Script for MPD notifications using gdbus and mpc

mpd_notifs.sh

#!/bin/sh
notify () {
	echo "$(gdbus call --session \
		--dest org.freedesktop.Notifications \
		--object-path /org/freedesktop/Notifications \
		--method org.freedesktop.Notifications.Notify \
		MPD \
		$1 \
		"" \
		"Now Playing:" \
		"${currentsong[0]} - ${currentsong[2]}" \
		[] \
		"{\"image-path\":<string '$2'>}" \
		5000
	)"
}
getSong () {
    songinfo="$(mpc current --format "%artist%;%album%;%title%;%file%")"
	IFS=";" # use ; as delimiter
	read -ra nowplaying <<< "$songinfo" # read to nowplaying array, since bash cant return one.
}

gdbus monitor --session --dest org.freedesktop.Notifications > /tmp/mpd-notif-gdbmon & # redirect out to tmp file, detach

getSong # update nowplaying
oldsong=( ${nowplaying[@]} ) # copy nowplaying
id=0

while "true" ; do
	getSong
	currentsong=( ${nowplaying[@]} )
    
	if [[ ${currentsong[@]} != ${oldsong[@]} ]] ; then

		if [ -n ${currentsong[1]} ] ; then # if no album name, use artist+song name for thumb file instead
			preview="$HOME/.config/mpd/previews/$(echo "${currentsong[0]}${currentsong[2]}" | basenc --base64url).png"
		else
			preview="$HOME/.config/mpd/previews/$(echo "${currentsong[1]}" | basenc --base64url).png"
		fi

        # generate thumb
		[ -e "$preview" ] || ffmpeg -y -i "$HOME/Music/${currentsong[3]}"  -an -vf scale=256:256 "$preview" > /dev/null 2>&1

		oldsong=(${currentsong[@]})

        # check if notif id is invalid.
		if [ -n "$(grep --binary-files=text "uint32 $id, uint32 1" /tmp/mpd-notif-gdbmon)" ] ; then
		   id=0
		fi

        # send notification, update id.
        id="$(notify $id $preview)"
        id="$(echo "$id" | sed -e "s/^(uint32 //" -e "s/,)$//")"
	fi

    mpc idle player > /dev/null # block till player state changes.
done