/* -- xdamage.c -- */

#include "x11vnc.h"
#include "xwrappers.h"
#include "userinput.h"
#include "unixpw.h"

#if LIBVNCSERVER_HAVE_LIBXDAMAGE
Damage xdamage = 0;
#endif
#ifndef XDAMAGE
#define XDAMAGE 1
#endif
int use_xdamage = XDAMAGE;	/* use the xdamage rects for scanline hints */
int xdamage_present = 0;
int xdamage_max_area = 20000;	/* pixels */
double xdamage_memory = 1.0;	/* in units of NSCAN */
int xdamage_tile_count = 0, xdamage_direct_count = 0;
double xdamage_scheduled_mark = 0.0;
sraRegionPtr xdamage_scheduled_mark_region = NULL;
sraRegionPtr *xdamage_regions = NULL;
int xdamage_ticker = 0;
int XD_skip = 0, XD_tot = 0, XD_des = 0;	/* for stats */

void add_region_xdamage(sraRegionPtr new_region);
void clear_xdamage_mark_region(sraRegionPtr markregion, int flush);
int collect_xdamage(int scancnt, int call);
int xdamage_hint_skip(int y);
void initialize_xdamage(void);
void create_xdamage_if_needed(void);
void destroy_xdamage_if_needed(void);
void check_xdamage_state(void);


static void record_desired_xdamage_rect(int x, int y, int w, int h);


static void record_desired_xdamage_rect(int x, int y, int w, int h) {
	/*
	 * Unfortunately we currently can't trust an xdamage event
	 * to correspond to real screen damage.  E.g. focus-in for
	 * mozilla (depending on wm) will mark the whole toplevel
	 * area as damaged, when only the border has changed.
	 * Similar things for terminal windows.
	 *
	 * This routine uses some heuristics to detect small enough
	 * damage regions that we will not have a performance problem
	 * if we believe them even though they are wrong.  We record
	 * the corresponding tiles the damage regions touch.
	 */
	int dt_x, dt_y, nt_x1, nt_y1, nt_x2, nt_y2, nt;
	int ix, iy, cnt = 0;
	int area = w*h, always_accept = 0;
	/*
	 * XXX: not working yet, slow and overlaps with scan_display()
	 * probably slow because tall skinny rectangles very inefficient
	 * in general and in direct_fb_copy() (100X slower then horizontal).
	 */
	int use_direct_fb_copy = 0;
	int wh_min, wh_max;
	static int first = 1, udfb = 0;

	/* compiler warning: */
	nt_x1 = 0; nt_y1 = 0; nt_x2 = 0; nt_y2 = 0;

	if (first) {
		if (getenv("XD_DFC")) {
			udfb = 1;
		}
		first = 0;
	}
	if (udfb) {
		use_direct_fb_copy = 1;
	}

	if (xdamage_max_area <= 0) {
		always_accept = 1;
	}

	if (!always_accept && area > xdamage_max_area) {
		return;
	}

	dt_x = w / tile_x;
	dt_y = h / tile_y;

	if (w < h) {
		wh_min = w;
		wh_max = h;
	} else {
		wh_min = h;
		wh_max = w;
	}

	if (!always_accept && dt_y >= 3 && area > 4000)  {
		/*
		 * if it is real it should be caught by a normal scanline
		 * poll, but we might as well keep if small (tall line?).
		 */
		return;
	}
	
	if (use_direct_fb_copy) {
		X_UNLOCK;
		direct_fb_copy(x, y, x + w, y + h, 1);
		xdamage_direct_count++;
		X_LOCK;
	} else if (0 && wh_min < tile_x/4 && wh_max > 30 * wh_min) {
		/* try it for long, skinny rects, XXX still no good */
		X_UNLOCK;
		direct_fb_copy(x, y, x + w, y + h, 1);
		xdamage_direct_count++;
		X_LOCK;
	} else {
		nt_x1 = nfix(  (x)/tile_x, ntiles_x);
		nt_x2 = nfix((x+w)/tile_x, ntiles_x);
		nt_y1 = nfix(  (y)/tile_y, ntiles_y);
		nt_y2 = nfix((y+h)/tile_y, ntiles_y);

		/*
		 * loop over the rectangle of tiles (1 tile for a small
		 * input rect).
		 */
		for (ix = nt_x1; ix <= nt_x2; ix++) {
			for (iy = nt_y1; iy <= nt_y2; iy++) {
				nt = ix + iy * ntiles_x;
				cnt++;
				if (! tile_has_xdamage_diff[nt]) {
					XD_des++;
					tile_has_xdamage_diff[nt] = 1;
				}
				/* not used: */
				tile_row_has_xdamage_diff[iy] = 1;
				xdamage_tile_count++;
			}
		}
	}
	if (debug_xdamage > 1) {
		fprintf(stderr, "xdamage: desired: %dx%d+%d+%d\tA: %6d  tiles="
		    "%02d-%02d/%02d-%02d  tilecnt: %d\n", w, h, x, y,
		    w * h, nt_x1, nt_x2, nt_y1, nt_y2, cnt);
	}
}

void add_region_xdamage(sraRegionPtr new_region) {
	sraRegionPtr reg;
	int prev_tick, nreg;

	if (! xdamage_regions) {
		return;
	}

	nreg = (xdamage_memory * NSCAN) + 1;
	prev_tick = xdamage_ticker - 1;
	if (prev_tick < 0) {
		prev_tick = nreg - 1;
	}

	reg = xdamage_regions[prev_tick];  
	if (reg != NULL) {
if (0) fprintf(stderr, "add_region_xdamage: prev_tick: %d reg %p\n", prev_tick, (void *)reg);
		sraRgnOr(reg, new_region);
	}
}

void clear_xdamage_mark_region(sraRegionPtr markregion, int flush) {
#if LIBVNCSERVER_HAVE_LIBXDAMAGE
	XEvent ev;
	sraRegionPtr tmpregion;
	int count = 0;

	if (! xdamage_present || ! use_xdamage) {
		return;
	}
	if (! xdamage) {
		return;
	}
	if (! xdamage_base_event_type) {
		return;
	}
	if (unixpw_in_progress) return;

	X_LOCK;
	if (flush) {
		XFlush(dpy);
	}
	while (XCheckTypedEvent(dpy, xdamage_base_event_type+XDamageNotify, &ev)) {
		count++;
	}
	/* clear the whole damage region */
	XDamageSubtract(dpy, xdamage, None, None);
	X_UNLOCK;

	if (debug_tiles || debug_xdamage) {
		fprintf(stderr, "clear_xdamage_mark_region: %d\n", count);
	}

	if (! markregion) {
		/* NULL means mark the whole display */
		tmpregion = sraRgnCreateRect(0, 0, dpy_x, dpy_y);
		add_region_xdamage(tmpregion);
		sraRgnDestroy(tmpregion);
	} else {
		add_region_xdamage(markregion);
	}
#else
	if (0) flush++;        /* compiler warnings */
	if (0) markregion = NULL;   
#endif
}

int collect_xdamage(int scancnt, int call) {
#if LIBVNCSERVER_HAVE_LIBXDAMAGE
	XDamageNotifyEvent *dev;
	XEvent ev;
	sraRegionPtr tmpregion;
	sraRegionPtr reg;
	static int rect_count = 0;
	int nreg, ccount = 0, dcount = 0, ecount = 0;
	static time_t last_rpt = 0;
	time_t now;
	int x, y, w, h, x2, y2;
	int i, dup, next = 0, dup_max = 0;
#define DUPSZ 32
	int dup_x[DUPSZ], dup_y[DUPSZ], dup_w[DUPSZ], dup_h[DUPSZ];
	double tm, dt;

	if (scancnt) {} /* unused vars warning: */

	if (! xdamage_present || ! use_xdamage) {
		return 0;
	}
	if (! xdamage) {
		return 0;
	}
	if (! xdamage_base_event_type) {
		return 0;
	}

	dtime0(&tm);

	nreg = (xdamage_memory * NSCAN) + 1;

	if (call == 0) {
		xdamage_ticker = (xdamage_ticker+1) % nreg;
		xdamage_direct_count = 0;
		reg = xdamage_regions[xdamage_ticker];  
		sraRgnMakeEmpty(reg);
	} else {
		reg = xdamage_regions[xdamage_ticker];  
	}


	X_LOCK;
if (0)	XFlush(dpy);
if (0)	XEventsQueued(dpy, QueuedAfterFlush);
	while (XCheckTypedEvent(dpy, xdamage_base_event_type+XDamageNotify, &ev)) {
		/*
		 * TODO max cut off time in this loop?
		 * Could check QLength and if huge just mark the whole
		 * screen.
		 */
		ecount++;
		if (ev.type != xdamage_base_event_type + XDamageNotify) {
			break;
		}
		dev = (XDamageNotifyEvent *) &ev;
		if (dev->damage != xdamage) {
			continue;	/* not ours! */
		}

		x = dev->area.x;
		y = dev->area.y;
		w = dev->area.width;
		h = dev->area.height;

		/*
		 * we try to manually remove some duplicates because
		 * certain activities can lead to many 10's of dups
		 * in a row.  The region work can be costly and reg is
		 * later used in xdamage_hint_skip loops, so it is good
		 * to skip them if possible.
		 */
		dup = 0;
		for (i=0; i < dup_max; i++) {
			if (dup_x[i] == x && dup_y[i] == y && dup_w[i] == w &&
			    dup_h[i] == h) {
				dup = 1;
				break;
			}
		}
		if (dup) {
			dcount++;
			continue;
		}
		if (dup_max < DUPSZ) {
			next = dup_max;
			dup_max++;
		} else {
			next = (next+1) % DUPSZ;
		}
		dup_x[next] = x;
		dup_y[next] = y;
		dup_w[next] = w;
		dup_h[next] = h;

		/* translate if needed */
		if (clipshift) {
			/* set coords relative to fb origin */
			if (0 && rootshift) {
				/*
				 * Note: not needed because damage is
				 * relative to subwin, not rootwin.
				 */
				x = x - off_x;
				y = y - off_y;
			}
			if (clipshift) {
				x = x - coff_x;
				y = y - coff_y;
			}

			x2 = x + w;		/* upper point */
			x  = nfix(x,  dpy_x);	/* place both in fb area */
			x2 = nfix(x2, dpy_x+1);
			w = x2 - x;		/* recompute w */
			
			y2 = y + h;
			y  = nfix(y,  dpy_y);
			y2 = nfix(y2, dpy_y+1);
			h = y2 - y;

			if (w <= 0 || h <= 0) {
				continue;
			}
		}
		if (debug_xdamage > 2) {
			fprintf(stderr, "xdamage: -> event %dx%d+%d+%d area:"
			    " %d  dups: %d  %s\n", w, h, x, y, w*h, dcount,
			    (w*h > xdamage_max_area) ? "TOO_BIG" : "");
		}

		record_desired_xdamage_rect(x, y, w, h);

		tmpregion = sraRgnCreateRect(x, y, x + w, y + h); 
		sraRgnOr(reg, tmpregion);
		sraRgnDestroy(tmpregion);
		rect_count++;
		ccount++;
	}
	/* clear the whole damage region for next time. XXX check */
	if (call == 1) {
		XDamageSubtract(dpy, xdamage, None, None);
	}
	X_UNLOCK;

	if (0 && xdamage_direct_count) {
		fb_push();
	}

	dt = dtime(&tm);
	if ((debug_tiles > 1 && ecount) || (debug_tiles && ecount > 200)
	    || debug_xdamage > 1) {
		fprintf(stderr, "collect_xdamage(%d): %.4f t: %.4f ev/dup/accept"
		    "/direct %d/%d/%d/%d\n", call, dt, tm - x11vnc_start, ecount,
		    dcount, ccount, xdamage_direct_count); 
	}
	now = time(0);
	if (! last_rpt) {
		last_rpt = now;
	}
	if (now > last_rpt + 15) {
		double rat = -1.0;

		if (XD_tot) {
			rat = ((double) XD_skip)/XD_tot;
		}
		if (debug_tiles || debug_xdamage) {
			fprintf(stderr, "xdamage: == scanline skip/tot: "
			    "%04d/%04d =%.3f  rects: %d  desired: %d\n",
			    XD_skip, XD_tot, rat, rect_count, XD_des);
		}
			
		XD_skip = 0;
		XD_tot  = 0;
		XD_des  = 0;
		rect_count = 0;
		last_rpt = now;
	}
#else
	if (0) scancnt++;	/* compiler warnings */
	if (0) call++;
	if (0) record_desired_xdamage_rect(0, 0, 0, 0);
#endif
	return 0;
}

int xdamage_hint_skip(int y) {
	static sraRegionPtr scanline = NULL;
	sraRegionPtr reg, tmpl;
	int ret, i, n, nreg;

	if (! xdamage_present || ! use_xdamage) {
		return 0;	/* cannot skip */
	}
	if (! xdamage_regions) {
		return 0;	/* cannot skip */
	}

	if (! scanline) {
		/* keep it around to avoid malloc etc, recreate */
		scanline = sraRgnCreate();
	}

	tmpl = sraRgnCreateRect(0, y, dpy_x, y+1);

	nreg = (xdamage_memory * NSCAN) + 1;
	ret = 1;
	for (i=0; i<nreg; i++) {
		/* go back thru the history starting at most recent */
		n = (xdamage_ticker + nreg - i) % nreg;
		reg = xdamage_regions[n];  
		if (sraRgnEmpty(reg)) {
			/* checking for emptiness is very fast */
			continue;
		}
		sraRgnMakeEmpty(scanline);
		sraRgnOr(scanline, tmpl);
		if (sraRgnAnd(scanline, reg)) {
			ret = 0;
			break;
		}
	}
	sraRgnDestroy(tmpl);

	return ret;
}

void initialize_xdamage(void) {
	sraRegionPtr *ptr;
	int i, nreg;

	if (! xdamage_present) {
		use_xdamage = 0;
	}
	if (xdamage_regions)  {
		ptr = xdamage_regions;
		while (*ptr != NULL) {
			sraRgnDestroy(*ptr);
			ptr++;
		}
		free(xdamage_regions);
		xdamage_regions = NULL;
	}
	if (use_xdamage) {
		nreg = (xdamage_memory * NSCAN) + 2;
		xdamage_regions = (sraRegionPtr *)
		    malloc(nreg * sizeof(sraRegionPtr));
		for (i = 0; i < nreg; i++) {
			ptr = xdamage_regions+i;
			if (i == nreg - 1) {
				*ptr = NULL;
			} else {
				*ptr = sraRgnCreate();
				sraRgnMakeEmpty(*ptr);
			}
		}
		/* set so will be 0 in first collect_xdamage call */
		xdamage_ticker = -1;
	}
}

void create_xdamage_if_needed(void) {

	if (raw_fb && ! dpy) return;	/* raw_fb hack */

#if LIBVNCSERVER_HAVE_LIBXDAMAGE
	if (! xdamage) {
		X_LOCK;
		xdamage = XDamageCreate(dpy, window, XDamageReportRawRectangles); 
		XDamageSubtract(dpy, xdamage, None, None);
		X_UNLOCK;
		rfbLog("created xdamage object: 0x%lx\n", xdamage);
	}
#endif
}

void destroy_xdamage_if_needed(void) {

	if (raw_fb && ! dpy) return;	/* raw_fb hack */

#if LIBVNCSERVER_HAVE_LIBXDAMAGE
	if (xdamage) {
		XEvent ev;
		X_LOCK;
		XDamageDestroy(dpy, xdamage);
		XFlush(dpy);
		if (xdamage_base_event_type) {
			while (XCheckTypedEvent(dpy,
			    xdamage_base_event_type+XDamageNotify, &ev)) {
				;
			}
		}
		X_UNLOCK;
		rfbLog("destroyed xdamage object: 0x%lx\n", xdamage);
		xdamage = 0;
	}
#endif
}

void check_xdamage_state(void) {
	if (! xdamage_present) {
		return;
	}
	/*
	 * Create or destroy the Damage object as needed, we don't want
	 * one if no clients are connected.
	 */
	if (client_count && use_xdamage) {
		create_xdamage_if_needed();
		if (xdamage_scheduled_mark > 0.0 && dnow() >
		    xdamage_scheduled_mark) {
			if (xdamage_scheduled_mark_region) {
				mark_region_for_xdamage(
				    xdamage_scheduled_mark_region);
				sraRgnDestroy(xdamage_scheduled_mark_region);
				xdamage_scheduled_mark_region = NULL;
			} else {
				mark_for_xdamage(0, 0, dpy_x, dpy_y);
			}
			xdamage_scheduled_mark = 0.0;
		}
	} else {
		destroy_xdamage_if_needed();
	}
}