/*
 * Copyright © 2006 Keith Packard
 *
 * 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 "randrstr.h"

/**
 * Returns the width/height that the crtc scans out from the framebuffer
 */
static void
RRCrtcGetScanoutSize(RRCrtcPtr crtc, int *width, int *height)
{
    if (crtc->mode == NULL) {
	*width = 0;
	*height = 0;
	return;
    }

    switch (crtc->rotation & 0xf) {
    case RR_Rotate_0:
    case RR_Rotate_180:
	*width = crtc->mode->mode.width;
	*height = crtc->mode->mode.height;
	break;
    case RR_Rotate_90:
    case RR_Rotate_270:
	*width = crtc->mode->mode.height;
	*height = crtc->mode->mode.width;
	break;
    }
}

/*
 * When the pointer moves, check to see if the specified position is outside
 * any of theavailable CRTCs and move it to a 'sensible' place if so, where
 * sensible is the closest monitor to the departing edge.
 *
 * Returns whether the position was adjusted
 */

static Bool
RRCrtcContainsPosition (RRCrtcPtr crtc, int x, int y)
{
    RRModePtr   mode = crtc->mode;
    int		scan_width, scan_height;

    if (!mode)
	return FALSE;

    RRCrtcGetScanoutSize (crtc, &scan_width, &scan_height);

    if (crtc->x <= x && x < crtc->x + scan_width &&
	crtc->y <= y && y < crtc->y + scan_height)
	return TRUE;
    return FALSE;
}

/*
 * Find the CRTC nearest the specified position, ignoring 'skip'
 */
static void
RRPointerToNearestCrtc (ScreenPtr pScreen, int x, int y, RRCrtcPtr skip)
{
    rrScrPriv (pScreen);
    int		c;
    RRCrtcPtr	nearest = NULL;
    int		best = 0;
    int		best_dx = 0, best_dy = 0;

    for (c = 0; c < pScrPriv->numCrtcs; c++)
    {
	RRCrtcPtr   crtc = pScrPriv->crtcs[c];
	RRModePtr   mode = crtc->mode;
	int	    dx, dy;
	int	    dist;
	int	    scan_width, scan_height;

	if (!mode)
	    continue;
	if (crtc == skip)
	    continue;

	RRCrtcGetScanoutSize (crtc, &scan_width, &scan_height);

	if (x < crtc->x)
	    dx = crtc->x - x;
	else if (x > crtc->x + scan_width)
	    dx = x - (crtc->x + scan_width);
	else
	    dx = 0;
	if (y < crtc->y)
	    dy = crtc->y - x;
	else if (y > crtc->y + scan_height)
	    dy = y - (crtc->y + scan_height);
	else
	    dy = 0;
	dist = dx + dy;
	if (!nearest || dist < best)
	{
	    nearest = crtc;
	    best_dx = dx;
	    best_dy = dy;
	}
    }
    if (best_dx || best_dy)
	(*pScreen->SetCursorPosition) (pScreen, x + best_dx, y + best_dy, TRUE);
    pScrPriv->pointerCrtc = nearest;
}

void
RRPointerMoved (ScreenPtr pScreen, int x, int y)
{
    rrScrPriv (pScreen);
    RRCrtcPtr	pointerCrtc = pScrPriv->pointerCrtc;;
    int	c;

    /* Check last known CRTC */
    if (pointerCrtc && RRCrtcContainsPosition (pointerCrtc, x, y))
	return;
    
    /* Check all CRTCs */
    for (c = 0; c < pScrPriv->numCrtcs; c++)
    {
	RRCrtcPtr   crtc = pScrPriv->crtcs[c];
	
	if (RRCrtcContainsPosition (crtc, x, y))
	{
	    /* Remember containing CRTC */
	    pScrPriv->pointerCrtc = crtc;
	    return;
	}
    }

    /* None contain pointer, find nearest */
    RRPointerToNearestCrtc (pScreen, x, y, pointerCrtc);
}

/*
 * When the screen is reconfigured, move the pointer to the nearest
 * CRTC
 */
void
RRPointerScreenConfigured (ScreenPtr pScreen)
{
    WindowPtr	pRoot = GetCurrentRootWindow ();
    ScreenPtr	pCurrentScreen = pRoot ? pRoot->drawable.pScreen : NULL;
    int		x, y;

    if (pScreen != pCurrentScreen)
	return;
    GetSpritePosition (&x, &y);
    RRPointerToNearestCrtc (pScreen, x, y, NULL);
}