#!/bin/bash
#
# fix-rog-z13-trackpad.sh
# Enables "Disable while typing" (DWT) + palm rejection on the
# ASUS ROG Flow Z13 folio keyboard touchpad.
#
# Usage:  ./fix-rog-z13-trackpad.sh
#         (must be run as root)
#
# Tested on: CachyOS / Arch Linux, KDE Plasma 6, Wayland
# Applies to: ROG Flow Z13 (2023 & 2025 models, USB 0b05:1a30)

set -euo pipefail

if [ "$(id -u)" -ne 0 ]; then
  echo "ERROR: This script must be run as root."
  echo "Usage: sudo ./fix-rog-z13-trackpad.sh"
  exit 1
fi

echo "=== ROG Flow Z13 Trackpad Fix ==="
echo ""

# ──────────────────────────────────────
# 1. udev rule — mark touchpad as internal
# ──────────────────────────────────────
UDEV_RULE="/etc/udev/rules.d/99-rog-z13-touchpad.rules"

if [ -f "$UDEV_RULE" ]; then
  echo "[SKIP] $UDEV_RULE already exists"
else
  echo "[CREATE] $UDEV_RULE"
  cat > "$UDEV_RULE" << 'EOF'
# ROG Flow Z13 folio keyboard touchpad integration override
#
# The Z13's detachable folio keyboard connects via USB (0b05:1a30).
# The touchpad on this device is correctly exposed as a touchpad, but
# udev marks it as ID_INPUT_TOUCHPAD_INTEGRATION=external because the
# USB device is flagged as "removable" (it's a detachable keyboard).
#
# Libinput refuses to enable "Disable While Typing" (DWT) for touchpads
# marked as external, which greyed out the checkbox in KDE Plasma.
#
# This rule overrides the integration type to "internal" for the Z13
# touchpad only, which allows DWT pairing with the keyboard (already
# marked internal via the libinput quirk in 50-system-asus.quirks).

ACTION=="add|change", SUBSYSTEM=="input", \
  ENV{ID_VENDOR_ID}=="0b05", ENV{ID_MODEL_ID}=="1a30", \
  ENV{ID_INPUT_TOUCHPAD}=="1", \
  ENV{ID_INPUT_TOUCHPAD_INTEGRATION}="internal"
EOF
fi

# ──────────────────────────────────────
# 2. libinput quirk — mark keyboard as internal (belt-and-suspenders)
# ──────────────────────────────────────
LIBINPUT_QUIRKS="/etc/libinput/local-overrides.quirks"

# Only create if it doesn't exist; if it does, it may have user customizations
if [ -f "$LIBINPUT_QUIRKS" ]; then
  echo "[SKIP] $LIBINPUT_QUIRKS already exists (not overwriting)"
else
  echo "[CREATE] $LIBINPUT_QUIRKS"
  mkdir -p /etc/libinput
  cat > "$LIBINPUT_QUIRKS" << 'EOF'
[ROG Flow Z13 All USB Keyboards]
MatchUdevType=keyboard
MatchBus=usb
MatchVendor=0x0B05
AttrKeyboardIntegration=internal
EOF
fi

# ──────────────────────────────────────
# 3. Apply udev changes
# ──────────────────────────────────────
echo ""
echo "[APPLY] Reloading udev rules..."
udevadm control --reload-rules

echo "[APPLY] Triggering udev for existing devices..."
udevadm trigger --subsystem-match=input

echo ""
echo "=== DONE ==="
echo ""
echo "The fix has been applied. To activate it:"
echo ""
echo "  1. Log out and log back in (or reboot)"
echo "  2. Open System Settings -> Touchpad"
echo "  3. Check \"Disable touchpad when typing\""
echo ""
echo "The checkbox should now be available. If the touchpad already"
echo "feels better at rejecting palm brushes while typing — that's"
echo "expected. DWT and improved palm rejection both activate when"
echo "the touchpad is recognized as internal."
echo ""
echo "To undo this fix later, run:"
echo "  sudo rm /etc/udev/rules.d/99-rog-z13-touchpad.rules"
echo "  sudo rm /etc/libinput/local-overrides.quirks"
echo "  sudo udevadm control --reload-rules"
echo "  sudo udevadm trigger --subsystem-match=input"
echo ""