/*
    This file is part of Magnum.

    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
                2020, 2021, 2022, 2023, 2024, 2025, 2026
              Vladimír Vondruš <mosra@centrum.cz>

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.
*/

#include "TextureImage.h"

#include "Magnum/Image.h"
#if defined(MAGNUM_BUILD_DEPRECATED) && !defined(MAGNUM_TARGET_GLES2)
#include "Magnum/GL/BufferImage.h"
#endif
#include "Magnum/GL/Context.h"
#include "Magnum/GL/Extensions.h"
#include "Magnum/GL/Framebuffer.h"
#include "Magnum/GL/Texture.h"
#ifndef MAGNUM_TARGET_GLES2
#include "Magnum/GL/TextureArray.h"
#endif

#if defined(MAGNUM_TARGET_GLES) && !defined(MAGNUM_TARGET_GLES2)
#include <Corrade/Containers/Iterable.h>
#include <Corrade/Containers/Reference.h>
#include <Corrade/Containers/StringView.h>
#include <Corrade/Utility/Resource.h>

#include "Magnum/GL/AbstractShaderProgram.h"
#include "Magnum/GL/Mesh.h"
#include "Magnum/GL/PixelFormat.h"
#include "Magnum/GL/Shader.h"
#include "Magnum/GL/TextureFormat.h"
#include "Magnum/GL/Version.h"

#ifdef MAGNUM_BUILD_STATIC
static void importDebugToolsResources() {
    CORRADE_RESOURCE_INITIALIZE(MagnumDebugTools_RESOURCES)
}
#endif
#endif

namespace Magnum { namespace DebugTools {

#if defined(MAGNUM_TARGET_GLES) && !defined(MAGNUM_TARGET_GLES2)
using namespace Containers::Literals;

namespace {

class FloatReinterpretShader: public GL::AbstractShaderProgram {
    public:
        explicit FloatReinterpretShader();

        FloatReinterpretShader& setTexture(GL::Texture2D& texture, Int level) {
            texture.bind(0);
            setUniform(_levelUniform, level);
            return *this;
        }

    private:
        Int _levelUniform;
};

FloatReinterpretShader::FloatReinterpretShader() {
    #ifdef MAGNUM_BUILD_STATIC
    importDebugToolsResources();
    #endif
    Utility::Resource rs{"MagnumDebugTools"};

    GL::Shader vert{GL::Version::GLES300, GL::Shader::Type::Vertex};
    GL::Shader frag{GL::Version::GLES300, GL::Shader::Type::Fragment};
    if(!GL::Context::current().isExtensionSupported<GL::Extensions::MAGNUM::shader_vertex_id>())
        vert.addSource("#define DISABLE_GL_MAGNUM_shader_vertex_id\n"_s);
    vert.addSource(rs.getString("TextureImage.vert"_s));
    frag.addSource(rs.getString("TextureImage.frag"_s));

    CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
    attachShaders({vert, frag});

    if(!GL::Context::current().isExtensionSupported<GL::Extensions::MAGNUM::shader_vertex_id>()) {
        bindAttributeLocation(0, "position"_s);
    }

    CORRADE_INTERNAL_ASSERT_OUTPUT(link());

    _levelUniform = uniformLocation("level"_s);
    setUniform(uniformLocation("textureData"_s), 0);
}

}
#endif

void textureSubImage(GL::Texture2D& texture, const Int level, const Range2Di& range, Image2D& image) {
    #ifndef MAGNUM_TARGET_GLES
    if(GL::Context::current().isExtensionSupported<GL::Extensions::ARB::get_texture_sub_image>()) {
        texture.subImage(level, range, image);
        return;
    }
    #endif

    /* While I cannot reproduce this on any drivers I tried, not even on WebGL,
       the ES3.0 and 3.1 spec says that Float isn't guaranteed to be supported,
       only UnsignedByte and Int or UnsignedInt. I could probably do some
       comparison against fb.implementationColorReadFormat() but this is more
       straightforward.

       ES3.2 says Float is supported. What still isn't guaranteed to be
       supported are one-, two- and three-component formats, but so far I
       didn't have a problem with these anywhere.

       Half floats aren't guaranteed to be supported either, but given that I
       cannot reproduce this issue anywhere anymore, I don't think I should
       waste time implementing a half-float variant. */
    /** @todo or just remove this altogether? */
    #if defined(MAGNUM_TARGET_GLES) && !defined(MAGNUM_TARGET_GLES2)
    GL::PixelType type = GL::pixelType(image.format(), image.formatExtra());
    if(type == GL::PixelType::Float
        #ifndef MAGNUM_TARGET_WEBGL
        && !GL::Context::current().isVersionSupported(GL::Version::GLES320)
        #endif
    ) {
        GL::TextureFormat textureFormat;
        GL::PixelFormat reinterpretFormat;
        GL::PixelFormat format = GL::pixelFormat(image.format());
        switch(format) {
            case GL::PixelFormat::Red:
                textureFormat = GL::TextureFormat::R32UI;
                reinterpretFormat = GL::PixelFormat::RedInteger;
                break;
            case GL::PixelFormat::RG:
                textureFormat = GL::TextureFormat::RG32UI;
                reinterpretFormat = GL::PixelFormat::RGInteger;
                break;
            case GL::PixelFormat::RGB:
                textureFormat = GL::TextureFormat::RGB32UI;
                reinterpretFormat = GL::PixelFormat::RGBInteger;
                break;
            case GL::PixelFormat::RGBA:
                textureFormat = GL::TextureFormat::RGBA32UI;
                reinterpretFormat = GL::PixelFormat::RGBAInteger;
                break;
            default:
                CORRADE_ASSERT_UNREACHABLE("DebugTools::textureSubImage(): unsupported pixel format" << format, );
        }

        GL::Texture2D output;
        output.setStorage(1, textureFormat, range.max());

        GL::Framebuffer fb{range};
        fb.attachTexture(GL::Framebuffer::ColorAttachment{0}, output, 0)
          .bind();

        CORRADE_INTERNAL_ASSERT(fb.checkStatus(GL::FramebufferTarget::Draw) == GL::Framebuffer::Status::Complete);
        CORRADE_INTERNAL_ASSERT(fb.checkStatus(GL::FramebufferTarget::Read) == GL::Framebuffer::Status::Complete);

        FloatReinterpretShader shader;
        shader.setTexture(texture, level);

        GL::Mesh mesh;
        mesh.setCount(3);

        if(!GL::Context::current().isExtensionSupported<GL::Extensions::MAGNUM::shader_vertex_id>()) {
            constexpr Vector2 triangle[]{
                {-1.0f,  1.0f},
                {-1.0f, -3.0f},
                { 3.0f,  1.0f}
            };
            GL::Buffer buffer{GL::Buffer::TargetHint::Array};
            buffer.setData(triangle, GL::BufferUsage::StaticDraw);
            mesh.addVertexBuffer(Utility::move(buffer), 0, GL::Attribute<0, Vector2>{});
        }

        shader.draw(mesh);

        /* release() needs to be called after querying the size to avoid zeroing it out */
        const Vector2i imageSize = image.size();
        Image2D temp{image.storage(), reinterpretFormat, GL::PixelType::UnsignedInt, imageSize, image.release()};
        fb.read(range, temp);
        image = Image2D{image.storage(), image.format(), image.formatExtra(), image.pixelSize(), range.size(), temp.release()};
        return;
    }
    #endif

    GL::Framebuffer fb{range};
    fb.attachTexture(GL::Framebuffer::ColorAttachment{0}, texture, level);

    CORRADE_ASSERT(fb.checkStatus(GL::FramebufferTarget::Read) == GL::Framebuffer::Status::Complete,
        "DebugTools::textureSubImage(): texture format not framebuffer-readable:" << fb.checkStatus(GL::FramebufferTarget::Read), );

    fb.read(range, image);
}

Image2D textureSubImage(GL::Texture2D& texture, const Int level, const Range2Di& range, Image2D&& image) {
    textureSubImage(texture, level, range, image);
    return Utility::move(image);
}

#if defined(MAGNUM_BUILD_DEPRECATED) && !defined(MAGNUM_TARGET_GLES2)
void textureSubImage(GL::Texture2D& texture, const Int level, const Range2Di& range, GL::BufferImage2D& image, const GL::BufferUsage usage) {
    #ifndef MAGNUM_TARGET_GLES
    if(GL::Context::current().isExtensionSupported<GL::Extensions::ARB::get_texture_sub_image>()) {
        texture.subImage(level, range, image, usage);
        return;
    }
    #endif

    GL::Framebuffer fb{range};
    fb.attachTexture(GL::Framebuffer::ColorAttachment{0}, texture, level);

    CORRADE_ASSERT(fb.checkStatus(GL::FramebufferTarget::Read) == GL::Framebuffer::Status::Complete,
        "DebugTools::textureSubImage(): texture format not framebuffer-readable:" << fb.checkStatus(GL::FramebufferTarget::Read), );

    fb.read(range, image, usage);
}

GL::BufferImage2D textureSubImage(GL::Texture2D& texture, const Int level, const Range2Di& range, GL::BufferImage2D&& image, const GL::BufferUsage usage) {
    CORRADE_IGNORE_DEPRECATED_PUSH
    textureSubImage(texture, level, range, image, usage);
    CORRADE_IGNORE_DEPRECATED_POP
    return Utility::move(image);
}
#endif

#ifndef MAGNUM_TARGET_GLES2
void textureSubImage(GL::Texture2DArray& texture, const Int level, const Int layer, const Range2Di& range, Image2D& image) {
    #ifndef MAGNUM_TARGET_GLES
    if(GL::Context::current().isExtensionSupported<GL::Extensions::ARB::get_texture_sub_image>()) {
        /* Make a temporary Image3D out of the input Image2D, read the pixels
           into it, and then move its ownership back to the Image2D */
        /** @todo have this on the Image APIs itself, in particular a
            rvalue-only ability to "updimension", and similarly a rvalue-only
            dimension slice */
        Vector2i size = image.size();
        Containers::Array<char> data = image.release();
        Image3D image3{image.storage(), image.format(), image.formatExtra(), image.pixelSize(), {size, 1}, Utility::move(data)};
        texture.subImage(level, {{range.min(), layer}, {range.max(), layer + 1}}, image3);
        Vector3i size3 = image3.size();
        Containers::Array<char> data3 = image3.release();
        image = Image2D{image3.storage(), image3.format(), image3.formatExtra(), image3.pixelSize(), size3.xy(), Utility::move(data3)};
        return;
    }
    #endif

    GL::Framebuffer fb{range};
    fb.attachTextureLayer(GL::Framebuffer::ColorAttachment{0}, texture, level, layer);

    CORRADE_ASSERT(fb.checkStatus(GL::FramebufferTarget::Read) == GL::Framebuffer::Status::Complete,
        "DebugTools::textureSubImage(): texture format not framebuffer-readable:" << fb.checkStatus(GL::FramebufferTarget::Read), );

    fb.read(range, image);
}

Image2D textureSubImage(GL::Texture2DArray& texture, const Int level, const Int layer, const Range2Di& range, Image2D&& image) {
    textureSubImage(texture, level, layer, range, image);
    return Utility::move(image);
}
#endif

void textureSubImage(GL::CubeMapTexture& texture, const GL::CubeMapCoordinate coordinate, const Int level, const Range2Di& range, Image2D& image) {
    /* Compared to textureSubImage(GL::CubeMapTexture&, ..., Image3D&), here's
       no ARB_get_texture_sub_image code path because it only works with 3D
       images */
    /** @todo implement a Image3D variant with this extension used once
        convenient Image slicing and direct allocation is done */

    GL::Framebuffer fb{range};
    fb.attachCubeMapTexture(GL::Framebuffer::ColorAttachment{0}, texture, coordinate, level);

    /* Compared to textureSubImage(GL::Texture2D&), here's no specialized code
       path for float formats, as it's impossible to sample it in a shader with
       2D coordinates. It's also questionable if that's still needed. */
    /** @todo or just remove this altogether? */

    CORRADE_ASSERT(fb.checkStatus(GL::FramebufferTarget::Read) == GL::Framebuffer::Status::Complete,
        "DebugTools::textureSubImage(): texture format not framebuffer-readable:" << fb.checkStatus(GL::FramebufferTarget::Read), );

    fb.read(range, image);
}

Image2D textureSubImage(GL::CubeMapTexture& texture, const GL::CubeMapCoordinate coordinate, const Int level, const Range2Di& range, Image2D&& image) {
    textureSubImage(texture, coordinate, level, range, image);
    return Utility::move(image);
}

#if defined(MAGNUM_BUILD_DEPRECATED) && !defined(MAGNUM_TARGET_GLES2)
void textureSubImage(GL::CubeMapTexture& texture, const GL::CubeMapCoordinate coordinate, const Int level, const Range2Di& range, GL::BufferImage2D& image, const GL::BufferUsage usage) {
    GL::Framebuffer fb{range};
    fb.attachCubeMapTexture(GL::Framebuffer::ColorAttachment{0}, texture, coordinate, level);

    CORRADE_ASSERT(fb.checkStatus(GL::FramebufferTarget::Read) == GL::Framebuffer::Status::Complete,
        "DebugTools::textureSubImage(): texture format not framebuffer-readable:" << fb.checkStatus(GL::FramebufferTarget::Read), );

    fb.read(range, image, usage);
}

GL::BufferImage2D textureSubImage(GL::CubeMapTexture& texture, const GL::CubeMapCoordinate coordinate, const Int level, const Range2Di& range, GL::BufferImage2D&& image, const GL::BufferUsage usage) {
    CORRADE_IGNORE_DEPRECATED_PUSH
    textureSubImage(texture, coordinate, level, range, image, usage);
    CORRADE_IGNORE_DEPRECATED_POP
    return Utility::move(image);
}
#endif

}}