/*
 * Input Multitouch Library
 *
 * Copyright (c) 2008-2010 Henrik Rydberg
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#include "input-mt.h"


#define TRKID_BITS	16
#define TRKID_MAX	((1 << TRKID_BITS) - 1)
#define TRKID_SGN	(1 << (TRKID_BITS - 1))

static int trkid; // destined for input_dev

int input_mt_create_slots_new(struct input_dev *dev, unsigned int num_slots)
{
	int ret;

	ret = input_mt_create_slots(dev, num_slots);
	if (ret)
		return ret;

	input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 0);

	return 0;
}

/**
 * input_mt_report_state() - report contact state
 * @dev: input device with allocated MT slots
 * @active: true if contact is active, false otherwise
 *
 * Reports an active touch via ABS_MT_TRACKING_ID. If active is
 * true and the slot is currently inactive, a new tracking id is
 * assigned to the slot.
 */
void input_mt_report_state(struct input_dev *dev, bool active)
{
	int id = -1;

	if (dev->mt && active) {
		id = input_mt_get_value(&dev->mt[dev->slot], ABS_MT_TRACKING_ID);
		if (id < 0)
			id = trkid++ & TRKID_MAX;
	}

	input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id);
}

/**
 * input_mt_report_emulation() - common pointer emulation
 * @dev: input device with allocated MT slots
 *
 * Performs legacy emulation emulation via BTN_TOUCH, etc.
 */
void input_mt_report_emulation(struct input_dev *dev)
{
	struct input_mt_slot *oldest = 0;
	int oldid = -1;
	int count = 0;
	int i;

	for (i = 0; i < dev->mtsize; ++i) {
		struct input_mt_slot *slot = &dev->mt[i];
		int id = input_mt_get_value(slot, ABS_MT_TRACKING_ID);

		if (id < 0)
			continue;

		if (!oldest || ((id - oldid) & TRKID_SGN)) {
			oldest = slot;
			oldid = id;
		}
		count++;
	}

	input_event(dev, EV_KEY, BTN_TOUCH, count > 0);
	input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1);
	input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2);
	input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3);
	input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count > 3);

	if (oldest) {
		int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);
		int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);
		int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);

		input_event(dev, EV_ABS, ABS_X, x);
		input_event(dev, EV_ABS, ABS_Y, y);
		input_event(dev, EV_ABS, ABS_PRESSURE, p);
	} else {
		input_event(dev, EV_ABS, ABS_PRESSURE, 0);
	}
}


/* generated by mtdev-kernel - do not edit */
static const u8 match_data[] = {
	0, 0, 1, 0, 1, 2, 0, 1, 2, 3, 0, 0, 0, 0, 1, 1,
	1, 0, 0, 0, 1, 2, 1, 1, 0, 2, 2, 1, 2, 0, 0, 0,
	1, 2, 3, 1, 1, 0, 2, 3, 2, 1, 2, 0, 3, 3, 1, 2,
	3, 0, 0, 0, 1, 1, 1, 2, 1, 0, 0, 3, 0, 1, 1, 3,
	1, 0, 2, 2, 3, 1, 2, 0, 0, 4, 0, 1, 2, 2, 4, 2,
	1, 0, 0, 5, 0, 2, 1, 1, 5, 2, 0, 1, 1, 4, 1, 0,
	2, 3, 2, 4, 1, 2, 0, 3, 3, 4, 1, 2, 3, 0, 0, 5,
	0, 1, 2, 3, 2, 5, 2, 1, 0, 3, 3, 5, 2, 1, 3, 0,
	0, 6, 0, 2, 1, 3, 1, 6, 2, 0, 1, 3, 3, 6, 2, 3,
	1, 0, 0, 7, 0, 2, 3, 1, 1, 7, 2, 0, 3, 1, 2, 7,
	2, 3, 0, 1, 0, 0, 1, 1, 2, 2, 1, 2, 1, 0, 0, 3,
	0, 1, 1, 4, 2, 0, 3, 4, 2, 1, 0, 5, 0, 2, 2, 5,
	1, 2, 2, 4, 6, 2, 1, 0, 1, 5, 6, 2, 0, 1, 2, 3,
	7, 1, 2, 0, 0, 5, 7, 0, 2, 1, 1, 3, 8, 1, 0, 2,
	0, 4, 8, 0, 1, 2, 2, 5, 8, 2, 1, 0, 3, 3, 5, 8,
	2, 1, 3, 0, 1, 6, 8, 2, 0, 1, 3, 3, 6, 8, 2, 3,
	1, 0, 1, 7, 8, 2, 0, 3, 1, 2, 7, 8, 2, 3, 0, 1,
	2, 4, 9, 1, 2, 0, 3, 3, 4, 9, 1, 2, 3, 0, 0, 6,
	9, 0, 2, 1, 3, 3, 6, 9, 3, 2, 1, 0, 0, 7, 9, 0,
	2, 3, 1, 2, 7, 9, 3, 2, 0, 1, 1, 4, 10, 1, 0, 2,
	3, 3, 4, 10, 1, 3, 2, 0, 0, 5, 10, 0, 1, 2, 3, 3,
	5, 10, 3, 1, 2, 0, 0, 7, 10, 0, 3, 2, 1, 1, 7, 10,
	3, 0, 2, 1, 1, 4, 11, 1, 0, 3, 2, 2, 4, 11, 1, 3,
	0, 2, 0, 5, 11, 0, 1, 3, 2, 2, 5, 11, 3, 1, 0, 2,
	0, 6, 11, 0, 3, 1, 2, 1, 6, 11, 3, 0, 1, 2, 0, 0,
	1, 1, 2, 2, 3, 3, 1, 2, 1, 0, 0, 3, 0, 1, 1, 4,
	2, 0, 3, 4, 2, 1, 0, 5, 0, 2, 2, 5, 1, 2, 1, 6,
	3, 0, 3, 6, 3, 1, 5, 6, 3, 2, 0, 7, 0, 3, 2, 7,
	1, 3, 4, 7, 2, 3, 2, 4, 6, 2, 1, 0, 1, 5, 6, 2,
	0, 1, 2, 3, 7, 1, 2, 0, 0, 5, 7, 0, 2, 1, 1, 3,
	8, 1, 0, 2, 0, 4, 8, 0, 1, 2, 2, 4, 9, 3, 1, 0,
	1, 5, 9, 3, 0, 1, 2, 7, 9, 3, 2, 0, 5, 7, 9, 3,
	2, 1, 1, 8, 9, 3, 0, 2, 4, 8, 9, 3, 1, 2, 2, 3,
	10, 1, 3, 0, 0, 5, 10, 0, 3, 1, 2, 6, 10, 2, 3, 0,
	5, 6, 10, 2, 3, 1, 0, 8, 10, 0, 3, 2, 3, 8, 10, 1,
	3, 2, 1, 3, 11, 1, 0, 3, 0, 4, 11, 0, 1, 3, 1, 6,
	11, 2, 0, 3, 4, 6, 11, 2, 1, 3, 0, 7, 11, 0, 2, 3,
	3, 7, 11, 1, 2, 3, 3, 6, 9, 12, 3, 2, 1, 0, 2, 7,
	9, 12, 3, 2, 0, 1, 3, 5, 10, 12, 3, 1, 2, 0, 1, 7,
	10, 12, 3, 0, 2, 1, 2, 5, 11, 12, 3, 1, 0, 2, 1, 6,
	11, 12, 3, 0, 1, 2, 3, 6, 8, 13, 2, 3, 1, 0, 2, 7,
	8, 13, 2, 3, 0, 1, 3, 4, 10, 13, 1, 3, 2, 0, 0, 7,
	10, 13, 0, 3, 2, 1, 2, 4, 11, 13, 1, 3, 0, 2, 0, 6,
	11, 13, 0, 3, 1, 2, 3, 5, 8, 14, 2, 1, 3, 0, 1, 7,
	8, 14, 2, 0, 3, 1, 3, 4, 9, 14, 1, 2, 3, 0, 0, 7,
	9, 14, 0, 2, 3, 1, 1, 4, 11, 14, 1, 0, 3, 2, 0, 5,
	11, 14, 0, 1, 3, 2, 2, 5, 8, 15, 2, 1, 0, 3, 1, 6,
	8, 15, 2, 0, 1, 3, 2, 4, 9, 15, 1, 2, 0, 3, 0, 6,
	9, 15, 0, 2, 1, 3, 1, 4, 10, 15, 1, 0, 2, 3, 0, 5,
	10, 15, 0, 1, 2, 3,
};

/* generated by mtdev-kernel - do not edit */
static const int match_index[][5] = {
	{ 0, 0, 1, 3, 6 },
	{ 10, 10, 12, 18, 30 },
	{ 50, 50, 54, 62, 92 },
	{ 164, 164, 170, 194, 230 },
	{ 398, 398, 406, 454, 598 },
	{ 790 }
};

static void set_dist(u32 *dist,
		     const struct trk_coord *b1, const struct trk_coord *e1,
		     const struct trk_coord *b2, const struct trk_coord *e2)
{
	const struct trk_coord *p, *q;

	for (p = b1; p != e1; p++)
		for (q = b2; q != e2; q++)
			*dist++ = abs(q->x - p->x) + abs(q->y - p->y);
}

const u8 *match_four(const struct trk_coord *old, int nslot,
		     const struct trk_coord *pos, int npos)
{
	u32 d[16], obj, t;
	const u8 *p, *b, *e;
	const int *at;

	set_dist(d, old, old + nslot, pos, pos + npos);

	at = &match_index[nslot][npos];
	b = &match_data[at[0]];
	e = &match_data[at[1]];

	obj = UINT_MAX, p = b;

	switch (min(nslot, npos)) {
	case 1:
		for (; b != e; b += npos) {
			t = d[*b++];
			if (t < obj)
				obj = t, p = b;
		}
		break;
	case 2:
		for (; b != e; b += npos) {
			t = d[*b++], t += d[*b++];
			if (t < obj)
				obj = t, p = b;
		}
		break;
	case 3:
		for (; b != e; b += npos) {
			t = d[*b++], t += d[*b++], t += d[*b++];
			if (t < obj)
				obj = t, p = b;
		}
		break;
	case 4:
		for (; b != e; b += npos) {
			t = d[*b++], t += d[*b++], t += d[*b++], t += d[*b++];
			if (t < obj)
				obj = t, p = b;
		}
		break;
	}

	return p;
}

/**
 * input_mt_assign_slots_by_coord() - perform a best-match assignment
 * @dev: input device with allocated MT slots
 * @slots: the slot assignment to be filled
 * @coords: the coordinate array to match
 * @num_coords: number of coordinates
 *
 * Performs a best match against the current contacts and returns
 * the slot assignment list. New contacts are assigned to unused
 * slots.
 *
 * Returns zero on success, or negative error in case of failure.
 */
int input_mt_assign_slots_by_coord(struct input_dev *dev, int *slots,
				   const struct trk_coord *coords,
				   int num_coords)
{
	struct trk_coord old[4];
	int old2slot[4], nold, i;
	const u8 *p;

	if (!dev->mt)
		return -ENXIO;
	if (dev->mtsize < 2 || dev->mtsize > 4)
		return -ENXIO;
	if (num_coords > dev->mtsize)
		return -EINVAL;
	if (num_coords < 1)
		return 0;

	nold = 0;
	for (i = 0; i < dev->mtsize; i++) {
		const struct input_mt_slot *mt = &dev->mt[i];
		if (input_mt_get_value(mt, ABS_MT_TRACKING_ID) < 0)
			continue;
		old[nold].x = input_mt_get_value(mt, ABS_MT_POSITION_X);
		old[nold].y = input_mt_get_value(mt, ABS_MT_POSITION_Y);
		old2slot[nold++] = i;
	}

	p = match_four(old, nold, coords, num_coords);

	for (i = 0; i < dev->mtsize; i++)
		if (input_mt_get_value(&dev->mt[i], ABS_MT_TRACKING_ID) < 0)
			old2slot[nold++] = i;

	for (i = 0; i < num_coords; i++)
		slots[i] = old2slot[p[i]];

	return 0;
}


/**
 * input_mt_sync_slot_complement() - send touchup for remaining slots
 * @dev: input device with allocated MT slots
 * @slots: the slot assignment to be filled
 * @coords: the coordinate array to match
 * @num_coords: number of coordinates
 *
 * Performs a best match against the current contacts and returns
 * the slot assignment list. New contacts are assigned to unused
 * slots.
 *
 * Returns zero on success, or negative error in case of failure.
 */
void input_mt_sync_slot_complement(struct input_dev *dev,
				   const int *slots,  int num_slots)
{
	unsigned long mask = 0;
	int i;

	for (i = 0; i < num_slots; i++)
		mask |= BIT(slots[i]);

	for (i = 0; i < dev->mtsize; i++) {
		if (mask & BIT(i))
			continue;
		input_mt_slot(dev, i);
		input_mt_report_state(dev, false);
	}
}