xrandr-smart

#!/usr/bin/env bash

# Wrapper around xrandr which allows shell globs in --output and automatically
# disables all other outputs.
#
# see https://work.lisk.in/2020/10/11/xrandr-ux.html

set -eu -o pipefail

export LC_ALL=C

unset xrandr_query

function o { printf -->&2 "%s:%s\\n" "${0##*/}" "$(printf " %q" "$@")"; "$@"; }

function get-xrandr-query {
	[[ "${xrandr_query-}" ]] && return

	xrandr_query=$(xrandr --query)
}

function get-xrandr-outputs {
	<<<"$xrandr_query" grep -P -o '^([\w-]+)(?= (dis)?connected)'
}

function get-xrandr-connected-outputs {
	<<<"$xrandr_query" grep -P -o '^([\w-]+)(?= connected)'
}

function get-xrandr-outputs-except {
	get-xrandr-outputs | grep -F -v -x -f <(printf "%s\n" "$@")
}

function find-one {
	local tmp one=

	while read -r tmp; do
		# shellcheck disable=SC2053
		if [[ $tmp == $1 ]]; then
			[[ $one ]] && return 1
			one="$tmp"
		fi
	done

	[[ $one ]] && printf "%s\n" "$one"
}

function find-xrandr-output { get-xrandr-outputs | find-one "$1"; }
function find-xrandr-connected-output { get-xrandr-connected-outputs | find-one "$1"; }

function xrandr-auto-off {
	local -a outputs=()
	local output
	local -a args=()
	local arg

	while (( $# )); do
		arg="$1"; shift
		args+=("$arg")

		[[ $arg == --output ]] && outputs+=("$1")
	done

	if ! (( ${outputs[@]+${#outputs[@]}} )); then
		printf -->&2 "Aborting, would disable all outputs.\n"
		exit 1
	fi

	for output in $(get-xrandr-outputs-except ${outputs[@]+"${outputs[@]}"}); do
		args+=(--output "$output" --off)
	done

	o xrandr "${args[@]}"
}

function xrandr-auto-find {
	local -a args=()
	local arg

	while (( $# )); do
		arg="$1"; shift
		args+=("$arg")

		if [[ $arg == --@(output|left-of|right-of|above|below|same-as) ]] && (( $# )); then
			arg="$1"; shift
			arg=$(find-xrandr-connected-output "$arg")
			args+=("$arg")
		fi
	done

	o xrandr-auto-off "${args[@]}"
}

get-xrandr-query

# skip main if sourced
return 0 2>/dev/null || :

if (( ! $# )); then
	echo "Usage: xmonad-smart --output …"
	exit 1
fi

xrandr-auto-find "$@"