/**
	This file is a part of our_dick
	Copyright (C) 2020 rexy712

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Affero General Public License as published by
	the Free Software Foundation, either version 3 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 Affero General Public License for more details.

	You should have received a copy of the GNU Affero General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef OUR_DICK_ENGINE_CAMERA_HPP
#define OUR_DICK_ENGINE_CAMERA_HPP

#include <rml/math.hpp>
#include "object.hpp"

namespace egn{

	//Virtual base for camera types
	//Provides general object functionality as well as projection and view matrices.
	//Derived classes must provide method of recalculating the projection matrix.
	class camera_iface : public object
	{
	protected:
		enum update{
			VIEW_UPDATE = 8,
			PROJ_UPDATE = 16,
		};
	protected:
		//mutable because they're only really a cached value representation of the data
		//in position, orientation, near, far, etc
		mutable rml::mat4f m_projection_matrix; //camera-to-sceen matrix
		mutable rml::mat4f m_view_matrix;       //world-to-camera matrix
		float m_near = 1;                        //near clipping plane in camera space
		float m_far = 100;                       //far clipping plane in camera space

	public:
		camera_iface(void) = default;
		//Initialize with given projection matrix and clipping planes
		camera_iface(const rml::mat4f& proj, float n, float f);
		camera_iface(const camera_iface&) = default;
		camera_iface(camera_iface&&) = default;
		virtual ~camera_iface(void) = default;

		camera_iface& operator=(const camera_iface&) = default;
		camera_iface& operator=(camera_iface&&) = default;

		//Set the camera's location and update relevant data structures
		void set_position(const rml::vec3f& pos)override;
		//Set the camera's facing angle and update relevant data structures
		void set_orientation(const rml::quat_f& distance)override;

		//getters
		const rml::mat4f& get_projection_matrix(void)const;
		const rml::mat4f& get_view_matrix(void)const;
		float get_near_plane(void)const;
		float get_far_plane(void)const;

		//setters
		void set_near_plane(float n);
		void set_far_plane(float f);
		//No control over matrices directly is done purposefully

	protected:
		void recalc_view_matrix(void)const;
		virtual void recalc_projection_matrix(void)const = 0;
	};

	//Camera which performs an orthographic projection. Essentially camera will have no depth perspective
	class ortho_camera : public camera_iface
	{
	protected:
		float m_width, m_height; //width and height of the camera space box

	public:
		//Build camera with width, height, near, and far planes
		ortho_camera(float w, float h, float n, float f);
		ortho_camera(const ortho_camera&) = default;
		ortho_camera(ortho_camera&&) = default;
		~ortho_camera(void) = default;

		ortho_camera& operator=(const ortho_camera&) = default;
		ortho_camera& operator=(ortho_camera&&) = default;

		//Getters
		float get_projection_width(void)const;
		float get_projection_height(void)const;

		//Setters
		void set_projection_width(float w);
		void set_projection_height(float h);
		void set_projection_box(float w, float h);
	protected:
		void recalc_projection_matrix(void)const override;
	};

	class flat_camera : public ortho_camera
	{
	public:
		flat_camera(float w, float h);
		flat_camera(const flat_camera&) = default;
		flat_camera(flat_camera&&) = default;
		~flat_camera(void) = default;

		flat_camera& operator=(const flat_camera&) = default;
		flat_camera& operator=(flat_camera&&) = default;
	};

}

#endif