#include <QGraphicsSceneMouseEvent>

#include <QGraphicsPathItem>

#include <QtEndian>

#include <QDebug>

#include "drawmapscene.h"

template <class T> T sqr(const T & x)

{

    return x*x;

}

DrawMapScene::DrawMapScene(QObject *parent) :

    QGraphicsScene(parent),

    m_pen(Qt::yellow),

    m_brush(Qt::yellow)

{

    setSceneRect(0, 0, 4096, 2048);

    QLinearGradient gradient(0, 0, 0, 2048);

    gradient.setColorAt(0, QColor(60, 60, 155));

    gradient.setColorAt(1, QColor(155, 155, 60));

    setBackgroundBrush(QBrush(gradient));

    m_pen.setWidth(67);

    m_pen.setJoinStyle(Qt::RoundJoin);

    m_pen.setCapStyle(Qt::RoundCap);

    m_currPath = 0;

}

void DrawMapScene::mouseMoveEvent(QGraphicsSceneMouseEvent * mouseEvent)

{

    if(m_currPath && (mouseEvent->buttons() & Qt::LeftButton))

    {

        QPainterPath path = m_currPath->path();

        if(mouseEvent->modifiers() & Qt::ControlModifier)

        {

            int c = path.elementCount();

            QPointF pos = mouseEvent->scenePos();

            path.setElementPositionAt(c - 1, pos.x(), pos.y());

        } else

        {

            path.lineTo(mouseEvent->scenePos());

            paths.first().append(mouseEvent->scenePos().toPoint());

        }

        m_currPath->setPath(path);

        emit pathChanged();

    }

}

void DrawMapScene::mousePressEvent(QGraphicsSceneMouseEvent * mouseEvent)

{

    m_currPath = addPath(QPainterPath(), m_pen);

    QPainterPath path = m_currPath->path();

    QPointF p = mouseEvent->scenePos();

    p += QPointF(0.01, 0.01);

    path.moveTo(p);

    path.lineTo(mouseEvent->scenePos());

    paths.prepend(QList<QPoint>() << mouseEvent->scenePos().toPoint());

    m_currPath->setPath(path);

    emit pathChanged();

}

void DrawMapScene::mouseReleaseEvent(QGraphicsSceneMouseEvent * mouseEvent)

{

    Q_UNUSED(mouseEvent);

    simplifyLast();

    m_currPath = 0;

}

void DrawMapScene::undo()

{

    if(items().size())

    {

        removeItem(items().first());

        paths.removeFirst();

        emit pathChanged();

    }

}

void DrawMapScene::clearMap()

{

    clear();

    paths.clear();

    emit pathChanged();

}

QByteArray DrawMapScene::encode()

{

    QByteArray b;

    for(int i = paths.size() - 1; i >= 0; --i)

    {

        int cnt = 0;

        QList<QPoint> points = paths.at(i);

        foreach(QPoint point, points)

        {

            qint16 px = qToBigEndian((qint16)point.x());

            qint16 py = qToBigEndian((qint16)point.y());

            quint8 flags = 2;

            if(!cnt) flags |= 0x80;

            b.append((const char *)&px, 2);

            b.append((const char *)&py, 2);

            b.append((const char *)&flags, 1);

            ++cnt;

        }

    }

    return b;

}

void DrawMapScene::decode(QByteArray data)

{

    clear();

    paths.clear();

    QList<QPoint> points;

    while(data.size() >= 5)

    {

        qint16 px = qFromBigEndian(*(qint16 *)data.data());

        data.remove(0, 2);

        qint16 py = qFromBigEndian(*(qint16 *)data.data());

        data.remove(0, 2);

        quint8 flags = *(quint8 *)data.data();

        data.remove(0, 1);

        if((flags & 0x80) && points.size())

        {

            addPath(pointsToPath(points), m_pen);

            paths.prepend(points);

            points.clear();

        }

        points.append(QPoint(px, py));

    }

    if(points.size())

    {

        addPath(pointsToPath(points), m_pen);

        paths.prepend(points);

    }

    emit pathChanged();

}

void DrawMapScene::simplifyLast()

{

    if(!paths.size()) return;

    QList<QPoint> points = paths.at(0);

    QPoint prevPoint = points.first();

    int i = 1;

    while(i < points.size())

    {

        if( (i != points.size() - 1)

            && (sqr(prevPoint.x() - points[i].x()) + sqr(prevPoint.y() - points[i].y()) < 1000)

          )

            points.removeAt(i);

        else

        {

            prevPoint = points[i];

            ++i;

        }

    }

    paths[0] = points;

    // redraw path

    {

        QGraphicsPathItem * pathItem = static_cast<QGraphicsPathItem *>(items()[0]);

        pathItem->setPath(pointsToPath(paths[0]));

    }

    emit pathChanged();

}

QPainterPath DrawMapScene::pointsToPath(const QList<QPoint> points)

{

    QPainterPath path;

    if(points.size())

    {

        QPointF p = points[0] + QPointF(0.01, 0.01);

        path.moveTo(p);

        foreach(QPoint p, points)

            path.lineTo(p);

    }

    return path;

}