/*##############################################################################
## Author: Shaun Reed                                                         ##
## Legal: All Content (c) 2022 Shaun Reed, all rights reserved                ##
## About: Main window for Qt6 OpenGL widget application                       ##
##                                                                            ##
## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com | GitHub: shaunrd0   ##
##############################################################################*/

#include <QKeyEvent>

#include <abstractscene.h>
#include <input.h>
#include <mesh.h>
#include <qtkwidget.h>

using namespace Qtk;

/*******************************************************************************
 * Constructors, Destructors
 ******************************************************************************/

QtkWidget::QtkWidget() : mScene(Q_NULLPTR), mDebugLogger(Q_NULLPTR) {
  initializeWidget();
}

// Constructor for using this widget in QtDesigner
QtkWidget::QtkWidget(QWidget * parent) :
    QOpenGLWidget(parent), mScene(Q_NULLPTR), mDebugLogger(Q_NULLPTR) {
  initializeWidget();
}

QtkWidget::QtkWidget(const QSurfaceFormat & format) :
    mScene(Q_NULLPTR), mDebugLogger(Q_NULLPTR) {
  setFormat(format);
  setFocusPolicy(Qt::ClickFocus);
}

QtkWidget::~QtkWidget() {
  makeCurrent();
  teardownGL();
}

/*******************************************************************************
 * Private Member Functions
 ******************************************************************************/

void QtkWidget::teardownGL() {
  // Nothing to teardown yet...
}

/*******************************************************************************
 * Inherited Virtual Member Functions
 ******************************************************************************/

void QtkWidget::paintGL() {
  // Clear buffers
  glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);

  // Draw the scene first, since it handles drawing our skybox
  if(mScene != Q_NULLPTR) {
    mScene->draw();
  }
}

void QtkWidget::initializeGL() {
  initializeOpenGLFunctions();
  // Connect the frameSwapped signal to call the update() function
  connect(this, SIGNAL(frameSwapped()), this, SLOT(update()));

  // Initialize OpenGL debug context
#ifdef QTK_DEBUG
  mDebugLogger = new QOpenGLDebugLogger(this);
  if(mDebugLogger->initialize()) {
    qDebug() << "GL_DEBUG Debug Logger" << mDebugLogger << "\n";
    connect(
        mDebugLogger, SIGNAL(messageLogged(QOpenGLDebugMessage)), this,
        SLOT(messageLogged(QOpenGLDebugMessage)));
    mDebugLogger->startLogging();
  }
#endif  // QTK_DEBUG

  printContextInformation();

  // Initialize opengl settings
  glEnable(GL_MULTISAMPLE);
  glEnable(GL_DEPTH_TEST);
  glDepthMask(GL_TRUE);
  glDepthFunc(GL_LEQUAL);
  glDepthRange(0.1f, 1.0f);
  glClearDepth(1.0f);
  glClearColor(0.0f, 0.25f, 0.0f, 0.0f);
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
}

void QtkWidget::resizeGL(int width, int height) {
  Scene::Projection().setToIdentity();
  Scene::Projection().perspective(
      45.0f, float(width) / float(height), 0.1f, 1000.0f);
}

/*******************************************************************************
 * Protected Slots
 ******************************************************************************/

void QtkWidget::update() {
  updateCameraInput();

  if(mScene != Q_NULLPTR) {
    mScene->update();
  }

  QWidget::update();
}

void QtkWidget::messageLogged(const QOpenGLDebugMessage & msg) {
  QString error;

  // Format based on severity
  switch(msg.severity()) {
    case QOpenGLDebugMessage::NotificationSeverity:
      error += "--";
      break;
    case QOpenGLDebugMessage::HighSeverity:
      error += "!!";
      break;
    case QOpenGLDebugMessage::MediumSeverity:
      error += "!~";
      break;
    case QOpenGLDebugMessage::LowSeverity:
      error += "~~";
      break;
  }

  error += " (";

  // Format based on source
#define CASE(c)                \
  case QOpenGLDebugMessage::c: \
    error += #c;               \
    break
  switch(msg.source()) {
    CASE(APISource);
    CASE(WindowSystemSource);
    CASE(ShaderCompilerSource);
    CASE(ThirdPartySource);
    CASE(ApplicationSource);
    CASE(OtherSource);
    CASE(InvalidSource);
  }
#undef CASE

  error += " : ";

// Format based on type
#define CASE(c)                \
  case QOpenGLDebugMessage::c: \
    error += #c;               \
    break
  switch(msg.type()) {
    CASE(InvalidType);
    CASE(ErrorType);
    CASE(DeprecatedBehaviorType);
    CASE(UndefinedBehaviorType);
    CASE(PortabilityType);
    CASE(PerformanceType);
    CASE(OtherType);
    CASE(MarkerType);
    CASE(GroupPushType);
    CASE(GroupPopType);
  }
#undef CASE

  error += ")";
  qDebug() << qPrintable(error) << "\n" << qPrintable(msg.message()) << "\n";
}

/*******************************************************************************
 * Protected Helpers
 ******************************************************************************/

void QtkWidget::keyPressEvent(QKeyEvent * event) {
  if(event->isAutoRepeat()) {
    // Do not repeat input while a key is held down
    event->ignore();
  } else {
    Input::registerKeyPress(event->key());
  }
}

void QtkWidget::keyReleaseEvent(QKeyEvent * event) {
  if(event->isAutoRepeat()) {
    event->ignore();
  } else {
    Input::registerKeyRelease(event->key());
  }
}

void QtkWidget::mousePressEvent(QMouseEvent * event) {
  Input::registerMousePress(event->button());
}

void QtkWidget::mouseReleaseEvent(QMouseEvent * event) {
  Input::registerMouseRelease(event->button());
}

/*******************************************************************************
 * Private Helpers
 ******************************************************************************/

void QtkWidget::initializeWidget() {
  QSurfaceFormat format;
  format.setRenderableType(QSurfaceFormat::OpenGL);
  format.setProfile(QSurfaceFormat::CoreProfile);
  format.setVersion(4, 6);
  // Set the number of samples used for glEnable(GL_MULTISAMPLING)
  format.setSamples(4);
  // Set the size of the depth bufer for glEnable(GL_DEPTH_TEST)
  format.setDepthBufferSize(16);
  // If QTK_DEBUG is set, enable debug context
#ifdef QTK_DEBUG
  format.setOption(QSurfaceFormat::DebugContext);
#endif
  setFormat(format);
  setFocusPolicy(Qt::ClickFocus);
}

void QtkWidget::printContextInformation() {
  QString glType;
  QString glVersion;
  QString glProfile;

  QString glVendor;
  QString glRenderer;

  // Get Version Information
  glType = (context()->isOpenGLES()) ? "OpenGL ES" : "OpenGL";
  glVersion = reinterpret_cast<const char *>(glGetString(GL_VERSION));
  glVendor = reinterpret_cast<const char *>(glGetString(GL_VENDOR));
  glRenderer = reinterpret_cast<const char *>(glGetString(GL_RENDERER));

  // Get Profile Information
#define CASE(c)           \
  case QSurfaceFormat::c: \
    glProfile = #c;       \
    break
  switch(format().profile()) {
    CASE(NoProfile);
    CASE(CoreProfile);
    CASE(CompatibilityProfile);
  }
#undef CASE

  // qPrintable() will print our QString w/o quotes around it.
  qDebug() << qPrintable(glType) << qPrintable(glVersion) << "("
           << qPrintable(glProfile) << ")"
           << "\nOpenGL Vendor: " << qPrintable(glVendor)
           << "\nRendering Device: " << qPrintable(glRenderer) << "\n";
}

void QtkWidget::updateCameraInput() {
  Input::update();
  // Camera Transformation
  if(Input::buttonPressed(Qt::RightButton)) {
    static const float transSpeed = 0.1f;
    static const float rotSpeed = 0.5f;

    // Handle rotations
    Scene::Camera().transform().rotate(
        -rotSpeed * Input::mouseDelta().x(), Camera3D::LocalUp);
    Scene::Camera().transform().rotate(
        -rotSpeed * Input::mouseDelta().y(), Scene::Camera().right());

    // Handle translations
    QVector3D translation;
    if(Input::keyPressed(Qt::Key_W)) {
      translation += Scene::Camera().forward();
    }
    if(Input::keyPressed(Qt::Key_S)) {
      translation -= Scene::Camera().forward();
    }
    if(Input::keyPressed(Qt::Key_A)) {
      translation -= Scene::Camera().right();
    }
    if(Input::keyPressed(Qt::Key_D)) {
      translation += Scene::Camera().right();
    }
    if(Input::keyPressed(Qt::Key_Q)) {
      translation -= Scene::Camera().up() / 2.0f;
    }
    if(Input::keyPressed(Qt::Key_E)) {
      translation += Scene::Camera().up() / 2.0f;
    }
    Scene::Camera().transform().translate(transSpeed * translation);
  }
}