/*
    This file is part of Magnum.

    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
                2020, 2021, 2022 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 "LineGL.h"

#include <Corrade/Containers/EnumSet.hpp>
#include <Corrade/Containers/Iterable.h>
#include <Corrade/Containers/String.h>
#include <Corrade/Utility/Format.h>
#include <Corrade/Utility/Resource.h>

#include "Magnum/GL/Buffer.h"
#include "Magnum/GL/Context.h"
#include "Magnum/GL/Extensions.h"
#include "Magnum/GL/Shader.h"
#include "Magnum/Math/Color.h"
#include "Magnum/Math/Matrix3.h"
#include "Magnum/Math/Matrix4.h"
#include "Magnum/Shaders/Line.h"
#include "Magnum/Shaders/Implementation/CreateCompatibilityShader.h"
#include "Magnum/Shaders/Implementation/lineMiterLimit.h"

namespace Magnum { namespace Shaders {

using namespace Containers::Literals;
using namespace Math::Literals;

namespace {
    enum: Int {
        /* 0/1/2/3 taken by Phong (A/D/S/N), 4 by MeshVisualizer colormap, 5 by
           object ID textures, 6 by Vector */
        TextureUnit = 7
    };

    enum: Int {
        /* Not using the zero binding to avoid conflicts with
           ProjectionBufferBinding from other shaders which can likely stay
           bound to the same buffer for the whole time */
        TransformationProjectionBufferBinding = 1,
        DrawBufferBinding = 2,
        MaterialBufferBinding = 3
    };
}

template<UnsignedInt dimensions> typename LineGL<dimensions>::CompileState LineGL<dimensions>::compile(const Configuration& configuration) {
    CORRADE_ASSERT(!(configuration.flags() >= Flag::UniformBuffers) || configuration.materialCount(),
        "Shaders::LineGL: material count can't be zero", CompileState{NoCreate});
    CORRADE_ASSERT(!(configuration.flags() >= Flag::UniformBuffers) || configuration.drawCount(),
        "Shaders::LineGL: draw count can't be zero", CompileState{NoCreate});

    #ifndef MAGNUM_TARGET_GLES
    MAGNUM_ASSERT_GL_EXTENSION_SUPPORTED(GL::Extensions::EXT::gpu_shader4);
    if(configuration.flags() >= Flag::UniformBuffers)
        MAGNUM_ASSERT_GL_EXTENSION_SUPPORTED(GL::Extensions::ARB::uniform_buffer_object);
    #endif
    if(configuration.flags() >= Flag::MultiDraw) {
        #ifndef MAGNUM_TARGET_GLES
        MAGNUM_ASSERT_GL_EXTENSION_SUPPORTED(GL::Extensions::ARB::shader_draw_parameters);
        #elif !defined(MAGNUM_TARGET_WEBGL)
        MAGNUM_ASSERT_GL_EXTENSION_SUPPORTED(GL::Extensions::ANGLE::multi_draw);
        #else
        MAGNUM_ASSERT_GL_EXTENSION_SUPPORTED(GL::Extensions::WEBGL::multi_draw);
        #endif
    }

    #ifdef MAGNUM_BUILD_STATIC
    /* Import resources on static build, if not already */
    if(!Utility::Resource::hasGroup("MagnumShadersGL"_s))
        importShaderResources();
    #endif
    Utility::Resource rs{"MagnumShadersGL"_s};


    #ifndef MAGNUM_TARGET_GLES
    const GL::Context& context = GL::Context::current();
    const GL::Version version = context.supportedVersion({GL::Version::GL320, GL::Version::GL310, GL::Version::GL300, GL::Version::GL210});
    #else
    constexpr GL::Version version = GL::Version::GLES300;
    #endif

    /* Cap and join style is needed by both the vertex and fragment shader,
       prepare their defines just once for both */
    Containers::StringView capStyleDefine, joinStyleDefine;
    switch(configuration.capStyle()) {
        case LineCapStyle::Butt:
            capStyleDefine = "#define CAP_STYLE_BUTT\n"_s;
            break;
        case LineCapStyle::Square:
            capStyleDefine = "#define CAP_STYLE_SQUARE\n"_s;
            break;
        case LineCapStyle::Round:
            capStyleDefine = "#define CAP_STYLE_ROUND\n"_s;
            break;
        case LineCapStyle::Triangle:
            capStyleDefine = "#define CAP_STYLE_TRIANGLE\n"_s;
            break;
    }
    switch(configuration.joinStyle()) {
        case LineJoinStyle::Miter:
            joinStyleDefine = "#define JOIN_STYLE_MITER\n"_s;
            break;
        case LineJoinStyle::Bevel:
            joinStyleDefine = "#define JOIN_STYLE_BEVEL\n"_s;
            break;
    }
    CORRADE_INTERNAL_ASSERT(capStyleDefine);
    CORRADE_INTERNAL_ASSERT(joinStyleDefine);

    GL::Shader vert = Implementation::createCompatibilityShader(rs, version, GL::Shader::Type::Vertex);
    vert.addSource(capStyleDefine)
        .addSource(joinStyleDefine)
        .addSource(configuration.flags() & Flag::VertexColor ? "#define VERTEX_COLOR\n"_s : ""_s)
        .addSource(dimensions == 2 ? "#define TWO_DIMENSIONS\n"_s : "#define THREE_DIMENSIONS\n"_s)
        .addSource(configuration.flags() >= Flag::InstancedObjectId ? "#define INSTANCED_OBJECT_ID\n"_s : ""_s)
        .addSource(configuration.flags() & Flag::InstancedTransformation ? "#define INSTANCED_TRANSFORMATION\n"_s : ""_s);
    if(configuration.flags() >= Flag::UniformBuffers) {
        vert.addSource(Utility::format(
            "#define UNIFORM_BUFFERS\n"
            "#define DRAW_COUNT {}\n"
            "#define MATERIAL_COUNT {}\n",
            configuration.drawCount(),
            configuration.materialCount()));
        vert.addSource(configuration.flags() >= Flag::MultiDraw ? "#define MULTI_DRAW\n"_s : ""_s);
    }
    vert.addSource(rs.getString("generic.glsl"_s))
        .addSource(rs.getString("Line.vert"_s))
        .submitCompile();

    GL::Shader frag = Implementation::createCompatibilityShader(rs, version, GL::Shader::Type::Fragment);
    frag.addSource(capStyleDefine)
        .addSource(joinStyleDefine)
        .addSource(configuration.flags() & Flag::VertexColor ? "#define VERTEX_COLOR\n"_s : ""_s)
        .addSource(configuration.flags() & Flag::ObjectId ? "#define OBJECT_ID\n"_s : ""_s)
        .addSource(configuration.flags() >= Flag::InstancedObjectId ? "#define INSTANCED_OBJECT_ID\n"_s : ""_s);
    if(configuration.flags() >= Flag::UniformBuffers) {
        frag.addSource(Utility::format(
            "#define UNIFORM_BUFFERS\n"
            "#define DRAW_COUNT {}\n"
            "#define MATERIAL_COUNT {}\n",
            configuration.drawCount(),
            configuration.materialCount()));
        frag.addSource(configuration.flags() >= Flag::MultiDraw ? "#define MULTI_DRAW\n"_s : ""_s);
    }
    frag.addSource(rs.getString("generic.glsl"_s))
        .addSource(rs.getString("Line.frag"_s))
        .submitCompile();

    LineGL<dimensions> out{NoInit};
    out._flags = configuration.flags();
    out._capStyle = configuration.capStyle();
    out._joinStyle = configuration.joinStyle();
    out._materialCount = configuration.materialCount();
    out._drawCount = configuration.drawCount();

    out.attachShaders({vert, frag});

    /* ES3 has this done in the shader directly and doesn't even provide
       bindFragmentDataLocation() */
    #ifndef MAGNUM_TARGET_GLES
    if(!context.isExtensionSupported<GL::Extensions::ARB::explicit_attrib_location>(version)) {
        out.bindAttributeLocation(Position::Location, "position"_s);
        out.bindAttributeLocation(PreviousPosition::Location, "previousPosition"_s);
        out.bindAttributeLocation(NextPosition::Location, "nextPosition"_s);
        out.bindAttributeLocation(Annotation::Location, "annotation"_s);
        if(configuration.flags() & Flag::VertexColor)
            out.bindAttributeLocation(Color3::Location, "vertexColor"_s); /* Color4 is the same */
        if(configuration.flags() & Flag::ObjectId) {
            out.bindFragmentDataLocation(ColorOutput, "color"_s);
            out.bindFragmentDataLocation(ObjectIdOutput, "objectId"_s);
        }
        if(configuration.flags() >= Flag::InstancedObjectId)
            out.bindAttributeLocation(ObjectId::Location, "instanceObjectId"_s);
        if(configuration.flags() & Flag::InstancedTransformation)
            out.bindAttributeLocation(TransformationMatrix::Location, "instancedTransformationMatrix"_s);
    }
    #endif

    out.submitLink();

    return CompileState{std::move(out), std::move(vert), std::move(frag)
        #ifndef MAGNUM_TARGET_GLES
        , version
        #endif
    };
}

template<UnsignedInt dimensions> LineGL<dimensions>::LineGL(CompileState&& state): LineGL{static_cast<LineGL&&>(std::move(state))} {
    #ifdef CORRADE_GRACEFUL_ASSERT
    /* When graceful assertions fire from within compile(), we get a NoCreate'd
       CompileState. Exiting makes it possible to test the assert. */
    if(!id()) return;
    #endif

    CORRADE_INTERNAL_ASSERT_OUTPUT(checkLink({GL::Shader(state._vert), GL::Shader(state._frag)}));

    #ifndef MAGNUM_TARGET_GLES
    const GL::Context& context = GL::Context::current();
    if(!context.isExtensionSupported<GL::Extensions::ARB::explicit_uniform_location>(state._version))
    #endif
    {
        _viewportSizeUniform = uniformLocation("viewportSize"_s);
        if(_flags >= Flag::UniformBuffers) {
            if(_drawCount > 1)
                _drawOffsetUniform = uniformLocation("drawOffset"_s);
        } else {
            _transformationProjectionMatrixUniform = uniformLocation("transformationProjectionMatrix"_s);
            _widthUniform = uniformLocation("width"_s);
            _smoothnessUniform = uniformLocation("smoothness"_s);
            if(_joinStyle == LineJoinStyle::Miter)
                _miterLimitUniform = uniformLocation("miterLimit"_s);
            _backgroundColorUniform = uniformLocation("backgroundColor"_s);
            _colorUniform = uniformLocation("color"_s);
            if(_flags & Flag::ObjectId)
                _objectIdUniform = uniformLocation("objectId"_s);
        }
    }

    #ifndef MAGNUM_TARGET_GLES
    if(!context.isExtensionSupported<GL::Extensions::ARB::shading_language_420pack>(state._version))
    #endif
    {
        if(_flags >= Flag::UniformBuffers) {
            setUniformBlockBinding(uniformBlockIndex("TransformationProjection"_s), TransformationProjectionBufferBinding);
            setUniformBlockBinding(uniformBlockIndex("Draw"_s), DrawBufferBinding);
            setUniformBlockBinding(uniformBlockIndex("Material"_s), MaterialBufferBinding);
        }
    }

    /* Set defaults in OpenGL ES (for desktop they are set in shader code itself) */
    #ifdef MAGNUM_TARGET_GLES
    if(_flags >= Flag::UniformBuffers) {
        /* Draw offset is zero by default */
    } else {
        setTransformationProjectionMatrix(MatrixTypeFor<dimensions, Float>{Math::IdentityInit});
        setWidth(1.0f);
        /* Smoothness is zero by default */
        if(_joinStyle == LineJoinStyle::Miter)
            setMiterLengthLimit(4.0f);
        setColor(Magnum::Color4{1.0f});
        /* Object ID is zero by default */
    }
    #endif
}

template<UnsignedInt dimensions> LineGL<dimensions>::LineGL(const Configuration& configuration): LineGL{compile(configuration)} {}

template<UnsignedInt dimensions> LineGL<dimensions>::LineGL(NoInitT) {}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::setViewportSize(const Vector2& size) {
    setUniform(_viewportSizeUniform, size);
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::setTransformationProjectionMatrix(const MatrixTypeFor<dimensions, Float>& matrix) {
    CORRADE_ASSERT(!(_flags >= Flag::UniformBuffers),
        "Shaders::LineGL::setTransformationProjectionMatrix(): the shader was created with uniform buffers enabled", *this);
    setUniform(_transformationProjectionMatrixUniform, matrix);
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::setBackgroundColor(const Magnum::Color4& color) {
    CORRADE_ASSERT(!(_flags >= Flag::UniformBuffers),
        "Shaders::LineGL::setBackgroundColor(): the shader was created with uniform buffers enabled", *this);
    setUniform(_backgroundColorUniform, color);
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::setColor(const Magnum::Color4& color) {
    CORRADE_ASSERT(!(_flags >= Flag::UniformBuffers),
        "Shaders::LineGL::setColor(): the shader was created with uniform buffers enabled", *this);
    setUniform(_colorUniform, color);
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::setWidth(const Float width) {
    CORRADE_ASSERT(!(_flags >= Flag::UniformBuffers),
        "Shaders::LineGL::setWidth(): the shader was created with uniform buffers enabled", *this);
    setUniform(_widthUniform, width);
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::setSmoothness(const Float smoothness) {
    CORRADE_ASSERT(!(_flags >= Flag::UniformBuffers),
        "Shaders::LineGL::setSmoothness(): the shader was created with uniform buffers enabled", *this);
    setUniform(_smoothnessUniform, smoothness);
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::setMiterLengthLimit(const Float limit) {
    CORRADE_ASSERT(!(_flags >= Flag::UniformBuffers),
        "Shaders::LineGL::setMiterLengthLimit(): the shader was created with uniform buffers enabled", *this);
    CORRADE_ASSERT(_joinStyle == LineJoinStyle::Miter,
        "Shaders::LineGL::setMiterLengthLimit(): the shader was created with" << _joinStyle, *this);
    setUniform(_miterLimitUniform, Implementation::lineMiterLengthLimit("Shaders::LineGL::setMiterLengthLimit():", limit));
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::setMiterAngleLimit(const Rad limit) {
    CORRADE_ASSERT(!(_flags >= Flag::UniformBuffers),
        "Shaders::LineGL::setMiterAngleLimit(): the shader was created with uniform buffers enabled", *this);
    CORRADE_ASSERT(_joinStyle == LineJoinStyle::Miter,
        "Shaders::LineGL::setMiterAngleLimit(): the shader was created with" << _joinStyle, *this);
    setUniform(_miterLimitUniform, Implementation::lineMiterAngleLimit("Shaders::LineGL::setMiterAngleLimit():", limit));
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::setObjectId(UnsignedInt id) {
    CORRADE_ASSERT(!(_flags >= Flag::UniformBuffers),
        "Shaders::LineGL::setObjectId(): the shader was created with uniform buffers enabled", *this);
    CORRADE_ASSERT(_flags & Flag::ObjectId,
        "Shaders::LineGL::setObjectId(): the shader was not created with object ID enabled", *this);
    setUniform(_objectIdUniform, id);
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::setDrawOffset(const UnsignedInt offset) {
    CORRADE_ASSERT(_flags >= Flag::UniformBuffers,
        "Shaders::LineGL::setDrawOffset(): the shader was not created with uniform buffers enabled", *this);
    CORRADE_ASSERT(offset < _drawCount,
        "Shaders::LineGL::setDrawOffset(): draw offset" << offset << "is out of bounds for" << _drawCount << "draws", *this);
    if(_drawCount > 1) setUniform(_drawOffsetUniform, offset);
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::bindTransformationProjectionBuffer(GL::Buffer& buffer) {
    CORRADE_ASSERT(_flags >= Flag::UniformBuffers,
        "Shaders::LineGL::bindTransformationProjectionBuffer(): the shader was not created with uniform buffers enabled", *this);
    buffer.bind(GL::Buffer::Target::Uniform, TransformationProjectionBufferBinding);
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::bindTransformationProjectionBuffer(GL::Buffer& buffer, const GLintptr offset, const GLsizeiptr size) {
    CORRADE_ASSERT(_flags >= Flag::UniformBuffers,
        "Shaders::LineGL::bindTransformationProjectionBuffer(): the shader was not created with uniform buffers enabled", *this);
    buffer.bind(GL::Buffer::Target::Uniform, TransformationProjectionBufferBinding, offset, size);
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::bindDrawBuffer(GL::Buffer& buffer) {
    CORRADE_ASSERT(_flags >= Flag::UniformBuffers,
        "Shaders::LineGL::bindDrawBuffer(): the shader was not created with uniform buffers enabled", *this);
    buffer.bind(GL::Buffer::Target::Uniform, DrawBufferBinding);
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::bindDrawBuffer(GL::Buffer& buffer, const GLintptr offset, const GLsizeiptr size) {
    CORRADE_ASSERT(_flags >= Flag::UniformBuffers,
        "Shaders::LineGL::bindDrawBuffer(): the shader was not created with uniform buffers enabled", *this);
    buffer.bind(GL::Buffer::Target::Uniform, DrawBufferBinding, offset, size);
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::bindMaterialBuffer(GL::Buffer& buffer) {
    CORRADE_ASSERT(_flags >= Flag::UniformBuffers,
        "Shaders::LineGL::bindMaterialBuffer(): the shader was not created with uniform buffers enabled", *this);
    buffer.bind(GL::Buffer::Target::Uniform, MaterialBufferBinding);
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>& LineGL<dimensions>::bindMaterialBuffer(GL::Buffer& buffer, const GLintptr offset, const GLsizeiptr size) {
    CORRADE_ASSERT(_flags >= Flag::UniformBuffers,
        "Shaders::LineGL::bindMaterialBuffer(): the shader was not created with uniform buffers enabled", *this);
    buffer.bind(GL::Buffer::Target::Uniform, MaterialBufferBinding, offset, size);
    return *this;
}

template<UnsignedInt dimensions> LineGL<dimensions>::Configuration::Configuration(): _capStyle{LineCapStyle::Square}, _joinStyle{LineJoinStyle::Miter} {}

template class MAGNUM_SHADERS_EXPORT LineGL<2>;
template class MAGNUM_SHADERS_EXPORT LineGL<3>;

namespace Implementation {

Debug& operator<<(Debug& debug, const LineGLFlag value) {
    debug << "Shaders::LineGL::Flag" << Debug::nospace;

    switch(value) {
        /* LCOV_EXCL_START */
        #define _c(v) case LineGLFlag::v: return debug << "::" #v;
        _c(VertexColor)
        _c(ObjectId)
        _c(InstancedObjectId)
        _c(InstancedTransformation)
        _c(UniformBuffers)
        _c(MultiDraw)
        #undef _c
        /* LCOV_EXCL_STOP */
    }

    return debug << "(" << Debug::nospace << reinterpret_cast<void*>(UnsignedShort(value)) << Debug::nospace << ")";
}

Debug& operator<<(Debug& debug, const LineGLFlags value) {
    return Containers::enumSetDebugOutput(debug, value, "Shaders::LineGL::Flags{}", {
        LineGLFlag::VertexColor,
        LineGLFlag::InstancedObjectId, /* Superset of ObjectId */
        LineGLFlag::ObjectId,
        LineGLFlag::InstancedTransformation,
        LineGLFlag::MultiDraw, /* Superset of UniformBuffers */
        LineGLFlag::UniformBuffers
    });
}

}

}}