/*
 * Copyright (C) 2021  Christopher J. Howard
 *
 * This file is part of Antkeeper source code.
 *
 * Antkeeper source code 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 3 of the License, or
 * (at your option) any later version.
 *
 * Antkeeper source code 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 Antkeeper source code.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef ANTKEEPER_ECS_WEATHER_SYSTEM_HPP
#define ANTKEEPER_ECS_WEATHER_SYSTEM_HPP

#include "entity-system.hpp"
#include "utility/fundamental-types.hpp"

class sky_pass;
class shadow_map_pass;
class material_pass;
class ambient_light;
class directional_light;
class image;

namespace ecs {

class weather_system:
	public entity_system
{
public:
	weather_system(ecs::registry& registry);
	virtual void update(double t, double dt);
	
	/**
	 *
	 * @param latitude Latitude, in radians.
	 * @param longitude Longitude, in radians.
	 * @param altitude Altitude, in radians.
	 */
	void set_location(float latitude, float longitude, float altitude);
	
	void set_sky_pass(::sky_pass* pass);
	void set_shadow_map_pass(::shadow_map_pass* pass);
	void set_material_pass(::material_pass* pass);
	
	/**
	 * Sets the current universal time.
	 *
	 * @param time Universal time, in days.
	 */
	void set_universal_time(double time);
	
	/**
	 * Sets the factor by which the timestep `dt` will be scaled before being added to the current universal time.
	 *
	 * @param scale Factor by which to scale the timestep.
	 */
	void set_time_scale(double scale);
	
private:
	static void load_palette(std::vector<float3>* palette, const ::image* image, unsigned int row);
	static float3 interpolate_gradient(const std::vector<float3>& gradient, float position);

	double universal_time;
	double days_per_timestep;
	sky_pass* sky_pass;
	shadow_map_pass* shadow_map_pass;
	material_pass* material_pass;
};

} // namespace ecs

#endif // ANTKEEPER_ECS_WEATHER_SYSTEM_HPP