/**
	This file is a part of our_dick
	Copyright (C) 2020-2022 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_GRAPHICS_OGL_TEXTURE_HPP
#define OUR_DICK_GRAPHICS_OGL_TEXTURE_HPP

#include "egn/image.hpp"
#include "gl_include.hpp"
#include <rml/vec.hpp>

namespace gfx::ogl{

	//class representing an opengl 2D texture
	class texture_base
	{
	public:
		//all available wrapping styles as a strongly typed enum
		enum class wrap : GLint{
			CLAMP_EDGE = GL_CLAMP_TO_EDGE,
			CLAMP_BORDER = GL_CLAMP_TO_BORDER,
			MIRROR_REPEAT = GL_MIRRORED_REPEAT,
			REPEAT = GL_REPEAT,
			MIRROR_CLAMP_EDGE = GL_MIRROR_CLAMP_TO_EDGE,
		};
		//all available minfilter styles as a strongly typed enum
		enum class minfilter : GLint{
			NEAREST = GL_NEAREST,
			LINEAR = GL_LINEAR,
			NMIPMAP_NEAREST = GL_NEAREST_MIPMAP_NEAREST,
			LMIPMAP_NEAREST = GL_LINEAR_MIPMAP_NEAREST,
			NMIPMAP_LINEAR = GL_NEAREST_MIPMAP_LINEAR,
			LMIPMAP_LINEAR = GL_LINEAR_MIPMAP_LINEAR,
		};
		//all available magfilter styles as a strongly typed enum
		enum class magfilter : GLint{
			NEAREST = GL_NEAREST,
			LINEAR = GL_LINEAR,
		};
	protected:
		GLuint m_tex_id = 0; //handle to texture object
		GLsizei m_width = 0;
		GLsizei m_height = 0;
		GLenum m_format = 0;
		GLenum m_type = GL_UNSIGNED_BYTE;
		bool m_mipmapped = true;

		texture_base(void) = default;
		texture_base(GLenum format, GLsizei w, GLsizei h, GLenum type, bool mipmap);
		texture_base(const texture_base&);
		texture_base(texture_base&&);
		~texture_base(void);

		texture_base& operator=(const texture_base&);
		texture_base& operator=(texture_base&&);

	public:
		GLuint raw(void)const;

		//change wrap mode for both x and y
		void set_wrap_mode(wrap w);
		void set_wrap_mode(wrap w, wrap h);
		//change wrap mode for one direction
		void set_wrap_x(wrap w);
		void set_wrap_y(wrap h);

		void set_border_color(GLfloat r, GLfloat g, GLfloat b, GLfloat a = 1.0f);
		void set_filter(minfilter min, magfilter mag);
		void set_mag_filter(magfilter m);
		void set_min_filter(minfilter m);

		magfilter get_mag_filter(void)const;
		minfilter get_min_filter(void)const;
		rml::vec4f get_border_color(void)const;

		wrap get_wrap_x(void)const;
		wrap get_wrap_y(void)const;

		GLsizei get_width(void)const;
		GLsizei get_height(void)const;

		void enable_auto_mipmap(bool enable);
		void generate_mipmap(void);

		//release ownership of this texture object
		GLuint release(void);
	};
	class texture : public texture_base
	{
	public:
		//create the texture with no image data
		texture(void);
		texture(const unsigned char* data, GLenum format, GLsizei w, GLsizei h, GLenum type, bool mipmap = true);
		texture(GLenum format, GLsizei w, GLsizei h, GLenum type, bool mipmap = true);
		//create the texture with image data from 'i'
		texture(const egn::image& i, bool mipmap = true);
		texture(const texture&);
		texture(texture&&);
		~texture(void) = default;

		texture& operator=(const texture&);
		texture& operator=(texture&&);

		//overwrite the current image data with 'i'
		bool set_image(const unsigned char* data, GLenum format, GLsizei w, GLsizei h, GLenum type);
		bool set_image(const egn::image& i);

		bool set_subimage(const unsigned char* data, GLenum format, GLenum type,
		                  GLsizei xoffset, GLsizei yoffset, GLsizei w, GLsizei h);
		bool set_subimage(const egn::image& i, GLsizei xoffset, GLsizei yoffset);

		//bind to target
		void bind(GLuint target = GL_TEXTURE_2D)const;
		//bind to given texture unit and load into given program uniform location
		void bind_unit(GLuint tunit)const;

	private:
		bool create_texture_storage_(void);
	};

	class texture_array;

	//Represents a single layer of a texture_array
	class texture_slice
	{
	private:
		texture_array* m_owner;
		size_t m_level;
	public:
		texture_slice(texture_array* tex, int level);
		texture_slice(const texture_slice&) = default;
		texture_slice(texture_slice&&) = default;
		~texture_slice(void) = default;

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

		bool valid(void)const;

		GLuint raw(void)const;
		int get_level(void)const;
		GLsizei get_width(void)const;
		GLsizei get_height(void)const;

		bool set_image(const unsigned char* data, GLenum format, GLsizei w, GLsizei h, GLenum type);
		bool set_image(const egn::image& i);

		bool set_subimage(const unsigned char* data, GLenum format, GLenum type, GLsizei xoffset, GLsizei yoffset, GLsizei w, GLsizei h);
		bool set_subimage(const egn::image& i, GLsizei xoffset, GLsizei yoffset);
	};

	class texture_array : public texture_base
	{
	private:
		size_t m_levels = 0;
	public:
		texture_array(void);
		texture_array(size_t layers);
		texture_array(const egn::image& i, size_t layers, bool mipmap = true);
		texture_array(GLenum format, GLsizei w, GLsizei h, GLenum type, size_t layers, bool mipmap = true);
		texture_array(const texture_array&);
		texture_array(texture_array&&);
		~texture_array(void) = default;

		texture_array& operator=(const texture_array&);
		texture_array& operator=(texture_array&&);

		//overwrite the current image data with 'i'
		bool set_image(const unsigned char* data, GLenum format, GLsizei w, GLsizei h, GLenum type, size_t layer);
		bool set_image(const egn::image& i, size_t layer);

		bool set_subimage(const unsigned char* data, GLenum format, GLenum type,
		                  GLsizei xoffset, GLsizei yoffset, GLsizei w, GLsizei h, size_t layer);
		bool set_subimage(const egn::image& i, GLsizei xoffset, GLsizei yoffset, size_t layer);

		//bind to target
		void bind(GLuint target = GL_TEXTURE_2D_ARRAY)const;
		//bind to given texture unit and load into given program uniform location
		void bind_unit(GLuint tunit)const;

		texture_slice operator[](size_t layer);

	private:
		bool create_texture_storage_(void);
	};

	class texture_view
	{
		//TODO
		//lookup glTextureView to remind yourself
	};
}

#endif