/*
 * Copyright © 2014 Red Hat, Inc.
 * Copyright © 2014 Stephen Chandler "Lyude" Paul
 *
 * Permission to use, copy, modify, distribute, and sell this software and
 * its documentation for any purpose is hereby granted without fee, provided
 * that the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation, and that the name of the copyright holders not be used in
 * advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission.  The copyright holders make
 * no representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
 * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
 * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
 * CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include "config.h"
#include "libinput-version.h"
#include "evdev-tablet.h"

#include <assert.h>
#include <stdbool.h>
#include <string.h>

#if HAVE_LIBWACOM
#include <libwacom/libwacom.h>
#endif

#define tablet_set_status(tablet_,s_) (tablet_)->status |= (s_)
#define tablet_unset_status(tablet_,s_) (tablet_)->status &= ~(s_)
#define tablet_has_status(tablet_,s_) (!!((tablet_)->status & (s_)))

static inline void
tablet_get_pressed_buttons(struct tablet_dispatch *tablet,
			   struct button_state *buttons)
{
	size_t i;
	const struct button_state *state = &tablet->button_state,
			          *prev_state = &tablet->prev_button_state;

	for (i = 0; i < sizeof(buttons->bits); i++)
		buttons->bits[i] = state->bits[i] & ~(prev_state->bits[i]);
}

static inline void
tablet_get_released_buttons(struct tablet_dispatch *tablet,
			    struct button_state *buttons)
{
	size_t i;
	const struct button_state *state = &tablet->button_state,
			          *prev_state = &tablet->prev_button_state;

	for (i = 0; i < sizeof(buttons->bits); i++)
		buttons->bits[i] = prev_state->bits[i] &
					~(state->bits[i]);
}

/* Merge the previous state with the current one so all buttons look like
 * they just got pressed in this frame */
static inline void
tablet_force_button_presses(struct tablet_dispatch *tablet)
{
	struct button_state *state = &tablet->button_state,
			    *prev_state = &tablet->prev_button_state;
	size_t i;

	for (i = 0; i < sizeof(state->bits); i++) {
		state->bits[i] = state->bits[i] | prev_state->bits[i];
		prev_state->bits[i] = 0;
	}
}

static int
tablet_device_has_axis(struct tablet_dispatch *tablet,
		       enum libinput_tablet_tool_axis axis)
{
	struct libevdev *evdev = tablet->device->evdev;
	bool has_axis = false;
	unsigned int code;

	if (axis == LIBINPUT_TABLET_TOOL_AXIS_ROTATION_Z) {
		has_axis = (libevdev_has_event_code(evdev,
						    EV_KEY,
						    BTN_TOOL_MOUSE) &&
			    libevdev_has_event_code(evdev,
						    EV_ABS,
						    ABS_TILT_X) &&
			    libevdev_has_event_code(evdev,
						    EV_ABS,
						    ABS_TILT_Y));
		code = axis_to_evcode(axis);
		has_axis |= libevdev_has_event_code(evdev,
						    EV_ABS,
						    code);
	} else if (axis == LIBINPUT_TABLET_TOOL_AXIS_REL_WHEEL) {
		has_axis = libevdev_has_event_code(evdev,
						   EV_REL,
						   REL_WHEEL);
	} else {
		code = axis_to_evcode(axis);
		has_axis = libevdev_has_event_code(evdev,
						   EV_ABS,
						   code);
	}

	return has_axis;
}

static inline bool
tablet_filter_axis_fuzz(const struct tablet_dispatch *tablet,
			const struct evdev_device *device,
			const struct input_event *e,
			enum libinput_tablet_tool_axis axis)
{
	int delta, fuzz;
	int current, previous;

	previous = tablet->prev_value[axis];
	current = e->value;
	delta = previous - current;

	fuzz = libevdev_get_abs_fuzz(device->evdev, e->code);

	/* ABS_DISTANCE doesn't have have fuzz set and causes continuous
	 * updates for the cursor/lens tools. Add a minimum fuzz of 2, same
	 * as the xf86-input-wacom driver
	 */
	switch (e->code) {
	case ABS_DISTANCE:
		fuzz = max(2, fuzz);
		break;
	default:
		break;
	}

	return abs(delta) <= fuzz;
}

static void
tablet_process_absolute(struct tablet_dispatch *tablet,
			struct evdev_device *device,
			struct input_event *e,
			uint64_t time)
{
	enum libinput_tablet_tool_axis axis;

	switch (e->code) {
	case ABS_X:
	case ABS_Y:
	case ABS_Z:
	case ABS_PRESSURE:
	case ABS_TILT_X:
	case ABS_TILT_Y:
	case ABS_DISTANCE:
	case ABS_WHEEL:
		axis = evcode_to_axis(e->code);
		if (axis == LIBINPUT_TABLET_TOOL_AXIS_NONE) {
			log_bug_libinput(tablet_libinput_context(tablet),
					 "Invalid ABS event code %#x\n",
					 e->code);
			break;
		}

		tablet->prev_value[axis] = tablet->current_value[axis];
		if (tablet_filter_axis_fuzz(tablet, device, e, axis))
			break;

		tablet->current_value[axis] = e->value;
		set_bit(tablet->changed_axes, axis);
		tablet_set_status(tablet, TABLET_AXES_UPDATED);
		break;
	/* tool_id is the identifier for the tool we can use in libwacom
	 * to identify it (if we have one anyway) */
	case ABS_MISC:
		tablet->current_tool_id = e->value;
		break;
	/* Intuos 3 strip data. Should only happen on the Pad device, not on
	   the Pen device. */
	case ABS_RX:
	case ABS_RY:
	/* Only on the 4D mouse (Intuos2), obsolete */
	case ABS_RZ:
	/* Only on the 4D mouse (Intuos2), obsolete.
	   The 24HD sends ABS_THROTTLE on the Pad device for the second
	   wheel but we shouldn't get here on kernel >= 3.17.
	   */
	case ABS_THROTTLE:
	default:
		log_info(tablet_libinput_context(tablet),
			 "Unhandled ABS event code %#x\n", e->code);
		break;
	}
}

static void
tablet_change_to_left_handed(struct evdev_device *device)
{
	struct tablet_dispatch *tablet =
		(struct tablet_dispatch*)device->dispatch;

	if (device->left_handed.enabled == device->left_handed.want_enabled)
		return;

	if (!tablet_has_status(tablet, TABLET_TOOL_OUT_OF_PROXIMITY))
		return;

	device->left_handed.enabled = device->left_handed.want_enabled;
}

static void
tablet_update_tool(struct tablet_dispatch *tablet,
		   struct evdev_device *device,
		   enum libinput_tablet_tool_type tool,
		   bool enabled)
{
	assert(tool != LIBINPUT_TOOL_NONE);

	if (enabled) {
		tablet->current_tool_type = tool;
		tablet_set_status(tablet, TABLET_TOOL_ENTERING_PROXIMITY);
		tablet_unset_status(tablet, TABLET_TOOL_OUT_OF_PROXIMITY);
	}
	else if (!tablet_has_status(tablet, TABLET_TOOL_OUT_OF_PROXIMITY))
		tablet_set_status(tablet, TABLET_TOOL_LEAVING_PROXIMITY);
}

static inline double
normalize_slider(const struct input_absinfo *absinfo)
{
	double range = absinfo->maximum - absinfo->minimum;
	double value = (absinfo->value - absinfo->minimum) / range;

	return value * 2 - 1;
}

static inline double
normalize_distance(const struct input_absinfo *absinfo)
{
	double range = absinfo->maximum - absinfo->minimum;
	double value = (absinfo->value - absinfo->minimum) / range;

	return value;
}

static inline double
normalize_pressure(const struct input_absinfo *absinfo,
		   struct libinput_tablet_tool *tool)
{
	double range = absinfo->maximum - absinfo->minimum;
	int offset = tool->has_pressure_offset ?
			tool->pressure_offset : 0;
	double value = (absinfo->value - offset - absinfo->minimum) / range;

	return value;
}

static inline double
adjust_tilt(const struct input_absinfo *absinfo)
{
	double range = absinfo->maximum - absinfo->minimum;
	double value = (absinfo->value - absinfo->minimum) / range;
	const int WACOM_MAX_DEGREES = 64;

	/* If resolution is nonzero, it's in units/radian. But require
	 * a min/max less/greater than zero so we can assume 0 is the
	 * center */
	if (absinfo->resolution != 0 &&
	    absinfo->maximum > 0 &&
	    absinfo->minimum < 0) {
		value = 180.0/M_PI * absinfo->value/absinfo->resolution;
	} else {
		/* Wacom supports physical [-64, 64] degrees, so map to that by
		 * default. If other tablets have a different physical range or
		 * nonzero physical offsets, they need extra treatment
		 * here.
		 */
		/* Map to the (-1, 1) range */
		value = (value * 2) - 1;
		value *= WACOM_MAX_DEGREES;
	}

	return value;
}

static inline int32_t
invert_axis(const struct input_absinfo *absinfo)
{
	return absinfo->maximum - (absinfo->value - absinfo->minimum);
}

static void
convert_tilt_to_rotation(struct tablet_dispatch *tablet)
{
	const int offset = 5;
	double x, y;
	double angle = 0.0;

	/* Wacom Intuos 4, 5, Pro mouse calculates rotation from the x/y tilt
	   values. The device has a 175 degree CCW hardware offset but since we use
	   atan2 the effective offset is just 5 degrees.
	   */
	x = tablet->axes.tilt.x;
	y = tablet->axes.tilt.y;

	/* atan2 is CCW, we want CW -> negate x */
	if (x || y)
		angle = ((180.0 * atan2(-x, y)) / M_PI);

	angle = fmod(360 + angle - offset, 360);

	tablet->axes.rotation = angle;
	set_bit(tablet->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_ROTATION_Z);
}

static double
convert_to_degrees(const struct input_absinfo *absinfo, double offset)
{
	/* range is [0, 360[, i.e. range + 1 */
	double range = absinfo->maximum - absinfo->minimum + 1;
	double value = (absinfo->value - absinfo->minimum) / range;

	return fmod(value * 360.0 + offset, 360.0);
}

static inline double
normalize_wheel(struct tablet_dispatch *tablet,
		int value)
{
	struct evdev_device *device = tablet->device;

	return value * device->scroll.wheel_click_angle;
}

static inline void
tablet_handle_xy(struct tablet_dispatch *tablet,
		 struct evdev_device *device,
		 struct device_coords *point_out,
		 struct device_coords *delta_out)
{
	struct device_coords point;
	struct device_coords delta = { 0, 0 };
	const struct input_absinfo *absinfo;
	int value;

	if (bit_is_set(tablet->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_X)) {
		absinfo = libevdev_get_abs_info(device->evdev, ABS_X);

		if (device->left_handed.enabled)
			value = invert_axis(absinfo);
		else
			value = absinfo->value;

		if (!tablet_has_status(tablet,
				       TABLET_TOOL_ENTERING_PROXIMITY))
			delta.x = value - tablet->axes.point.x;
		tablet->axes.point.x = value;
	}
	point.x = tablet->axes.point.x;

	if (bit_is_set(tablet->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_Y)) {
		absinfo = libevdev_get_abs_info(device->evdev, ABS_Y);

		if (device->left_handed.enabled)
			value = invert_axis(absinfo);
		else
			value = absinfo->value;

		if (!tablet_has_status(tablet,
				       TABLET_TOOL_ENTERING_PROXIMITY))
			delta.y = value - tablet->axes.point.y;
		tablet->axes.point.y = value;
	}
	point.y = tablet->axes.point.y;

	evdev_transform_absolute(device, &point);
	evdev_transform_relative(device, &delta);

	*delta_out = delta;
	*point_out = point;
}

static inline struct normalized_coords
tool_process_delta(struct libinput_tablet_tool *tool,
		   const struct evdev_device *device,
		   const struct device_coords *delta,
		   uint64_t time)
{
	struct normalized_coords accel;

	accel.x = 1.0 * delta->x;
	accel.y = 1.0 * delta->y;

	if (normalized_is_zero(accel))
		return accel;

	return filter_dispatch(device->pointer.filter,
			       &accel,
			       tool,
			       time);
}

static inline double
tablet_handle_pressure(struct tablet_dispatch *tablet,
		       struct evdev_device *device,
		       struct libinput_tablet_tool *tool)
{
	const struct input_absinfo *absinfo;

	if (bit_is_set(tablet->changed_axes,
		       LIBINPUT_TABLET_TOOL_AXIS_PRESSURE)) {
		absinfo = libevdev_get_abs_info(device->evdev, ABS_PRESSURE);
		tablet->axes.pressure = normalize_pressure(absinfo, tool);
	}

	return tablet->axes.pressure;
}

static inline double
tablet_handle_distance(struct tablet_dispatch *tablet,
		       struct evdev_device *device)
{
	const struct input_absinfo *absinfo;

	if (bit_is_set(tablet->changed_axes,
		       LIBINPUT_TABLET_TOOL_AXIS_DISTANCE)) {
		absinfo = libevdev_get_abs_info(device->evdev, ABS_DISTANCE);
		tablet->axes.distance = normalize_distance(absinfo);
	}

	return tablet->axes.distance;
}

static inline double
tablet_handle_slider(struct tablet_dispatch *tablet,
		     struct evdev_device *device)
{
	const struct input_absinfo *absinfo;

	if (bit_is_set(tablet->changed_axes,
		       LIBINPUT_TABLET_TOOL_AXIS_SLIDER)) {
		absinfo = libevdev_get_abs_info(device->evdev, ABS_WHEEL);
		tablet->axes.slider = normalize_slider(absinfo);
	}

	return tablet->axes.slider;
}

static inline struct tilt_degrees
tablet_handle_tilt(struct tablet_dispatch *tablet,
		   struct evdev_device *device)
{
	struct tilt_degrees tilt;
	const struct input_absinfo *absinfo;

	if (bit_is_set(tablet->changed_axes,
		       LIBINPUT_TABLET_TOOL_AXIS_TILT_X)) {
		absinfo = libevdev_get_abs_info(device->evdev, ABS_TILT_X);
		tablet->axes.tilt.x = adjust_tilt(absinfo);
		if (device->left_handed.enabled)
			tablet->axes.tilt.x *= -1;
	}
	tilt.x = tablet->axes.tilt.x;

	if (bit_is_set(tablet->changed_axes,
		       LIBINPUT_TABLET_TOOL_AXIS_TILT_Y)) {
		absinfo = libevdev_get_abs_info(device->evdev, ABS_TILT_Y);
		tablet->axes.tilt.y = adjust_tilt(absinfo);
		if (device->left_handed.enabled)
			tablet->axes.tilt.y *= -1;
	}
	tilt.y = tablet->axes.tilt.y;

	return tilt;
}

static inline double
tablet_handle_artpen_rotation(struct tablet_dispatch *tablet,
			      struct evdev_device *device)
{
	const struct input_absinfo *absinfo;

	if (bit_is_set(tablet->changed_axes,
		       LIBINPUT_TABLET_TOOL_AXIS_ROTATION_Z)) {
		absinfo = libevdev_get_abs_info(device->evdev,
						ABS_Z);
		/* artpen has 0 with buttons pointing east */
		tablet->axes.rotation = convert_to_degrees(absinfo, 90);
	}

	return tablet->axes.rotation;
}

static inline double
tablet_handle_mouse_rotation(struct tablet_dispatch *tablet,
			     struct evdev_device *device)
{
	if (bit_is_set(tablet->changed_axes,
		       LIBINPUT_TABLET_TOOL_AXIS_TILT_X) ||
	    bit_is_set(tablet->changed_axes,
		       LIBINPUT_TABLET_TOOL_AXIS_TILT_Y)) {
		convert_tilt_to_rotation(tablet);
	}

	return tablet->axes.rotation;
}

static inline double
tablet_handle_wheel(struct tablet_dispatch *tablet,
		    struct evdev_device *device,
		    int *wheel_discrete)
{
	int a;

	a = LIBINPUT_TABLET_TOOL_AXIS_REL_WHEEL;
	if (bit_is_set(tablet->changed_axes, a)) {
		*wheel_discrete = tablet->axes.wheel_discrete;
		tablet->axes.wheel = normalize_wheel(tablet,
						     tablet->axes.wheel_discrete);
	} else {
		tablet->axes.wheel = 0;
		*wheel_discrete = 0;
	}

	return tablet->axes.wheel;
}

static bool
tablet_check_notify_axes(struct tablet_dispatch *tablet,
			 struct evdev_device *device,
			 struct libinput_tablet_tool *tool,
			 struct tablet_axes *axes_out,
			 uint64_t time)
{
	struct tablet_axes axes = {0};
	const char tmp[sizeof(tablet->changed_axes)] = {0};
	struct device_coords delta;

	if (memcmp(tmp, tablet->changed_axes, sizeof(tmp)) == 0)
		return false;

	tablet_handle_xy(tablet, device, &axes.point, &delta);
	axes.pressure = tablet_handle_pressure(tablet, device, tool);
	axes.distance = tablet_handle_distance(tablet, device);
	axes.slider = tablet_handle_slider(tablet, device);
	axes.tilt = tablet_handle_tilt(tablet, device);
	axes.delta = tool_process_delta(tool, device, &delta, time);

	/* We must check ROTATION_Z after TILT_X/Y so that the tilt axes are
	 * already normalized and set if we have the mouse/lens tool */
	if (tablet->current_tool_type == LIBINPUT_TABLET_TOOL_TYPE_MOUSE ||
	    tablet->current_tool_type == LIBINPUT_TABLET_TOOL_TYPE_LENS) {
		axes.rotation = tablet_handle_mouse_rotation(tablet, device);
		clear_bit(tablet->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_TILT_X);
		clear_bit(tablet->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_TILT_Y);
		axes.tilt.x = 0;
		axes.tilt.y = 0;

		/* tilt is already converted to left-handed, so mouse
		 * rotation is converted to left-handed automatically */
	} else {
		axes.rotation = tablet_handle_artpen_rotation(tablet, device);
		if (device->left_handed.enabled)
			axes.rotation = fmod(180 + axes.rotation, 360);
	}

	axes.wheel = tablet_handle_wheel(tablet, device, &axes.wheel_discrete);

	*axes_out = axes;

	return true;
}

static void
tablet_update_button(struct tablet_dispatch *tablet,
		     uint32_t evcode,
		     uint32_t enable)
{
	switch (evcode) {
	case BTN_TOUCH:
		return;
	case BTN_LEFT:
	case BTN_RIGHT:
	case BTN_MIDDLE:
	case BTN_SIDE:
	case BTN_EXTRA:
	case BTN_FORWARD:
	case BTN_BACK:
	case BTN_TASK:
	case BTN_STYLUS:
	case BTN_STYLUS2:
		break;
	default:
		log_info(tablet_libinput_context(tablet),
			 "Unhandled button %s (%#x)\n",
			 libevdev_event_code_get_name(EV_KEY, evcode), evcode);
		return;
	}

	if (enable) {
		set_bit(tablet->button_state.bits, evcode);
		tablet_set_status(tablet, TABLET_BUTTONS_PRESSED);
	} else {
		clear_bit(tablet->button_state.bits, evcode);
		tablet_set_status(tablet, TABLET_BUTTONS_RELEASED);
	}
}

static inline enum libinput_tablet_tool_type
tablet_evcode_to_tool(int code)
{
	enum libinput_tablet_tool_type type;

	switch (code) {
	case BTN_TOOL_PEN:	type = LIBINPUT_TABLET_TOOL_TYPE_PEN;		break;
	case BTN_TOOL_RUBBER:	type = LIBINPUT_TABLET_TOOL_TYPE_ERASER;	break;
	case BTN_TOOL_BRUSH:	type = LIBINPUT_TABLET_TOOL_TYPE_BRUSH;	break;
	case BTN_TOOL_PENCIL:	type = LIBINPUT_TABLET_TOOL_TYPE_PENCIL;	break;
	case BTN_TOOL_AIRBRUSH:	type = LIBINPUT_TABLET_TOOL_TYPE_AIRBRUSH;	break;
	case BTN_TOOL_MOUSE:	type = LIBINPUT_TABLET_TOOL_TYPE_MOUSE;	break;
	case BTN_TOOL_LENS:	type = LIBINPUT_TABLET_TOOL_TYPE_LENS;		break;
	default:
		abort();
	}

	return type;
}

static void
tablet_process_key(struct tablet_dispatch *tablet,
		   struct evdev_device *device,
		   struct input_event *e,
		   uint64_t time)
{
	switch (e->code) {
	case BTN_TOOL_FINGER:
		log_bug_libinput(tablet_libinput_context(tablet),
				 "Invalid tool 'finger' on tablet interface\n");
		break;
	case BTN_TOOL_PEN:
	case BTN_TOOL_RUBBER:
	case BTN_TOOL_BRUSH:
	case BTN_TOOL_PENCIL:
	case BTN_TOOL_AIRBRUSH:
	case BTN_TOOL_MOUSE:
	case BTN_TOOL_LENS:
		tablet_update_tool(tablet,
				   device,
				   tablet_evcode_to_tool(e->code),
				   e->value);
		break;
	case BTN_TOUCH:
		if (!bit_is_set(tablet->axis_caps,
				LIBINPUT_TABLET_TOOL_AXIS_PRESSURE)) {
			if (e->value)
				tablet_set_status(tablet,
						  TABLET_TOOL_ENTERING_CONTACT);
			else
				tablet_set_status(tablet,
						  TABLET_TOOL_LEAVING_CONTACT);
		}
		break;
	case BTN_LEFT:
	case BTN_RIGHT:
	case BTN_MIDDLE:
	case BTN_SIDE:
	case BTN_EXTRA:
	case BTN_FORWARD:
	case BTN_BACK:
	case BTN_TASK:
	case BTN_STYLUS:
	case BTN_STYLUS2:
	default:
		tablet_update_button(tablet, e->code, e->value);
		break;
	}
}

static void
tablet_process_relative(struct tablet_dispatch *tablet,
			struct evdev_device *device,
			struct input_event *e,
			uint64_t time)
{
	enum libinput_tablet_tool_axis axis;

	switch (e->code) {
	case REL_WHEEL:
		axis = rel_evcode_to_axis(e->code);
		if (axis == LIBINPUT_TABLET_TOOL_AXIS_NONE) {
			log_bug_libinput(tablet_libinput_context(tablet),
					 "Invalid ABS event code %#x\n",
					 e->code);
			break;
		}
		set_bit(tablet->changed_axes, axis);
		tablet->axes.wheel_discrete = -1 * e->value;
		tablet_set_status(tablet, TABLET_AXES_UPDATED);
		break;
	default:
		log_info(tablet_libinput_context(tablet),
			 "Unhandled relative axis %s (%#x)\n",
			 libevdev_event_code_get_name(EV_REL, e->code),
			 e->code);
		return;
	}
}

static void
tablet_process_misc(struct tablet_dispatch *tablet,
		    struct evdev_device *device,
		    struct input_event *e,
		    uint64_t time)
{
	switch (e->code) {
	case MSC_SERIAL:
		if (e->value != -1)
			tablet->current_tool_serial = e->value;

		break;
	default:
		log_info(tablet_libinput_context(tablet),
			 "Unhandled MSC event code %s (%#x)\n",
			 libevdev_event_code_get_name(EV_MSC, e->code),
			 e->code);
		break;
	}
}

static inline void
copy_axis_cap(const struct tablet_dispatch *tablet,
	      struct libinput_tablet_tool *tool,
	      enum libinput_tablet_tool_axis axis)
{
	if (bit_is_set(tablet->axis_caps, axis))
		set_bit(tool->axis_caps, axis);
}

static inline void
copy_button_cap(const struct tablet_dispatch *tablet,
		struct libinput_tablet_tool *tool,
		uint32_t button)
{
	struct libevdev *evdev = tablet->device->evdev;
	if (libevdev_has_event_code(evdev, EV_KEY, button))
		set_bit(tool->buttons, button);
}

static inline int
tool_set_bits_from_libwacom(const struct tablet_dispatch *tablet,
			    struct libinput_tablet_tool *tool)
{
	int rc = 1;

#if HAVE_LIBWACOM
	struct libinput *libinput = tablet_libinput_context(tablet);
	WacomDeviceDatabase *db;
	const WacomStylus *s = NULL;
	int code;
	WacomStylusType type;
	WacomAxisTypeFlags axes;

	db = libwacom_database_new();
	if (!db) {
		log_info(libinput,
			 "Failed to initialize libwacom context.\n");
		goto out;
	}
	s = libwacom_stylus_get_for_id(db, tool->tool_id);
	if (!s)
		goto out;

	type = libwacom_stylus_get_type(s);
	if (type == WSTYLUS_PUCK) {
		for (code = BTN_LEFT;
		     code < BTN_LEFT + libwacom_stylus_get_num_buttons(s);
		     code++)
			copy_button_cap(tablet, tool, code);
	} else {
		if (libwacom_stylus_get_num_buttons(s) >= 2)
			copy_button_cap(tablet, tool, BTN_STYLUS2);
		if (libwacom_stylus_get_num_buttons(s) >= 1)
			copy_button_cap(tablet, tool, BTN_STYLUS);
	}

	if (libwacom_stylus_has_wheel(s))
		copy_axis_cap(tablet, tool, LIBINPUT_TABLET_TOOL_AXIS_REL_WHEEL);

	axes = libwacom_stylus_get_axes(s);

	if (axes & WACOM_AXIS_TYPE_TILT) {
		/* tilt on the puck is converted to rotation */
		if (type == WSTYLUS_PUCK) {
			set_bit(tool->axis_caps,
				LIBINPUT_TABLET_TOOL_AXIS_ROTATION_Z);
		} else {
			copy_axis_cap(tablet,
				      tool,
				      LIBINPUT_TABLET_TOOL_AXIS_TILT_X);
			copy_axis_cap(tablet,
				      tool,
				      LIBINPUT_TABLET_TOOL_AXIS_TILT_Y);
		}
	}
	if (axes & WACOM_AXIS_TYPE_ROTATION_Z)
		copy_axis_cap(tablet, tool, LIBINPUT_TABLET_TOOL_AXIS_ROTATION_Z);
	if (axes & WACOM_AXIS_TYPE_DISTANCE)
		copy_axis_cap(tablet, tool, LIBINPUT_TABLET_TOOL_AXIS_DISTANCE);
	if (axes & WACOM_AXIS_TYPE_SLIDER)
		copy_axis_cap(tablet, tool, LIBINPUT_TABLET_TOOL_AXIS_SLIDER);
	if (axes & WACOM_AXIS_TYPE_PRESSURE)
		copy_axis_cap(tablet, tool, LIBINPUT_TABLET_TOOL_AXIS_PRESSURE);

	rc = 0;
out:
	if (db)
		libwacom_database_destroy(db);
#endif
	return rc;
}

static void
tool_set_bits(const struct tablet_dispatch *tablet,
	      struct libinput_tablet_tool *tool)
{
	enum libinput_tablet_tool_type type = tool->type;

	copy_axis_cap(tablet, tool, LIBINPUT_TABLET_TOOL_AXIS_X);
	copy_axis_cap(tablet, tool, LIBINPUT_TABLET_TOOL_AXIS_Y);

#if HAVE_LIBWACOM
	if (tool_set_bits_from_libwacom(tablet, tool) == 0)
		return;
#endif
	/* If we don't have libwacom, we simply copy any axis we have on the
	   tablet onto the tool. Except we know that mice only have rotation
	   anyway.
	 */
	switch (type) {
	case LIBINPUT_TABLET_TOOL_TYPE_PEN:
	case LIBINPUT_TABLET_TOOL_TYPE_ERASER:
	case LIBINPUT_TABLET_TOOL_TYPE_PENCIL:
	case LIBINPUT_TABLET_TOOL_TYPE_BRUSH:
	case LIBINPUT_TABLET_TOOL_TYPE_AIRBRUSH:
		copy_axis_cap(tablet, tool, LIBINPUT_TABLET_TOOL_AXIS_PRESSURE);
		copy_axis_cap(tablet, tool, LIBINPUT_TABLET_TOOL_AXIS_DISTANCE);
		copy_axis_cap(tablet, tool, LIBINPUT_TABLET_TOOL_AXIS_TILT_X);
		copy_axis_cap(tablet, tool, LIBINPUT_TABLET_TOOL_AXIS_TILT_Y);
		copy_axis_cap(tablet, tool, LIBINPUT_TABLET_TOOL_AXIS_SLIDER);
		copy_axis_cap(tablet, tool, LIBINPUT_TABLET_TOOL_AXIS_ROTATION_Z);
		break;
	case LIBINPUT_TABLET_TOOL_TYPE_MOUSE:
	case LIBINPUT_TABLET_TOOL_TYPE_LENS:
		copy_axis_cap(tablet, tool, LIBINPUT_TABLET_TOOL_AXIS_ROTATION_Z);
		copy_axis_cap(tablet, tool, LIBINPUT_TABLET_TOOL_AXIS_REL_WHEEL);
		break;
	default:
		break;
	}

	/* If we don't have libwacom, copy all pen-related buttons from the
	   tablet vs all mouse-related buttons */
	switch (type) {
	case LIBINPUT_TABLET_TOOL_TYPE_PEN:
	case LIBINPUT_TABLET_TOOL_TYPE_BRUSH:
	case LIBINPUT_TABLET_TOOL_TYPE_AIRBRUSH:
	case LIBINPUT_TABLET_TOOL_TYPE_PENCIL:
	case LIBINPUT_TABLET_TOOL_TYPE_ERASER:
		copy_button_cap(tablet, tool, BTN_STYLUS);
		copy_button_cap(tablet, tool, BTN_STYLUS2);
		break;
	case LIBINPUT_TABLET_TOOL_TYPE_MOUSE:
	case LIBINPUT_TABLET_TOOL_TYPE_LENS:
		copy_button_cap(tablet, tool, BTN_LEFT);
		copy_button_cap(tablet, tool, BTN_MIDDLE);
		copy_button_cap(tablet, tool, BTN_RIGHT);
		copy_button_cap(tablet, tool, BTN_SIDE);
		copy_button_cap(tablet, tool, BTN_EXTRA);
		break;
	default:
		break;
	}
}

static inline int
axis_range_percentage(const struct input_absinfo *a, double percent)
{
	return (a->maximum - a->minimum) * percent/100.0 + a->minimum;
}

static struct libinput_tablet_tool *
tablet_get_tool(struct tablet_dispatch *tablet,
		enum libinput_tablet_tool_type type,
		uint32_t tool_id,
		uint32_t serial)
{
	struct libinput_tablet_tool *tool = NULL, *t;
	struct list *tool_list;

	if (serial) {
		struct libinput *libinput = tablet_libinput_context(tablet);
		tool_list = &libinput->tool_list;

		/* Check if we already have the tool in our list of tools */
		list_for_each(t, tool_list, link) {
			if (type == t->type && serial == t->serial) {
				tool = t;
				break;
			}
		}
	} else {
		/* We can't guarantee that tools without serial numbers are
		 * unique, so we keep them local to the tablet that they come
		 * into proximity of instead of storing them in the global tool
		 * list */
		tool_list = &tablet->tool_list;

		/* Same as above, but don't bother checking the serial number */
		list_for_each(t, tool_list, link) {
			if (type == t->type) {
				tool = t;
				break;
			}
		}
	}

	/* If we didn't already have the new_tool in our list of tools,
	 * add it */
	if (!tool) {
		const struct input_absinfo *pressure;

		tool = zalloc(sizeof *tool);
		if (!tool)
			return NULL;
		*tool = (struct libinput_tablet_tool) {
			.type = type,
			.serial = serial,
			.tool_id = tool_id,
			.refcount = 1,
		};

		tool->pressure_offset = 0;
		tool->has_pressure_offset = false;
		tool->pressure_threshold.lower = 0;
		tool->pressure_threshold.upper = 1;

		pressure = libevdev_get_abs_info(tablet->device->evdev,
						 ABS_PRESSURE);
		if (pressure) {
			tool->pressure_offset = pressure->minimum;

			/* 5% of the pressure range */
			tool->pressure_threshold.upper =
				axis_range_percentage(pressure, 5);
			tool->pressure_threshold.lower =
				pressure->minimum;
		}

		tool_set_bits(tablet, tool);

		list_insert(tool_list, &tool->link);
	}

	return tool;
}

static void
tablet_notify_button_mask(struct tablet_dispatch *tablet,
			  struct evdev_device *device,
			  uint64_t time,
			  struct libinput_tablet_tool *tool,
			  const struct button_state *buttons,
			  enum libinput_button_state state)
{
	struct libinput_device *base = &device->base;
	size_t i;
	size_t nbits = 8 * sizeof(buttons->bits);
	enum libinput_tablet_tool_tip_state tip_state;

	tip_state = tablet_has_status(tablet, TABLET_TOOL_IN_CONTACT) ?
			LIBINPUT_TABLET_TOOL_TIP_DOWN : LIBINPUT_TABLET_TOOL_TIP_UP;

	for (i = 0; i < nbits; i++) {
		if (!bit_is_set(buttons->bits, i))
			continue;

		tablet_notify_button(base,
				     time,
				     tool,
				     tip_state,
				     &tablet->axes,
				     i,
				     state);
	}
}

static void
tablet_notify_buttons(struct tablet_dispatch *tablet,
		      struct evdev_device *device,
		      uint64_t time,
		      struct libinput_tablet_tool *tool,
		      enum libinput_button_state state)
{
	struct button_state buttons;

	if (state == LIBINPUT_BUTTON_STATE_PRESSED)
		tablet_get_pressed_buttons(tablet, &buttons);
	else
		tablet_get_released_buttons(tablet, &buttons);

	tablet_notify_button_mask(tablet,
				  device,
				  time,
				  tool,
				  &buttons,
				  state);
}

static void
sanitize_pressure_distance(struct tablet_dispatch *tablet,
			   struct libinput_tablet_tool *tool)
{
	bool tool_in_contact;
	const struct input_absinfo *distance,
	                           *pressure;

	distance = libevdev_get_abs_info(tablet->device->evdev, ABS_DISTANCE);
	pressure = libevdev_get_abs_info(tablet->device->evdev, ABS_PRESSURE);

	if (!pressure || !distance)
		return;

	if (!bit_is_set(tablet->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_DISTANCE) &&
	    !bit_is_set(tablet->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_PRESSURE))
		return;

	tool_in_contact = (pressure->value > tool->pressure_offset);

	/* Keep distance and pressure mutually exclusive */
	if (distance &&
	    (bit_is_set(tablet->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_DISTANCE) ||
	     bit_is_set(tablet->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_PRESSURE)) &&
	    distance->value > distance->minimum &&
	    pressure->value > pressure->minimum) {
		if (tool_in_contact) {
			clear_bit(tablet->changed_axes,
				  LIBINPUT_TABLET_TOOL_AXIS_DISTANCE);
			tablet->axes.distance = 0;
		} else {
			clear_bit(tablet->changed_axes,
				  LIBINPUT_TABLET_TOOL_AXIS_PRESSURE);
			tablet->axes.pressure = 0;
		}
	} else if (bit_is_set(tablet->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_PRESSURE) &&
		   !tool_in_contact) {
		/* Make sure that the last axis value sent to the caller is a 0 */
		if (tablet->axes.pressure == 0)
			clear_bit(tablet->changed_axes,
				  LIBINPUT_TABLET_TOOL_AXIS_PRESSURE);
		else
			tablet->axes.pressure = 0;
	}
}

static inline void
sanitize_mouse_lens_rotation(struct tablet_dispatch *tablet)
{
	/* If we have a mouse/lens cursor and the tilt changed, the rotation
	   changed. Mark this, calculate the angle later */
	if ((tablet->current_tool_type == LIBINPUT_TABLET_TOOL_TYPE_MOUSE ||
	    tablet->current_tool_type == LIBINPUT_TABLET_TOOL_TYPE_LENS) &&
	    (bit_is_set(tablet->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_TILT_X) ||
	     bit_is_set(tablet->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_TILT_Y)))
		set_bit(tablet->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_ROTATION_Z);
}

static void
sanitize_tablet_axes(struct tablet_dispatch *tablet,
		     struct libinput_tablet_tool *tool)
{
	sanitize_pressure_distance(tablet, tool);
	sanitize_mouse_lens_rotation(tablet);
}

static void
detect_pressure_offset(struct tablet_dispatch *tablet,
		       struct evdev_device *device,
		       struct libinput_tablet_tool *tool)
{
	const struct input_absinfo *pressure, *distance;
	int offset;

	if (!bit_is_set(tablet->changed_axes,
			LIBINPUT_TABLET_TOOL_AXIS_PRESSURE))
		return;

	pressure = libevdev_get_abs_info(device->evdev, ABS_PRESSURE);
	distance = libevdev_get_abs_info(device->evdev, ABS_DISTANCE);

	if (!pressure || !distance)
		return;

	offset = pressure->value - pressure->minimum;

	if (tool->has_pressure_offset) {
		if (offset < tool->pressure_offset)
			tool->pressure_offset = offset;
		return;
	}

	if (offset == 0)
		return;

	/* we only set a pressure offset on proximity in */
	if (!tablet_has_status(tablet, TABLET_TOOL_ENTERING_PROXIMITY))
		return;

	/* If we're closer than 50% of the distance axis, skip pressure
	 * offset detection, too likely to be wrong */
	if (distance->value < axis_range_percentage(distance, 50))
		return;

	if (offset > axis_range_percentage(pressure, 20)) {
		log_error(tablet_libinput_context(tablet),
			 "Ignoring pressure offset greater than 20%% detected on tool %s (serial %#x). "
			 "See http://wayland.freedesktop.org/libinput/doc/%s/tablet-support.html\n",
			 tablet_tool_type_to_string(tool->type),
			 tool->serial,
			 LIBINPUT_VERSION);
		return;
	}

	log_info(tablet_libinput_context(tablet),
		 "Pressure offset detected on tool %s (serial %#x).  "
		 "See http://wayland.freedesktop.org/libinput/doc/%s/tablet-support.html\n",
		 tablet_tool_type_to_string(tool->type),
		 tool->serial,
		 LIBINPUT_VERSION);
	tool->pressure_offset = offset;
	tool->has_pressure_offset = true;
}

static void
detect_tool_contact(struct tablet_dispatch *tablet,
		    struct evdev_device *device,
		    struct libinput_tablet_tool *tool)
{
	const struct input_absinfo *p;
	int pressure;

	if (!bit_is_set(tool->axis_caps, LIBINPUT_TABLET_TOOL_AXIS_PRESSURE))
		return;

	/* if we have pressure, always use that for contact, not BTN_TOUCH */
	if (tablet_has_status(tablet, TABLET_TOOL_ENTERING_CONTACT))
		log_bug_libinput(tablet_libinput_context(tablet),
				 "Invalid status: entering contact\n");
	if (tablet_has_status(tablet, TABLET_TOOL_LEAVING_CONTACT) &&
	    !tablet_has_status(tablet, TABLET_TOOL_LEAVING_PROXIMITY))
		log_bug_libinput(tablet_libinput_context(tablet),
				 "Invalid status: leaving contact\n");

	p = libevdev_get_abs_info(tablet->device->evdev, ABS_PRESSURE);
	if (!p) {
		log_bug_libinput(tablet_libinput_context(tablet),
				 "Missing pressure axis\n");
		return;
	}
	pressure = p->value;

	if (tool->has_pressure_offset)
		pressure -= (tool->pressure_offset - p->minimum);

	if (pressure <= tool->pressure_threshold.lower &&
	    tablet_has_status(tablet, TABLET_TOOL_IN_CONTACT)) {
		tablet_set_status(tablet, TABLET_TOOL_LEAVING_CONTACT);
	} else if (pressure >= tool->pressure_threshold.upper &&
		   !tablet_has_status(tablet, TABLET_TOOL_IN_CONTACT)) {
		tablet_set_status(tablet, TABLET_TOOL_ENTERING_CONTACT);
	}
}

static void
tablet_mark_all_axes_changed(struct tablet_dispatch *tablet,
			     struct libinput_tablet_tool *tool)
{
	static_assert(sizeof(tablet->changed_axes) ==
			      sizeof(tool->axis_caps),
		      "Mismatching array sizes");

	memcpy(tablet->changed_axes,
	       tool->axis_caps,
	       sizeof(tablet->changed_axes));
}

static void
tablet_update_proximity_state(struct tablet_dispatch *tablet,
			      struct evdev_device *device,
			      struct libinput_tablet_tool *tool)
{
	const struct input_absinfo *distance;
	int dist_max = tablet->cursor_proximity_threshold;
	int dist;

	distance = libevdev_get_abs_info(tablet->device->evdev, ABS_DISTANCE);
	if (!distance)
		return;

	dist = distance->value;
	if (dist == 0)
		return;

	/* Tool got into permitted range */
	if (dist < dist_max &&
	    (tablet_has_status(tablet, TABLET_TOOL_OUT_OF_RANGE) ||
	     tablet_has_status(tablet, TABLET_TOOL_OUT_OF_PROXIMITY))) {
		tablet_unset_status(tablet,
				    TABLET_TOOL_OUT_OF_RANGE);
		tablet_unset_status(tablet,
				    TABLET_TOOL_OUT_OF_PROXIMITY);
		tablet_set_status(tablet, TABLET_TOOL_ENTERING_PROXIMITY);
		tablet_mark_all_axes_changed(tablet, tool);

		tablet_set_status(tablet, TABLET_BUTTONS_PRESSED);
		tablet_force_button_presses(tablet);
		return;
	}

	if (dist < dist_max)
		return;

	/* Still out of range/proximity */
	if (tablet_has_status(tablet, TABLET_TOOL_OUT_OF_RANGE) ||
	    tablet_has_status(tablet, TABLET_TOOL_OUT_OF_PROXIMITY))
	    return;

	/* Tool entered prox but is outside of permitted range */
	if (tablet_has_status(tablet,
			      TABLET_TOOL_ENTERING_PROXIMITY)) {
		tablet_set_status(tablet,
				  TABLET_TOOL_OUT_OF_RANGE);
		tablet_unset_status(tablet,
				    TABLET_TOOL_ENTERING_PROXIMITY);
		return;
	}

	/* Tool was in prox and is now outside of range. Set leaving
	 * proximity, on the next event it will be OUT_OF_PROXIMITY and thus
	 * caught by the above conditions */
	tablet_set_status(tablet, TABLET_TOOL_LEAVING_PROXIMITY);
}

static void
tablet_send_axis_proximity_tip_down_events(struct tablet_dispatch *tablet,
					   struct evdev_device *device,
					   struct libinput_tablet_tool *tool,
					   uint64_t time)
{
	struct tablet_axes axes = {0};

	/* We need to make sure that we check that the tool is not out of
	 * proximity before we send any axis updates. This is because many
	 * tablets will send axis events with incorrect values if the tablet
	 * tool is close enough so that the tablet can partially detect that
	 * it's there, but can't properly receive any data from the tool. */
	if (tablet_has_status(tablet, TABLET_TOOL_OUT_OF_PROXIMITY))
		goto out;
	else if (tablet_has_status(tablet, TABLET_TOOL_LEAVING_PROXIMITY)) {
		/* Tool is leaving proximity, we can't rely on the last axis
		 * information (it'll be mostly 0), so we just get the
		 * current state and skip over updating the axes.
		 */
		axes = tablet->axes;

		/* Dont' send an axis event, but we may have a tip event
		 * update */
		tablet_unset_status(tablet, TABLET_AXES_UPDATED);
	} else if (!tablet_check_notify_axes(tablet,
					     device,
					     tool,
					     &axes,
					     time)) {
		goto out;
	}

	if (tablet_has_status(tablet, TABLET_TOOL_ENTERING_PROXIMITY)) {
		tablet_notify_proximity(&device->base,
					time,
					tool,
					LIBINPUT_TABLET_TOOL_PROXIMITY_STATE_IN,
					tablet->changed_axes,
					&axes);
		tablet_unset_status(tablet, TABLET_TOOL_ENTERING_PROXIMITY);
		tablet_unset_status(tablet, TABLET_AXES_UPDATED);
	}

	if (tablet_has_status(tablet, TABLET_TOOL_ENTERING_CONTACT)) {
		tablet_notify_tip(&device->base,
				  time,
				  tool,
				  LIBINPUT_TABLET_TOOL_TIP_DOWN,
				  tablet->changed_axes,
				  &tablet->axes);
		tablet_unset_status(tablet, TABLET_AXES_UPDATED);
		tablet_unset_status(tablet, TABLET_TOOL_ENTERING_CONTACT);
		tablet_set_status(tablet, TABLET_TOOL_IN_CONTACT);
	} else if (tablet_has_status(tablet, TABLET_TOOL_LEAVING_CONTACT)) {
		tablet_notify_tip(&device->base,
				  time,
				  tool,
				  LIBINPUT_TABLET_TOOL_TIP_UP,
				  tablet->changed_axes,
				  &tablet->axes);
		tablet_unset_status(tablet, TABLET_AXES_UPDATED);
		tablet_unset_status(tablet, TABLET_TOOL_LEAVING_CONTACT);
		tablet_unset_status(tablet, TABLET_TOOL_IN_CONTACT);
	} else if (tablet_has_status(tablet, TABLET_AXES_UPDATED)) {
		enum libinput_tablet_tool_tip_state tip_state;

		if (tablet_has_status(tablet,
				      TABLET_TOOL_IN_CONTACT))
			tip_state = LIBINPUT_TABLET_TOOL_TIP_DOWN;
		else
			tip_state = LIBINPUT_TABLET_TOOL_TIP_UP;

		tablet_notify_axis(&device->base,
				   time,
				   tool,
				   tip_state,
				   tablet->changed_axes,
				   &axes);
		tablet_unset_status(tablet, TABLET_AXES_UPDATED);
	}

out:
	memset(tablet->changed_axes, 0, sizeof(tablet->changed_axes));
	tablet_unset_status(tablet, TABLET_TOOL_ENTERING_CONTACT);
}

static void
tablet_flush(struct tablet_dispatch *tablet,
	     struct evdev_device *device,
	     uint64_t time)
{
	struct libinput_tablet_tool *tool =
		tablet_get_tool(tablet,
				tablet->current_tool_type,
				tablet->current_tool_id,
				tablet->current_tool_serial);

	if (!tool)
		return; /* OOM */

	if (tool->type == LIBINPUT_TABLET_TOOL_TYPE_MOUSE ||
	    tool->type == LIBINPUT_TABLET_TOOL_TYPE_LENS)
		tablet_update_proximity_state(tablet, device, tool);

	if (tablet_has_status(tablet, TABLET_TOOL_OUT_OF_PROXIMITY) ||
	    tablet_has_status(tablet, TABLET_TOOL_OUT_OF_RANGE))
		return;

	if (tablet_has_status(tablet, TABLET_TOOL_LEAVING_PROXIMITY)) {
		/* Release all stylus buttons */
		memset(tablet->button_state.bits,
		       0,
		       sizeof(tablet->button_state.bits));
		tablet_set_status(tablet, TABLET_BUTTONS_RELEASED);
		if (tablet_has_status(tablet, TABLET_TOOL_IN_CONTACT))
			tablet_set_status(tablet, TABLET_TOOL_LEAVING_CONTACT);
	} else if (tablet_has_status(tablet, TABLET_AXES_UPDATED) ||
		   tablet_has_status(tablet, TABLET_TOOL_ENTERING_PROXIMITY)) {
		if (tablet_has_status(tablet,
				      TABLET_TOOL_ENTERING_PROXIMITY))
			tablet_mark_all_axes_changed(tablet, tool);
		detect_pressure_offset(tablet, device, tool);
		detect_tool_contact(tablet, device, tool);
		sanitize_tablet_axes(tablet, tool);
	}

	tablet_send_axis_proximity_tip_down_events(tablet,
						   device,
						   tool,
						   time);

	if (tablet_has_status(tablet, TABLET_BUTTONS_RELEASED)) {
		tablet_notify_buttons(tablet,
				      device,
				      time,
				      tool,
				      LIBINPUT_BUTTON_STATE_RELEASED);
		tablet_unset_status(tablet, TABLET_BUTTONS_RELEASED);
	}

	if (tablet_has_status(tablet, TABLET_BUTTONS_PRESSED)) {
		tablet_notify_buttons(tablet,
				      device,
				      time,
				      tool,
				      LIBINPUT_BUTTON_STATE_PRESSED);
		tablet_unset_status(tablet, TABLET_BUTTONS_PRESSED);
	}

	if (tablet_has_status(tablet, TABLET_TOOL_LEAVING_PROXIMITY)) {
		memset(tablet->changed_axes, 0, sizeof(tablet->changed_axes));
		tablet_notify_proximity(&device->base,
					time,
					tool,
					LIBINPUT_TABLET_TOOL_PROXIMITY_STATE_OUT,
					tablet->changed_axes,
					&tablet->axes);

		tablet_set_status(tablet, TABLET_TOOL_OUT_OF_PROXIMITY);
		tablet_unset_status(tablet, TABLET_TOOL_LEAVING_PROXIMITY);

		tablet_change_to_left_handed(device);
	}
}

static inline void
tablet_reset_state(struct tablet_dispatch *tablet)
{
	/* Update state */
	memcpy(&tablet->prev_button_state,
	       &tablet->button_state,
	       sizeof(tablet->button_state));
}

static void
tablet_process(struct evdev_dispatch *dispatch,
	       struct evdev_device *device,
	       struct input_event *e,
	       uint64_t time)
{
	struct tablet_dispatch *tablet =
		(struct tablet_dispatch *)dispatch;

	switch (e->type) {
	case EV_ABS:
		tablet_process_absolute(tablet, device, e, time);
		break;
	case EV_REL:
		tablet_process_relative(tablet, device, e, time);
		break;
	case EV_KEY:
		tablet_process_key(tablet, device, e, time);
		break;
	case EV_MSC:
		tablet_process_misc(tablet, device, e, time);
		break;
	case EV_SYN:
		tablet_flush(tablet, device, time);
		tablet_reset_state(tablet);
		break;
	default:
		log_error(tablet_libinput_context(tablet),
			  "Unexpected event type %s (%#x)\n",
			  libevdev_event_type_get_name(e->type),
			  e->type);
		break;
	}
}

static void
tablet_destroy(struct evdev_dispatch *dispatch)
{
	struct tablet_dispatch *tablet =
		(struct tablet_dispatch*)dispatch;
	struct libinput_tablet_tool *tool, *tmp;

	list_for_each_safe(tool, tmp, &tablet->tool_list, link) {
		libinput_tablet_tool_unref(tool);
	}

	free(tablet);
}

static void
tablet_check_initial_proximity(struct evdev_device *device,
			       struct evdev_dispatch *dispatch)
{
	bool tool_in_prox = false;
	int code, state;
	enum libinput_tablet_tool_type tool;
	struct tablet_dispatch *tablet = (struct tablet_dispatch*)dispatch;

	for (tool = LIBINPUT_TABLET_TOOL_TYPE_PEN; tool <= LIBINPUT_TABLET_TOOL_TYPE_MAX; tool++) {
		code = tablet_tool_to_evcode(tool);

		/* we only expect one tool to be in proximity at a time */
		if (libevdev_fetch_event_value(device->evdev,
						EV_KEY,
						code,
						&state) && state) {
			tool_in_prox = true;
			break;
		}
	}

	if (!tool_in_prox)
		return;

	tablet_update_tool(tablet, device, tool, state);

	tablet->current_tool_id =
		libevdev_get_event_value(device->evdev,
					 EV_ABS,
					 ABS_MISC);

	/* we can't fetch MSC_SERIAL from the kernel, so we set the serial
	 * to 0 for now. On the first real event from the device we get the
	 * serial (if any) and that event will be converted into a proximity
	 * event */
	tablet->current_tool_serial = 0;
}

static struct evdev_dispatch_interface tablet_interface = {
	tablet_process,
	NULL, /* suspend */
	NULL, /* remove */
	tablet_destroy,
	NULL, /* device_added */
	NULL, /* device_removed */
	NULL, /* device_suspended */
	NULL, /* device_resumed */
	tablet_check_initial_proximity,
};

static void
tablet_init_calibration(struct tablet_dispatch *tablet,
			struct evdev_device *device)
{
	if (libevdev_has_property(device->evdev, INPUT_PROP_DIRECT))
		evdev_init_calibration(device, &tablet->base);
}

static void
tablet_init_proximity_threshold(struct tablet_dispatch *tablet,
				struct evdev_device *device)
{
	/* This rules out most of the bamboos and other devices, we're
	 * pretty much down to
	 */
	if (!libevdev_has_event_code(device->evdev, EV_KEY, BTN_TOOL_MOUSE) &&
	    !libevdev_has_event_code(device->evdev, EV_KEY, BTN_TOOL_LENS))
		return;

	/* 42 is the default proximity threshold the xf86-input-wacom driver
	 * uses for Intuos/Cintiq models. Graphire models have a threshold
	 * of 10 but since they haven't been manufactured in ages and the
	 * intersection of users having a graphire, running libinput and
	 * wanting to use the mouse/lens cursor tool is small enough to not
	 * worry about it for now. If we need to, we can introduce a udev
	 * property later.
	 *
	 * Value is in device coordinates.
	 */
	tablet->cursor_proximity_threshold = 42;
}

static uint32_t
tablet_accel_config_get_profiles(struct libinput_device *libinput_device)
{
	return LIBINPUT_CONFIG_ACCEL_PROFILE_NONE;
}

static enum libinput_config_status
tablet_accel_config_set_profile(struct libinput_device *libinput_device,
			    enum libinput_config_accel_profile profile)
{
	return LIBINPUT_CONFIG_STATUS_UNSUPPORTED;
}

static enum libinput_config_accel_profile
tablet_accel_config_get_profile(struct libinput_device *libinput_device)
{
	return LIBINPUT_CONFIG_ACCEL_PROFILE_NONE;
}

static enum libinput_config_accel_profile
tablet_accel_config_get_default_profile(struct libinput_device *libinput_device)
{
	return LIBINPUT_CONFIG_ACCEL_PROFILE_NONE;
}

static int
tablet_init_accel(struct tablet_dispatch *tablet, struct evdev_device *device)
{
	const struct input_absinfo *x, *y;
	struct motion_filter *filter;
	int rc;

	x = device->abs.absinfo_x;
	y = device->abs.absinfo_y;

	filter = create_pointer_accelerator_filter_tablet(x->resolution,
							  y->resolution);

	rc = evdev_device_init_pointer_acceleration(device, filter);
	if (rc != 0)
		return rc;

	/* we override the profile hooks for accel configuration with hooks
	 * that don't allow selection of profiles */
	device->pointer.config.get_profiles = tablet_accel_config_get_profiles;
	device->pointer.config.set_profile = tablet_accel_config_set_profile;
	device->pointer.config.get_profile = tablet_accel_config_get_profile;
	device->pointer.config.get_default_profile = tablet_accel_config_get_default_profile;

	return 0;
}

static void
tablet_init_left_handed(struct evdev_device *device)
{
	if (evdev_tablet_has_left_handed(device))
		    evdev_init_left_handed(device,
					   tablet_change_to_left_handed);
}

static int
tablet_reject_device(struct evdev_device *device)
{
	struct libevdev *evdev = device->evdev;
	int rc = -1;

	if (!libevdev_has_event_code(evdev, EV_ABS, ABS_X) ||
	    !libevdev_has_event_code(evdev, EV_ABS, ABS_Y))
		goto out;

	if (!libevdev_has_event_code(evdev, EV_KEY, BTN_TOOL_PEN))
		goto out;

	rc = 0;

out:
	if (rc) {
		log_bug_libinput(evdev_libinput_context(device),
				 "Device '%s' does not meet tablet criteria. "
				 "Ignoring this device.\n",
				 device->devname);
	}
	return rc;
}

static int
tablet_init(struct tablet_dispatch *tablet,
	    struct evdev_device *device)
{
	enum libinput_tablet_tool_axis axis;
	int rc;

	tablet->base.interface = &tablet_interface;
	tablet->device = device;
	tablet->status = TABLET_NONE;
	tablet->current_tool_type = LIBINPUT_TOOL_NONE;
	list_init(&tablet->tool_list);

	if (tablet_reject_device(device))
		return -1;

	tablet_init_calibration(tablet, device);
	tablet_init_proximity_threshold(tablet, device);
	rc = tablet_init_accel(tablet, device);
	if (rc != 0)
		return rc;

	tablet_init_left_handed(device);

	for (axis = LIBINPUT_TABLET_TOOL_AXIS_X;
	     axis <= LIBINPUT_TABLET_TOOL_AXIS_MAX;
	     axis++) {
		if (tablet_device_has_axis(tablet, axis))
			set_bit(tablet->axis_caps, axis);
	}

	tablet_set_status(tablet, TABLET_TOOL_OUT_OF_PROXIMITY);

	return 0;
}

struct evdev_dispatch *
evdev_tablet_create(struct evdev_device *device)
{
	struct tablet_dispatch *tablet;

	tablet = zalloc(sizeof *tablet);
	if (!tablet)
		return NULL;

	if (tablet_init(tablet, device) != 0) {
		tablet_destroy(&tablet->base);
		return NULL;
	}

	return &tablet->base;
}