#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <wlr/interfaces/wlr_output.h>
#include <wlr/util/log.h>
#include "backend/noop.h"
#include "util/signal.h"

static const uint32_t SUPPORTED_OUTPUT_STATE =
	WLR_OUTPUT_STATE_BACKEND_OPTIONAL |
	WLR_OUTPUT_STATE_MODE;

static struct wlr_noop_output *noop_output_from_output(
		struct wlr_output *wlr_output) {
	assert(wlr_output_is_noop(wlr_output));
	return (struct wlr_noop_output *)wlr_output;
}

static bool output_attach_render(struct wlr_output *wlr_output,
		int *buffer_age) {
	return false;
}

static void output_rollback_render(struct wlr_output *wlr_output) {
	// This space is intentionally left blank
}

static bool output_commit(struct wlr_output *wlr_output) {
	uint32_t unsupported =
		wlr_output->pending.committed & ~SUPPORTED_OUTPUT_STATE;
	if (unsupported != 0) {
		wlr_log(WLR_DEBUG, "Unsupported output state fields: 0x%"PRIx32,
			unsupported);
		return false;
	}

	if (wlr_output->pending.committed & WLR_OUTPUT_STATE_MODE) {
		assert(wlr_output->pending.mode_type == WLR_OUTPUT_STATE_MODE_CUSTOM);
		wlr_output_update_custom_mode(wlr_output,
			wlr_output->pending.custom_mode.width,
			wlr_output->pending.custom_mode.height,
			wlr_output->pending.custom_mode.refresh);
	}

	if (wlr_output->pending.committed & WLR_OUTPUT_STATE_BUFFER) {
		return false;
	}

	return true;
}

static void output_destroy(struct wlr_output *wlr_output) {
	struct wlr_noop_output *output =
		noop_output_from_output(wlr_output);

	wl_list_remove(&output->link);

	free(output);
}

static const struct wlr_output_impl output_impl = {
	.destroy = output_destroy,
	.attach_render = output_attach_render,
	.rollback_render = output_rollback_render,
	.commit = output_commit,
};

bool wlr_output_is_noop(struct wlr_output *wlr_output) {
	return wlr_output->impl == &output_impl;
}

struct wlr_output *wlr_noop_add_output(struct wlr_backend *wlr_backend) {
	struct wlr_noop_backend *backend = noop_backend_from_backend(wlr_backend);

	struct wlr_noop_output *output = calloc(1, sizeof(struct wlr_noop_output));
	if (output == NULL) {
		wlr_log(WLR_ERROR, "Failed to allocate wlr_noop_output");
		return NULL;
	}
	output->backend = backend;
	wlr_output_init(&output->wlr_output, &backend->backend, &output_impl,
			backend->display);
	struct wlr_output *wlr_output = &output->wlr_output;

	strncpy(wlr_output->make, "noop", sizeof(wlr_output->make));
	strncpy(wlr_output->model, "noop", sizeof(wlr_output->model));
	snprintf(wlr_output->name, sizeof(wlr_output->name), "NOOP-%zd",
		++backend->last_output_num);

	wl_list_insert(&backend->outputs, &output->link);

	if (backend->started) {
		wlr_output_update_enabled(wlr_output, true);
		wlr_signal_emit_safe(&backend->backend.events.new_output, wlr_output);
	}

	return wlr_output;
}
