#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/extensions/Xfixes.h>
#include <X11/extensions/Xrandr.h>
#include <X11/Xlib-xcb.h>
#include <xcb/xcb.h>
#include <xcb/xcbext.h>
#include <xcb/dri2.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <time.h>

#include <xf86drm.h>
#include <drm.h>

#include "dri2.h"

#define COUNT 60

static inline XRRScreenResources *_XRRGetScreenResourcesCurrent(Display *dpy, Window window)
{
	XRRScreenResources *res;

	res = XRRGetScreenResourcesCurrent(dpy, window);
	if (res == NULL)
		res = XRRGetScreenResources(dpy, window);

	return res;
}

static XRRModeInfo *lookup_mode(XRRScreenResources *res, int id)
{
	int i;

	for (i = 0; i < res->nmode; i++) {
		if (res->modes[i].id == id)
			return &res->modes[i];
	}

	return NULL;
}

static int dri2_open(Display *dpy)
{
	drm_auth_t auth;
	char *driver, *device;
	int fd;

	if (!DRI2Connect(dpy, DefaultRootWindow(dpy), &driver, &device))
		return -1;

	printf ("Connecting to %s driver on %s\n", driver, device);

	fd = open(device, O_RDWR);
	if (fd < 0)
		return -1;

	if (drmIoctl(fd, DRM_IOCTL_GET_MAGIC, &auth))
		return -1;

	if (!DRI2Authenticate(dpy, DefaultRootWindow(dpy), auth.magic))
		return -1;

	return fd;
}

static void dri2_copy_swap(Display *dpy, Drawable d,
			   int width, int height, int has_front)
{
	XRectangle rect;
	XserverRegion region;

	rect.x = 0;
	rect.y = 0;
	rect.width = width;
	rect.height = height;

	region = XFixesCreateRegion(dpy, &rect, 1);
	DRI2CopyRegion(dpy, d, region, DRI2BufferFrontLeft, DRI2BufferBackLeft);
	if (has_front)
		DRI2CopyRegion(dpy, d, region, DRI2BufferFakeFrontLeft, DRI2BufferFrontLeft);
	XFixesDestroyRegion(dpy, region);
}

static double elapsed(const struct timespec *start,
		      const struct timespec *end)
{
	return (end->tv_sec - start->tv_sec) +
		1e-9*(end->tv_nsec - start->tv_nsec);
}

static uint64_t check_msc(Display *dpy, Window win, uint64_t last_msc)
{
	uint64_t current_msc, current_ust, current_sbc;
	DRI2GetMSC(dpy, win, &current_ust, &current_msc, &current_sbc);
	if (current_msc < last_msc) {
		printf("Invalid MSC: was %llu, now %llu\n",
		       (long long)last_msc, (long long)current_msc);
	}
	return current_msc;
}

static void swap_buffers(xcb_connection_t *c, Window win,
		unsigned int *attachments, int nattachments)
{
	unsigned int seq[2];

	seq[0] = xcb_dri2_swap_buffers_unchecked(c, win,
						 0, 0, 0, 0, 0, 0).sequence;


	seq[1] = xcb_dri2_get_buffers_unchecked(c, win,
						nattachments, nattachments,
						attachments).sequence;

	xcb_flush(c);
	xcb_discard_reply(c, seq[0]);
	xcb_discard_reply(c, seq[1]);
}

static void run(Display *dpy, int width, int height,
		unsigned int *attachments, int nattachments,
		const char *name)
{
	xcb_connection_t *c = XGetXCBConnection(dpy);
	Window win;
	XSetWindowAttributes attr;
	int count;
	DRI2Buffer *buffers;
	struct timespec start, end;
	uint64_t msc;

	/* Be nasty and install a fullscreen window on top so that we
	 * can guarantee we do not get clipped by children.
	 */
	attr.override_redirect = 1;
	win = XCreateWindow(dpy, DefaultRootWindow(dpy),
			 0, 0, width, height, 0,
			 DefaultDepth(dpy, DefaultScreen(dpy)),
			 InputOutput,
			 DefaultVisual(dpy, DefaultScreen(dpy)),
			 CWOverrideRedirect, &attr);
	XMapWindow(dpy, win);

	DRI2CreateDrawable(dpy, win);
	msc = check_msc(dpy, win, 0);

	buffers = DRI2GetBuffers(dpy, win, &width, &height,
				 attachments, nattachments, &count);
	if (count != nattachments)
		return;

	swap_buffers(c, win, attachments, nattachments);
	msc = check_msc(dpy, win, msc);
	clock_gettime(CLOCK_MONOTONIC, &start);
	for (count = 0; count < COUNT; count++)
		swap_buffers(c, win, attachments, nattachments);
	msc = check_msc(dpy, win, msc);
	clock_gettime(CLOCK_MONOTONIC, &end);
	printf("%d %s (%dx%d) swaps in %fs.\n",
	       count, name, width, height, elapsed(&start, &end));

	swap_buffers(c, win, attachments, nattachments);
	msc = check_msc(dpy, win, msc);
	clock_gettime(CLOCK_MONOTONIC, &start);
	for (count = 0; count < COUNT; count++)
		dri2_copy_swap(dpy, win, width, height, nattachments == 2);
	msc = check_msc(dpy, win, msc);
	clock_gettime(CLOCK_MONOTONIC, &end);

	printf("%d %s (%dx%d) blits in %fs.\n",
	       count, name, width, height, elapsed(&start, &end));

	DRI2SwapInterval(dpy, win, 0);

	swap_buffers(c, win, attachments, nattachments);
	msc = check_msc(dpy, win, msc);
	clock_gettime(CLOCK_MONOTONIC, &start);
	for (count = 0; count < COUNT; count++)
		swap_buffers(c, win, attachments, nattachments);
	msc = check_msc(dpy, win, msc);
	clock_gettime(CLOCK_MONOTONIC, &end);
	printf("%d %s (%dx%d) vblank=0 swaps in %fs.\n",
	       count, name, width, height, elapsed(&start, &end));

	XDestroyWindow(dpy, win);
	free(buffers);

	XSync(dpy, 1);
}

int main(void)
{
	Display *dpy;
	int i, j, fd;
	unsigned int attachments[] = {
		DRI2BufferBackLeft,
		DRI2BufferFrontLeft,
	};
	XRRScreenResources *res;
	XRRCrtcInfo **original_crtc;
	Window root;
	uint64_t last_msc;

	dpy = XOpenDisplay(NULL);
	if (dpy == NULL)
		return 77;

	if (!XRRQueryVersion(dpy, &i, &j))
		return 77;

	fd = dri2_open(dpy);
	if (fd < 0)
		return 1;

	root = DefaultRootWindow(dpy);
	DRI2CreateDrawable(dpy, root);

	res = _XRRGetScreenResourcesCurrent(dpy, root);
	if (res == NULL)
		return 1;

	original_crtc = malloc(sizeof(XRRCrtcInfo *)*res->ncrtc);
	for (i = 0; i < res->ncrtc; i++)
		original_crtc[i] = XRRGetCrtcInfo(dpy, res, res->crtcs[i]);

	printf("noutput=%d, ncrtc=%d\n", res->noutput, res->ncrtc);
	last_msc = check_msc(dpy, root, 0);
	for (i = 0; i < res->ncrtc; i++)
		XRRSetCrtcConfig(dpy, res, res->crtcs[i], CurrentTime,
				 0, 0, None, RR_Rotate_0, NULL, 0);
	last_msc = check_msc(dpy, root, last_msc);

	for (i = 0; i < res->noutput; i++) {
		XRROutputInfo *output;
		XRRModeInfo *mode;

		output = XRRGetOutputInfo(dpy, res, res->outputs[i]);
		if (output == NULL)
			continue;

		mode = NULL;
		if (res->nmode)
			mode = lookup_mode(res, output->modes[0]);

		for (j = 0; mode && j < 2*output->ncrtc; j++) {
			int c = j;
			if (c >= output->ncrtc)
				c = 2*output->ncrtc - j - 1;

			printf("[%d, %d] -- OUTPUT:%ld, CRTC:%ld\n",
			       i, c, (long)res->outputs[i], (long)output->crtcs[c]);
			last_msc = check_msc(dpy, root, last_msc);
			XRRSetCrtcConfig(dpy, res, output->crtcs[c], CurrentTime,
					 0, 0, output->modes[0], RR_Rotate_0, &res->outputs[i], 1);
			last_msc = check_msc(dpy, root, last_msc);

			run(dpy, mode->width, mode->height, attachments, 1, "fullscreen");
			run(dpy, mode->width, mode->height, attachments, 2, "fullscreen (with front)");

			run(dpy, mode->width/2, mode->height/2, attachments, 1, "windowed");
			run(dpy, mode->width/2, mode->height/2, attachments, 2, "windowed (with front)");

			last_msc = check_msc(dpy, root, last_msc);
			XRRSetCrtcConfig(dpy, res, output->crtcs[c], CurrentTime,
					 0, 0, None, RR_Rotate_0, NULL, 0);
			last_msc = check_msc(dpy, root, last_msc);
		}

		XRRFreeOutputInfo(output);
	}

	for (i = 0; i < res->ncrtc; i++)
		XRRSetCrtcConfig(dpy, res, res->crtcs[i], CurrentTime,
				 original_crtc[i]->x,
				 original_crtc[i]->y,
				 original_crtc[i]->mode,
				 original_crtc[i]->rotation,
				 original_crtc[i]->outputs,
				 original_crtc[i]->noutput);
	return 0;
}