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

static void surface_destroy(struct wl_client *client, struct wl_resource *resource) {
	wl_resource_destroy(resource);
}

static void surface_attach(struct wl_client *client,
		struct wl_resource *resource,
		struct wl_resource *buffer, int32_t sx, int32_t sy) {
	struct wlr_surface *surface = wl_resource_get_user_data(resource);
	surface->pending_buffer = buffer;
	surface->pending_attached = true;
}

static void surface_damage(struct wl_client *client,
		struct wl_resource *resource,
		int32_t x, int32_t y, int32_t width, int32_t height) {
	wlr_log(L_DEBUG, "damage: %dx%d@%d,%d", width, height, x, y);
}

static void destroy_frame_callback(struct wl_resource *resource) {
	struct wlr_frame_callback *cb = wl_resource_get_user_data(resource);

	wl_list_remove(&cb->link);
	free(cb);
}

static void surface_frame(struct wl_client *client,
		struct wl_resource *resource, uint32_t callback) {
	struct wlr_frame_callback *cb;
	struct wlr_surface *surface = wl_resource_get_user_data(resource);

	cb = malloc(sizeof(struct wlr_frame_callback));
	if (cb == NULL) {
		wl_resource_post_no_memory(resource);
		return;
	}

	cb->resource = wl_resource_create(client,
			&wl_callback_interface, 1, callback);
	if (cb->resource == NULL) {
		free(cb);
		wl_resource_post_no_memory(resource);
		return;
	}

	wl_resource_set_implementation(cb->resource,
			NULL, cb, destroy_frame_callback);

	wl_list_insert(surface->frame_callback_list.prev, &cb->link);
}

static void surface_set_opaque_region(struct wl_client *client,
		struct wl_resource *resource,
		struct wl_resource *region_resource) {
	wlr_log(L_DEBUG, "TODO: surface opaque region");
}

static void surface_set_input_region(struct wl_client *client,
		struct wl_resource *resource,
		struct wl_resource *region_resource) {
	wlr_log(L_DEBUG, "TODO: surface input region");
}

static void surface_commit(struct wl_client *client,
		struct wl_resource *resource) {
	struct wlr_surface *surface = wl_resource_get_user_data(resource);

	// apply pending state
	if (surface->pending_attached) {
		surface->attached = surface->pending_buffer;
		if (surface->pending_buffer) {
			struct wl_shm_buffer *buffer = wl_shm_buffer_get(surface->pending_buffer);
			if (!buffer) {
				wlr_log(L_INFO, "Unknown buffer handle attached");
			} else {
				uint32_t format = wl_shm_buffer_get_format(buffer);
				wlr_texture_upload_shm(surface->texture, format, buffer);
				wl_resource_queue_event(surface->pending_buffer, WL_BUFFER_RELEASE);
			}
		}
	}

	// reset pending state
	surface->pending_buffer = NULL;
	surface->pending_attached = false;

	wl_signal_emit(&surface->signals.commit, surface);
}

static void surface_set_buffer_transform(struct wl_client *client,
		struct wl_resource *resource, int transform) {
	wlr_log(L_DEBUG, "TODO: surface surface buffer transform");
}

static void surface_set_buffer_scale(struct wl_client *client,
		struct wl_resource *resource,
		int32_t scale) {
	wlr_log(L_DEBUG, "TODO: surface set buffer scale");
}


static void surface_damage_buffer(struct wl_client *client,
		struct wl_resource *resource,
		int32_t x, int32_t y, int32_t width,
		int32_t height) {
	wlr_log(L_DEBUG, "TODO: surface damage buffer");
}

const struct wl_surface_interface surface_interface = {
	surface_destroy,
	surface_attach,
	surface_damage,
	surface_frame,
	surface_set_opaque_region,
	surface_set_input_region,
	surface_commit,
	surface_set_buffer_transform,
	surface_set_buffer_scale,
	surface_damage_buffer
};

static void destroy_surface(struct wl_resource *resource) {
	struct wlr_surface *surface = wl_resource_get_user_data(resource);
	wl_signal_emit(&surface->signals.destroy, surface);
	wlr_texture_destroy(surface->texture);

	struct wlr_frame_callback *cb, *next;
	wl_list_for_each_safe(cb, next, &surface->frame_callback_list, link) {
		wl_resource_destroy(cb->resource);
	}
	free(surface);
}

struct wlr_surface *wlr_surface_create(struct wl_resource *res,
		struct wlr_renderer *renderer) {
	struct wlr_surface *surface = calloc(1, sizeof(struct wlr_surface));
	surface->texture = wlr_render_texture_init(renderer);
	surface->resource = res;
	wl_signal_init(&surface->signals.commit);
	wl_signal_init(&surface->signals.destroy);
	wl_list_init(&surface->frame_callback_list);
	wl_resource_set_implementation(res, &surface_interface,
			surface, destroy_surface);
	return surface;
}