/*****************************************************************************************
 *                                                                                       *
 * OpenSpace                                                                             *
 *                                                                                       *
 * Copyright (c) 2014-2018                                                               *
 *                                                                                       *
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 ****************************************************************************************/

#include <modules/spacecraftinstruments/rendering/renderablemodelprojection.h>

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

#include <openspace/documentation/documentation.h>
#include <openspace/documentation/verifier.h>
#include <openspace/engine/openspaceengine.h>
#include <openspace/rendering/renderengine.h>
#include <openspace/scene/scenegraphnode.h>
#include <openspace/scene/scene.h>
#include <openspace/util/spicemanager.h>
#include <openspace/util/time.h>
#include <openspace/util/updatestructures.h>

#include <ghoul/filesystem/filesystem.h>
#include <ghoul/io/texture/texturereader.h>
#include <ghoul/opengl/programobject.h>
#include <ghoul/opengl/texture.h>
#include <ghoul/opengl/textureunit.h>

namespace {
    constexpr const char* _loggerCat = "RenderableModelProjection";

    constexpr const char* keyGeometry = "Geometry";
    constexpr const char* keyProjection = "Projection";
    constexpr const char* keyBoundingSphereRadius = "BoundingSphereRadius";

    constexpr const char* DestinationFrame = "GALACTIC";

    static const openspace::properties::Property::PropertyInfo ColorTextureInfo = {
        "ColorTexture",
        "Color Base Texture",
        "This is the path to a local image file that is used as the base texture for the "
        "model on which the image projections are layered."
    };

    static const openspace::properties::Property::PropertyInfo PerformShadingInfo = {
        "PerformShading",
        "Perform Shading",
        "If this value is enabled, the model will be shaded based on the relative "
        "location to the Sun. If this value is disabled, shading is disabled and the "
        "entire model is rendered brightly."
    };
} // namespace

namespace openspace {

documentation::Documentation RenderableModelProjection::Documentation() {
    using namespace documentation;

    return {
        "Renderable Model Projection",
        "newhorizons_renderable_modelprojection",
        {
            {
                "Type",
                new StringEqualVerifier("RenderableModelProjection"),
                Optional::No
            },
            {
                keyGeometry,
                new ReferencingVerifier("base_geometry_model"),
                Optional::No,
                "The geometry that is used for rendering this model."
            },
            {
                keyProjection,
                new ReferencingVerifier("newhorizons_projectioncomponent"),
                Optional::No,
                "Contains information about projecting onto this planet."
            },
            {
                ColorTextureInfo.identifier,
                new StringVerifier,
                Optional::No,
                ColorTextureInfo.description
            },
            {
                PerformShadingInfo.identifier,
                new BoolVerifier,
                Optional::Yes,
                PerformShadingInfo.description
            },
            {
                keyBoundingSphereRadius,
                new DoubleVerifier,
                Optional::Yes,
                "The radius of the bounding sphere of this object. This has to be a "
                "radius that is larger than anything that is rendered by it. It has to "
                "be at least as big as the convex hull of the object. The default value "
                "is 10e9 meters."
            }
        }
    };
}

RenderableModelProjection::RenderableModelProjection(const ghoul::Dictionary& dictionary)
    : Renderable(dictionary)
    , _colorTexturePath(ColorTextureInfo)
    , _programObject(nullptr)
    , _fboProgramObject(nullptr)
    , _baseTexture(nullptr)
    , _geometry(nullptr)
    , _performShading(PerformShadingInfo, true)
{
    documentation::testSpecificationAndThrow(
        Documentation(),
        dictionary,
        "RenderableModelProjection"
    );

    std::string name;
    [[ maybe_unused ]] bool success = dictionary.getValue(SceneGraphNode::KeyName, name);
    ghoul_assert(success, "Name was not passed to RenderableModelProjection");

    using ghoul::Dictionary;
    Dictionary geometryDictionary = dictionary.value<Dictionary>(keyGeometry);
    using modelgeometry::ModelGeometry;
    geometryDictionary.setValue(SceneGraphNode::KeyName, name);
    _geometry = ModelGeometry::createFromDictionary(geometryDictionary);

    _colorTexturePath = absPath(dictionary.value<std::string>(
        ColorTextureInfo.identifier
    ));

    addPropertySubOwner(_geometry.get());
    addPropertySubOwner(_projectionComponent);

    addProperty(_colorTexturePath);
    _colorTexturePath.onChange(std::bind(&RenderableModelProjection::loadTextures, this));

    _projectionComponent.initialize(
        dictionary.value<ghoul::Dictionary>(keyProjection)
    );

    float boundingSphereRadius = 1.0e9;
    dictionary.getValue(keyBoundingSphereRadius, boundingSphereRadius);
    setBoundingSphere(boundingSphereRadius);

    if (dictionary.hasKey(PerformShadingInfo.identifier)) {
        _performShading = dictionary.value<bool>(PerformShadingInfo.identifier);
    }

    Renderable::addProperty(_performShading);
}

// This empty method needs to be here in order to use forward declaration with
// std::unique_ptr
RenderableModelProjection::~RenderableModelProjection() {}

bool RenderableModelProjection::isReady() const {
    bool ready = true;
    ready &= (_programObject != nullptr);
    ready &= (_baseTexture != nullptr);
    ready &= (_projectionComponent.isReady());
    return ready;
}

void RenderableModelProjection::initializeGL() {
    RenderEngine& renderEngine = OsEng.renderEngine();
    _programObject = renderEngine.buildRenderProgram(
        "ModelShader",
        absPath("${MODULE_SPACECRAFTINSTRUMENTS}/shaders/renderableModel_vs.glsl"),
        absPath("${MODULE_SPACECRAFTINSTRUMENTS}/shaders/renderableModel_fs.glsl")
    );

    _mainUniformCache.performShading = _programObject->uniformLocation("_performShading");
    _mainUniformCache.directionToSunViewSpace = _programObject->uniformLocation(
        "directionToSunViewSpace"
    );
    _mainUniformCache.modelViewTransform = _programObject->uniformLocation(
        "modelViewTransform"
    );
    _mainUniformCache.projectionTransform = _programObject->uniformLocation(
        "projectionTransform"
    );
    _mainUniformCache.projectionFading = _programObject->uniformLocation(
        "_projectionFading"
    );
    _mainUniformCache.baseTexture = _programObject->uniformLocation(
        "baseTexture"
    );
    _mainUniformCache.projectionTexture = _programObject->uniformLocation(
        "projectionTexture"
    );

    _fboProgramObject = ghoul::opengl::ProgramObject::Build(
        "ProjectionPass",
        absPath(
            "${MODULE_SPACECRAFTINSTRUMENTS}/shaders/renderableModelProjection_vs.glsl"
        ),
        absPath(
            "${MODULE_SPACECRAFTINSTRUMENTS}/shaders/renderableModelProjection_fs.glsl"
        )
    );

    _fboUniformCache.projectionTexture = _fboProgramObject->uniformLocation(
        "projectionTexture"
    );
    _fboUniformCache.needShadowMap = _fboProgramObject->uniformLocation("needShadowMap");
    _fboUniformCache.ProjectorMatrix = _fboProgramObject->uniformLocation(
        "ProjectorMatrix"
    );
    _fboUniformCache.ModelTransform = _fboProgramObject->uniformLocation("ModelTransform");
    _fboUniformCache.boresight = _fboProgramObject->uniformLocation("boresight");


    _depthFboProgramObject = ghoul::opengl::ProgramObject::Build(
        "DepthPass",
        absPath("${MODULE_SPACECRAFTINSTRUMENTS}/shaders/renderableModelDepth_vs.glsl"),
        absPath("${MODULE_SPACECRAFTINSTRUMENTS}/shaders/renderableModelDepth_fs.glsl")
    );

    _depthFboUniformCache.ProjectorMatrix = _depthFboProgramObject->uniformLocation(
        "ProjectorMatrix"
    );
    _depthFboUniformCache.ModelTransform = _depthFboProgramObject->uniformLocation(
        "ModelTransform"
    );


    loadTextures();
    _projectionComponent.initializeGL();

    float bs = boundingSphere();
    _geometry->initialize(this);
    setBoundingSphere(bs); // ignore bounding sphere set by geometry.
}

void RenderableModelProjection::deinitializeGL() {
    if (_geometry) {
        _geometry->deinitialize();
    }

    _geometry = nullptr;
    _baseTexture = nullptr;

    _projectionComponent.deinitialize();

    OsEng.renderEngine().removeRenderProgram(_programObject);
    _programObject = nullptr;
}

ghoul::opengl::Texture& RenderableModelProjection::baseTexture() const {
    return _projectionComponent.projectionTexture();
}

void RenderableModelProjection::render(const RenderData& data, RendererTasks&) {
    if (_projectionComponent.needsClearProjection()) {
        _projectionComponent.clearAllProjections();
    }

    _up = data.camera.lookUpVectorCameraSpace();

    if (_capture && _projectionComponent.doesPerformProjection()) {
        project();
    }

    _programObject->activate();

    attitudeParameters(_time);
    _imageTimes.clear();

    // Calculate variables to be used as uniform variables in shader
    glm::dvec3 bodyPosition = data.modelTransform.translation;

    // Model transform and view transform needs to be in double precision
    glm::dmat4 modelTransform =
        glm::translate(glm::dmat4(1.0), data.modelTransform.translation) * // Translation
        glm::dmat4(data.modelTransform.rotation) * // Rotation
        glm::scale(glm::dmat4(1.0), glm::dvec3(data.modelTransform.scale)); // Scale
    glm::dmat4 modelViewTransform = data.camera.combinedViewMatrix() * modelTransform;
    glm::vec3 directionToSun = glm::normalize(
        _sunPosition.vec3() - glm::vec3(bodyPosition)
    );
    glm::vec3 directionToSunViewSpace = glm::mat3(
        data.camera.combinedViewMatrix()
    ) * directionToSun;

    _programObject->setUniform(_mainUniformCache.performShading, _performShading);
    _programObject->setUniform(
        _mainUniformCache.directionToSunViewSpace,
        directionToSunViewSpace
    );
    _programObject->setUniform(
        _mainUniformCache.modelViewTransform,
        glm::mat4(modelViewTransform)
    );
    _programObject->setUniform(
        _mainUniformCache.projectionTransform,
        data.camera.projectionMatrix()
    );
    _programObject->setUniform(
        _mainUniformCache.projectionFading,
        _projectionComponent.projectionFading()
    );

    _geometry->setUniforms(*_programObject);

    ghoul::opengl::TextureUnit unit[2];
    unit[0].activate();
    _baseTexture->bind();
    _programObject->setUniform(_mainUniformCache.baseTexture, unit[0]);

    unit[1].activate();
    _projectionComponent.projectionTexture().bind();
    _programObject->setUniform(_mainUniformCache.projectionTexture, unit[1]);

    _geometry->render();

    _programObject->deactivate();
}

void RenderableModelProjection::update(const UpdateData& data) {
    if (_programObject->isDirty()) {
        _programObject->rebuildFromFile();

        _mainUniformCache.performShading = _programObject->uniformLocation(
            "_performShading"
        );
        _mainUniformCache.directionToSunViewSpace = _programObject->uniformLocation(
            "directionToSunViewSpace"
        );
        _mainUniformCache.modelViewTransform = _programObject->uniformLocation(
            "modelViewTransform"
        );
        _mainUniformCache.projectionTransform = _programObject->uniformLocation(
            "projectionTransform"
        );
        _mainUniformCache.projectionFading = _programObject->uniformLocation(
            "_projectionFading"
        );
        _mainUniformCache.baseTexture = _programObject->uniformLocation(
            "baseTexture"
        );
        _mainUniformCache.projectionTexture = _programObject->uniformLocation(
            "projectionTexture"
        );
    }

    if (_fboProgramObject->isDirty()) {
        _fboProgramObject->rebuildFromFile();

        _fboUniformCache.projectionTexture = _fboProgramObject->uniformLocation(
            "projectionTexture"
        );
        _fboUniformCache.needShadowMap = _fboProgramObject->uniformLocation(
            "needShadowMap"
        );
        _fboUniformCache.ProjectorMatrix = _fboProgramObject->uniformLocation(
            "ProjectorMatrix"
        );
        _fboUniformCache.ModelTransform = _fboProgramObject->uniformLocation(
            "ModelTransform"
        );
        _fboUniformCache.boresight = _fboProgramObject->uniformLocation("boresight");
    }

    _projectionComponent.update();

    if (_depthFboProgramObject->isDirty()) {
        _depthFboProgramObject->rebuildFromFile();

        _depthFboUniformCache.ProjectorMatrix = _depthFboProgramObject->uniformLocation(
            "ProjectorMatrix"
        );
        _depthFboUniformCache.ModelTransform = _depthFboProgramObject->uniformLocation(
            "ModelTransform"
        );
    }

    const double time = data.time.j2000Seconds();

    // Only project new images if time changed since last update.
    if (time != _time) {
        if (openspace::ImageSequencer::ref().isReady()) {
            openspace::ImageSequencer::ref().updateSequencer(time);
            if (_projectionComponent.doesPerformProjection()) {
                _capture = openspace::ImageSequencer::ref().getImagePaths(
                    _imageTimes,
                    _projectionComponent.projecteeId(),
                    _projectionComponent.instrumentId(),
                    _time
                );
            }
        }
        _time = time;
    }

    _stateMatrix = data.modelTransform.rotation;

    glm::dvec3 p =
        OsEng.renderEngine().scene()->sceneGraphNode("Sun")->worldPosition() -
        data.modelTransform.translation;

    _sunPosition = PowerScaledCoordinate::CreatePowerScaledCoordinate(p.x, p.y, p.z);
}

void RenderableModelProjection::imageProjectGPU(
                                std::shared_ptr<ghoul::opengl::Texture> projectionTexture)
{
    if (_projectionComponent.needsShadowMap()) {
        _projectionComponent.depthMapRenderBegin();
        _depthFboProgramObject->activate();
        _depthFboProgramObject->setUniform(
            _depthFboUniformCache.ProjectorMatrix,
            _projectorMatrix
        );
        _depthFboProgramObject->setUniform(
            _depthFboUniformCache.ModelTransform,
            _transform
        );
        _geometry->setUniforms(*_fboProgramObject);

        _geometry->render();

        _depthFboProgramObject->deactivate();
        _projectionComponent.depthMapRenderEnd();
    }

    _projectionComponent.imageProjectBegin();
    _fboProgramObject->activate();

    ghoul::opengl::TextureUnit unitFbo;
    unitFbo.activate();
    projectionTexture->bind();
    _fboProgramObject->setUniform(_fboUniformCache.projectionTexture, unitFbo);

    _fboProgramObject->setUniform(
        _fboUniformCache.needShadowMap,
        _projectionComponent.needsShadowMap()
    );

    ghoul::opengl::TextureUnit unitDepthFbo;
    if (_projectionComponent.needsShadowMap()) {
        unitDepthFbo.activate();
        _projectionComponent.depthTexture().bind();
        _fboProgramObject->setUniform("depthTexture", unitDepthFbo);
    }

    _fboProgramObject->setUniform(_fboUniformCache.ProjectorMatrix, _projectorMatrix);
    _fboProgramObject->setUniform(_fboUniformCache.ModelTransform, _transform);
    _fboProgramObject->setUniform(_fboUniformCache.boresight, _boresight);

    _geometry->setUniforms(*_fboProgramObject);
    _geometry->render();

    _fboProgramObject->deactivate();

    _projectionComponent.imageProjectEnd();
}

void RenderableModelProjection::attitudeParameters(double time) {
    try {
        _instrumentMatrix = SpiceManager::ref().positionTransformMatrix(
            _projectionComponent.instrumentId(),
            DestinationFrame,
            time
        );
    }
    catch (const SpiceManager::SpiceException&) {
        return;
    }

    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            _transform[i][j] = static_cast<float>(_stateMatrix[i][j]);
        }
    }
    glm::dvec3 boresight;
    try {
        SpiceManager::FieldOfViewResult res = SpiceManager::ref().fieldOfView(
            _projectionComponent.instrumentId()
        );
        boresight = std::move(res.boresightVector);
    } catch (const SpiceManager::SpiceException&) {
        return;
    }

    double lightTime;
    glm::dvec3 p = SpiceManager::ref().targetPosition(
        _projectionComponent.projectorId(),
        _projectionComponent.projecteeId(),
        DestinationFrame,
        _projectionComponent.aberration(),
        time, lightTime
    );

    psc position = PowerScaledCoordinate::CreatePowerScaledCoordinate(p.x, p.y, p.z);

    position[3] += 4;
    glm::vec3 cpos = position.vec3();

    float distance = glm::length(cpos);
    float radius = boundingSphere();

    _projectorMatrix = _projectionComponent.computeProjectorMatrix(
        cpos, boresight, _up, _instrumentMatrix,
        _projectionComponent.fieldOfViewY(),
        _projectionComponent.aspectRatio(),
        distance - radius,
        distance + radius,
        _boresight
    );
}

void RenderableModelProjection::project() {
    for (auto img : _imageTimes) {
        attitudeParameters(img.timeRange.start);
        auto projTexture = _projectionComponent.loadProjectionTexture(
            img.path,
            img.isPlaceholder
        );
        imageProjectGPU(projTexture);
    }
    _capture = false;
}

bool RenderableModelProjection::loadTextures() {
    _baseTexture = nullptr;
    if (_colorTexturePath.value() != "") {
        _baseTexture = ghoul::io::TextureReader::ref().loadTexture(
            absPath(_colorTexturePath)
        );
        if (_baseTexture) {
            LDEBUG("Loaded texture from '" << absPath(_colorTexturePath) << "'");
            _baseTexture->uploadTexture();
            _baseTexture->setFilter(ghoul::opengl::Texture::FilterMode::LinearMipMap);
        }
    }

    return _baseTexture != nullptr;
}

}  // namespace openspace