#include <psemek/gfx/texture.hpp>
#include <optional>

namespace psemek::gfx
{

	texture_2d::texture_2d()
	{
		gl::GenTextures(1, &id_);
	}

	texture_2d::texture_2d(GLuint id)
		: id_(id)
	{}

	texture_2d texture_2d::null()
	{
		return texture_2d(0);
	}

	void texture_2d::bind() const
	{
		gl::BindTexture(gl::TEXTURE_2D, id_);
	}

	texture_2d::texture_2d(texture_2d && other)
		: id_(other.id_)
		, width_(other.width_)
		, height_(other.height_)
	{
		other.id_ = 0;
		other.width_ = 0;
		other.height_ = 0;
	}

	texture_2d & texture_2d::operator = (texture_2d && other)
	{
		if (this == &other) return *this;

		gl::DeleteTextures(1, &id_);
		id_ = other.id_;
		width_ = other.width_;
		height_ = other.height_;
		other.id_ = 0;
		other.width_ = 0;
		other.height_ = 0;

		return *this;
	}

	texture_2d::~texture_2d()
	{
		gl::DeleteTextures(1, &id_);
	}

	void texture_2d::load(GLint internal_format, std::size_t width, std::size_t height, GLenum format, GLenum type, const void * data)
	{
		bind();
		gl::TexImage2D(gl::TEXTURE_2D, 0, internal_format, width, height, 0, format, type, data);

		width_ = width;
		height_ = height;
	}

	void texture_2d::pixels(GLenum format, GLenum type, void * data) const
	{
		bind();
		gl::GetTexImage(gl::TEXTURE_2D, 0, format, type, data);
	}

	texture_2d texture_2d::from_data(GLint internal_format, std::size_t width, std::size_t height, GLenum format, GLenum type, const void * data)
	{
		texture_2d tex;
		tex.load(internal_format, width, height, format, type, data);
		return tex;
	}

	void texture_2d::generate_mipmap()
	{
		bind();
		gl::GenerateMipmap(gl::TEXTURE_2D);
	}

	void texture_2d::nearest_filter()
	{
		bind();
		gl::TexParameteri(gl::TEXTURE_2D, gl::TEXTURE_MAG_FILTER, gl::NEAREST);
		gl::TexParameteri(gl::TEXTURE_2D, gl::TEXTURE_MIN_FILTER, gl::LINEAR_MIPMAP_LINEAR);
	}

	void texture_2d::linear_filter()
	{
		bind();
		gl::TexParameteri(gl::TEXTURE_2D, gl::TEXTURE_MAG_FILTER, gl::LINEAR);
		gl::TexParameteri(gl::TEXTURE_2D, gl::TEXTURE_MIN_FILTER, gl::LINEAR_MIPMAP_LINEAR);
	}

	void texture_2d::anisotropy()
	{
		if (!gl::exts::var_EXT_texture_filter_anisotropic) return;

		static std::optional<float> level;
		if (!level)
		{
			level = 0;
			gl::GetFloatv(gl::MAX_TEXTURE_MAX_ANISOTROPY_EXT, &(*level));
		}
		gl::TexParameterf(gl::TEXTURE_2D, gl::TEXTURE_MAX_ANISOTROPY_EXT, *level);
	}

	void texture_2d::repeat()
	{
		bind();
		gl::TexParameteri(gl::TEXTURE_2D, gl::TEXTURE_WRAP_S, gl::REPEAT);
		gl::TexParameteri(gl::TEXTURE_2D, gl::TEXTURE_WRAP_T, gl::REPEAT);
	}

	void texture_2d::clamp()
	{
		bind();
		gl::TexParameteri(gl::TEXTURE_2D, gl::TEXTURE_WRAP_S, gl::CLAMP_TO_EDGE);
		gl::TexParameteri(gl::TEXTURE_2D, gl::TEXTURE_WRAP_T, gl::CLAMP_TO_EDGE);
	}

}