#include "viewer/OsgOpenGLWindow.h"
#include "viewer/OSGRenderer.h"

#include <osgViewer/Viewer>
#include <osg/GL>

#include <QApplication>
#include <QKeyEvent>
#include <QInputDialog>
#include <QLayout>
#include <QMainWindow>
#include <QScreen>
#include <QWindow>
#include <QOpenGLShaderProgram>
#include <QOpenGLVertexArrayObject>

#include "config.h"
#include "common/SpdLogger.h"
#include "viewer/GraphicsWindowEx.h"

static const char* vertexShaderSource =
"#version 330\n"
"out vec2 uv;\n"
"void main(void)\n"
"{\n"
"vec2 pos[] = vec2[](vec2(-1.0, -1.0),\n"
"vec2( 1.0, -1.0),\n"
"vec2(-1.0,  1.0),\n"
"vec2( 1.0,  1.0));\n"
"vec2 uvpos[] = vec2[](vec2(0, 0.0),\n"
"vec2( 1.0, 0.0),\n"
"vec2(0.0,  1.0),\n"
"vec2( 1.0,  1.0));\n"
"gl_Position = vec4(pos[gl_VertexID], 0.0, 1.0);\n"
"uv = uvpos[gl_VertexID];\n"
"}\n";

static const char* fragmentShaderSource =
"#version 330\n"
"in vec2 uv;\n"
"uniform sampler2D tex;\n"
"out vec4 vFragColor;"
"void main() {\n"
"   vFragColor = vec4(texture(tex, uv).rgb, 1.0);\n"
"}\n";



OsgOpenGLWindow::OsgOpenGLWindow(QWidget* parent)
    : QOpenGLWindow(QOpenGLWindow::NoPartialUpdate, nullptr) {
    widget_ = QWidget::createWindowContainer(this);
    gw_ = new GraphicsWindowEx(0, 0, width(), height());
    renderer_ = new OSGRenderer(this);
    connect(renderer_, &OSGRenderer::RenderFlush, this, &OsgOpenGLWindow::OnRenderFlush, Qt::QueuedConnection);
    connect(&timer_, &QTimer::timeout, this, &OsgOpenGLWindow::OnRender);
}

OsgOpenGLWindow::~OsgOpenGLWindow() {}

osgViewer::Viewer* OsgOpenGLWindow::getOsgViewer() {
    return renderer_;
}

void OsgOpenGLWindow::initializeGL() {
    //// Initializes OpenGL function resolution for the current context.
    //initializeOpenGLFunctions();
    //createRenderer();
    //emit initialized();
    QOpenGLContext* ctx = context();
    dyt_check(nullptr != ctx);
    ctx->doneCurrent();
    gw_->SetSharedContext(context());
    QApplication::postEvent(renderer_, new RenderBindGraphicsContextEvent(gw_));

    setDefaultDisplaySettings();

    double pixelRatio = screen()->devicePixelRatio();
    gw_->UpdateWindowScale(pixelRatio);
    QApplication::postEvent(renderer_, new GraphicsWindowResizeEvent(gw_, width() * pixelRatio, height() * pixelRatio));

    QApplication::postEvent(renderer_, new QEvent(QEvent::Type(RENDER)));

    context()->makeCurrent(this);

    shaderProgram_ = new QOpenGLShaderProgram(this);
    vao_ = new QOpenGLVertexArrayObject(this);
    if (!vao_->create()) {
        LOG_ERROR("Failed to create VAO");
        return;
    }

    if (!shaderProgram_->addCacheableShaderFromSourceCode(QOpenGLShader::Vertex, vertexShaderSource)) {
        LOG_ERROR("Failed to add vertex shader");
        return;
    }
    if (!shaderProgram_->addCacheableShaderFromSourceCode(QOpenGLShader::Fragment, fragmentShaderSource)) {
        LOG_ERROR("Failed to add fragment shader");
        return;
    }

    if (!shaderProgram_->link()) {
        LOG_ERROR("Failed to link shader program, {}", shaderProgram_->log().toLocal8Bit().constData());
        return;
    }

    timer_.start(1000 / 60);
}

void OsgOpenGLWindow::resizeGL(int w, int h) {
    double pixelRatio = screen()->devicePixelRatio();
    gw_->UpdateWindowScale(pixelRatio);
    QApplication::postEvent(renderer_, new GraphicsWindowResizeEvent(gw_, w * pixelRatio, h * pixelRatio));
}

void OsgOpenGLWindow::paintUnderGL() {
    if (0 == shaderTextureId_) {
        return;
    }

    QOpenGLFunctions* f = QOpenGLContext::currentContext()->functions();
    f->glViewport(0, 0, width() * devicePixelRatio(), height() * devicePixelRatio());
    f->glBindTexture(GL_TEXTURE_2D, shaderTextureId_);
    dyt_check(nullptr != shaderProgram_);
    dyt_check(shaderProgram_->bind());
    QOpenGLVertexArrayObject::Binder vaoBinder(vao_);
    f->glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    shaderProgram_->release();

    if (updateTexture_) {
        updateTexture_ = false;
        QApplication::postEvent(renderer_, new QEvent(QEvent::Type(RENDER)));
    }
}

void OsgOpenGLWindow::keyPressEvent(QKeyEvent* event) {
    Q_ASSERT(gw_);
    // forward event to renderer
    gw_->keyPressEvent(event);
}

void OsgOpenGLWindow::keyReleaseEvent(QKeyEvent* event) {
    Q_ASSERT(gw_);
    // forward event to renderer
    gw_->keyReleaseEvent(event);
}

void OsgOpenGLWindow::mousePressEvent(QMouseEvent* event) {
    Q_ASSERT(gw_);
    // forward event to renderer
    gw_->mousePressEvent(event);
}

void OsgOpenGLWindow::mouseReleaseEvent(QMouseEvent* event) {
    Q_ASSERT(gw_);
    // forward event to renderer
    gw_->mouseReleaseEvent(event);
}

void OsgOpenGLWindow::mouseDoubleClickEvent(QMouseEvent* event) {
    Q_ASSERT(gw_);
    // forward event to renderer
    gw_->mouseDoubleClickEvent(event);
}

void OsgOpenGLWindow::mouseMoveEvent(QMouseEvent* event) {
    Q_ASSERT(gw_);
    // forward event to renderer
    gw_->mouseMoveEvent(event);
}

void OsgOpenGLWindow::wheelEvent(QWheelEvent* event) {
    Q_ASSERT(gw_);
    // forward event to renderer
    gw_->wheelEvent(event);
}

void OsgOpenGLWindow::setDefaultDisplaySettings() {
    osg::DisplaySettings* ds = osg::DisplaySettings::instance().get();
    ds->setNvOptimusEnablement(1);
    ds->setStereo(false);
}

void OsgOpenGLWindow::OnRenderFlush() {
    shaderTextureId_ = gw_->GetFrameBufferId();
    updateTexture_ = true;
}

void OsgOpenGLWindow::OnRender() {
    requestUpdate();
}