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#include <QtGui>

#include "puzzlewidget.h"

PuzzleWidget::PuzzleWidget(QWidget *parent)

    : QWidget(parent)

{

    setAcceptDrops(true);

    setMinimumSize(400, 400);

    setMaximumSize(400, 400);

}

void PuzzleWidget::clear()

{

    pieceLocations.clear();

    piecePixmaps.clear();

    pieceRects.clear();

    highlightedRect = QRect();

    inPlace = 0;

    update();

}

void PuzzleWidget::dragEnterEvent(QDragEnterEvent *event)

{

    if (event->mimeData()->hasFormat("image/x-puzzle-piece"))

        event->accept();

    else

        event->ignore();

}

void PuzzleWidget::dragLeaveEvent(QDragLeaveEvent *event)

{

    QRect updateRect = highlightedRect;

    highlightedRect = QRect();

    update(updateRect);

    event->accept();

}

void PuzzleWidget::dragMoveEvent(QDragMoveEvent *event)

{

    QRect updateRect = highlightedRect.unite(targetSquare(event->pos()));

    if (event->mimeData()->hasFormat("image/x-puzzle-piece")

        && findPiece(targetSquare(event->pos())) == -1) {

        highlightedRect = targetSquare(event->pos());

        event->setDropAction(Qt::MoveAction);

        event->accept();

    } else {

        highlightedRect = QRect();

        event->ignore();

    }

    update(updateRect);

}

void PuzzleWidget::dropEvent(QDropEvent *event)

{

    if (event->mimeData()->hasFormat("image/x-puzzle-piece")

        && findPiece(targetSquare(event->pos())) == -1) {

        QByteArray pieceData = event->mimeData()->data("image/x-puzzle-piece");

        QDataStream stream(&pieceData, QIODevice::ReadOnly);

        QRect square = targetSquare(event->pos());

        QPixmap pixmap;

        QPoint location;

        stream >> pixmap >> location;

        pieceLocations.append(location);

        piecePixmaps.append(pixmap);

        pieceRects.append(square);

        highlightedRect = QRect();

        update(square);

        event->setDropAction(Qt::MoveAction);

        event->accept();

        if (location == QPoint(square.x()/80, square.y()/80)) {

            inPlace++;

            if (inPlace == 25)

                emit puzzleCompleted();

        }

    } else {

        highlightedRect = QRect();

        event->ignore();

    }

}

int PuzzleWidget::findPiece(const QRect &pieceRect) const

{

    for (int i = 0; i < pieceRects.size(); ++i) {

        if (pieceRect == pieceRects[i]) {

            return i;

        }

    }

    return -1;

}

void PuzzleWidget::mousePressEvent(QMouseEvent *event)

{

    QRect square = targetSquare(event->pos());

    int found = findPiece(square);

    if (found == -1)

        return;

    QPoint location = pieceLocations[found];

    QPixmap pixmap = piecePixmaps[found];

    pieceLocations.removeAt(found);

    piecePixmaps.removeAt(found);

    pieceRects.removeAt(found);

    if (location == QPoint(square.x()/80, square.y()/80))

        inPlace--;

    update(square);

    QByteArray itemData;

    QDataStream dataStream(&itemData, QIODevice::WriteOnly);

    dataStream << pixmap << location;

    QMimeData *mimeData = new QMimeData;

    mimeData->setData("image/x-puzzle-piece", itemData);

    QDrag *drag = new QDrag(this);

    drag->setMimeData(mimeData);

    drag->setHotSpot(event->pos() - square.topLeft());

    drag->setPixmap(pixmap);

    if (drag->start(Qt::MoveAction) == 0) {

        pieceLocations.insert(found, location);

        piecePixmaps.insert(found, pixmap);

        pieceRects.insert(found, square);

        update(targetSquare(event->pos()));

        if (location == QPoint(square.x()/80, square.y()/80))

            inPlace++;

    }

}

void PuzzleWidget::paintEvent(QPaintEvent *event)

{

    QPainter painter;

    painter.begin(this);

    painter.fillRect(event->rect(), Qt::white);

    if (highlightedRect.isValid()) {

        painter.setBrush(QColor("#ffcccc"));

        painter.setPen(Qt::NoPen);

        painter.drawRect(highlightedRect.adjusted(0, 0, -1, -1));

    }

    for (int i = 0; i < pieceRects.size(); ++i) {

        painter.drawPixmap(pieceRects[i], piecePixmaps[i]);

    }

    painter.end();

}

const QRect PuzzleWidget::targetSquare(const QPoint &position) const

{

    return QRect(position.x()/80 * 80, position.y()/80 * 80, 80, 80);

}