//
//  MetavoxelEditor.cpp
//  interface
//
//  Created by Andrzej Kapolka on 1/21/14.
//  Copyright (c) 2014 High Fidelity, Inc. All rights reserved.

#include <QComboBox>
#include <QDialogButtonBox>
#include <QDoubleSpinBox>
#include <QFormLayout>
#include <QGroupBox>
#include <QLineEdit>
#include <QListWidget>
#include <QMetaProperty>
#include <QPushButton>
#include <QScrollArea>
#include <QVBoxLayout>

#include <AttributeRegistry.h>

#include "Application.h"
#include "MetavoxelEditor.h"

enum GridPlane {
    GRID_PLANE_XY, GRID_PLANE_XZ, GRID_PLANE_YZ
};

const glm::vec2 INVALID_VECTOR(FLT_MAX, FLT_MAX);

MetavoxelEditor::MetavoxelEditor() :
    QDialog(Application::getInstance()->getGLWidget()) {
    
    setWindowTitle("Metavoxel Editor");
    setAttribute(Qt::WA_DeleteOnClose);

    QVBoxLayout* topLayout = new QVBoxLayout();
    setLayout(topLayout);
    
    QGroupBox* attributeGroup = new QGroupBox();
    attributeGroup->setTitle("Attributes");
    topLayout->addWidget(attributeGroup);
    
    QVBoxLayout* attributeLayout = new QVBoxLayout();
    attributeGroup->setLayout(attributeLayout);
    
    attributeLayout->addWidget(_attributes = new QListWidget());
    connect(_attributes, SIGNAL(itemSelectionChanged()), SLOT(updateValueEditor()));

    QPushButton* newAttribute = new QPushButton("New...");
    attributeLayout->addWidget(newAttribute);
    connect(newAttribute, SIGNAL(clicked()), SLOT(createNewAttribute()));

    QFormLayout* formLayout = new QFormLayout();
    topLayout->addLayout(formLayout);
    
    formLayout->addRow("Grid Plane:", _gridPlane = new QComboBox());
    _gridPlane->addItem("X/Y");
    _gridPlane->addItem("X/Z");
    _gridPlane->addItem("Y/Z");
    _gridPlane->setCurrentIndex(GRID_PLANE_XZ);
    connect(_gridPlane, SIGNAL(currentIndexChanged(int)), SLOT(centerGridPosition()));
    
    formLayout->addRow("Grid Spacing:", _gridSpacing = new QDoubleSpinBox());
    _gridSpacing->setMinimum(-FLT_MAX);
    _gridSpacing->setMaximum(FLT_MAX);
    _gridSpacing->setPrefix("2^");
    _gridSpacing->setValue(-3.0);
    connect(_gridSpacing, SIGNAL(valueChanged(double)), SLOT(alignGridPosition()));

    formLayout->addRow("Grid Position:", _gridPosition = new QDoubleSpinBox());
    _gridPosition->setMinimum(-FLT_MAX);
    _gridPosition->setMaximum(FLT_MAX);
    alignGridPosition();
    centerGridPosition();
    
    _value = new QGroupBox();
    _value->setTitle("Value");
    topLayout->addWidget(_value);
    
    QVBoxLayout* valueLayout = new QVBoxLayout();
    _value->setLayout(valueLayout);

    updateAttributes();
    
    connect(Application::getInstance(), SIGNAL(renderingInWorldInterface()), SLOT(render()));
    
    Application::getInstance()->getGLWidget()->installEventFilter(this);
    
    resetState();
    
    show();
    
    if (_gridProgram.isLinked()) {
        return;
    }
    switchToResourcesParentIfRequired();
    _gridProgram.addShaderFromSourceFile(QGLShader::Fragment, "resources/shaders/grid.frag");
    _gridProgram.link();
}

bool MetavoxelEditor::eventFilter(QObject* watched, QEvent* event) {
    switch (_state) {
        case HOVERING_STATE:
            if (event->type() == QEvent::MouseButtonPress && _startPosition != INVALID_VECTOR) {
                _state = DRAGGING_STATE;
                return true;
            }
            break;
            
        case DRAGGING_STATE:
            if (event->type() == QEvent::MouseButtonRelease) {
                _state = RAISING_STATE;
                return true;
            }
            break;
            
        case RAISING_STATE:
            if (event->type() == QEvent::MouseButtonPress) {
                if (_height != 0) {
                    // find the start and end corners in X/Y
                    float base = _gridPosition->value();
                    float top = base + _height;
                    glm::quat rotation = getGridRotation();
                    glm::vec3 start = rotation * glm::vec3(glm::min(_startPosition, _endPosition), glm::min(base, top));
                    float spacing = getGridSpacing();
                    glm::vec3 end = rotation * glm::vec3(glm::max(_startPosition, _endPosition) +
                        glm::vec2(spacing, spacing), glm::max(base, top));
                    
                    // find the minimum and maximum extents after rotation
                    applyValue(glm::min(start, end), glm::max(start, end));
                }
                resetState();
                return true;
            }
            break;
    }
    return false;
}

void MetavoxelEditor::updateValueEditor() {
    QString selected = getSelectedAttribute();
    if (selected.isNull()) {
        _value->setVisible(false);
        return;
    }
    _value->setVisible(true);
    
    if (!_value->layout()->isEmpty()) {
        QLayoutItem* item = _value->layout()->takeAt(0);
        delete item->widget();
        delete item;
    }
      
    AttributePointer attribute = AttributeRegistry::getInstance()->getAttribute(selected);
    QWidget* editor = attribute->createEditor();
    if (editor) {
        QScrollArea* area = new QScrollArea();
        area->setWidgetResizable(true);
        area->setWidget(editor);
        _value->layout()->addWidget(area);
    }
}

void MetavoxelEditor::createNewAttribute() {
    QDialog dialog(this);
    dialog.setWindowTitle("New Attribute");
    
    QVBoxLayout layout;
    dialog.setLayout(&layout);
    
    QFormLayout form;
    layout.addLayout(&form);
    
    QLineEdit name;
    form.addRow("Name:", &name);
    
    QDialogButtonBox buttons(QDialogButtonBox::Ok | QDialogButtonBox::Cancel);
    dialog.connect(&buttons, SIGNAL(accepted()), SLOT(accept()));
    dialog.connect(&buttons, SIGNAL(rejected()), SLOT(reject()));
    
    layout.addWidget(&buttons);
    
    if (!dialog.exec()) {
        return;
    }
    QString nameText = name.text().trimmed();
    AttributeRegistry::getInstance()->registerAttribute(new QRgbAttribute(nameText));
    
    updateAttributes(nameText);
}

void MetavoxelEditor::centerGridPosition() {
    const float CENTER_OFFSET = 0.625f;
    float eyePosition = (glm::inverse(getGridRotation()) * Application::getInstance()->getCamera()->getPosition()).z -
        Application::getInstance()->getAvatar()->getScale() * CENTER_OFFSET;
    double step = getGridSpacing();
    _gridPosition->setValue(step * floor(eyePosition / step));
}

void MetavoxelEditor::alignGridPosition() {
    // make sure our grid position matches our grid spacing
    double step = getGridSpacing();
    _gridPosition->setSingleStep(step);
    _gridPosition->setValue(step * floor(_gridPosition->value() / step));
}

void MetavoxelEditor::render() {
    QString selected = getSelectedAttribute();
    if (selected.isNull()) {
        resetState();
        return;
    }

    glDisable(GL_LIGHTING);
    glDepthMask(GL_FALSE);
    
    glPushMatrix();
    
    glm::quat rotation = getGridRotation();
    glm::vec3 axis = glm::axis(rotation);
    glRotatef(glm::angle(rotation), axis.x, axis.y, axis.z);
    
    glm::quat inverseRotation = glm::inverse(rotation);
    glm::vec3 rayOrigin = inverseRotation * Application::getInstance()->getMouseRayOrigin();
    glm::vec3 rayDirection = inverseRotation * Application::getInstance()->getMouseRayDirection();
    float spacing = getGridSpacing();
    float position = _gridPosition->value();
    if (_state == RAISING_STATE) {
        // find the plane at the mouse position, orthogonal to the plane, facing the eye position
        glLineWidth(4.0f);  
        glm::vec3 eyePosition = inverseRotation * Application::getInstance()->getViewFrustum()->getOffsetPosition();
        glm::vec3 mousePoint = glm::vec3(_mousePosition, position);
        glm::vec3 right = glm::cross(glm::vec3(0.0f, 0.0f, 1.0f), eyePosition - mousePoint);
        glm::vec3 normal = glm::cross(right, glm::vec3(0.0f, 0.0f, 1.0f));
        float divisor = glm::dot(normal, rayDirection);
        if (fabs(divisor) > EPSILON) {
            float distance = (glm::dot(normal, mousePoint) - glm::dot(normal, rayOrigin)) / divisor;
            float projection = rayOrigin.z + distance * rayDirection.z;
            _height = spacing * roundf(projection / spacing) - position;
        }
    } else if (fabs(rayDirection.z) > EPSILON) {
        // find the intersection of the rotated mouse ray with the plane
        float distance = (position - rayOrigin.z) / rayDirection.z;
        _mousePosition = glm::vec2(rayOrigin + rayDirection * distance);
        glm::vec2 snappedPosition = spacing * glm::floor(_mousePosition / spacing);
        
        if (_state == HOVERING_STATE) {
            _startPosition = _endPosition = snappedPosition;
            glLineWidth(2.0f);
            
        } else if (_state == DRAGGING_STATE) {
            _endPosition = snappedPosition;
            glLineWidth(4.0f);
        }
    } else {
        // cancel any operation in progress
        resetState();
    }
    
    const float GRID_BRIGHTNESS = 0.5f;
    if (_startPosition != INVALID_VECTOR) {   
        glm::vec2 minimum = glm::min(_startPosition, _endPosition);
        glm::vec2 maximum = glm::max(_startPosition, _endPosition);
    
        glPushMatrix();
        glTranslatef(minimum.x, minimum.y, position);
        glScalef(maximum.x + spacing - minimum.x, maximum.y + spacing - minimum.y, _height);
    
        glTranslatef(0.5f, 0.5f, 0.5f);
        if (_state != HOVERING_STATE) {
            const float BOX_ALPHA = 0.25f;
            QColor color = getValue().value<QColor>();
            if (color.isValid()) {
                glColor4f(color.redF(), color.greenF(), color.blueF(), BOX_ALPHA);
            } else {
                glColor4f(GRID_BRIGHTNESS, GRID_BRIGHTNESS, GRID_BRIGHTNESS, BOX_ALPHA);
            }
            glEnable(GL_CULL_FACE);
            glutSolidCube(1.0);
            glDisable(GL_CULL_FACE);
        }
        glColor3f(GRID_BRIGHTNESS, GRID_BRIGHTNESS, GRID_BRIGHTNESS);
        glutWireCube(1.0);
    
        glPopMatrix();
        
    } else {
        glColor3f(GRID_BRIGHTNESS, GRID_BRIGHTNESS, GRID_BRIGHTNESS);
    }
    
    glLineWidth(1.0f);
    
    // center the grid around the camera position on the plane
    glm::vec3 rotated = inverseRotation * Application::getInstance()->getCamera()->getPosition();
    const int GRID_DIVISIONS = 300;
    glTranslatef(spacing * (floorf(rotated.x / spacing) - GRID_DIVISIONS / 2),
        spacing * (floorf(rotated.y / spacing) - GRID_DIVISIONS / 2), position);
    
    float scale = GRID_DIVISIONS * spacing;
    glScalef(scale, scale, scale);
    
    _gridProgram.bind();
    
    Application::getInstance()->getGeometryCache()->renderGrid(GRID_DIVISIONS, GRID_DIVISIONS);
    
    _gridProgram.release();
    
    glPopMatrix();
    
    glEnable(GL_LIGHTING);
    glDepthMask(GL_TRUE);
}

void MetavoxelEditor::updateAttributes(const QString& select) {
    // remember the selection in order to preserve it
    QString selected = select.isNull() ? getSelectedAttribute() : select;
    _attributes->clear();
    
    // sort the names for consistent ordering
    QList<QString> names = AttributeRegistry::getInstance()->getAttributes().keys();
    qSort(names);
    
    foreach (const QString& name, names) {
        QListWidgetItem* item = new QListWidgetItem(name);
        _attributes->addItem(item);
        if (name == selected || selected.isNull()) {
            item->setSelected(true);
            selected = name;
        }
    }
}

QString MetavoxelEditor::getSelectedAttribute() const {
    QList<QListWidgetItem*> selectedItems = _attributes->selectedItems();
    return selectedItems.isEmpty() ? QString() : selectedItems.first()->text();
}

double MetavoxelEditor::getGridSpacing() const {
    return pow(2.0, _gridSpacing->value());
}

glm::quat MetavoxelEditor::getGridRotation() const {
    // for simplicity, we handle the other two planes by rotating them onto X/Y and performing computation there
    switch (_gridPlane->currentIndex()) {
        case GRID_PLANE_XY:
            return glm::quat();
            
        case GRID_PLANE_XZ:
            return glm::angleAxis(-90.0f, 1.0f, 0.0f, 0.0f);
            
        case GRID_PLANE_YZ:
        default:
            return glm::angleAxis(90.0f, 0.0f, 1.0f, 0.0f);
    }
}

void MetavoxelEditor::resetState() {
    _state = HOVERING_STATE;
    _startPosition = INVALID_VECTOR;
    _height = 0.0f;
}

void MetavoxelEditor::applyValue(const glm::vec3& minimum, const glm::vec3& maximum) {
    AttributePointer attribute = AttributeRegistry::getInstance()->getAttribute(getSelectedAttribute());
    if (!attribute) {
        return;
    }
    OwnedAttributeValue value(attribute, attribute->createFromVariant(getValue()));
    MetavoxelEditMessage edit = { { minimum, maximum }, getGridSpacing(), value };
    Application::getInstance()->getMetavoxels()->applyEdit(edit);
}

QVariant MetavoxelEditor::getValue() const {
    if (_value->layout()->isEmpty()) {
        return QVariant();
    }
    QWidget* editor = _value->layout()->itemAt(0)->widget();
    return editor->metaObject()->userProperty().read(editor);
}

ProgramObject MetavoxelEditor::_gridProgram;