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#include "qgraphicsanchorlayout_p.h"

QGraphicsAnchorLayout::QGraphicsAnchorLayout(QGraphicsLayoutItem *parent)
    : QGraphicsLayout(*new QGraphicsAnchorLayoutPrivate(), parent)
{
    Q_D(QGraphicsAnchorLayout);
    d->createLayoutEdges();
}

QGraphicsAnchorLayout::~QGraphicsAnchorLayout()
{
    Q_D(QGraphicsAnchorLayout);

    for (int i = count() - 1; i >= 0; --i) {
        QGraphicsLayoutItem *item = d->items.at(i);
        removeAt(i);
        if (item) {
            if (item->ownedByLayout())
                delete item;
        }
    }

    d->removeCenterConstraints(this, QGraphicsAnchorLayoutPrivate::Horizontal);
    d->removeCenterConstraints(this, QGraphicsAnchorLayoutPrivate::Vertical);
    d->deleteLayoutEdges();

    Q_ASSERT(d->itemCenterConstraints[0].isEmpty());
    Q_ASSERT(d->itemCenterConstraints[1].isEmpty());
    Q_ASSERT(d->items.isEmpty());
    Q_ASSERT(d->m_vertexList.isEmpty());
}

/*!
 * Creates an anchor between the edge \a firstEdge of item \a firstItem and the edge \a secondEdge
 * of item \a secondItem. The magnitude of the anchor is picked up from the style. Anchors
 * between  a layout edge and an item edge will have a size of 0.
 * If there is already an anchor between the edges, the the new anchor will replace the old one.
 *
 * \a firstItem and \a secondItem are automatically added to the layout if they are not part
 * of the layout. This means that count() can increase with up to 2.
 */
void QGraphicsAnchorLayout::anchor(QGraphicsLayoutItem *firstItem,
                                   Edge firstEdge,
                                   QGraphicsLayoutItem *secondItem,
                                   Edge secondEdge)
{
    Q_D(QGraphicsAnchorLayout);
    d->anchor(firstItem, firstEdge, secondItem, secondEdge);
    invalidate();
}

/*!
 * \overload
 *
 * By calling this function the caller can specify the magnitude of the anchor with \a spacing.
 *
 */
void QGraphicsAnchorLayout::anchor(QGraphicsLayoutItem *firstItem,
                                   Edge firstEdge,
                                   QGraphicsLayoutItem *secondItem,
                                   Edge secondEdge, qreal spacing)
{
    Q_D(QGraphicsAnchorLayout);
    d->anchor(firstItem, firstEdge, secondItem, secondEdge, &spacing);
    invalidate();
}

/*!
 * Creates two anchors between \a firstItem and \a secondItem, where one is for the horizontal
 * edge and another one for the vertical edge that the corners \a firstCorner and \a
 * secondCorner specifies.
 * The magnitude of the anchors is picked up from the style.
 *
 * This is a convenience function, since anchoring corners can be expressed as anchoring two edges.
 * For instance,
 * \code
 *  layout->anchor(layout, QGraphicsAnchorLayout::Top, b, QGraphicsAnchorLayout::Top);
 *  layout->anchor(layout, QGraphicsAnchorLayout::Left, b, QGraphicsAnchorLayout::Left);
 * \endcode
 *
 * has the same effect as
 *
 * \code
 * layout->anchor(layout, Qt::TopLeft, b, Qt::TopLeft);
 * \endcode
 *
 * If there is already an anchor between the edge pairs, it will be replaced by the anchors that
 * this function specifies.
 *
 * \a firstItem and \a secondItem are automatically added to the layout if they are not part
 * of the layout. This means that count() can increase with up to 2.
 */
void QGraphicsAnchorLayout::anchorCorner(QGraphicsLayoutItem *firstItem,
                                         Qt::Corner firstCorner,
                                         QGraphicsLayoutItem *secondItem,
                                         Qt::Corner secondCorner)
{
    Q_D(QGraphicsAnchorLayout);

    // Horizontal anchor
    QGraphicsAnchorLayout::Edge firstEdge = (firstCorner & 1 ? QGraphicsAnchorLayout::Right: QGraphicsAnchorLayout::Left);
    QGraphicsAnchorLayout::Edge secondEdge = (secondCorner & 1 ? QGraphicsAnchorLayout::Right: QGraphicsAnchorLayout::Left);
    d->anchor(firstItem, firstEdge, secondItem, secondEdge);

    // Vertical anchor
    firstEdge = (firstCorner & 2 ? QGraphicsAnchorLayout::Bottom: QGraphicsAnchorLayout::Top);
    secondEdge = (secondCorner & 2 ? QGraphicsAnchorLayout::Bottom: QGraphicsAnchorLayout::Top);
    d->anchor(firstItem, firstEdge, secondItem, secondEdge);

    invalidate();
}

/*!
 * \overload
 *
 * By calling this function the caller can specify the magnitude of the anchor with \a spacing.
 *
 */
void QGraphicsAnchorLayout::anchorCorner(QGraphicsLayoutItem *firstItem,
                                         Qt::Corner firstCorner,
                                         QGraphicsLayoutItem *secondItem,
                                         Qt::Corner secondCorner, qreal spacing)
{
    Q_D(QGraphicsAnchorLayout);

    // Horizontal anchor
    QGraphicsAnchorLayout::Edge firstEdge = (firstCorner & 1 ? QGraphicsAnchorLayout::Right: QGraphicsAnchorLayout::Left);
    QGraphicsAnchorLayout::Edge secondEdge = (secondCorner & 1 ? QGraphicsAnchorLayout::Right: QGraphicsAnchorLayout::Left);
    d->anchor(firstItem, firstEdge, secondItem, secondEdge, &spacing);

    // Vertical anchor
    firstEdge = (firstCorner & 2 ? QGraphicsAnchorLayout::Bottom: QGraphicsAnchorLayout::Top);
    secondEdge = (secondCorner & 2 ? QGraphicsAnchorLayout::Bottom: QGraphicsAnchorLayout::Top);
    d->anchor(firstItem, firstEdge, secondItem, secondEdge, &spacing);

    invalidate();
}

void QGraphicsAnchorLayout::removeAnchor(QGraphicsLayoutItem *firstItem, Edge firstEdge,
                                         QGraphicsLayoutItem *secondItem, Edge secondEdge)
{
    Q_D(QGraphicsAnchorLayout);
    if ((firstItem == 0) || (secondItem == 0)) {
        qWarning("QGraphicsAnchorLayout::removeAnchor: "
                 "Cannot remove anchor between NULL items");
        return;
    }

    if (firstItem == secondItem) {
        qWarning("QGraphicsAnchorLayout::removeAnchor: "
                 "Cannot remove anchor from the item to itself");
        return;
    }

    if (d->edgeOrientation(secondEdge) != d->edgeOrientation(firstEdge)) {
        qWarning("QGraphicsAnchorLayout::removeAnchor: "
                 "Cannot remove anchor from edges of different orientations");
        return;
    }

    d->removeAnchor(firstItem, firstEdge, secondItem, secondEdge);
    invalidate();
}

void QGraphicsAnchorLayout::setSpacing(qreal spacing, Qt::Orientations orientations /*= Qt::Horizontal|Qt::Vertical*/)
{
    Q_D(QGraphicsAnchorLayout);
    if (orientations & Qt::Horizontal)
        d->spacing[0] = spacing;
    if (orientations & Qt::Vertical)
        d->spacing[1] = spacing;
}

qreal QGraphicsAnchorLayout::spacing(Qt::Orientation orientation) const
{
    Q_D(const QGraphicsAnchorLayout);
    return d->effectiveSpacing(QGraphicsAnchorLayoutPrivate::Orientation(orientation - 1));
}

void QGraphicsAnchorLayout::setGeometry(const QRectF &geom)
{
    Q_D(QGraphicsAnchorLayout);
    QGraphicsLayout::setGeometry(geom);
    d->calculateVertexPositions(QGraphicsAnchorLayoutPrivate::Horizontal);
    d->calculateVertexPositions(QGraphicsAnchorLayoutPrivate::Vertical);
    d->setItemsGeometries();
}

void QGraphicsAnchorLayout::removeAt(int index)
{
    Q_D(QGraphicsAnchorLayout);
    QGraphicsLayoutItem *item = d->items.value(index);

    if (!item)
        return;

    d->removeCenterConstraints(item, QGraphicsAnchorLayoutPrivate::Horizontal);
    d->removeCenterConstraints(item, QGraphicsAnchorLayoutPrivate::Vertical);
    d->removeAnchors(item);
    d->items.remove(index);

    item->setParentLayoutItem(0);
    invalidate();
}

int QGraphicsAnchorLayout::count() const
{
    Q_D(const QGraphicsAnchorLayout);
    return d->items.size();
}

QGraphicsLayoutItem *QGraphicsAnchorLayout::itemAt(int index) const
{
    Q_D(const QGraphicsAnchorLayout);
    return d->items.value(index);
}

void QGraphicsAnchorLayout::invalidate()
{
    Q_D(QGraphicsAnchorLayout);
    QGraphicsLayout::invalidate();
    d->calculateGraphCacheDirty = 1;
}

QSizeF QGraphicsAnchorLayout::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const
{
    Q_UNUSED(which);
    Q_UNUSED(constraint);
    Q_D(const QGraphicsAnchorLayout);

    // Some setup calculations are delayed until the information is
    // actually needed, avoiding unnecessary recalculations when
    // adding multiple anchors.

    // sizeHint() / effectiveSizeHint() already have a cache
    // mechanism, using invalidate() to force recalculation. However
    // sizeHint() is called three times after invalidation (for max,
    // min and pref), but we just need do our setup once.

    const_cast<QGraphicsAnchorLayoutPrivate *>(d)->calculateGraphs();

    // ### apply constraint!
    QSizeF engineSizeHint(
        d->sizeHints[QGraphicsAnchorLayoutPrivate::Horizontal][which],
        d->sizeHints[QGraphicsAnchorLayoutPrivate::Vertical][which]);

    qreal left, top, right, bottom;
    getContentsMargins(&left, &top, &right, &bottom);

    return engineSizeHint + QSizeF(left + right, top + bottom);
}

//////// DEBUG /////////
#include <QFile>
void QGraphicsAnchorLayout::dumpGraph()
{
    Q_D(QGraphicsAnchorLayout);

    QFile file(QString::fromAscii("anchorlayout.dot"));
    if (!file.open(QIODevice::WriteOnly | QIODevice::Text | QIODevice::Truncate))
        qWarning("Could not write to %s", file.fileName().toLocal8Bit().constData());

    QString str = QString::fromAscii("digraph anchorlayout {\nnode [shape=\"rect\"]\n%1}");
    QString dotContents = d->graph[0].serializeToDot();
    dotContents += d->graph[1].serializeToDot();
    file.write(str.arg(dotContents).toLocal8Bit());

    file.close();
}