//
//  Text3DOverlay.cpp
//  interface/src/ui/overlays
//
//  Copyright 2014 High Fidelity, Inc.
//
//  Distributed under the Apache License, Version 2.0.
//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//

// include this before QGLWidget, which includes an earlier version of OpenGL
#include "InterfaceConfig.h"

#include <QGLWidget>
#include <SharedUtil.h>

#include "Application.h"
#include "Text3DOverlay.h"
#include "ui/TextRenderer.h"

const xColor DEFAULT_BACKGROUND_COLOR = { 0, 0, 0 };
const float DEFAULT_MARGIN = 0.1f;

Text3DOverlay::Text3DOverlay() :
    _backgroundColor(DEFAULT_BACKGROUND_COLOR),
    _lineHeight(0.1f),
    _leftMargin(DEFAULT_MARGIN),
    _topMargin(DEFAULT_MARGIN),
    _rightMargin(DEFAULT_MARGIN),
    _bottomMargin(DEFAULT_MARGIN),
    _isFacingAvatar(false)
{
}

Text3DOverlay::~Text3DOverlay() {
}

xColor Text3DOverlay::getBackgroundColor() {
    if (_colorPulse == 0.0f) {
        return _backgroundColor; 
    }

    float pulseLevel = updatePulse();
    xColor result = _backgroundColor;
    if (_colorPulse < 0.0f) {
        result.red *= (1.0f - pulseLevel);
        result.green *= (1.0f - pulseLevel);
        result.blue *= (1.0f - pulseLevel);
    } else {
        result.red *= pulseLevel;
        result.green *= pulseLevel;
        result.blue *= pulseLevel;
    }
    return result;
}


void Text3DOverlay::render() {
    if (!_visible) {
        return; // do nothing if we're not visible
    }

    glPushMatrix(); {
        glTranslatef(_position.x, _position.y, _position.z);
        glm::quat rotation;
        if (_isFacingAvatar) {
            // rotate about vertical to face the camera
            rotation = Application::getInstance()->getCamera()->getRotation();
            rotation *= glm::angleAxis(glm::pi<float>(), glm::vec3(0.0f, 1.0f, 0.0f));
        } else {
            rotation = getRotation();
        }
        glm::vec3 axis = glm::axis(rotation);
        glRotatef(glm::degrees(glm::angle(rotation)), axis.x, axis.y, axis.z);

        const float MAX_COLOR = 255.0f;
        xColor backgroundColor = getBackgroundColor();
        float alpha = getAlpha();
        glColor4f(backgroundColor.red / MAX_COLOR, backgroundColor.green / MAX_COLOR, backgroundColor.blue / MAX_COLOR, alpha);

        glm::vec2 dimensions = getDimensions();
        glm::vec2 halfDimensions = dimensions * 0.5f;
        
        const float SLIGHTLY_BEHIND = -0.005f;

        glBegin(GL_QUADS);
            glVertex3f(-halfDimensions.x, -halfDimensions.y, SLIGHTLY_BEHIND);
            glVertex3f(halfDimensions.x, -halfDimensions.y, SLIGHTLY_BEHIND);
            glVertex3f(halfDimensions.x, halfDimensions.y, SLIGHTLY_BEHIND);
            glVertex3f(-halfDimensions.x, halfDimensions.y, SLIGHTLY_BEHIND);
        glEnd();
        
        //TextRenderer(const char* family, int pointSize = -1, int weight = -1, bool italic = false,
        //             EffectType effect = NO_EFFECT, int effectThickness = 1);

        const int FIXED_FONT_POINT_SIZE = 40;
        const int FIXED_FONT_SCALING_RATIO = FIXED_FONT_POINT_SIZE * 40.0f; // this is a ratio determined through experimentation
        
        TextRenderer* textRenderer = TextRenderer::getInstance(SANS_FONT_FAMILY, FIXED_FONT_POINT_SIZE);
        float LINE_SCALE_RATIO = 1.2f;
        float maxHeight = (float)textRenderer->calculateHeight("Xy") * LINE_SCALE_RATIO;
        
        float scaleFactor =  (maxHeight / FIXED_FONT_SCALING_RATIO) * _lineHeight; 

        glTranslatef(-(halfDimensions.x - _leftMargin), halfDimensions.y - _topMargin, 0.0f);

        glm::vec2 clipMinimum(0.0f, 0.0f);
        glm::vec2 clipDimensions((dimensions.x - (_leftMargin + _rightMargin)) / scaleFactor, 
                                 (dimensions.y - (_topMargin + _bottomMargin)) / scaleFactor);

        glScalef(scaleFactor, -scaleFactor, 1.0);
        enableClipPlane(GL_CLIP_PLANE0, -1.0f, 0.0f, 0.0f, clipMinimum.x + clipDimensions.x);
        enableClipPlane(GL_CLIP_PLANE1, 1.0f, 0.0f, 0.0f, -clipMinimum.x);
        enableClipPlane(GL_CLIP_PLANE2, 0.0f, -1.0f, 0.0f, clipMinimum.y + clipDimensions.y);
        enableClipPlane(GL_CLIP_PLANE3, 0.0f, 1.0f, 0.0f, -clipMinimum.y);
    
        glColor3f(_color.red / MAX_COLOR, _color.green / MAX_COLOR, _color.blue / MAX_COLOR);
        QStringList lines = _text.split("\n");
        int lineOffset = maxHeight;
        foreach(QString thisLine, lines) {
            textRenderer->draw(0, lineOffset, qPrintable(thisLine));
            lineOffset += maxHeight;
        }

        glDisable(GL_CLIP_PLANE0);
        glDisable(GL_CLIP_PLANE1);
        glDisable(GL_CLIP_PLANE2);
        glDisable(GL_CLIP_PLANE3);
        
    } glPopMatrix();
    
}

void Text3DOverlay::enableClipPlane(GLenum plane, float x, float y, float z, float w) {
    GLdouble coefficients[] = { x, y, z, w };
    glClipPlane(plane, coefficients);
    glEnable(plane);
}

void Text3DOverlay::setProperties(const QScriptValue& properties) {
    Planar3DOverlay::setProperties(properties);
    
    QScriptValue text = properties.property("text");
    if (text.isValid()) {
        setText(text.toVariant().toString());
    }

    QScriptValue backgroundColor = properties.property("backgroundColor");
    if (backgroundColor.isValid()) {
        QScriptValue red = backgroundColor.property("red");
        QScriptValue green = backgroundColor.property("green");
        QScriptValue blue = backgroundColor.property("blue");
        if (red.isValid() && green.isValid() && blue.isValid()) {
            _backgroundColor.red = red.toVariant().toInt();
            _backgroundColor.green = green.toVariant().toInt();
            _backgroundColor.blue = blue.toVariant().toInt();
        }
    }

    if (properties.property("lineHeight").isValid()) {
        setLineHeight(properties.property("lineHeight").toVariant().toFloat());
    }

    if (properties.property("leftMargin").isValid()) {
        setLeftMargin(properties.property("leftMargin").toVariant().toFloat());
    }

    if (properties.property("topMargin").isValid()) {
        setTopMargin(properties.property("topMargin").toVariant().toFloat());
    }

    if (properties.property("rightMargin").isValid()) {
        setRightMargin(properties.property("rightMargin").toVariant().toFloat());
    }

    if (properties.property("bottomMargin").isValid()) {
        setBottomMargin(properties.property("bottomMargin").toVariant().toFloat());
    }


    QScriptValue isFacingAvatarValue = properties.property("isFacingAvatar");
    if (isFacingAvatarValue.isValid()) {
        _isFacingAvatar = isFacingAvatarValue.toVariant().toBool();
    }

}