#!/usr/bin/env bash

# Rate the currently playing song in mpd.
#
# Under the hood, this simply appends the playing song to the
# $playlist_directory/$N-star.m3u playlist.
#
# If rating = 0,
#     then clear it from all playlists
# Else if 1 <= rating <= 5,
#     then clear it from all playlists,
#     and add it to ${rating}-star.m3u
# Else, error out
#
# Usage: rate [N]

if (( $# != 1 )); then
    echo "Usage: rate [N]"
    exit 1
fi

rating="$1"
playlistdir=$(awk '/playlist_directory/ { print gensub(/"/, "", "g", $2); }' "$HOME/.config/mpd/mpd.conf")
playlistdir="${playlistdir/#\~/$HOME}"
currentsong=$(mpc current -f '%file%')
if [[ -z "$currentsong" ]]; then
    >&2 echo 'Nothing is playing!'
    exit 1
fi

#
_clearPlaylists() {
    # Remove the song from other playlists
    for playlist in "${playlistdir}/"*-star.m3u; do
        if grep "^$1$" "$playlist" >/dev/null; then
            sed -i "\#^$1\$#d" "$playlist"
        fi
    done
}

#
target="${playlistdir}/${rating}-star.m3u"

if (( rating == 0 )); then
    _clearPlaylists "$currentsong"
    echo "Rating cleared"
elif [[ ! -f "$target" ]]; then
    >&2 echo "Not a valid rating, must be between 0-5!"
    exit 2
elif ! grep "^${currentsong}$" "$target" >/dev/null; then
    _clearPlaylists "$currentsong"
    echo "$currentsong" >> "$target"
fi

# Display new rating
stars=""
star_filled_icon="★"
star_empty_icon="☆"
for ((i=1;i<=5;i++)); do
    if (( "$rating" >= "$i" )); then
        stars="${stars}${star_filled_icon}"
    else
        stars="${stars}${star_empty_icon}"
    fi
done
echo "($stars) $currentsong"