/*
 * Copyright © 2008-2010 Kristian Høgsberg
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>

#define GL_GLEXT_PROTOTYPES
#define EGL_EGLEXT_PROTOTYPES
#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>
#include <EGL/egl.h>
#include <EGL/eglext.h>

#include "compositor.h"

struct drm_compositor {
	struct wlsc_compositor base;

	struct udev *udev;
	struct wl_event_source *drm_source;

	struct tty *tty;
};

struct drm_output {
	struct wlsc_output   base;

	drmModeModeInfo mode;
	uint32_t crtc_id;
	uint32_t connector_id;
	GLuint rbo[2];
	uint32_t fb_id[2];
	EGLImageKHR image[2];
	uint32_t current;	
};

static void
drm_compositor_present(struct wlsc_compositor *ec)
{
	struct drm_compositor *c = (struct drm_compositor *) ec;
	struct drm_output *output;

	wl_list_for_each(output, &ec->output_list, base.link) {
		output->current ^= 1;

		glFramebufferRenderbuffer(GL_FRAMEBUFFER,
					  GL_COLOR_ATTACHMENT0,
					  GL_RENDERBUFFER,
					  output->rbo[output->current]);

		drmModePageFlip(c->base.drm.fd, output->crtc_id,
				output->fb_id[output->current ^ 1],
				DRM_MODE_PAGE_FLIP_EVENT, output);
	}	
}

static void
page_flip_handler(int fd, unsigned int frame,
		  unsigned int sec, unsigned int usec, void *data)
{
	struct wlsc_output *output = data;
	struct wlsc_compositor *compositor = output->compositor;
	uint32_t msecs;

	msecs = sec * 1000 + usec / 1000;
	wlsc_compositor_finish_frame(compositor, msecs);
}

static void
on_drm_input(int fd, uint32_t mask, void *data)
{
	drmEventContext evctx;

	memset(&evctx, 0, sizeof evctx);
	evctx.version = DRM_EVENT_CONTEXT_VERSION;
	evctx.page_flip_handler = page_flip_handler;
	drmHandleEvent(fd, &evctx);
}

static int
init_egl(struct drm_compositor *ec, struct udev_device *device)
{
	EGLint major, minor;
	const char *extensions, *filename;
	int fd;
	static const EGLint context_attribs[] = {
		EGL_CONTEXT_CLIENT_VERSION, 2,
		EGL_NONE
	};

	filename = udev_device_get_devnode(device);
	fd = open(filename, O_RDWR);
	if (fd < 0) {
		/* Probably permissions error */
		fprintf(stderr, "couldn't open %s, skipping\n",
			udev_device_get_devnode(device));
		return -1;
	}

	wlsc_drm_init(&ec->base, fd, filename);

	ec->base.display = eglGetDRMDisplayMESA(ec->base.drm.fd);
	if (ec->base.display == NULL) {
		fprintf(stderr, "failed to create display\n");
		return -1;
	}

	if (!eglInitialize(ec->base.display, &major, &minor)) {
		fprintf(stderr, "failed to initialize display\n");
		return -1;
	}

	extensions = eglQueryString(ec->base.display, EGL_EXTENSIONS);
	if (!strstr(extensions, "EGL_KHR_surfaceless_opengl")) {
		fprintf(stderr, "EGL_KHR_surfaceless_opengl not available\n");
		return -1;
	}

	if (!eglBindAPI(EGL_OPENGL_ES_API)) {
		fprintf(stderr, "failed to bind api EGL_OPENGL_ES_API\n");
		return -1;
	}

	ec->base.context = eglCreateContext(ec->base.display, NULL,
					    EGL_NO_CONTEXT, context_attribs);
	if (ec->base.context == NULL) {
		fprintf(stderr, "failed to create context\n");
		return -1;
	}

	if (!eglMakeCurrent(ec->base.display, EGL_NO_SURFACE,
			    EGL_NO_SURFACE, ec->base.context)) {
		fprintf(stderr, "failed to make context current\n");
		return -1;
	}

	return 0;
}

static drmModeModeInfo builtin_1024x768 = {
	63500,			/* clock */
	1024, 1072, 1176, 1328, 0,
	768, 771, 775, 798, 0,
	59920,
	DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_PVSYNC,
	0,
	"1024x768"
};

static int
create_output_for_connector(struct drm_compositor *ec,
			    drmModeRes *resources,
			    drmModeConnector *connector)
{
	struct drm_output *output;
	drmModeEncoder *encoder;
	drmModeModeInfo *mode;
	int i, ret;
	EGLint handle, stride, attribs[] = {
		EGL_WIDTH,		0,
		EGL_HEIGHT,		0,
		EGL_DRM_BUFFER_FORMAT_MESA,	EGL_DRM_BUFFER_FORMAT_ARGB32_MESA,
		EGL_DRM_BUFFER_USE_MESA,	EGL_DRM_BUFFER_USE_SCANOUT_MESA,
		EGL_NONE
	};

	output = malloc(sizeof *output);
	if (output == NULL)
		return -1;

	if (connector->count_modes > 0) 
		mode = &connector->modes[0];
	else
		mode = &builtin_1024x768;

	encoder = drmModeGetEncoder(ec->base.drm.fd, connector->encoders[0]);
	if (encoder == NULL) {
		fprintf(stderr, "No encoder for connector.\n");
		return -1;
	}

	for (i = 0; i < resources->count_crtcs; i++) {
		if (encoder->possible_crtcs & (1 << i))
			break;
	}
	if (i == resources->count_crtcs) {
		fprintf(stderr, "No usable crtc for encoder.\n");
		return -1;
	}

	memset(output, 0, sizeof *output);
	wlsc_output_init(&output->base, &ec->base, 0, 0,
			 mode->hdisplay, mode->vdisplay);

	output->crtc_id = resources->crtcs[i];
	output->connector_id = connector->connector_id;
	output->mode = *mode;

	drmModeFreeEncoder(encoder);

	glGenRenderbuffers(2, output->rbo);
	for (i = 0; i < 2; i++) {
		glBindRenderbuffer(GL_RENDERBUFFER, output->rbo[i]);

		attribs[1] = output->base.width;
		attribs[3] = output->base.height;
		output->image[i] =
			eglCreateDRMImageMESA(ec->base.display, attribs);
		glEGLImageTargetRenderbufferStorageOES(GL_RENDERBUFFER,
						       output->image[i]);
		eglExportDRMImageMESA(ec->base.display, output->image[i],
				      NULL, &handle, &stride);

		ret = drmModeAddFB(ec->base.drm.fd,
				   output->base.width, output->base.height,
				   32, 32, stride, handle, &output->fb_id[i]);
		if (ret) {
			fprintf(stderr, "failed to add fb %d: %m\n", i);
			return -1;
		}
	}

	output->current = 0;
	glFramebufferRenderbuffer(GL_FRAMEBUFFER,
				  GL_COLOR_ATTACHMENT0,
				  GL_RENDERBUFFER,
				  output->rbo[output->current]);
	ret = drmModeSetCrtc(ec->base.drm.fd, output->crtc_id,
			     output->fb_id[output->current ^ 1], 0, 0,
			     &output->connector_id, 1, &output->mode);
	if (ret) {
		fprintf(stderr, "failed to set mode: %m\n");
		return -1;
	}

	wl_list_insert(ec->base.output_list.prev, &output->base.link);

	return 0;
}

static int
create_outputs(struct drm_compositor *ec, int option_connector)
{
	drmModeConnector *connector;
	drmModeRes *resources;
	int i;

	resources = drmModeGetResources(ec->base.drm.fd);
	if (!resources) {
		fprintf(stderr, "drmModeGetResources failed\n");
		return -1;
	}

	for (i = 0; i < resources->count_connectors; i++) {
		connector = drmModeGetConnector(ec->base.drm.fd, resources->connectors[i]);
		if (connector == NULL)
			continue;

		if (connector->connection == DRM_MODE_CONNECTED &&
		    (option_connector == 0 ||
		     connector->connector_id == option_connector))
			if (create_output_for_connector(ec, resources, connector) < 0)
				return -1;

		drmModeFreeConnector(connector);
	}

	if (wl_list_empty(&ec->base.output_list)) {
		fprintf(stderr, "No currently active connector found.\n");
		return -1;
	}

	drmModeFreeResources(resources);

	return 0;
}

static int
drm_authenticate(struct wlsc_compositor *c, uint32_t id)
{
	struct drm_compositor *ec = (struct drm_compositor *) c;

	return drmAuthMagic(ec->base.drm.fd, id);
}

static void
drm_destroy(struct wlsc_compositor *ec)
{
	struct drm_compositor *d = (struct drm_compositor *) ec;

	tty_destroy(d->tty);

	free(d);
}

struct wlsc_compositor *
drm_compositor_create(struct wl_display *display, int connector)
{
	struct drm_compositor *ec;
	struct udev_enumerate *e;
        struct udev_list_entry *entry;
	struct udev_device *device;
	const char *path;
	struct wl_event_loop *loop;

	ec = malloc(sizeof *ec);
	if (ec == NULL)
		return NULL;

	memset(ec, 0, sizeof *ec);
	ec->udev = udev_new();
	if (ec->udev == NULL) {
		fprintf(stderr, "failed to initialize udev context\n");
		return NULL;
	}

	e = udev_enumerate_new(ec->udev);
	udev_enumerate_add_match_subsystem(e, "drm");
	udev_enumerate_add_match_property(e, "WAYLAND_SEAT", "1");
        udev_enumerate_scan_devices(e);
	device = NULL;
        udev_list_entry_foreach(entry, udev_enumerate_get_list_entry(e)) {
		path = udev_list_entry_get_name(entry);
		device = udev_device_new_from_syspath(ec->udev, path);
		break;
	}
        udev_enumerate_unref(e);

	if (device == NULL) {
		fprintf(stderr, "no drm device found\n");
		return NULL;
	}

	ec->base.wl_display = display;
	if (init_egl(ec, device) < 0) {
		fprintf(stderr, "failed to initialize egl\n");
		return NULL;
	}

	ec->base.destroy = drm_destroy;
	ec->base.authenticate = drm_authenticate;
	ec->base.present = drm_compositor_present;
	ec->base.create_buffer = wlsc_drm_buffer_create;
	ec->base.focus = 1;

	/* Can't init base class until we have a current egl context */
	if (wlsc_compositor_init(&ec->base, display) < 0)
		return NULL;

	if (create_outputs(ec, connector) < 0) {
		fprintf(stderr, "failed to create output for %s\n", path);
		return NULL;
	}

	evdev_input_add_devices(&ec->base, ec->udev);

	loop = wl_display_get_event_loop(ec->base.wl_display);
	ec->drm_source =
		wl_event_loop_add_fd(loop, ec->base.drm.fd,
				     WL_EVENT_READABLE, on_drm_input, ec);
	ec->tty = tty_create(&ec->base);

	return &ec->base;
}