volume-control

#!/usr/bin/env bash

# ./volume-control
#
# see --help for usage
#
# example:
#   ./script --card 1 --toggle
#   ./script -t
#   ./script -i 5
#   ./script -d 5
#
# depends: amixer
# optional depends: dzen2, dbar (for --dzen)
# author: @qbbr

# for --dzen only
readonly DZEN_FONT="hack-10"
readonly DZEN_BG="#b58900"
readonly DZEN_FG="#fdf6e3"
readonly DZEN_WIDTH=272

usage() {
	echo "Usage: ${0##*/} [option] [argument]"
	echo
	echo "Options:"
	echo "	-c, --card      - set card, optional [default=1]"
	echo "	-t, --toggle    - toggle mute on/off"
	echo "	-i, --increment - increment by argument in percent"
	echo "	-d, --decrement - decrement by argument in percent"
	echo "	-m, --max       - set volume to max"
	echo "	--dzen          - show dbar in dzen2"
	echo "	-h, --help      - display this help and exit"
	exit 0
}

fail() {
	echo "$1"
	exit 1
}

POSITIONAL=()

while [[ $# -gt 0 ]]; do
	key="$1"

	case ${key} in
		-c|--card)
			CARD_ARG="-c $2"
			shift # past argument
			shift # past value
		;;
		-t|--toggle)
			CMD="toggle"
			shift # past argument
			;;
		-i|--increment)
			CMD="${2}%+"
			shift
			shift
			;;
		-d|--decrement)
			CMD="${2}%-"
			shift
			shift
			;;
		-m|--max)
			CMD="100%"
			shift
			;;
		--dzen)
			SHOW_DZEN2=1
			shift
			;;
		-h|--help)
			usage
			;;
		*) # unknown option
			POSITIONAL+=("$1") # save it in an array for later
			shift # past argument
			;;
	esac
done

set -- "${POSITIONAL[@]}" # restore positional parameter

if [[ -z "${CMD}" ]] || [[ "${CMD}" == "%+" ]] || [[ "${CMD}" == "%-" ]]; then
	fail "nothing to do, see --help"
fi

SCONTROL="Master"
SCONTROL_HEADPHONE="Headphone"

call_amixer() {
	amixer ${CARD_ARG} -D pulse $@
}

# use Headphone if it is on and Master is switch off
[[ "${CMD}" != "toggle" ]] \
&& [[ -n "$(echo $(call_amixer get ${SCONTROL}) | grep '\[off\]')" ]] \
&& [[ -n "$(echo $(call_amixer get ${SCONTROL_HEADPHONE}) | grep '\[on\]')" ]] \
&& SCONTROL="${SCONTROL_HEADPHONE}"

output="$(echo $(call_amixer set ${SCONTROL} ${CMD}) | tail -n 1)"

if [[ -z "${SHOW_DZEN2}" ]]; then
	exit 0
fi

PIPE_FILE="/tmp/pipe-${0##*/}"
# calculate center
SCREEN_SIZE=$(xdpyinfo | grep dimensions | cut -d ' ' -f 7)
SCREEN_WIDTH=$(echo ${SCREEN_SIZE} | cut -d 'x' -f 1)
SCREEN_HEIGHT=$(echo ${SCREEN_SIZE} | cut -d 'x' -f 2)
((XPOS = SCREEN_WIDTH / 2 - DZEN_WIDTH / 2))
((YPOS = SCREEN_HEIGHT / 2))

if [[ -n "$(echo ${output} | grep '\[off\]')" ]]; then
	vol="0"
else
	vol="$(echo ${output} | cut -d '[' -f 2 | tr -d '[%]]')"
fi

# prevents multiple dzen instance
if [[ ! -e "${PIPE_FILE}" ]]; then
	mkfifo "${PIPE_FILE}"
	(dzen2 -l 1 -x "${XPOS}" -y "${YPOS}" -w "${DZEN_WIDTH}" -fn "${DZEN_FONT}" -bg "${DZEN_BG}" -fg "${DZEN_FG}" -e 'onstart=uncollapse' < "${PIPE_FILE}"; rm -f "${PIPE_FILE}") &
fi

(echo "Volume (${SCONTROL})" ; echo "${vol}" | dbar ; sleep 1) > "${PIPE_FILE}"