#!/bin/sh
# SPDX-FileCopyrightText:  2023-2025 The Remph <lhr@disroot.org>
# SPDX-License-Identifier: GPL-3.0-or-later

set ${BASH_VERSION:+-o pipefail} -efu

# $wobdir is a `wrapper' directory that prevents a race between `test -p
# $wobfifo` and `>$wobfifo', during which $wobfifo can be removed, causing
# it to be created again as a regular file. If the removal also removes the
# parent directory $wobdir, then sh's > operator can't creat(2). Of course,
# the race could still happen between removing $wobfifo and $wobdir, but
# this is less likely.
wobdir=$XDG_RUNTIME_DIR/swob.$WAYLAND_DISPLAY

wobfifo=$wobdir/pipe wobini= SWOB_AUDIO= SWOB_MAX_VOLUME=${SWOB_MAX_VOLUME:-100}

scan_confdirs() {
	for dir in ${XDG_CONFIG_HOME:+"$XDG_CONFIG_HOME"} ~/.config /etc "${0%/*}"/../etc; do
		test -d "$dir"/swob || continue
		if test -z "$wobini" -a -r "$dir"/swob/wob.ini; then
			wobini=$dir/swob/wob.ini
		fi
		if test -z "$SWOB_AUDIO" -a -r "$dir"/swob/audio; then
			SWOB_AUDIO=`cat "$dir"/swob/audio`
		fi
		if test -n "$wobini" -a -n "$SWOB_AUDIO"; then
			return
		fi
	done
}

new_wobini() {
	# fine, I will make my own wob.ini(5)
	wobini=${XDG_CONFIG_HOME:-~/.config}/swob/wob.ini
	echo >&2 "$0: no swob/wob.ini found; writing default to $wobini"
	mkdir -p "${wobini%/*}"
	cat >$wobini <<EOF
[style.volume]
background_color = 000000

[style.mute]
background_color = af0000

[style.brightness]
background_color = a89800
EOF
}

start_wob() {
	if test -p "$wobfifo"; then
		return	# Already started
	fi

	rm -rf "$wobdir" # clear the decks

	# temporary fifo (call mkfifo(1) asap to minimise possibility of races)
	mkdir "$wobdir"
	mkfifo -m600 "$wobfifo"

	test -n "$wobini" || new_wobini

	# spawn wob process with temporary file(s)
	{
		trap 'rm -r "$wobdir"' 0
		# Don't `exec' wob here, else the trap won't work
		wob -c "$wobini" <$wobfifo
	} &
}

glob_match() {
	# MUST be called with set +f
	test $# -gt 1 -o -e "$1"
}

select_audio() {
	# could guess at /run/user/`id -u`, but let's not jump the gun here
	sound_sys=$1 rundir=${2:-$XDG_RUNTIME_DIR} tool=$3
	test -n "$rundir"	&&
		glob_match "$rundir/$sound_sys"*	&&
		command -v "$tool" >/dev/null 2>&1	&&
		SWOB_AUDIO=$sound_sys
}

get_audio_type() {
	# MUST be called with set +fu

	case $SWOB_AUDIO in
	pipewire|pulse|alsa)	return ;;
	'')	;;
	*)	echo >&2 "$0: warning: unrecognised SWOB_AUDIO: $SWOB_AUDIO" ;;
	esac

	select_audio pipewire	"$PIPEWIRE_RUNTIME_DIR"	wpctl	&& return
	select_audio pulse	"$PULSE_RUNTIME_PATH"	pactl	&& return
	SWOB_AUDIO=alsa # default to ALSA
}

set_vol() {
	set +fu
	get_audio_type
	set -fu

	case $SWOB_AUDIO in
	pipewire)
		case $1 in
		toggle)	to_set=mute ;;
		*)	to_set="volume -l $(awk -v percent="$SWOB_MAX_VOLUME" 'BEGIN{printf "%.1f", percent/100}')" ;;
		esac
		wpctl set-$to_set @DEFAULT_AUDIO_SINK@ "$1"
		wpctl get-volume @DEFAULT_AUDIO_SINK@ | sed -E \
			-e 's/^Volume: ([0-9]+)\.([0-9][0-9])/\1\2/'	\
			-e 's/\[MUTED\]/mute/'
		;;

	pulse)
		case $1 in
		toggle)	to_set=mute ;;
		*)	to_set=volume ;;
		esac
		sign="${1:(-1)}"
		percent=`pactl get-sink-volume @DEFAULT_SINK@ | sed -En 's/.* ([0-9]+)%.*/\1/p'`

		if test "$to_set" = "mute" \
			-o \( "$percent" -lt "$SWOB_MAX_VOLUME" \) \
			-o \( "$percent" -eq "$SWOB_MAX_VOLUME" -a "$sign" = "-" \); then
			pactl set-sink-$to_set @DEFAULT_SINK@ "$(echo "$1" | sed -E 's/(.*)([+-])$/\2\1/')"
		else
			pactl set-sink-$to_set @DEFAULT_SINK@ "${SWOB_MAX_VOLUME}%"
		fi

		mute_cmd='pactl get-sink-mute @DEFAULT_SINK@'
		mute_out=`$mute_cmd`
		case $mute_out in
		'Mute: yes')	muted=1 ;;
		'Mute: no')	muted= ;;
		*)	echo >&2 "$0: warning: bad output from $mute_cmd: $mute_out" ;;
		esac
		echo "$percent ${muted:+mute}"
		;;

	*)
		if test "$SWOB_AUDIO" != alsa; then
			echo >&2 "$0: WARNING: internal inconsistency! SWOB_AUDIO: \`$SWOB_AUDIO'"
		fi

		amixer sset Master "$1" | sed -E '
# Extract percentage, keep original line for later
h
s/.*\[([0-9]+)%\].*/\1/
t match
d

: match
# Get original line back
x
# Test if audio is muted
/\[off\]/ {
	x
	s/$/ mute/
	b
}
# else
x
s/$/ volume/'
		;;
	esac
}

do_cmd_get_percent() {
	case $1 in
	volume|vol)
		set_vol "$2"
		;;
	brightness|brt)
		brightnessctl -m set "$2" | sed -En 's/(.*[^0-9])?([0-9]+)%.*/\2 brightness/p'
		;;
	*)
		echo >&2 "$0: error: unrecognised argument: $target"
		exit -1
		;;
	esac
}

## MAIN ##

scan_confdirs
start_wob

{
	do_cmd_get_percent "$@"
	sleep 3	# Needs to be long enough that there aren't too many wob(1)
		# processes spawned and respawned consecutively on repeated
		# taps, but short enough that there aren't too many /bin/sh
		# processes hanging around simultaneously running sleep(1)
		# from this script! 3 seconds is an uneducated guess.
} >$wobfifo

# Don't let wob die if it's still receiving input from another process; wait
# until it says it's finished
# To solve the above mentioned problem of too many /bin/sh processes hanging
# around, we could setsid(1) wob so the script can exit without waiting as
# soon as it's done sleeping (the existing situation is that as long as one
# script sleeps, the shell that spawned the wob process will wait until that
# sleep is done)
test -z ${!-} || wait $! # surprisingly, $! could be unset (not just zero-length)