#ifndef GRAPHICWIDGET_H
#define GRAPHICWIDGET_H

#include "ui_GraphicWidget.h"
#include "PlotSettings.h"

#include <QtGui/QWidget>

class QPaintEvent;
class QPainter;

/// Виджет, где будет отрисовываться график
class GraphicWidget: public QWidget, public Ui::GraphicWidgetClass
{
    Q_OBJECT

private:
    PlotSettings settings;        ///< настройка для различных масштабов

private:
    void drawGrid(QPainter *painter);

protected:
    void paintEvent(QPaintEvent* event);

public:
    GraphicWidget(QWidget *parent = 0, Qt::WFlags flags = 0);
    ~GraphicWidget();
    void setPlotSettings(const PlotSettings& sts) { settings = sts; settings.adjust(); update(); }
};

#endif // GRAPHICWIDGET_H

#include "GraphicWidget.h"

#include <QPainter>
#include <QRect>
#include <QString>
#include <algorithm>
using namespace std;

GraphicWidget::GraphicWidget(QWidget *parent, Qt::WFlags flags): QWidget(parent, flags)
{
    setupUi(this);

    /// Инициализация необходимых параметров
    setPlotSettings(PlotSettings());
}

GraphicWidget::~GraphicWidget()
{}

/// Отрисовка сетки
void GraphicWidget::drawGrid(QPainter *painter)
{
    QRect rect(graphWidget -> rect());
    if(!rect.isValid()) return;
    
    QRect boundString;    
    double great_max = max(settings.numXTicks, settings.numYTicks) + 1;
    for(register int i=0, j=0, k=0; i<=great_max; ++i, ++j, ++k)
    {
        if(j <= settings.numXTicks)                ///< отрисовка вдоль оси X
        {
            int x = rect.left() + (j * (rect.width() - 1) / settings.numXTicks);
            double label = settings.minX + (j * settings.spanX() / settings.numXTicks);
            QString s_label(QString::number(label, 'f', 3));

            painter -> setPen(Qt::black);
            painter -> drawLine(x, rect.top(), x, rect.bottom());

            int flags = Qt::AlignHCenter | Qt::AlignTop;
            boundString = painter -> boundingRect(boundString, flags, s_label);    
            painter -> drawText(x - (boundString.width() + 5), rect.bottom() - (boundString.height() + 5), 
                            boundString.width(), boundString.height(), flags, s_label);
        }
        if(k <= settings.numYTicks)                ///< отрисовка вдоль оси Y
        {
            int y = rect.bottom() - (k * (rect.height() - 1) / settings.numYTicks);
            double label = settings.minY + (k * settings.spanY() / settings.numYTicks);
            QString s_label(QString::number(label, 'f', 3));

            painter -> setPen(Qt::black);
            painter -> drawLine(rect.left(), y, rect.right(), y);

            int flags = Qt::AlignRight | Qt::AlignTop;
            boundString = painter -> boundingRect(boundString, flags, s_label);    
            painter -> drawText(rect.left() + 7, y - boundString.height(),
                                boundString.width(), boundString.height(), flags, s_label);
        }
    }
    painter -> drawRect(rect.adjusted(0, 0, -1, -1));
}

/// Отрисовка графика
void GraphicWidget::paintEvent(QPaintEvent* event)
{
    QPainter painter(this);
    drawGrid(&painter);

    QWidget::paintEvent(event);
}

#include <QRubberBand>
#include <QKeyEvent>
#include <QWheelEvent>
#include <QMouseEvent>


/// Отрисовка графика
void GraphicWidget::paintEvent(QPaintEvent* events)
{
    QPainter painter(this);
    drawGrid(&painter);

    QWidget::paintEvent(events);
}

/// Нажатие на кнопки клавиатуры
void GraphicWidget::keyPressEvent(QKeyEvent* events)
{
    switch(events -> key())
    {
    case Qt::Key_Plus:
        zoom(-1.0);
    break;
    case Qt::Key_Minus:
        zoom(1.0);
    break;
    case Qt::Key_Left:
        settings.scroll(-1.0, 0.0);
        update();
    break;
    case Qt::Key_Right:
        settings.scroll(1.0, 0.0);
        update();
    break;
    case Qt::Key_Up:
        settings.scroll(0.0, 1.0);
        update();
    break;
    case Qt::Key_Down:
        settings.scroll(0.0, -1.0);
        update();
    break;
    case Qt::Key_X:
        if(events -> modifiers() & Qt::ALT) close();
    break;
    case Qt::Key_Return:
        if(events -> modifiers() & Qt::ALT)
        {
            if(!isMaximized()) showMaximized();
            else showNormal();
        }
    break;
    default:
        QWidget::keyPressEvent(events);
    }
}

/// Изменение масштаба при движении колесика
void GraphicWidget::wheelEvent(QWheelEvent* events)
{
    int numDegrees = events -> delta() / 8;
    double numTicks = numDegrees / 15.0;
    
    zoom(numTicks);
    update();
}

/// Нажатие на кнопку - изменение масштаба
void GraphicWidget::mousePressEvent(QMouseEvent* events)
{
    QWidget::mousePressEvent(events);

    QRect r;
    switch(events -> button())
    {
    case Qt::LeftButton:                ///< если нажата левая кнопка мыши
        origin = events -> pos();
        rubberBandIsShown = true;
        setCursor(Qt::CrossCursor);
        r = QRect(origin, QSize());
        rubber -> setGeometry(r);
        rubber -> show();
    break;
    case Qt::RightButton:                ///< если нажата правая кнопка мыши
    break;
    default:
    break;
    }
}

/// Переопределение функции передвижения мыши
void GraphicWidget::mouseMoveEvent(QMouseEvent* events)
{
    if(rubberBandIsShown)
    {
        rubber -> setWindowOpacity(0.0);
        rubber -> setGeometry(QRect(origin, events -> pos()).normalized());
    }

    update();
}

/// Возвращение прежнего вида курсору и изменение масштаба
void GraphicWidget::mouseReleaseEvent(QMouseEvent* events)
{
    if(events -> button() == Qt::LeftButton && rubberBandIsShown)
    {
        rubberBandIsShown = false;
        unsetCursor();
        
        QRect rect = rubber -> geometry().normalized();
        if(rect.width() < 10 || rect.height() < 10)
        {
            double dx = rect.width() / settings.spanX();
            double dy = rect.height() / settings.spanY();
            settings.scroll(dx, dy);

            update();
            return;
        }
        PlotSettings prevSettings = settings;

        double dx = prevSettings.spanX() / width();
        double dy = prevSettings.spanY() / height();
        settings.minX = prevSettings.minX + dx * rect.left();
        settings.maxX = prevSettings.minX + dx * rect.right();
        settings.minY = prevSettings.maxY - dy * rect.bottom();
        settings.maxY = prevSettings.maxY - dy * rect.top();
        settings.adjust();

        rubber -> hide();
        update();
    }
}