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#include "qboxlayout.h"

#include "qapplication.h"

#include "qwidget.h"

#include "qlist.h"

#include "qsizepolicy.h"

#include "qvector.h"

#include "qlayoutengine_p.h"

#include "qlayout_p.h"

QT_BEGIN_NAMESPACE

/*

    Returns true if the \a widget can be added to the \a layout;

    otherwise returns false.

*/

static bool checkWidget(QLayout *layout, QWidget *widget)

{

    if (!widget) {

        qWarning("QLayout: Cannot add null widget to %s/%s", layout->metaObject()->className(),

                  layout->objectName().toLocal8Bit().data());

        return false;

    }

    return true;

}

struct QBoxLayoutItem

{

    QBoxLayoutItem(QLayoutItem *it, int stretch_ = 0)

        : item(it), stretch(stretch_), magic(false) { }

    ~QBoxLayoutItem() { delete item; }

    int hfw(int w) {

        if (item->hasHeightForWidth()) {

            return item->heightForWidth(w);

        } else {

            return item->sizeHint().height();

        }

    }

    int mhfw(int w) {

        if (item->hasHeightForWidth()) {

            return item->heightForWidth(w);

        } else {

            return item->minimumSize().height();

        }

    }

    int hStretch() {

        if (stretch == 0 && item->widget()) {

            return item->widget()->sizePolicy().horizontalStretch();

        } else {

            return stretch;

        }

    }

    int vStretch() {

        if (stretch == 0 && item->widget()) {

            return item->widget()->sizePolicy().verticalStretch();

        } else {

            return stretch;

        }

    }

    QLayoutItem *item;

    int stretch;

    bool magic;

};

class QBoxLayoutPrivate : public QLayoutPrivate

{

    Q_DECLARE_PUBLIC(QBoxLayout)

public:

    QBoxLayoutPrivate() : hfwWidth(-1), dirty(true), spacing(-1) { }

    ~QBoxLayoutPrivate();

    void setDirty() {

        geomArray.clear();

        hfwWidth = -1;

        hfwHeight = -1;

        dirty = true;

    }

    QList<QBoxLayoutItem *> list;

    QVector<QLayoutStruct> geomArray;

    int hfwWidth;

    int hfwHeight;

    int hfwMinHeight;

    QSize sizeHint;

    QSize minSize;

    QSize maxSize;

    int leftMargin, topMargin, rightMargin, bottomMargin;

    Qt::Orientations expanding;

    uint hasHfw : 1;

    uint dirty : 1;

    QBoxLayout::Direction dir;

    int spacing;

    inline void deleteAll() { while (!list.isEmpty()) delete list.takeFirst(); }

    void setupGeom();

    void calcHfw(int);

    void effectiveMargins(int *left, int *top, int *right, int *bottom) const;

};

QBoxLayoutPrivate::~QBoxLayoutPrivate()

{

}

static inline bool horz(QBoxLayout::Direction dir)

{

    return dir == QBoxLayout::RightToLeft || dir == QBoxLayout::LeftToRight;

}

/**

 * The purpose of this function is to make sure that widgets are not laid out outside its layout.

 * E.g. the layoutItemRect margins are only meant to take of the surrounding margins/spacings.

 * However, if the margin is 0, it can easily cover the area of a widget above it.

 */

void QBoxLayoutPrivate::effectiveMargins(int *left, int *top, int *right, int *bottom) const

{

    int l = leftMargin;

    int t = topMargin;

    int r = rightMargin;

    int b = bottomMargin;

#ifdef Q_WS_MAC

    Q_Q(const QBoxLayout);

    if (horz(dir)) {

        QBoxLayoutItem *leftBox = 0;

        QBoxLayoutItem *rightBox = 0;

        if (left || right) {

            leftBox = list.value(0);

            rightBox = list.value(list.count() - 1);

            if (dir == QBoxLayout::RightToLeft)

                qSwap(leftBox, rightBox);

            int leftDelta = 0;

            int rightDelta = 0;

            if (leftBox) {

                QLayoutItem *itm = leftBox->item;

                if (QWidget *w = itm->widget())

                    leftDelta = itm->geometry().left() - w->geometry().left();

            }

            if (rightBox) {

                QLayoutItem *itm = rightBox->item;

                if (QWidget *w = itm->widget())

                    rightDelta = w->geometry().right() - itm->geometry().right();

            }

            QWidget *w = q->parentWidget();

            Qt::LayoutDirection layoutDirection = w ? w->layoutDirection() : QApplication::layoutDirection();

            if (layoutDirection == Qt::RightToLeft)

                qSwap(leftDelta, rightDelta);

            l = qMax(l, leftDelta);

            r = qMax(r, rightDelta);

        }

        int count = top || bottom ? list.count() : 0;

        for (int i = 0; i < count; ++i) {

            QBoxLayoutItem *box = list.at(i);

            QLayoutItem *itm = box->item;

            QWidget *w = itm->widget();

            if (w) {

                QRect lir = itm->geometry();

                QRect wr = w->geometry();

                if (top)

                    t = qMax(t, lir.top() - wr.top());

                if (bottom)

                    b = qMax(b, wr.bottom() - lir.bottom());

            }

        }

    } else {    // vertical layout

        QBoxLayoutItem *topBox = 0;

        QBoxLayoutItem *bottomBox = 0;

        if (top || bottom) {

            topBox = list.value(0);

            bottomBox = list.value(list.count() - 1);

            if (dir == QBoxLayout::BottomToTop) {

                qSwap(topBox, bottomBox);

            }

            if (top && topBox) {

                QLayoutItem *itm = topBox->item;

                QWidget *w = itm->widget();

                if (w)

                    t = qMax(t, itm->geometry().top() - w->geometry().top());

            }

            if (bottom && bottomBox) {

                QLayoutItem *itm = bottomBox->item;

                QWidget *w = itm->widget();

                if (w)

                    b = qMax(b, w->geometry().bottom() - itm->geometry().bottom());

            }

        }

        int count = left || right ? list.count() : 0;

        for (int i = 0; i < count; ++i) {

            QBoxLayoutItem *box = list.at(i);

            QLayoutItem *itm = box->item;

            QWidget *w = itm->widget();

            if (w) {

                QRect lir = itm->geometry();

                QRect wr = w->geometry();

                if (left)

                    l = qMax(l, lir.left() - wr.left());

                if (right)

                    r = qMax(r, wr.right() - lir.right());

            }

        }        

    }

#endif

    if (left)

        *left = l;

    if (top)

        *top = t;

    if (right)

        *right = r;

    if (bottom)

        *bottom = b;

}

/*

    Initializes the data structure needed by qGeomCalc and

    recalculates max/min and size hint.

*/

void QBoxLayoutPrivate::setupGeom()

{

    if (!dirty)

        return;

    Q_Q(QBoxLayout);

    int maxw = horz(dir) ? 0 : QLAYOUTSIZE_MAX;

    int maxh = horz(dir) ? QLAYOUTSIZE_MAX : 0;

    int minw = 0;

    int minh = 0;

    int hintw = 0;

    int hinth = 0;

    bool horexp = false;

    bool verexp = false;

    hasHfw = false;

    int n = list.count();

    geomArray.clear();

    QVector<QLayoutStruct> a(n);

    QSizePolicy::ControlTypes controlTypes1;

    QSizePolicy::ControlTypes controlTypes2;

    int fixedSpacing = q->spacing();

    int previousNonEmptyIndex = -1;

    QStyle *style = 0;

    if (fixedSpacing < 0) {

        if (QWidget *parentWidget = q->parentWidget())

            style = parentWidget->style();

    }

    for (int i = 0; i < n; i++) {

        QBoxLayoutItem *box = list.at(i);

        QSize max = box->item->maximumSize();

        QSize min = box->item->minimumSize();

        QSize hint = box->item->sizeHint();

        Qt::Orientations exp = box->item->expandingDirections();

        bool empty = box->item->isEmpty();

        int spacing = 0;

        if (!empty) {

            if (fixedSpacing >= 0) {

                spacing = (previousNonEmptyIndex >= 0) ? fixedSpacing : 0;

#ifdef Q_WS_MAC

                if (!horz(dir) && previousNonEmptyIndex >= 0) {

                    QBoxLayoutItem *sibling = (dir == QBoxLayout::TopToBottom  ? box : list.at(previousNonEmptyIndex));

                    if (sibling) {

                        QWidget *wid = sibling->item->widget();

                        if (wid)

                            spacing = qMax(spacing, sibling->item->geometry().top() - wid->geometry().top());

                    }

                }

#endif

            } else {

                controlTypes1 = controlTypes2;

                controlTypes2 = box->item->controlTypes();

                if (previousNonEmptyIndex >= 0) {

                    QSizePolicy::ControlTypes actual1 = controlTypes1;

                    QSizePolicy::ControlTypes actual2 = controlTypes2;

                    if (dir == QBoxLayout::RightToLeft || dir == QBoxLayout::BottomToTop)

                        qSwap(actual1, actual2);

                    if (style) {

                        spacing = style->combinedLayoutSpacing(actual1, actual2,

                                             horz(dir) ? Qt::Horizontal : Qt::Vertical,

                                             0, q->parentWidget());

                        if (spacing < 0)

                            spacing = 0;

                    }

                }

            }

            if (previousNonEmptyIndex >= 0)

                a[previousNonEmptyIndex].spacing = spacing;

            previousNonEmptyIndex = i;

        }

        bool ignore = empty && box->item->widget(); // ignore hidden widgets

        bool dummy = true;

        if (horz(dir)) {

            bool expand = (exp & Qt::Horizontal || box->stretch > 0);

            horexp = horexp || expand;

            maxw += spacing + max.width();

            minw += spacing + min.width();

            hintw += spacing + hint.width();

            if (!ignore)

                qMaxExpCalc(maxh, verexp, dummy,

                            max.height(), exp & Qt::Vertical, box->item->isEmpty());

            minh = qMax(minh, min.height());

            hinth = qMax(hinth, hint.height());

            a[i].sizeHint = hint.width();

            a[i].maximumSize = max.width();

            a[i].minimumSize = min.width();

            a[i].expansive = expand;

            a[i].stretch = box->stretch ? box->stretch : box->hStretch();

        } else {

            bool expand = (exp & Qt::Vertical || box->stretch > 0);

            verexp = verexp || expand;

            maxh += spacing + max.height();

            minh += spacing + min.height();

            hinth += spacing + hint.height();

            if (!ignore)

                qMaxExpCalc(maxw, horexp, dummy,

                            max.width(), exp & Qt::Horizontal, box->item->isEmpty());

            minw = qMax(minw, min.width());

            hintw = qMax(hintw, hint.width());

            a[i].sizeHint = hint.height();

            a[i].maximumSize = max.height();

            a[i].minimumSize = min.height();

            a[i].expansive = expand;

            a[i].stretch = box->stretch ? box->stretch : box->vStretch();

        }

        a[i].empty = empty;

        a[i].spacing = 0;   // might be be initialized with a non-zero value in a later iteration

        hasHfw = hasHfw || box->item->hasHeightForWidth();

    }

    geomArray = a;

    expanding = (Qt::Orientations)

                       ((horexp ? Qt::Horizontal : 0)

                         | (verexp ? Qt::Vertical : 0));

    minSize = QSize(minw, minh);

    maxSize = QSize(maxw, maxh).expandedTo(minSize);

    sizeHint = QSize(hintw, hinth).expandedTo(minSize).boundedTo(maxSize);

    q->getContentsMargins(&leftMargin, &topMargin, &rightMargin, &bottomMargin);

    int left, top, right, bottom;

    effectiveMargins(&left, &top, &right, &bottom);

    QSize extra(left + right, top + bottom);

    minSize += extra;

    maxSize += extra;

    sizeHint += extra;

    dirty = false;

}

/*

  Calculates and stores the preferred height given the width \a w.

*/

void QBoxLayoutPrivate::calcHfw(int w)

{

    QVector<QLayoutStruct> &a = geomArray;

    int n = a.count();

    int h = 0;

    int mh = 0;

    Q_ASSERT(n == list.size());

    if (horz(dir)) {

        qGeomCalc(a, 0, n, 0, w);

        for (int i = 0; i < n; i++) {

            QBoxLayoutItem *box = list.at(i);

            h = qMax(h, box->hfw(a.at(i).size));

            mh = qMax(mh, box->mhfw(a.at(i).size));

        }

    } else {

        for (int i = 0; i < n; ++i) {

            QBoxLayoutItem *box = list.at(i);

            int spacing = a.at(i).spacing;

            h += box->hfw(w);

            mh += box->mhfw(w);

            h += spacing;

            mh += spacing;

        }

    }

    hfwWidth = w;

    hfwHeight = h;

    hfwMinHeight = mh;

}

/*!

    \class QBoxLayout

    \brief The QBoxLayout class lines up child widgets horizontally or

    vertically.

    \ingroup geomanagement

    QBoxLayout takes the space it gets (from its parent layout or from

    the parentWidget()), divides it up into a row of boxes, and makes

    each managed widget fill one box.

    \image qhboxlayout-with-5-children.png Horizontal box layout with five child widgets

    If the QBoxLayout's orientation is Qt::Horizontal the boxes are

    placed in a row, with suitable sizes. Each widget (or other box)

    will get at least its minimum size and at most its maximum size.

    Any excess space is shared according to the stretch factors (more

    about that below).

    \image qvboxlayout-with-5-children.png Vertical box layout with five child widgets

    If the QBoxLayout's orientation is Qt::Vertical, the boxes are

    placed in a column, again with suitable sizes.

    The easiest way to create a QBoxLayout is to use one of the

    convenience classes, e.g. QHBoxLayout (for Qt::Horizontal boxes)

    or QVBoxLayout (for Qt::Vertical boxes). You can also use the

    QBoxLayout constructor directly, specifying its direction as

    LeftToRight, RightToLeft, TopToBottom, or BottomToTop.

    If the QBoxLayout is not the top-level layout (i.e. it is not

    managing all of the widget's area and children), you must add it

    to its parent layout before you can do anything with it. The

    normal way to add a layout is by calling

    parentLayout-\>addLayout().

    Once you have done this, you can add boxes to the QBoxLayout using

    one of four functions:

    \list

    \o addWidget() to add a widget to the QBoxLayout and set the

    widget's stretch factor. (The stretch factor is along the row of

    boxes.)

    \o addSpacing() to create an empty box; this is one of the

    functions you use to create nice and spacious dialogs. See below

    for ways to set margins.

    \o addStretch() to create an empty, stretchable box.

    \o addLayout() to add a box containing another QLayout to the row

    and set that layout's stretch factor.

    \endlist

    Use insertWidget(), insertSpacing(), insertStretch() or

    insertLayout() to insert a box at a specified position in the

    layout.

    QBoxLayout also includes two margin widths:

    \list

    \o setContentsMargins() sets the width of the outer border on 

       each side of the widget. This is the width of the reserved space 

       along each of the QBoxLayout's four sides.

    \o setSpacing() sets the width between neighboring boxes. (You

       can use addSpacing() to get more space at a particular spot.)

    \endlist

    The margin default is provided by the style. The default margin

    most Qt styles specify is 9 for child widgets and 11 for windows.

    The spacing defaults to the same as the margin width for a

    top-level layout, or to the same as the parent layout.

    To remove a widget from a layout, call removeWidget(). Calling

    QWidget::hide() on a widget also effectively removes the widget

    from the layout until QWidget::show() is called.

    You will almost always want to use QVBoxLayout and QHBoxLayout

    rather than QBoxLayout because of their convenient constructors.