#!/bin/bash

# Sanity checks:
if (( $# == 0 )); then
	echo -e "No arguments provided.\n\nUsage: env GAMECLASS='<executable>=<window class>' gameclass \033[1m[COMMAND]\033[0m..."
	exit 1
else
	if [[ -z ${GAMECLASS} ]]; then
		echo -e "No environment variable set.\n\nUsage: env \033[1mGAMECLASS='<executable>=<window class>'\033[0m gameclass [COMMAND]..."
		exit 1
	fi
fi

_get_variable_field() {
	echo "$GAMECLASS" | awk -v FIELD="$1" 'BEGIN { FS = "=" } ; { print $FIELD }'
}

EXE="$( _get_variable_field 1 )"
WM_CLASS="$( _get_variable_field 2 )"

if [[ -z "$EXE" ]] || [[ -z "$WM_CLASS" ]]; then
	echo -e "Incorrect environment variable formatting.\n\nUsage: env GAMECLASS='\033[1m<executable>=<window class>\033[0m' gameclass [COMMAND]..."
	exit 1
fi

# Adapted from — https://github.com/tactikauan/thcrap-steam-proton-wrapper/blob/3adb608f7aa58323f441aedbe40a3b5096fe9d23/thcrap_proton
if [[ -z "$COMMAND" ]]; then
	shift $((OPTIND -1))
        COMMAND=''
        # Quote all arguments which contain whitespace
        for i in "$@"; do
            [[ $i =~ ( ) ]] && i=${i@Q}
            COMMAND="$COMMAND $i"
        done
fi
COMMAND=$(printf %s "$COMMAND")

_get_exe_window() {
	local windowlist ; windowlist=$( wmctrl -l -p )
	local windowcount ; windowcount=$( echo "$windowlist" | wc -l )

	for (( n = 1 ; n <= windowcount ; n++ )); do
		local window ; window=$( echo "$windowlist" | sed -n "$n"p )

		_get_window_property() {
			echo "$window" | awk -v prop="$1" '{ print $prop }'
		}

		local wid ; wid=$( _get_window_property 1 )
		local pid ; pid=$( _get_window_property 3 )

		local cmd ; cmd=$( cat /proc/"$pid"/cmdline | tr -d '\0' ) # Trim null bytes from cmdline to avoid log spam
		unset -v WID
		if [[ "$cmd" =~ $EXE ]]; then
			WID="$wid"
		fi
	done
}

_set_class() {
	if [[ -z $WID ]]; then
		:
	else
		if [[ $( xdotool getwindowclassname "$WID" ) = $WM_CLASS ]]; then
			:
		else
			xdotool set_window --class "$WM_CLASS" "$WID"
			echo "Set WM_CLASS."
		fi
	fi
}

_window_watcher() {
	while sleep 1; do
		_get_exe_window
		_set_class
	done
}

set -m

_window_watcher &
GAMECLASS_PID="$!"

# Let it rip.
sh -c "$COMMAND"

# Let it die.
kill -- -$GAMECLASS_PID