#!/bin/sh
# SPDX-FileCopyrightText:  2023-2024 The Remph <lhr@disroot.org>
# SPDX-License-Identifier: FSFULLRWD

wobfifo=${XDG_RUNTIME_DIR:-${TMPDIR:-/tmp}}/wob
readonly wobfifo
set -o pipefail -e	# `set -e' comes after readonly and pipefail, they
			# aren't vital enough to kill the script for

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

	# temporary fifo (call mkfifo(1) asap to minimise possibility of races)
	# TODO: should this be in C, so we can call mkfifo(2) and check for
	# EEXIST, rather than using test(1)? Alternatively, there is flock(1),
	# or any other IPC or SHM system
	mkfifo -m600 "$wobfifo"

	default_wobini=
	for dir in ${XDG_CONFIG_HOME:+"$XDG_CONFIG_HOME"} ~/.config /etc; do
		if test -r "$dir"/wob/wob.ini; then
			default_wobini="$dir"/wob/wob.ini
			break
		fi
	done

	# temporary wob.ini(5) file, to set wob colours
	wobini=`mktemp`
	{
		# This order means that a user can change the styles in
		# their own config if they like
		printf '[style.mute]\nbackground_color = af0000\n\n'
		cat - ${default_wobini:+"$default_wobini"} <<EOF
[style.volume]
background_color = 000000
[style.mute]
background_color = af0000
[style.brightness]
background_color = a89800

EOF
	} >$wobini

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

do_cmd_get_percent() {
	case $1 in
		volume|vol)
			amixer sset Master "$2" | 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
/\[off\]/ {
	g
	s/$/ mute/
	b
}
# else
g
s/$/ volume/
'		;;
		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 ##

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 $!