#!/usr/bin/env bash
set -euo pipefail

# Install a local udev hwdb override that marks the ASUS GZ302EA detachable
# touchpad as internal so libinput enables disable-while-typing.
#
# Idempotent: exits early if the hwdb file is already installed with the
# expected contents and every detected touchpad is tagged as internal.

DEST="/etc/udev/hwdb.d/71-touchpad-local.hwdb"

read -r -d '' HWDB <<'EOF' || true
# Local touchpad integration overrides. Managed by
# scripts/install-touchpad-quirk in the dotfiles repo; edits here will be
# overwritten the next time the script runs.

# ASUS ROG Flow Z13 2025 (GZ302EA) detachable keyboard/touchpad.
# Lives on USB but is the laptop's only touchpad, so tag it as internal so
# libinput pairs it with the keyboard and enables disable-while-typing.
touchpad:usb:v0b05p1a30:*
 ID_INPUT_TOUCHPAD_INTEGRATION=internal
EOF

# Check whether the setup is already in the desired state.
already_set_up() {
	[[ -f "$DEST" ]] || return 1
	[[ "$(cat "$DEST")" == "$HWDB" ]] || return 1

	local found=0
	for ev in /dev/input/event*; do
		udevadm info "$ev" 2>/dev/null | grep -q "ID_INPUT_TOUCHPAD=1" || continue
		found=1
		udevadm info "$ev" 2>/dev/null |
			grep -q "ID_INPUT_TOUCHPAD_INTEGRATION=internal" || return 1
	done
	[[ $found -eq 1 ]]
}

if already_set_up; then
	echo "Touchpad quirk already installed and active. Nothing to do."
	exit 0
fi

SUDO=""
if [[ $EUID -ne 0 ]]; then
	if ! command -v sudo &>/dev/null; then
		echo "error: sudo not found; re-run as root" >&2
		exit 1
	fi
	SUDO="sudo"
fi

echo "Installing hwdb override to $DEST"
$SUDO install -d -m 0755 "$(dirname "$DEST")"
printf '%s\n' "$HWDB" | $SUDO tee "$DEST" >/dev/null
$SUDO chmod 0644 "$DEST"

echo "Updating hwdb..."
$SUDO systemd-hwdb update

echo "Triggering udev for input devices..."
$SUDO udevadm trigger /dev/input/event*

echo
echo "Done. Verifying:"
for ev in /dev/input/event*; do
	if udevadm info "$ev" 2>/dev/null | grep -q "ID_INPUT_TOUCHPAD=1"; then
		name=$(udevadm info "$ev" 2>/dev/null | awk -F= '/NAME=/{print $2}')
		integ=$(udevadm info "$ev" 2>/dev/null |
			awk -F= '/ID_INPUT_TOUCHPAD_INTEGRATION/{print $2}')
		printf "  %s %s integration=%s\n" "$ev" "$name" "$integ"
	fi
done

if command -v libinput &>/dev/null; then
	echo
	libinput list-devices 2>/dev/null |
		awk '/^Device:/{d=$0} /Disable-w-typing/{print d"\n  "$0"\n"}' |
		grep -B1 -A1 -i touchpad || true
fi

echo
echo "Log out and back in for libinput to re-read the device."