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#include "private/qdeclarativepath_p.h"

#include "private/qdeclarativepath_p_p.h"

#include <QSet>

#include <QTime>

#include <private/qbezier_p.h>

QT_BEGIN_NAMESPACE

/*!

    \qmlclass PathElement QDeclarativePathElement

    \since 4.7

    \brief PathElement is the base path type.

    This type is the base for all path types.  It cannot

    be instantiated.

    \sa Path, PathAttribute, PathPercent, PathLine, PathQuad, PathCubic

*/

/*!

    \qmlclass Path QDeclarativePath

    \since 4.7

    \brief A Path object defines a path for use by \l PathView.

    A Path is composed of one or more path segments - PathLine, PathQuad,

    PathCubic.

    The spacing of the items along the Path can be adjusted via a

    PathPercent object.

    PathAttribute allows named attributes with values to be defined

    along the path.

    \sa PathView, PathAttribute, PathPercent, PathLine, PathQuad, PathCubic

*/

QDeclarativePath::QDeclarativePath(QObject *parent)

 : QObject(*(new QDeclarativePathPrivate), parent)

{

}

QDeclarativePath::~QDeclarativePath()

{

}

/*!

    \qmlproperty real Path::startX

    \qmlproperty real Path::startY

    These properties hold the starting position of the path.

*/

qreal QDeclarativePath::startX() const

{

    Q_D(const QDeclarativePath);

    return d->startX;

}

void QDeclarativePath::setStartX(qreal x)

{

    Q_D(QDeclarativePath);

    if (qFuzzyCompare(x, d->startX))

        return;

    d->startX = x;

    emit startXChanged();

    processPath();

}

qreal QDeclarativePath::startY() const

{

    Q_D(const QDeclarativePath);

    return d->startY;

}

void QDeclarativePath::setStartY(qreal y)

{

    Q_D(QDeclarativePath);

    if (qFuzzyCompare(y, d->startY))

        return;

    d->startY = y;

    emit startYChanged();

    processPath();

}

/*!

    \qmlproperty bool Path::closed

    This property holds whether the start and end of the path are identical.

*/

bool QDeclarativePath::isClosed() const

{

    Q_D(const QDeclarativePath);

    return d->closed;

}

/*!

    \qmlproperty list<PathElement> Path::pathElements

    This property holds the objects composing the path.

    \default

    A path can contain the following path objects:

    \list

        \i \l PathLine - a straight line to a given position.

        \i \l PathQuad - a quadratic Bezier curve to a given position with a control point.

        \i \l PathCubic - a cubic Bezier curve to a given position with two control points.

        \i \l PathAttribute - an attribute at a given position in the path.

        \i \l PathPercent - a way to spread out items along various segments of the path.

    \endlist

    \snippet doc/src/snippets/declarative/pathview/pathattributes.qml 2

*/

QDeclarativeListProperty<QDeclarativePathElement> QDeclarativePath::pathElements()

{

    Q_D(QDeclarativePath);

    return QDeclarativeListProperty<QDeclarativePathElement>(this, d->_pathElements);

}

void QDeclarativePath::interpolate(int idx, const QString &name, qreal value)

{

    Q_D(QDeclarativePath);

    if (!idx)

        return;

    qreal lastValue = 0;

    qreal lastPercent = 0;

    int search = idx - 1;

    while(search >= 0) {

        const AttributePoint &point = d->_attributePoints.at(search);

        if (point.values.contains(name)) {

            lastValue = point.values.value(name);

            lastPercent = point.origpercent;

            break;

        }

        --search;

    }

    ++search;

    const AttributePoint &curPoint = d->_attributePoints.at(idx);

    for (int ii = search; ii < idx; ++ii) {

        AttributePoint &point = d->_attributePoints[ii];

        qreal val = lastValue + (value - lastValue) * (point.origpercent - lastPercent) / (curPoint.origpercent - lastPercent);

        point.values.insert(name, val);

    }

}

void QDeclarativePath::endpoint(const QString &name)

{

    Q_D(QDeclarativePath);

    const AttributePoint &first = d->_attributePoints.first();

    qreal val = first.values.value(name);

    for (int ii = d->_attributePoints.count() - 1; ii >= 0; ii--) {

        const AttributePoint &point = d->_attributePoints.at(ii);

        if (point.values.contains(name)) {

            for (int jj = ii + 1; jj < d->_attributePoints.count(); ++jj) {

                AttributePoint &setPoint = d->_attributePoints[jj];

                setPoint.values.insert(name, val);

            }

            return;

        }

    }

}

void QDeclarativePath::processPath()

{

    Q_D(QDeclarativePath);

    if (!d->componentComplete)

        return;

    d->_pointCache.clear();

    d->_attributePoints.clear();

    d->_path = QPainterPath();

    AttributePoint first;

    for (int ii = 0; ii < d->_attributes.count(); ++ii)

        first.values[d->_attributes.at(ii)] = 0;

    d->_attributePoints << first;

    d->_path.moveTo(d->startX, d->startY);

    QDeclarativeCurve *lastCurve = 0;

    foreach (QDeclarativePathElement *pathElement, d->_pathElements) {

        if (QDeclarativeCurve *curve = qobject_cast<QDeclarativeCurve *>(pathElement)) {

            curve->addToPath(d->_path);

            AttributePoint p;

            p.origpercent = d->_path.length();

            d->_attributePoints << p;

            lastCurve = curve;

        } else if (QDeclarativePathAttribute *attribute = qobject_cast<QDeclarativePathAttribute *>(pathElement)) {

            AttributePoint &point = d->_attributePoints.last();

            point.values[attribute->name()] = attribute->value();

            interpolate(d->_attributePoints.count() - 1, attribute->name(), attribute->value());

        } else if (QDeclarativePathPercent *percent = qobject_cast<QDeclarativePathPercent *>(pathElement)) {

            AttributePoint &point = d->_attributePoints.last();

            point.values[QLatin1String("_qfx_percent")] = percent->value();

            interpolate(d->_attributePoints.count() - 1, QLatin1String("_qfx_percent"), percent->value());

        }

    }

    // Fixup end points

    const AttributePoint &last = d->_attributePoints.last();

    for (int ii = 0; ii < d->_attributes.count(); ++ii) {

        if (!last.values.contains(d->_attributes.at(ii)))

            endpoint(d->_attributes.at(ii));

    }

    // Adjust percent

    qreal length = d->_path.length();

    qreal prevpercent = 0;

    qreal prevorigpercent = 0;

    for (int ii = 0; ii < d->_attributePoints.count(); ++ii) {

        const AttributePoint &point = d->_attributePoints.at(ii);

        if (point.values.contains(QLatin1String("_qfx_percent"))) { //special string for QDeclarativePathPercent

            if ( ii > 0) {

                qreal scale = (d->_attributePoints[ii].origpercent/length - prevorigpercent) /

                            (point.values.value(QLatin1String("_qfx_percent"))-prevpercent);

                d->_attributePoints[ii].scale = scale;

            }

            d->_attributePoints[ii].origpercent /= length;

            d->_attributePoints[ii].percent = point.values.value(QLatin1String("_qfx_percent"));

            prevorigpercent = d->_attributePoints[ii].origpercent;

            prevpercent = d->_attributePoints[ii].percent;

        } else {

            d->_attributePoints[ii].origpercent /= length;

            d->_attributePoints[ii].percent = d->_attributePoints[ii].origpercent;

        }

    }

    d->closed = lastCurve && d->startX == lastCurve->x() && d->startY == lastCurve->y();

    emit changed();

}

void QDeclarativePath::classBegin()

{

    Q_D(QDeclarativePath);

    d->componentComplete = false;

}

void QDeclarativePath::componentComplete()

{

    Q_D(QDeclarativePath);

    QSet<QString> attrs;

    d->componentComplete = true;

    // First gather up all the attributes

    foreach (QDeclarativePathElement *pathElement, d->_pathElements) {

        if (QDeclarativePathAttribute *attribute =

            qobject_cast<QDeclarativePathAttribute *>(pathElement))

            attrs.insert(attribute->name());

    }

    d->_attributes = attrs.toList();

    processPath();

    foreach (QDeclarativePathElement *pathElement, d->_pathElements)

        connect(pathElement, SIGNAL(changed()), this, SLOT(processPath()));

}

QPainterPath QDeclarativePath::path() const

{

    Q_D(const QDeclarativePath);

    return d->_path;

}

QStringList QDeclarativePath::attributes() const

{

    Q_D(const QDeclarativePath);

    if (!d->componentComplete) {

        QSet<QString> attrs;

        // First gather up all the attributes

        foreach (QDeclarativePathElement *pathElement, d->_pathElements) {

            if (QDeclarativePathAttribute *attribute =

                qobject_cast<QDeclarativePathAttribute *>(pathElement))

                attrs.insert(attribute->name());

        }

        return attrs.toList();

    }

    return d->_attributes;

}

static inline QBezier nextBezier(const QPainterPath &path, int *from, qreal *bezLength)

{

    const int lastElement = path.elementCount() - 1;

    for (int i=*from; i <= lastElement; ++i) {

        const QPainterPath::Element &e = path.elementAt(i);

        switch (e.type) {

        case QPainterPath::MoveToElement:

            break;

        case QPainterPath::LineToElement:

        {

            QLineF line(path.elementAt(i-1), e);

            *bezLength = line.length();

            QPointF a = path.elementAt(i-1);

            QPointF delta = e - a;

            *from = i+1;

            return QBezier::fromPoints(a, a + delta / 3, a + 2 * delta / 3, e);

        }

        case QPainterPath::CurveToElement:

        {

            QBezier b = QBezier::fromPoints(path.elementAt(i-1),

                                            e,

                                            path.elementAt(i+1),

                                            path.elementAt(i+2));

            *bezLength = b.length();

            *from = i+3;

            return b;

        }

        default:

            break;

        }

    }

    *from = lastElement;

    *bezLength = 0;

    return QBezier();

}

void QDeclarativePath::createPointCache() const

{

    Q_D(const QDeclarativePath);

    qreal pathLength = d->_path.length();

    // more points means less jitter between items as they move along the

    // path, but takes longer to generate

    const int points = int(pathLength*5);

    const int lastElement = d->_path.elementCount() - 1;

    d->_pointCache.resize(points+1);

    int currElement = 0;

    qreal bezLength = 0;

    QBezier currBez = nextBezier(d->_path, &currElement, &bezLength);

    qreal currLength = bezLength;

    qreal epc = currLength / pathLength;

    for (int i = 0; i < d->_pointCache.size(); i++) {

        //find which set we are in

        qreal prevPercent = 0;

        qreal prevOrigPercent = 0;

        for (int ii = 0; ii < d->_attributePoints.count(); ++ii) {

            qreal percent = qreal(i)/points;

            const AttributePoint &point = d->_attributePoints.at(ii);

            if (percent < point.percent || ii == d->_attributePoints.count() - 1) { //### || is special case for very last item

                qreal elementPercent = (percent - prevPercent);

                qreal spc = prevOrigPercent + elementPercent * point.scale;

                while (spc > epc) {

                    if (currElement > lastElement)

                        break;

                    currBez = nextBezier(d->_path, &currElement, &bezLength);

                    if (bezLength == 0.0) {

                        currLength = pathLength;

                        epc = 1.0;

                        break;

                    }

                    currLength += bezLength;

                    epc = currLength / pathLength;

                }

                qreal realT = (pathLength * spc - (currLength - bezLength)) / bezLength;

                d->_pointCache[i] = currBez.pointAt(qBound(qreal(0), realT, qreal(1)));

                break;

            }

            prevOrigPercent = point.origpercent;

            prevPercent = point.percent;

        }

    }

}

QPointF QDeclarativePath::pointAt(qreal p) const

{

    Q_D(const QDeclarativePath);

    if (d->_pointCache.isEmpty()) {

        createPointCache();

    }

    int idx = qRound(p*d->_pointCache.size());

    if (idx >= d->_pointCache.size())

        idx = d->_pointCache.size() - 1;

    else if (idx < 0)

        idx = 0;

    return d->_pointCache.at(idx);

}

qreal QDeclarativePath::attributeAt(const QString &name, qreal percent) const

{

    Q_D(const QDeclarativePath);

    if (percent < 0 || percent > 1)

        return 0;

    for (int ii = 0; ii < d->_attributePoints.count(); ++ii) {

        const AttributePoint &point = d->_attributePoints.at(ii);

        if (point.percent == percent) {

            return point.values.value(name);

        } else if (point.percent > percent) {

            qreal lastValue =

                ii?(d->_attributePoints.at(ii - 1).values.value(name)):0;

            qreal lastPercent =

                ii?(d->_attributePoints.at(ii - 1).percent):0;

            qreal curValue = point.values.value(name);

            qreal curPercent = point.percent;

            return lastValue + (curValue - lastValue) * (percent - lastPercent) / (curPercent - lastPercent);

        }

    }

    return 0;

}

/****************************************************************************/

qreal QDeclarativeCurve::x() const

{

    return _x;

}

void QDeclarativeCurve::setX(qreal x)

{

    if (_x != x) {

        _x = x;

        emit changed();

    }

}

qreal QDeclarativeCurve::y() const

{

    return _y;

}

void QDeclarativeCurve::setY(qreal y)

{

    if (_y != y) {

        _y = y;

        emit changed();

    }

}

/****************************************************************************/

/*!

    \qmlclass PathAttribute QDeclarativePathAttribute

    \since 4.7

    \brief The PathAttribute allows setting an attribute at a given position in a Path.

    The PathAttribute object allows attibutes consisting of a name and

    a value to be specified for the endpoints of path segments.  The

    attributes are exposed to the delegate as

    \l{qdeclarativeintroduction.html#attached-properties} {Attached Properties}.

    The value of an attribute at any particular point is interpolated

    from the PathAttributes bounding the point.

    The example below shows a path with the items scaled to 30% with

    opacity 50% at the top of the path and scaled 100% with opacity

    100% at the bottom.  Note the use of the PathView.scale and

    PathView.opacity attached properties to set the scale and opacity

    of the delegate.

    \table

    \row

    \o \image declarative-pathattribute.png

    \o

    \snippet doc/src/snippets/declarative/pathview/pathattributes.qml 0

    \endtable

   \sa Path

*/

/*!

    \qmlproperty string PathAttribute::name

    the name of the attribute to change.

    This attribute will be available to the delegate as PathView.<name>

    Note that using an existing Item property name such as "opacity" as an

    attribute is allowed.  This is because path attributes add a new

    \l{qdeclarativeintroduction.html#attached-properties} {Attached Property}

    which in no way clashes with existing properties.

*/