/*****************************************************************************************
 *                                                                                       *
 * OpenSpace                                                                             *
 *                                                                                       *
 * Copyright (c) 2014-2019                                                               *
 *                                                                                       *
 * 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,    *
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 * permit persons to whom the Software is furnished to do so, subject to the following   *
 * conditions:                                                                           *
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 * The above copyright notice and this permission notice shall be included in all copies *
 * or substantial portions of the Software.                                              *
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 * 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    *
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 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE  *
 * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                                         *
 ****************************************************************************************/

#include <modules/base/rendering/renderableplane.h>

#include <modules/base/basemodule.h>
#include <openspace/documentation/documentation.h>
#include <openspace/documentation/verifier.h>
#include <openspace/engine/globals.h>
#include <openspace/rendering/renderengine.h>
#include <openspace/scene/scenegraphnode.h>
#include <openspace/util/updatestructures.h>
#include <ghoul/filesystem/filesystem.h>
#include <ghoul/io/texture/texturereader.h>
#include <ghoul/misc/defer.h>
#include <ghoul/opengl/programobject.h>
#include <ghoul/opengl/texture.h>
#include <ghoul/opengl/textureunit.h>
#include <ghoul/glm.h>
#include <glm/gtx/string_cast.hpp>

namespace {
    constexpr const char* ProgramName = "Plane";

    enum BlendMode {
        BlendModeNormal = 0,
        BlendModeAdditive
    };

    constexpr openspace::properties::Property::PropertyInfo BillboardInfo = {
        "Billboard",
        "Billboard mode",
        "This value specifies whether the plane is a billboard, which means that it is "
        "always facing the camera. If this is false, it can be oriented using other "
        "transformations."
    };

    constexpr openspace::properties::Property::PropertyInfo SizeInfo = {
        "Size",
        "Size (in meters)",
        "This value specifies the size of the plane in meters."
    };

    constexpr openspace::properties::Property::PropertyInfo BlendModeInfo = {
        "BlendMode",
        "Blending Mode",
        "This determines the blending mode that is applied to this plane."
    };
} // namespace

namespace openspace {

documentation::Documentation RenderablePlane::Documentation() {
    using namespace documentation;
    return {
        "Renderable Plane",
        "base_renderable_plane",
        {
            {
                SizeInfo.identifier,
                new DoubleVerifier,
                Optional::No,
                SizeInfo.description
            },
            {
                BillboardInfo.identifier,
                new BoolVerifier,
                Optional::Yes,
                BillboardInfo.description
            },
            {
                BlendModeInfo.identifier,
                new StringInListVerifier({ "Normal", "Additive" }),
                Optional::Yes,
                BlendModeInfo.description, // + " The default value is 'Normal'.",
            }
        }
    };
}

RenderablePlane::RenderablePlane(const ghoul::Dictionary& dictionary)
    : Renderable(dictionary)
    , _billboard(BillboardInfo, false)
    , _size(SizeInfo, 10.f, 0.f, 1e25f)
    , _blendMode(BlendModeInfo, properties::OptionProperty::DisplayType::Dropdown)
{
    documentation::testSpecificationAndThrow(
        Documentation(),
        dictionary,
        "RenderablePlane"
    );

    addProperty(_opacity);
    registerUpdateRenderBinFromOpacity();

    _size = static_cast<float>(dictionary.value<double>(SizeInfo.identifier));

    if (dictionary.hasKey(BillboardInfo.identifier)) {
        _billboard = dictionary.value<bool>(BillboardInfo.identifier);
    }

    _blendMode.addOptions({
        { BlendModeNormal, "Normal" },
        { BlendModeAdditive, "Additive"}
    });
    _blendMode.onChange([&]() {
        switch (_blendMode) {
            case BlendModeNormal:
                setRenderBinFromOpacity();
                break;
            case BlendModeAdditive:
                setRenderBin(Renderable::RenderBin::Transparent);
                break;
            default:
                throw ghoul::MissingCaseException();
        }
    });

    _opacity.onChange([&]() {
        if (_blendMode == BlendModeNormal) {
            setRenderBinFromOpacity();
        }
    });

    if (dictionary.hasKey(BlendModeInfo.identifier)) {
        const std::string v = dictionary.value<std::string>(BlendModeInfo.identifier);
        if (v == "Normal") {
            _blendMode = BlendModeNormal;
        }
        else if (v == "Additive") {
            _blendMode = BlendModeAdditive;
        }
    }

    addProperty(_billboard);

    addProperty(_size);
    _size.onChange([this](){ _planeIsDirty = true; });

    setBoundingSphere(_size);
}

bool RenderablePlane::isReady() const {
    return _shader != nullptr;
}

void RenderablePlane::initializeGL() {
    glGenVertexArrays(1, &_quad); // generate array
    glGenBuffers(1, &_vertexPositionBuffer); // generate buffer
    createPlane();

    _shader = BaseModule::ProgramObjectManager.request(
        ProgramName,
        []() -> std::unique_ptr<ghoul::opengl::ProgramObject> {
            return global::renderEngine.buildRenderProgram(
                ProgramName,
                absPath("${MODULE_BASE}/shaders/plane_vs.glsl"),
                absPath("${MODULE_BASE}/shaders/plane_fs.glsl")
            );
        }
    );
}

void RenderablePlane::deinitializeGL() {
    glDeleteVertexArrays(1, &_quad);
    _quad = 0;

    glDeleteBuffers(1, &_vertexPositionBuffer);
    _vertexPositionBuffer = 0;

    BaseModule::ProgramObjectManager.release(
        ProgramName,
        [](ghoul::opengl::ProgramObject* p) {
            global::renderEngine.removeRenderProgram(p);
        }
    );
    _shader = nullptr;
}

void RenderablePlane::render(const RenderData& data, RendererTasks&) {
    _shader->activate();

    _shader->setUniform("opacity", _opacity);

    glm::dvec3 objectPositionWorld = glm::dvec3(
        glm::translate(
            glm::dmat4(1.0),
            data.modelTransform.translation) * glm::dvec4(0.0, 0.0, 0.0, 1.0)
    );

    glm::dvec3 normal = glm::normalize(data.camera.positionVec3() - objectPositionWorld);
    glm::dvec3 newRight = glm::normalize(
        glm::cross(data.camera.lookUpVectorWorldSpace(), normal)
    );
    glm::dvec3 newUp = glm::cross(normal, newRight);

    glm::dmat4 cameraOrientedRotation;
    cameraOrientedRotation[0] = glm::dvec4(newRight, 0.0);
    cameraOrientedRotation[1] = glm::dvec4(newUp, 0.0);
    cameraOrientedRotation[2] = glm::dvec4(normal, 0.0);

    const glm::dmat4 rotationTransform = _billboard ?
        cameraOrientedRotation :
        glm::dmat4(data.modelTransform.rotation);

    const glm::dmat4 modelTransform =
        glm::translate(glm::dmat4(1.0), data.modelTransform.translation) *
        rotationTransform *
        glm::scale(glm::dmat4(1.0), glm::dvec3(data.modelTransform.scale)) *
        glm::dmat4(1.0);
    const glm::dmat4 modelViewTransform =
        data.camera.combinedViewMatrix() * modelTransform;

    _shader->setUniform("modelViewProjectionTransform",
        data.camera.projectionMatrix() * glm::mat4(modelViewTransform));

    _shader->setUniform("modelViewTransform",
        glm::mat4(data.camera.combinedViewMatrix() * glm::dmat4(modelViewTransform)));

    ghoul::opengl::TextureUnit unit;
    unit.activate();
    bindTexture();
    defer { unbindTexture(); };

    _shader->setUniform("texture1", unit);

    bool usingFramebufferRenderer = global::renderEngine.rendererImplementation() ==
                                    RenderEngine::RendererImplementation::Framebuffer;

    bool usingABufferRenderer = global::renderEngine.rendererImplementation() ==
                                RenderEngine::RendererImplementation::ABuffer;

    if (usingABufferRenderer) {
        _shader->setUniform("additiveBlending", _blendMode == BlendModeAdditive);
    }

    bool additiveBlending = (_blendMode == BlendModeAdditive) && usingFramebufferRenderer;
    if (additiveBlending) {
        glDepthMask(false);
        glBlendFunc(GL_SRC_ALPHA, GL_ONE);
    }

    glBindVertexArray(_quad);
    glDrawArrays(GL_TRIANGLES, 0, 6);

    if (additiveBlending) {
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
        glDepthMask(true);
    }

    _shader->deactivate();
}

void RenderablePlane::bindTexture() {}

void RenderablePlane::unbindTexture() {}

void RenderablePlane::update(const UpdateData&) {
    if (_shader->isDirty()) {
        _shader->rebuildFromFile();
    }

    if (_planeIsDirty) {
        createPlane();
    }
}

void RenderablePlane::createPlane() {
    const GLfloat size = _size;
    const GLfloat vertexData[] = {
        //      x      y     z     w     s     t
        -size, -size, 0.f, 0.f, 0.f, 0.f,
        size, size, 0.f, 0.f, 1.f, 1.f,
        -size, size, 0.f, 0.f, 0.f, 1.f,
        -size, -size, 0.f, 0.f, 0.f, 0.f,
        size, -size, 0.f, 0.f, 1.f, 0.f,
        size, size, 0.f, 0.f, 1.f, 1.f,
    };

    glBindVertexArray(_quad);
    glBindBuffer(GL_ARRAY_BUFFER, _vertexPositionBuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertexData), vertexData, GL_STATIC_DRAW);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(GLfloat) * 6, nullptr);

    glEnableVertexAttribArray(1);
    glVertexAttribPointer(
        1,
        2,
        GL_FLOAT,
        GL_FALSE,
        sizeof(GLfloat) * 6,
        reinterpret_cast<void*>(sizeof(GLfloat) * 4)
    );
}

} // namespace openspace