/*****************************************************************************************
 *                                                                                       *
 * OpenSpace                                                                             *
 *                                                                                       *
 * Copyright (c) 2014-2017                                                               *
 *                                                                                       *
 * 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:                                                                           *
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 * 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 <modules/base/rendering/screenspaceframebuffer.h>

#include <openspace/documentation/documentation.h>
#include <openspace/engine/openspaceengine.h>
#include <openspace/rendering/renderengine.h>
#include <openspace/util/camera.h>

#include <openspace/rendering/renderer.h>
#include <openspace/rendering/abufferrenderer.h>
#include <openspace/rendering/framebufferrenderer.h>
#include <openspace/engine/wrapper/windowwrapper.h>


namespace {
    static const openspace::properties::Property::PropertyInfo SizeInfo = {
        "Size",
        "Size",
        "This value explicitly specifies the size of the screen space plane."
    };
} // namespace

namespace openspace {

documentation::Documentation ScreenSpaceFramebuffer::Documentation() {
    using namespace documentation;
    return {
        "ScreenSpace Framebuffer",
        "base_screenspace_framebuffer",
        {}
    };
}

ScreenSpaceFramebuffer::ScreenSpaceFramebuffer(const ghoul::Dictionary& dictionary) 
    : ScreenSpaceRenderable(dictionary)
    , _size(SizeInfo, glm::vec4(0), glm::vec4(0), glm::vec4(16384))
    , _framebuffer(nullptr)
{
    documentation::testSpecificationAndThrow(
        Documentation(),
        dictionary,
        "ScreenSpaceFramebuffer"
    );

    _id = id();
    setName("ScreenSpaceFramebuffer" + std::to_string(_id));

    glm::vec2 resolution = OsEng.windowWrapper().currentWindowResolution();
    addProperty(_size);
    _size.set(glm::vec4(0, 0, resolution.x,resolution.y));
}

ScreenSpaceFramebuffer::~ScreenSpaceFramebuffer() {}

bool ScreenSpaceFramebuffer::initializeGL() {
    ScreenSpaceRenderable::initializeGL();
    createFragmentbuffer();

    return isReady();
}

bool ScreenSpaceFramebuffer::deinitializeGL() {
    ScreenSpaceRenderable::deinitializeGL();

    _framebuffer->detachAll();
    removeAllRenderFunctions();

    return true;
}

void ScreenSpaceFramebuffer::render() {
    glm::vec2 resolution = OsEng.windowWrapper().currentWindowResolution();
    glm::vec4 size = _size.value();

    float xratio = _originalViewportSize.x / (size.z-size.x);
    float yratio = _originalViewportSize.y / (size.w-size.y);;

    if (!_renderFunctions.empty()) {
        glViewport(
            static_cast<GLint>(-size.x * xratio),
            static_cast<GLint>(-size.y * yratio),
            static_cast<GLsizei>(_originalViewportSize.x * xratio),
            static_cast<GLsizei>(_originalViewportSize.y * yratio)
        );
        GLint defaultFBO = _framebuffer->getActiveObject();
        _framebuffer->activate();

        glClearColor (0.0f, 0.0f, 0.0f, 0.0f);
        glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glEnable(GL_ALPHA_TEST);
        for (const auto& renderFunction : _renderFunctions) {
            (*renderFunction)();
        }
        _framebuffer->deactivate();

        glBindFramebuffer(GL_FRAMEBUFFER, defaultFBO);
        glViewport(
            0,
            0,
            static_cast<GLsizei>(resolution.x),
            static_cast<GLsizei>(resolution.y)
        );

        glm::mat4 rotation = rotationMatrix();
        glm::mat4 translation = translationMatrix();
        glm::mat4 scale = scaleMatrix();
        scale = glm::scale(scale, glm::vec3((1.0/xratio), -(1.0/yratio), 1.0f));
        glm::mat4 modelTransform = rotation*translation*scale;
        draw(modelTransform);
    }
}

void ScreenSpaceFramebuffer::update() {}

bool ScreenSpaceFramebuffer::isReady() const {
    bool ready = true;
    if (!_shader) {
        ready &= false;
    }
    if (!_texture) {
        ready &= false;
    }
    return ready;
}

void ScreenSpaceFramebuffer::setSize(glm::vec4 size) {
    _size.set(size);
}

void ScreenSpaceFramebuffer::addRenderFunction(
                                    std::shared_ptr<std::function<void()>> renderFunction)
{
    _renderFunctions.push_back(renderFunction);
}

void ScreenSpaceFramebuffer::removeAllRenderFunctions() {
    _renderFunctions.clear();
}

void ScreenSpaceFramebuffer::createFragmentbuffer() {
    _framebuffer = std::make_unique<ghoul::opengl::FramebufferObject>();
    _framebuffer->activate();
    _texture = std::make_unique<ghoul::opengl::Texture>(glm::uvec3(
        _originalViewportSize.x,
        _originalViewportSize.y,
        1
    ));
    _texture->uploadTexture();
    _texture->setFilter(ghoul::opengl::Texture::FilterMode::Linear);
    _framebuffer->attachTexture(_texture.get(), GL_COLOR_ATTACHMENT0);
    _framebuffer->deactivate();
}

int ScreenSpaceFramebuffer::id() {
    static int id = 0;
    return id++;
}

} //namespace openspace