#!/usr/bin/env bash

################################################################################
usage() {
	cat <<EOF
Usage: run-in-xephyr.sh [options]

  -d NxN  Set the screen size to NxN
  -h      This message
  -n NUM  Set the internal DISPLAY to NUM
  -s NUM  Set the number of screens to NUM
EOF
}

################################################################################
ARCH=$(uname -m)
OS=$(uname -s | tr '[:upper:]' '[:lower:]')
SCREENS=1
SCREEN_SIZE="800x600"
DISPLAY_NUMBER=5

################################################################################
while getopts "hs:" o; do
	case "${o}" in
		d)
			SCREEN_SIZE=$OPTARG
			;;

		h)
			usage
			exit
			;;

		n)
			DISPLAY_NUMBER=$OPTARG
			;;

		s)
			SCREENS=$OPTARG
			;;

		*)
			echo
			usage
			exit 1
			;;
	esac
done

shift $((OPTIND - 1))

################################################################################
if [ -d .stack-work ]; then
	echo "stack build detected"
	options=""
	[ "${NIX_PATH:-NO}" = "NO" ] || options="--nix"
	BIN_PATH=$(stack path $options --dist-dir)/build/xmonad-ng
elif [ -d dist-newstyle ]; then
	echo "cabal build detected"
	BIN_PATH=$(find dist-newstyle/ -type f -executable -name xmonad-ng -printf '%h')
else
	echo "you need to build xmonad-ng first, see README for instructions"
	exit 1
fi

RAW_BIN=$BIN_PATH/xmonad-ng
ARCH_BIN=$BIN_PATH/xmonad-$ARCH-$OS

################################################################################
cp -p "$RAW_BIN" "$ARCH_BIN"

################################################################################
XMONAD_CONFIG_DIR=$(pwd)/state/config
XMONAD_CACHE_DIR=$(pwd)/state/cache
XMONAD_DATA_DIR=$(pwd)/state/data
export XMONAD_CONFIG_DIR XMONAD_CACHE_DIR XMONAD_DATA_DIR

mkdir -p "$XMONAD_CONFIG_DIR" "$XMONAD_CACHE_DIR" "$XMONAD_DATA_DIR"
echo "xmonad will store state files in $(pwd)/state"

################################################################################
SCREEN_COUNTER=0
SCREEN_OPTS=""
X_OFFSET_CURRENT="0"
X_OFFSET_ADD=$(echo "$SCREEN_SIZE" | cut -dx -f1)

while expr "$SCREEN_COUNTER" "<" "$SCREENS"; do
	SCREEN_OPTS="$SCREEN_OPTS -origin ${X_OFFSET_CURRENT},0 -screen ${SCREEN_SIZE}+${X_OFFSET_CURRENT}"
	SCREEN_COUNTER=$(("$SCREEN_COUNTER" + 1))
	X_OFFSET_CURRENT=$(("$X_OFFSET_CURRENT" + "$X_OFFSET_ADD"))
done

(
	# shellcheck disable=SC2086
	Xephyr $SCREEN_OPTS +xinerama +extension RANDR \
		-ac -br -reset -terminate -verbosity 10 \
		-softCursor ":$DISPLAY_NUMBER" &

	export DISPLAY=":$DISPLAY_NUMBER"
	echo "Waiting for windows to appear..." && sleep 2

	$ARCH_BIN
)