#include <modules/blackhole/rendering/renderableblackhole.h>
#include <modules/blackhole/blackholemodule.h>
#include <openspace/engine/globals.h>
#include <openspace/engine/windowdelegate.h>
#include <openspace/rendering/framebufferrenderer.h>
#include <openspace/navigation/navigationhandler.h>

#include <openspace/rendering/renderengine.h>
#include <ghoul/opengl/framebufferobject.h>
#include <ghoul/opengl/openglstatecache.h>
#include <ghoul/opengl/textureunit.h>
#include <ghoul/io/texture/texturereader.h>
#include <ghoul/logging/logmanager.h>
#include <ghoul/filesystem/filesystem.h>
#include <filesystem>

#include <modules/blackhole/cuda/blackhole_cuda.h>

namespace {
    constexpr std::string_view _loggerCat = "BlackHoleModule";
    constexpr std::string_view ProgramName = "BlackHoleProgram";

    constexpr std::array<GLfloat, 24> QuadVtx = {
        -1.f, -1.f,  0.f,  0.f,
         1.f,  1.f,  1.f,  1.f,
        -1.f,  1.f,  0.f,  1.f,
        -1.f, -1.f,  0.f,  0.f,
         1.f, -1.f,  1.f,  0.f,
         1.f,  1.f,  1.f,  1.f
    };
}

namespace openspace {
    RenderableBlackHole::RenderableBlackHole(const ghoul::Dictionary& dictionary)
        : Renderable(dictionary, { .automaticallyUpdateRenderBin = false }) {
    }

    void RenderableBlackHole::initialize() {
        _viewport = ViewPort(global::navigationHandler->camera());
        cuda_test();
    }

    void RenderableBlackHole::initializeGL() {
        ZoneScoped;
        setupQuad();
        setupShaders();
        loadEnvironmentTexture();
    }

    void RenderableBlackHole::deinitializeGL() {
        glDeleteFramebuffers(1, &_framebuffer);
        glDeleteBuffers(1, &_quadVbo);
        glDeleteVertexArrays(1, &_quadVao);
    }

    bool RenderableBlackHole::isReady() const {
        return _program;
    }

    void RenderableBlackHole::render(const RenderData&, RendererTasks&) {
        _program->activate();
        bindFramebuffer();
        bindEnvironmentTexture();
        drawQuad();
        _program->deactivate();
        glBindTexture(GL_TEXTURE_2D, 0);
    }

    void RenderableBlackHole::setupShaders() {
        const std::string vertexShaderPath = "${MODULE_BLACKHOLE}/shaders/gradiant_vs.glsl";
        const std::string fragmentShaderPath = "${MODULE_BLACKHOLE}/shaders/gradiant_fs.glsl";

        // Initialize shaders
        std::string program = std::string(ProgramName);
        program += "|vs=" + vertexShaderPath;
        program += "|fs=" + fragmentShaderPath;
        _program = BlackHoleModule::ProgramObjectManager.request(
            program,
            [this, fragmentShaderPath, vertexShaderPath, program]() -> std::unique_ptr<ghoul::opengl::ProgramObject> {
                const std::filesystem::path vs = absPath(vertexShaderPath);
                const std::filesystem::path fs = absPath(fragmentShaderPath);

                return global::renderEngine->buildRenderProgram(program, vs, fs);
            }
        );

        ghoul::opengl::updateUniformLocations(*_program, _uniformCache);
    }

    void RenderableBlackHole::setupQuad() {
        glGenVertexArrays(1, &_quadVao);
        glBindVertexArray(_quadVao);

        glGenBuffers(1, &_quadVbo);
        glBindBuffer(GL_ARRAY_BUFFER, _quadVbo);
        glBufferData(GL_ARRAY_BUFFER, sizeof(QuadVtx), QuadVtx.data(), GL_STATIC_DRAW);

        glEnableVertexAttribArray(0);
        glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), nullptr);

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

    void RenderableBlackHole::loadEnvironmentTexture() {
        const std::string texturePath = "${MODULE_BLACKHOLE}/rendering/uv.png";
        _enviromentTexture = ghoul::io::TextureReader::ref().loadTexture(absPath(texturePath), 2);

        if (_enviromentTexture) {
            _enviromentTexture->uploadTexture();
        }
        else {
            LWARNING(std::format("Failed to load environment texture from path '{}'", absPath(texturePath).string()));
        }
    }

    void RenderableBlackHole::bindFramebuffer() {
        const GLint defaultFBO = ghoul::opengl::FramebufferObject::getActiveObject();
        glBindFramebuffer(GL_FRAMEBUFFER, defaultFBO);
    }

    void RenderableBlackHole::bindEnvironmentTexture() {
        if (_uniformCache.enviromentTexture != -1 && _enviromentTexture) {
            ghoul::opengl::TextureUnit enviromentUnit;
            enviromentUnit.activate();
            _enviromentTexture->bind();
            _program->setUniform(_uniformCache.enviromentTexture, enviromentUnit);
        }
        else {
            LWARNING("UniformCache is missing 'enviromentTexture'");
        }

        //invProjection, invView
    }

    void RenderableBlackHole::drawQuad() {
        glBindVertexArray(_quadVao);
        glDrawArrays(GL_TRIANGLES, 0, 6);
    }

    void RenderableBlackHole::update(const UpdateData&) {}

    documentation::Documentation RenderableBlackHole::Documentation() {
        return documentation::Documentation();
    }
} // namespace openspace