/******************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the Qt Data Visualization module.
**
** $QT_BEGIN_LICENSE:COMM$
**
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
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** $QT_END_LICENSE$
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******************************************************************************/

#include "selectionpointer_p.h"
#include "shaderhelper_p.h"
#include "objecthelper_p.h"
#include "texturehelper_p.h"
#include "q3dcamera_p.h"
#include "utils_p.h"

QT_BEGIN_NAMESPACE_DATAVISUALIZATION

const GLfloat sliceUnits = 2.5;

SelectionPointer::SelectionPointer(Drawer *drawer)
    : QObject(0),
      m_labelShader(0),
      m_pointShader(0),
      m_labelObj(0),
      m_pointObj(0),
      m_textureHelper(0),
      m_cachedTheme(drawer->theme()),
      m_labelBackground(false),
      m_drawer(drawer),
      m_cachedScene(0)
{
    initializeOpenGL();

    QObject::connect(m_drawer, &Drawer::drawerChanged,
                     this, &SelectionPointer::handleDrawerChange);
}

SelectionPointer::~SelectionPointer()
{
    delete m_labelShader;
    delete m_pointShader;
    delete m_textureHelper;
}

void SelectionPointer::initializeOpenGL()
{
    initializeOpenGLFunctions();

    m_textureHelper = new TextureHelper();
    m_drawer->initializeOpenGL();

    initShaders();
}

void SelectionPointer::updateScene(Q3DScene *scene)
{
    m_cachedScene = scene;
}

void SelectionPointer::render(GLuint defaultFboHandle, bool useOrtho)
{
    Q_UNUSED(defaultFboHandle)

    glViewport(m_mainViewPort.x(), m_mainViewPort.y(),
               m_mainViewPort.width(), m_mainViewPort.height());

    Q3DCamera *camera = m_cachedScene->activeCamera();
    QSize textureSize = m_labelItem.size();

    QMatrix4x4 itModelMatrix;

    // Get view matrix
    QMatrix4x4 viewMatrix;
    QMatrix4x4 projectionMatrix;
    GLfloat viewPortRatio = (GLfloat)m_mainViewPort.width() / (GLfloat)m_mainViewPort.height();
    if (m_cachedIsSlicingActivated) {
        GLfloat sliceUnitsScaled = sliceUnits / m_autoScaleAdjustment;
        viewMatrix.lookAt(QVector3D(0.0f, 0.0f, 1.0f), zeroVector, upVector);
        projectionMatrix.ortho(-sliceUnitsScaled * viewPortRatio, sliceUnitsScaled * viewPortRatio,
                               -sliceUnitsScaled, sliceUnitsScaled,
                               -1.0f, 4.0f);
    } else if (useOrtho) {
        viewMatrix = camera->d_ptr->viewMatrix();
        GLfloat orthoRatio = 2.0f;
        projectionMatrix.ortho(-viewPortRatio * orthoRatio, viewPortRatio * orthoRatio,
                               -orthoRatio, orthoRatio,
                               0.0f, 100.0f);
    } else {
        viewMatrix = camera->d_ptr->viewMatrix();
        projectionMatrix.perspective(45.0f, viewPortRatio, 0.1f, 100.0f);
    }

    // Calculate scale factor to get uniform font size
    GLfloat scaledFontSize = 0.05f + m_drawer->font().pointSizeF() / 500.0f;
    GLfloat scaleFactor = scaledFontSize / (GLfloat)textureSize.height();

    QMatrix4x4 modelMatrix;
    QMatrix4x4 MVPMatrix;

    // Position the pointer ball
    modelMatrix.translate(m_position);

    if (!m_rotation.isIdentity()) {
        modelMatrix.rotate(m_rotation);
        itModelMatrix.rotate(m_rotation);
    }

    // Scale the point with fixed values (at this point)
    QVector3D scaleVector(0.05f, 0.05f, 0.05f);
    modelMatrix.scale(scaleVector);
    itModelMatrix.scale(scaleVector);

    MVPMatrix = projectionMatrix * viewMatrix * modelMatrix;

    QVector3D lightPos =  m_cachedScene->activeLight()->position();

    //
    // Draw the point
    //
    m_pointShader->bind();
    m_pointShader->setUniformValue(m_pointShader->lightP(), lightPos);
    m_pointShader->setUniformValue(m_pointShader->view(), viewMatrix);
    m_pointShader->setUniformValue(m_pointShader->model(), modelMatrix);
    m_pointShader->setUniformValue(m_pointShader->nModel(), itModelMatrix.inverted().transposed());
    m_pointShader->setUniformValue(m_pointShader->color(), m_highlightColor);
    m_pointShader->setUniformValue(m_pointShader->MVP(), MVPMatrix);
    m_pointShader->setUniformValue(m_pointShader->ambientS(),
                                   m_cachedTheme->ambientLightStrength());
    m_pointShader->setUniformValue(m_pointShader->lightS(), m_cachedTheme->lightStrength() * 2.0f);
    m_pointShader->setUniformValue(m_pointShader->lightColor(),
                                   Utils::vectorFromColor(m_cachedTheme->lightColor()));

    m_drawer->drawObject(m_pointShader, m_pointObj);

    //
    // Draw the label
    //
    QMatrix4x4 modelMatrixLabel;

    // Position label
    QVector3D labelAlign(0.0f, 1.0f * scaledFontSize + 0.05f, 0.0f);
    modelMatrixLabel.translate(m_position + labelAlign);

    // Position the label towards the camera
    float camRotationsX = camera->xRotation();
    float camRotationsY = camera->yRotation();
    if (!m_cachedIsSlicingActivated) {
        modelMatrixLabel.rotate(-camRotationsX, 0.0f, 1.0f, 0.0f);
        modelMatrixLabel.rotate(-camRotationsY, 1.0f, 0.0f, 0.0f);
    }

    // Scale label based on text size
    modelMatrixLabel.scale(QVector3D((GLfloat)textureSize.width() * scaleFactor,
                                     scaledFontSize,
                                     0.0f));

    // Make label to be always on top
    glDisable(GL_DEPTH_TEST);

    // Make label transparent
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    m_labelShader->bind();

    // Set shader bindings
    MVPMatrix = projectionMatrix * viewMatrix * modelMatrixLabel;
    m_labelShader->setUniformValue(m_labelShader->MVP(), MVPMatrix);

    // Draw the object
    m_drawer->drawObject(m_labelShader, m_labelObj, m_labelItem.textureId());

    // Release shader
    glUseProgram(0);

    // Disable transparency
    glDisable(GL_BLEND);

    // Depth test back to normal
    glEnable(GL_DEPTH_TEST);
}

void SelectionPointer::setPosition(const QVector3D &position)
{
    m_position = position;
}

void SelectionPointer::updateSliceData(bool sliceActivated, GLfloat autoScaleAdjustment)
{
    m_cachedIsSlicingActivated = sliceActivated;
    m_autoScaleAdjustment = autoScaleAdjustment;
}

void SelectionPointer::setHighlightColor(const QVector4D &colorVector)
{
    m_highlightColor = colorVector;
}

void SelectionPointer::setRotation(const QQuaternion &rotation)
{
    m_rotation = rotation;
}

void SelectionPointer::setLabel(const QString &label, bool themeChange)
{
    if (themeChange || m_label != label) {
        m_label = label;
        m_drawer->generateLabelItem(m_labelItem, m_label);
    }
}

void SelectionPointer::setPointerObject(ObjectHelper *object)
{
    m_pointObj = object;
}

void SelectionPointer::setLabelObject(ObjectHelper *object)
{
    m_labelObj = object;
}

void SelectionPointer::handleDrawerChange()
{
    m_cachedTheme = m_drawer->theme();
    setLabel(m_label, true);
}

void SelectionPointer::updateBoundingRect(const QRect &rect)
{
    m_mainViewPort = rect;
}

void SelectionPointer::initShaders()
{
    // The shader for printing the text label
    if (m_labelShader)
        delete m_labelShader;
    m_labelShader = new ShaderHelper(this, QStringLiteral(":/shaders/vertexLabel"),
                                     QStringLiteral(":/shaders/fragmentLabel"));
    m_labelShader->initialize();

    // The shader for the small point ball
    if (m_pointShader)
        delete m_pointShader;

    if (Utils::isOpenGLES()) {
        m_pointShader = new ShaderHelper(this, QStringLiteral(":/shaders/vertex"),
                                         QStringLiteral(":/shaders/fragmentES2"));
    } else {
        m_pointShader = new ShaderHelper(this, QStringLiteral(":/shaders/vertex"),
                                         QStringLiteral(":/shaders/fragment"));
    }

    m_pointShader->initialize();
}

QT_END_NAMESPACE_DATAVISUALIZATION
