/*

 * Hedgewars, a free turn based strategy game

 * Copyright (c) 2004-2015 Andrey Korotaev <unC0Rr@gmail.com>

 *

 * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 */

#include <QGraphicsSceneMouseEvent>

#include <QGraphicsPathItem>

#include <QtEndian>

#include <QDebug>

#include <QTransform>

#include <math.h>

#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_pathType = Polyline;

    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();

        QPointF currentPos = mouseEvent->scenePos();

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

            currentPos = putSomeConstraints(paths.first().initialPoint, currentPos);

        switch (m_pathType)

        {

        case Polyline:

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

            {

                int c = path.elementCount();

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

            }

            else

            {

                path.lineTo(currentPos);

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

            }

            break;

        case Rectangle: {

            path = QPainterPath();

            QPointF p1 = paths.first().initialPoint;

            QPointF p2 = currentPos;

            path.moveTo(p1);

            path.lineTo(p1.x(), p2.y());

            path.lineTo(p2);

            path.lineTo(p2.x(), p1.y());

            path.lineTo(p1);

            break;

            }

        case Ellipse: {

            path = QPainterPath();

            QList<QPointF> points = makeEllipse(paths.first().initialPoint, currentPos);

            path.addPolygon(QPolygonF(QVector<QPointF>::fromList(points)));

            break;

        }

        }

        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.initialPoint = mouseEvent->scenePos().toPoint();

    params.points = QList<QPoint>() << params.initialPoint;

    paths.prepend(params);

    m_currPath->setPath(path);

    emit pathChanged();

}

void DrawMapScene::mouseReleaseEvent(QGraphicsSceneMouseEvent * mouseEvent)

{

    if (m_currPath)

    {

        QPointF currentPos = mouseEvent->scenePos();

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

            currentPos = putSomeConstraints(paths.first().initialPoint, currentPos);

        switch (m_pathType)

        {

        case Polyline: {

            QPainterPath path = m_currPath->path();

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

            paths.first().points.append(currentPos.toPoint());

            m_currPath->setPath(path);

            simplifyLast();

            break;

        }

        case Rectangle: {

            QPoint p1 = paths.first().initialPoint;

            QPoint p2 = currentPos.toPoint();

            QList<QPoint> rpoints;

            rpoints << p1 << QPoint(p1.x(), p2.y()) << p2 << QPoint(p2.x(), p1.y()) << p1;

            paths.first().points = rpoints;

            break;

        }

        case Ellipse:

            QPoint p1 = paths.first().initialPoint;

            QPoint p2 = currentPos.toPoint();

            QList<QPointF> points = makeEllipse(p1, p2);

            QList<QPoint> epoints;

            foreach(const QPointF & p, points)

                epoints.append(p.toPoint());

            paths.first().points = epoints;

            break;

        }

        m_currPath = 0;

        emit pathChanged();

    }

}

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(paths.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;

    m_specialPoints.clear();

    oldItems.clear();

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

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

    {

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

        removeItem(items().first());

    }

    items().clear();

    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(m_specialPoints);

    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)

{

    hideCursor();

    bool erasing = m_isErasing;

    oldItems.clear();

    oldPaths.clear();

    clear();

    paths.clear();

    m_specialPoints.clear();

    PathParams params;

    bool isSpecial = true;

    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);

        //qDebug() << px << py;

        if(flags & 0x80)

        {

            isSpecial = false;

            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;

        } else

            if(isSpecial)

            {

                QPainterPath path;

                path.addEllipse(QPointF(px, py), 10, 10);

                addPath(path);

                qint16 x = qToBigEndian(px);

                qint16 y = qToBigEndian(py);

                m_specialPoints.append((const char *)&x, 2);

                m_specialPoints.append((const char *)&y, 2);

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

            }

        if(!isSpecial)

            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) || (prevPoint == points[i]))

                && (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));

    }

}

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;

}

void DrawMapScene::setPathType(PathType pathType)

{

    m_pathType = pathType;

}

QList<QPointF> DrawMapScene::makeEllipse(const QPointF &center, const QPointF &corner)

{

    QList<QPointF> l;

    qreal rx = qAbs(center.x() - corner.x());

    qreal ry = qAbs(center.y() - corner.y());

    qreal r = qMax(rx, ry);

    if(r < 4)

    {

        l.append(center);

    } else

    {

        qreal angleDelta = qMax(static_cast<qreal> (0.1), qMin(static_cast<qreal> (0.7), 120 / r));

        for(qreal angle = 0.0; angle < 2*M_PI; angle += angleDelta)

            l.append(center + QPointF(rx * cos(angle), ry * sin(angle)));

        l.append(l.first());

    }

    return l;

}

QPointF DrawMapScene::putSomeConstraints(const QPointF &initialPoint, const QPointF &point)

{

    QPointF vector = point - initialPoint;

    for(int angle = 0; angle < 180; angle += 15)

    {

        QTransform transform;

        transform.rotate(angle);

        QPointF rotated = transform.map(vector);

        if(rotated.x() == 0) return point;

        if(qAbs(rotated.y() / rotated.x()) < 0.05) return initialPoint + transform.inverted().map(QPointF(rotated.x(), 0));