#!/bin/sh -e
# Based on:
# 	https://wiki.archlinux.org/title/Ncmpcpp#With_album_art

# Sends notification of currently playing MPD music with album cover art.
# Dependencies:
# 	mpc
# 	ffmpeg
# 	notify-send
# 	and my other script, notify-replace.
# 	recommended: a home directory setup with xdg-user-dirs (for finding your
# 	music directory
# For notification on song change:
# 	Assign execute_on_song_change to this script in ncmpcpp's config file.
# For notification on media keys:
# 	Bind media key to a call to mpc with the approprite command.

# exit early if we're in tty
if [ -z "$WAYLAND_DISPLAY" ] && [ -z "$DISPLAY" ]; then
	exit 2
fi

# globals
command="$1"
use_preview=0

# defaults
# FEATURE: make defaults configurable through flags
preview_dir="${XDG_CONFIG_HOME:-$HOME/.config}/mpc/previews"
preview_width=64
preview_height=64
default_song_icon="media-playback-start"

# issue an mpc command based on arguments and assemble notification message
case "$command" in
"")
	# use defaults
	song_head="Now Playing"
	use_preview=1
	;;
"toggle")
	mpc -q toggle
	state="$(mpc status %state%)"
	case "$state" in
	"playing")
		song_head="Now Playing"
		use_preview=1
		;;
	"paused")
		song_head="Paused"
		song_icon="media-playback-pause"
		;;
	esac
	;;
"shuffle")
	mpc -q shuffle
	song_head="Shuffled Playlist"
	song_icon="media-playlist-shuffle"
	;;
"single")
	mpc -q single
	state="$(mpc status %single%)"
	case "$state" in
	"on")
		song_head="Single Mode: On";;
	"once")
		song_head="Single Mode: Once";;
	"off")
		song_head="Single Mode: Off";;
	esac
	song_icon="multimedia-player"
	;;
"random")
	mpc -q random
	state="$(mpc status %random%)"
	case "$state" in
	"on")
		song_head="Random Mode: On";;
	"off")
		song_head="Random Mode: Off";;
	esac
	song_icon="media-eject"
	;;
"repeat")
	mpc -q repeat
	state="$(mpc status %repeat%)"
	case "$state" in
	"on")
		song_head="Repeat Mode: On";;
	"off")
		song_head="Repeat Mode: Off";;
	esac
	song_icon="media-playlist-repeat"
	;;
*)
	mpc -q "$command"
	# don't notify if mpc changed song because ncmpcpp would notify on
	# song change anway
	[ "$command" = "next" ] || [ "$command" = "prev" ] && exit
	;;
esac

# use album preview for song icon
if [ "$use_preview" -eq 1 ]; then
	[ -d "$preview_dir" ] || mkdir -p "$preview_dir"

	# find xdg music directory
	# user-dirs.dirs is not guaranteed to exist
	# shellcheck disable=SC1091
	. "${XDG_CONFIG_HOME:-$HOME/.config}/user-dirs.dirs" 2>/dev/null || true
	xdg_music_dir="${XDG_MUSIC_DIR:-$HOME/Music}"

	# get preview filename
	song_filename="$(mpc --format "${xdg_music_dir}/%file%" current)"
	song_album="$(mpc --format %album% current)"
	if [ -z "$song_album" ]; then
		# fallback to default for empty album name
		song_icon="$default_song_icon"
	else
		preview_path="${preview_dir}/$(echo "$song_album" | base64).png"
		if [ -f "$preview_path" ]; then
			# use cached preview
			song_icon="$preview_path"
		elif ffmpeg -y -i "$song_filename" -an -vf \
			scale="${preview_width}:${preview_height}" \
			"$preview_path" >/dev/null 2>&1;
		then
			# or use generated preview
			song_icon="$preview_path"
		else
			song_dirname=$(dirname "$song_filename")
			if art_filename="$(find "$song_dirname" -type f |
				grep -Esm 1 '.*\.(jpg|png)')"
			then
				# or use scaled cover art from directory
				ffmpeg -y -i "$art_filename" -an -vf \
					scale="${preview_width}:${preview_height}" \
					"$preview_path" >/dev/null 2>&1;
				song_icon="$preview_path"
			else
				# or fallback to default icon
				song_icon="$default_song_icon"
			fi
		fi
		unset song_dirname
	fi
	unset preview_path
fi
unset xdg_music_dir song_filename song_album

# send the actual notification
song_body="$(mpc --format '[%title%[ \n%artist% - %album%]]|[%file%]' current)"
notify-replace 'mpc-notify' "$song_head" "$song_body" -i "$song_icon" -u low

# cleanup
unset command preview_dir preview_width preview_height default_song_icon \
	use_preview song_head song_body song_icon