/*
 * Copyright (C) 2023  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/>.
 */

#include <engine/gl/image-view.hpp>
#include <engine/gl/opengl/gl-format-lut.hpp>
#include <stdexcept>
#include <glad/gl.h>

namespace gl {

image_view::image_view
(
	std::shared_ptr<gl::image> image,
	std::uint8_t dimensionality,
	gl::format format,
	std::uint32_t first_mip_level,
	std::uint32_t mip_level_count,
	std::uint32_t first_array_layer,
	std::uint32_t array_layer_count,
	std::uint8_t flags
)
{
	if (!image)
	{
		throw std::invalid_argument("Image view has null image.");
	}
	
	if (format == gl::format::undefined)
	{
		format = image->get_format();
	}
	
	const auto format_index = std::to_underlying(format);
	const auto gl_internal_format = gl_format_lut[format_index][0];
	
	if (!gl_internal_format)
	{
		throw std::invalid_argument("Image view has unsupported format.");
	}
	
	if (!mip_level_count)
	{
		throw std::invalid_argument("Image view has zero mip levels.");
	}
	
	if (first_mip_level + mip_level_count > image->get_mip_levels())
	{
		throw std::out_of_range("Image view mip range out of image mip range.");
	}
	
	if (!array_layer_count)
	{
		throw std::invalid_argument("Image view has zero array layers.");
	}
	
	if (first_array_layer + array_layer_count > image->get_array_layers())
	{
		throw std::out_of_range("Image view array layer range out of image array layer range.");
	}
	
	if (dimensionality != image->get_dimensionality())
	{
		throw std::invalid_argument("Image view dimensionality must match image dimensionality.");
	}
	
	if (flags & std::to_underlying(image_view_flag::cube))
	{
		if (!image->is_cube_compatible())
		{
			throw std::invalid_argument("Cube image views must be constructed from cube-compatible images.");
		}
		
		if (array_layer_count % 6 != 0)
		{
			throw std::invalid_argument("Cube image views array layer count must be a multiple of 6.");
		}
	}
	
	m_image = image;
	m_dimensionality = dimensionality;
	m_format = format;
	m_first_mip_level = first_mip_level;
	m_mip_level_count = mip_level_count;
	m_first_array_layer = first_array_layer;
	m_array_layer_count = array_layer_count;
	m_flags = flags;
	
	unsigned int gl_target = 0;
	switch (dimensionality)
	{
		case 1:
			gl_target = is_array() ? GL_TEXTURE_1D_ARRAY : GL_TEXTURE_1D;
			break;
		
		case 2:
			if (is_cube())
			{
				gl_target = is_array() ? GL_TEXTURE_CUBE_MAP_ARRAY : GL_TEXTURE_CUBE_MAP;
			}
			else
			{
				gl_target = is_array() ? GL_TEXTURE_2D_ARRAY : GL_TEXTURE_2D;
			}
			break;
		
		case 3:
			gl_target = GL_TEXTURE_3D;
			break;
		
		default:
			break;
	}
	
	glGenTextures(1, &m_gl_texture_name);
	glTextureView
	(
		m_gl_texture_name,
		gl_target,
		m_image->m_gl_texture_name,
		gl_internal_format,
		m_first_mip_level,
		m_mip_level_count,
		m_first_array_layer,
		m_array_layer_count
	);
}

image_view::~image_view()
{
	glDeleteTextures(1, &m_gl_texture_name);
}

image_view_1d::image_view_1d
(
	std::shared_ptr<gl::image> image,
	gl::format format,
	std::uint32_t first_mip_level,
	std::uint32_t mip_level_count,
	std::uint32_t first_array_layer
):
	image_view
	(
		image,
		1,
		format,
		first_mip_level,
		mip_level_count,
		first_array_layer,
		1,
		0
	)
{}

image_view_1d_array::image_view_1d_array
(
	std::shared_ptr<gl::image> image,
	gl::format format,
	std::uint32_t first_mip_level,
	std::uint32_t mip_level_count,
	std::uint32_t first_array_layer,
	std::uint32_t array_layer_count
):
	image_view
	(
		image,
		1,
		format,
		first_mip_level,
		mip_level_count,
		first_array_layer,
		array_layer_count,
		std::to_underlying(image_view_flag::array)
	)
{}

image_view_2d::image_view_2d
(
	std::shared_ptr<gl::image> image,
	gl::format format,
	std::uint32_t first_mip_level,
	std::uint32_t mip_level_count,
	std::uint32_t first_array_layer
):
	image_view
	(
		image,
		2,
		format,
		first_mip_level,
		mip_level_count,
		first_array_layer,
		1,
		0
	)
{}

image_view_2d_array::image_view_2d_array
(
	std::shared_ptr<gl::image> image,
	gl::format format,
	std::uint32_t first_mip_level,
	std::uint32_t mip_level_count,
	std::uint32_t first_array_layer,
	std::uint32_t array_layer_count
):
	image_view
	(
		image,
		2,
		format,
		first_mip_level,
		mip_level_count,
		first_array_layer,
		array_layer_count,
		std::to_underlying(image_view_flag::array)
	)
{}

image_view_3d::image_view_3d
(
	std::shared_ptr<gl::image> image,
	gl::format format,
	std::uint32_t first_mip_level,
	std::uint32_t mip_level_count
):
	image_view
	(
		image,
		3,
		format,
		first_mip_level,
		mip_level_count,
		0,
		1,
		0
	)
{}

image_view_cube::image_view_cube
(
	std::shared_ptr<gl::image> image,
	gl::format format,
	std::uint32_t first_mip_level,
	std::uint32_t mip_level_count,
	std::uint32_t first_array_layer
):
	image_view
	(
		image,
		2,
		format,
		first_mip_level,
		mip_level_count,
		first_array_layer,
		6,
		std::to_underlying(image_view_flag::cube)
	)
{}

image_view_cube_array::image_view_cube_array
(
	std::shared_ptr<gl::image> image,
	gl::format format,
	std::uint32_t first_mip_level,
	std::uint32_t mip_level_count,
	std::uint32_t first_array_layer,
	std::uint32_t array_layer_count
):
	image_view
	(
		image,
		2,
		format,
		first_mip_level,
		mip_level_count,
		first_array_layer,
		array_layer_count,
		std::to_underlying(image_view_flag::array) | std::to_underlying(image_view_flag::cube)
	)
{}

} // namespace gl