#!/bin/sh
startdir=$1
pkgname=$2

if [ -z "$startdir" ] || [ -z "$pkgname" ]; then
	echo "ERROR: missing argument!"
	echo "Please call $0 with \$startdir \$pkgname as arguments."
	exit 1
fi

srcdir="$startdir/src"

if [ ! -f "$srcdir/deviceinfo" ]; then
	echo "NOTE: $0 is intended to be used inside of the build() function"
	echo "of a device package's APKBUILD only."
	echo "ERROR: deviceinfo file missing!"
	exit 1
fi

# shellcheck disable=SC1090,SC1091
. "$srcdir/deviceinfo"

# Convert an input calibration matrix from pixel coordinates to 0-1 coordinates
# and echo it for libinput.
# Parameters:
# $1: x multiplier for x coordinate
# $2: y multiplier for x coordinate
# $3: pixel offset for x coordinate
# $4: x multiplier for y coordinate
# $5: y multiplier for y coordinate
# $6: pixel offset for y coordinate
echo_libinput_calibration()
{
	# Check if we have got the required number of parameters.
	if [ $# -ne 6 ]; then
		echo "WARNING: There must be exactly 6 (or 0) values for the touchscreen calibration." >&2
		echo "WARNING: No calibration matrix for x11/libinput will be generated." >&2
		return
	fi

	# Check if we have got a screen width and screen height.
	# shellcheck disable=SC2154
	if [ -z "$deviceinfo_screen_width" ] || [ -z "$deviceinfo_screen_height" ]; then
		echo "WARNING: Screen width and height are required to generate a calibration matrix for x11/libinput." >&2
		echo "WARNING: No calibration matrix for x11/libinput will be generated." >&2
		return
	fi

	# Perform the actual conversion: divide both offsets by width/height.
	# As the "dc" command from "bc" is incompatible to the one provided by busybox,
	# this calls busybox explicitly.
	# shellcheck disable=SC2154
	x_offset=$(busybox dc "$3" "$deviceinfo_screen_width" / p)
	# shellcheck disable=SC2154
	y_offset=$(busybox dc "$6" "$deviceinfo_screen_height" / p)
	# Check if we have got results from dc. If there was an error, dc should have
	# printed an error message that hopefully gives the user a hint why it failed.
	if [ -z "$x_offset" ] || [ -z "$y_offset" ]; then
		echo "WARNING: Calculating the offsets for the calibration matrix for x11/libinput failed." >&2
		echo "No calibration matrix for x11/libinput will be generated." >&2
		return
	fi

	echo "ENV{LIBINPUT_CALIBRATION_MATRIX}=\"$1 $2 $x_offset $4 $5 $y_offset\", \\"
}

# shellcheck disable=SC2154
if [ ! -z "$deviceinfo_dev_touchscreen" ]; then
	# Create touchscreen udev rule
	{
		echo "SUBSYSTEM==\"input\", ENV{DEVNAME}==\"$deviceinfo_dev_touchscreen\", \\"
		# shellcheck disable=SC2154
		if [ ! -z "$deviceinfo_dev_touchscreen_calibration" ]; then
			echo "ENV{WL_CALIBRATION}=\"$deviceinfo_dev_touchscreen_calibration\", \\"

			# The following intentionally expands the touchscreen calibration into the
			# 6 values that should be there.
			# shellcheck disable=SC2086
			echo_libinput_calibration $deviceinfo_dev_touchscreen_calibration
		fi
		echo "ENV{ID_INPUT}=\"1\", ENV{ID_INPUT_TOUCHSCREEN}=\"1\""
	} > "$srcdir/90-$pkgname.rules"
fi