# tag_music_file() {
#     while IFS= read -r file; do
#         # Extract artist and song title from filename
#         artist=$(basename "$file" | cut -d '-' -f 1)
#         title=$(basename "$file" | cut -d '-' -f 2- | cut -d '.' -f 1)
#         outputfile="$(dirname "$file")/$title.flac"

#         # Delete all tags using mid3v2
#         mid3v2 --delete-all "$file"

#         # Convert to flac and save to new file
#         ffmpeg -i "$file" -vn -c:a flac "$outputfile"

#         # Set artist and song title tags using metaflac
#         metaflac --set-tag="ARTIST=$artist" --set-tag="TITLE=$title" "$outputfile"
#     done
# }

# tag_music_file() {
#     while IFS= read -r file; do
#         # Extract artist and song title from filename
#         artist=$(basename "$file" | cut -d '-' -f 1)
#         title=$(basename "$file" | cut -d '-' -f 2 | cut -d '.' -f 1)
#         outputfile="$(dirname "$file")/$title.flac"

#         # Delete all tags using mid3v2
#         mid3v2 --delete-all "$file"

#         # Set artist and song title tags using mid3v2
#         mid3v2 --artist="$artist" --song="$title" "$file"
#         # Convert to flac and save to new file
#         ffmpeg -i "$file" -vn -c:a flac "$outputfile"
#     done
# }

# tag_music_file() {
#     while IFS= read -r file; do
#         # Extract artist and song title from filename
#         artist=$(basename "$file" | cut -d '-' -f 1)
#         title=$(basename "$file" | cut -d '-' -f 2 | cut -d '.' -f 1)

#         # Delete all tags using mid3v2
#         mid3v2 --delete-all "$file"

#         # Set artist and song title tags using mid3v2
#         mid3v2 --artist="$artist" --song="$title" "$file"
#     done
# }

 generate_music_m3u() {
     printf "retagging music files....\n"
     find "$(pwd)" -print | file -if - | grep -E '(audio)' | awk -F: '{print $1}' | tag_music_file

     printf "generating playlist.'%s'...\n" "$LOCAL_PLAYLIST"
     find "$(pwd)" -print | file -if - | grep -E '(video|audio)' |
         awk -F: '{print $1}' | while read -r line; do basename "$line"; done > "$LOCAL_PLAYLIST"
     printf "generating playlist '%s'....\n" "$MUSIC_PLAYLIST"
     find "$(pwd)" -print | file -if - | grep -E '(video|audio)' | awk -F: '{print $1}' > "$MUSIC_PLAYLIST"
     printf "Done.\n\n"
 }

 #  ----------------------------- Script ----------------------------

 # display usage if user specifically requests it
 TYPE=$(tr '[a-z]' '[A-Z]' <<< "$@");
 [ "$TYPE" = "HELP" ] && usage && exit 1
 [ "$TYPE" = "-H" ] &&  usage&& exit 1

 # check that all necessary tools are installed
 for tool in ${REQUIRED_TOOLS[@]}; do
     if ! type "$tool" >/dev/null 2>&1; then
         printf "ERROR: The script requires '%s' but it is not installed or not in PATH.\n" "$tool"
         exit 1
     fi
 done

 # use directory name for playlist name when parameter doesn't exist
 if [ $# -eq 0 ]
 then
     set -- "$(basename "$PWD")"
     echo "no playlist name entered, so using directory name: '$(basename "$PWD")'"
 fi

 # ask to overwrite if the playlist already exists
 MUSIC_PLAYLIST="$MUSIC_DIR/$@.m3u"
 LOCAL_PLAYLIST="./$@.m3u"

 if [ -f "$MUSIC_PLAYLIST" ]; then
     read -p "$MUSIC_PLAYLIST exists. Overwrite (y/n) " yn
     if [ "$yn" != "y" ] && [ "$yn" != "Y" ]; then
         exit 0
     fi
 fi

 generate_music_m3u