/*

 * Hedgewars, a free turn based strategy game

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; version 2 of the License

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA

 */

#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),

    m_cursor(new QGraphicsEllipseItem(-0.5, -0.5, 1, 1))

{

    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));

    m_eraser = QBrush(gradient);

    setBackgroundBrush(m_eraser);

    m_isErasing = false;

    m_pen.setWidth(76);

    m_pen.setJoinStyle(Qt::RoundJoin);

    m_pen.setCapStyle(Qt::RoundCap);

    m_currPath = 0;

    m_isCursorShown = false;

    m_cursor->setPen(QPen(Qt::green));

    m_cursor->setZValue(1);

    m_cursor->setScale(m_pen.width());

}

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().points.append(mouseEvent->scenePos().toPoint());

        }

        m_currPath->setPath(path);

        emit pathChanged();

    }

    if(!m_isCursorShown)

        showCursor();

    m_cursor->setPos(mouseEvent->scenePos());

}

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());

    PathParams params;

    params.width = serializePenWidth(m_pen.width());

    params.erasing = m_isErasing;

    params.points = QList<QPoint>() << mouseEvent->scenePos().toPoint();

    paths.prepend(params);

    m_currPath->setPath(path);

    emit pathChanged();

}

void DrawMapScene::mouseReleaseEvent(QGraphicsSceneMouseEvent * mouseEvent)

{

    if (m_currPath)

    {

        QPainterPath path = m_currPath->path();

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

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

        m_currPath->setPath(path);

        simplifyLast();

        m_currPath = 0;

    }

}

void DrawMapScene::wheelEvent(QGraphicsSceneWheelEvent * wheelEvent)

{

    if(wheelEvent->delta() > 0 && m_pen.width() < 516)

        m_pen.setWidth(m_pen.width() + 10);

    else if(wheelEvent->delta() < 0 && m_pen.width() >= 16)

        m_pen.setWidth(m_pen.width() - 10);

    m_cursor->setScale(m_pen.width());

    if(m_currPath)

    {

        m_currPath->setPen(m_pen);

        paths.first().width = serializePenWidth(m_pen.width());

    }

}

void DrawMapScene::showCursor()

{

    if(!m_isCursorShown)

        addItem(m_cursor);

    m_isCursorShown = true;

}

void DrawMapScene::hideCursor()

{

    if(m_isCursorShown)

        removeItem(m_cursor);

    m_isCursorShown = false;

}

void DrawMapScene::undo()

{

    // cursor is a part of items()

    if(m_isCursorShown)

        return;

    if(items().size())

    {

        removeItem(items().first());

        paths.removeFirst();

        emit pathChanged();

    }

    else if(oldItems.size())

    {

        while(oldItems.size())

            addItem(oldItems.takeFirst());

        paths = oldPaths;

        emit pathChanged();

    }

}

void DrawMapScene::clearMap()

{

    // cursor is a part of items()

    if(m_isCursorShown)

        return;

    // don't clear if already cleared

    if(!items().size())

        return;

    oldItems.clear();

    // do this since clear() would _destroy_ all items

    while(items().size())

    {

        oldItems.push_front(items().first());

        removeItem(items().first());

    }

    oldPaths = paths;

    paths.clear();

    emit pathChanged();

}

void DrawMapScene::setErasing(bool erasing)

{

    m_isErasing = erasing;

    if(erasing)

        m_pen.setBrush(m_eraser);

    else

        m_pen.setBrush(m_brush);

}

QByteArray DrawMapScene::encode()

{

    QByteArray b;

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

    {

        int cnt = 0;

        PathParams params = paths.at(i);

        foreach(QPoint point, params.points)

        {

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

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

            quint8 flags = 0;

            if(!cnt)

            {

                flags = 0x80 + params.width;

                if(params.erasing) flags |= 0x40;

            }

            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)

{

    bool erasing = m_isErasing;

    oldItems.clear();

    oldPaths.clear();

    clear();

    paths.clear();

    PathParams params;

    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)

        {

            if(params.points.size())

            {

                addPath(pointsToPath(params.points), m_pen);

                paths.prepend(params);

                params.points.clear();

            }

            quint8 penWidth = flags & 0x3f;

            m_pen.setWidth(deserializePenWidth(penWidth));

            params.erasing = flags & 0x40;

            if(params.erasing)

                m_pen.setBrush(m_eraser);

            else

                m_pen.setBrush(m_brush);

            params.width = penWidth;

        }

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

    }

    if(params.points.size())

    {

        addPath(pointsToPath(params.points), m_pen);

        paths.prepend(params);

    }

    emit pathChanged();

    setErasing(erasing);

}

void DrawMapScene::simplifyLast()

{

    if(!paths.size()) return;

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

    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 = points;

    // redraw path

    {

        QGraphicsPathItem * pathItem = static_cast<QGraphicsPathItem *>(items()[m_isCursorShown ? 1 : 0]);

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

    }

    emit pathChanged();

}

int DrawMapScene::pointsCount()

{

    int cnt = 0;

    foreach(PathParams p, paths)

        cnt += p.points.size();

    return cnt;

}

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;

}

quint8 DrawMapScene::serializePenWidth(int width)

{

    return (width - 6) / 10;

}

int DrawMapScene::deserializePenWidth(quint8 width)

{

    return width * 10 + 6;

}