#include <assert.h>
#include <stdlib.h>
#include <wayland-server.h>
#include <wlr/util/log.h>
#include <wlr/types/wlr_surface.h>
#include <wlr/types/wlr_region.h>
#include <wlr/types/wlr_compositor.h>

static void destroy_surface_listener(struct wl_listener *listener, void *data) {
	wl_list_remove(wl_resource_get_link(data));
}

static void wl_compositor_create_surface(struct wl_client *client,
		struct wl_resource *resource, uint32_t id) {
	struct wlr_compositor *compositor = wl_resource_get_user_data(resource);
	struct wl_resource *surface_resource = wl_resource_create(client,
			&wl_surface_interface, wl_resource_get_version(resource), id);
	struct wlr_surface *surface = wlr_surface_create(surface_resource,
			compositor->renderer);
	surface->compositor_data = compositor;
	surface->compositor_listener.notify = &destroy_surface_listener;
	wl_resource_add_destroy_listener(surface_resource, &surface->compositor_listener);

	wl_list_insert(&compositor->surfaces, wl_resource_get_link(surface_resource));
	wl_signal_emit(&compositor->events.create_surface, surface);
}

static void wl_compositor_create_region(struct wl_client *client,
		struct wl_resource *resource, uint32_t id) {
	wlr_region_create(client, resource, id);
}

struct wl_compositor_interface wl_compositor_impl = {
	.create_surface = wl_compositor_create_surface,
	.create_region = wl_compositor_create_region
};

static void wl_compositor_destroy(struct wl_resource *resource) {
	struct wlr_compositor *compositor = wl_resource_get_user_data(resource);
	struct wl_resource *_resource = NULL;
	wl_resource_for_each(_resource, &compositor->wl_resources) {
		if (_resource == resource) {
			struct wl_list *link = wl_resource_get_link(_resource);
			wl_list_remove(link);
			break;
		}
	}
}

static void wl_compositor_bind(struct wl_client *wl_client, void *_compositor,
		uint32_t version, uint32_t id) {
	struct wlr_compositor *compositor = _compositor;
	assert(wl_client && compositor);
	if (version > 4) {
		wlr_log(L_ERROR, "Client requested unsupported wl_compositor version, disconnecting");
		wl_client_destroy(wl_client);
		return;
	}
	struct wl_resource *wl_resource = wl_resource_create(
			wl_client, &wl_compositor_interface, version, id);
	wl_resource_set_implementation(wl_resource, &wl_compositor_impl,
			compositor, wl_compositor_destroy);
	wl_list_insert(&compositor->wl_resources, wl_resource_get_link(wl_resource));
}

void wlr_compositor_destroy(struct wlr_compositor *compositor) {
	wl_global_destroy(compositor->wl_global);
	free(compositor);
}

struct wlr_compositor *wlr_compositor_create(struct wl_display *display,
		struct wlr_renderer *renderer) {
	struct wlr_compositor *compositor = calloc(1, sizeof(struct wlr_compositor));
	if (!compositor) {
		wlr_log_errno(L_ERROR, "Could not allocate wlr compositor");
		return NULL;
	}
	struct wl_global *wl_global = wl_global_create(display,
		&wl_compositor_interface, 4, compositor, wl_compositor_bind);
	compositor->wl_global = wl_global;
	compositor->renderer = renderer;
	wl_list_init(&compositor->wl_resources);
	wl_list_init(&compositor->surfaces);
	wl_signal_init(&compositor->events.create_surface);
	return compositor;
}