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

**

** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

** All rights reserved.

** Contact: Nokia Corporation (qt-info@nokia.com)

**

** This file is part of the Qt3Support module of the Qt Toolkit.

**

** $QT_BEGIN_LICENSE:LGPL$

** No Commercial Usage

** This file contains pre-release code and may not be distributed.

** You may use this file in accordance with the terms and conditions

** contained in the Technology Preview License Agreement accompanying

** this package.

**

** GNU Lesser General Public License Usage

** Alternatively, this file may be used under the terms of the GNU Lesser

** General Public License version 2.1 as published by the Free Software

** Foundation and appearing in the file LICENSE.LGPL included in the

** packaging of this file.  Please review the following information to

** ensure the GNU Lesser General Public License version 2.1 requirements

** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.

**

** In addition, as a special exception, Nokia gives you certain additional

** rights.  These rights are described in the Nokia Qt LGPL Exception

** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.

**

** If you have questions regarding the use of this file, please contact

** Nokia at qt-info@nokia.com.

**

**

**

**

**

**

**

**

** $QT_END_LICENSE$

**

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

#include "q3textbrowser.h"

#ifndef QT_NO_TEXTBROWSER

#include <private/q3richtext_p.h>

#include "qevent.h"

#include "qdesktopwidget.h"

#include "qapplication.h"

#include "qlayout.h"

#include "qpainter.h"

#include "qstack.h"

#include "stdio.h"

#include "qfile.h"

#include "qtextstream.h"

#include "qbitmap.h"

#include "qtimer.h"

#include "qimage.h"

#include "q3simplerichtext.h"

#include "q3dragobject.h"

#include "qurl.h"

#include "qcursor.h"

QT_BEGIN_NAMESPACE

/*!

    \class Q3TextBrowser

    \brief The Q3TextBrowser class provides a rich text browser with hypertext navigation.

    \compat

    This class extends Q3TextEdit (in read-only mode), adding some

    navigation functionality so that users can follow links in

    hypertext documents. The contents of Q3TextEdit is set with

    setText(), but Q3TextBrowser has an additional function,

    setSource(), which makes it possible to set the text to a named

    document. The name is looked up in the text view's mime source

    factory. If a document name ends with an anchor (for example, "\c

    #anchor"), the text browser automatically scrolls to that position

    (using scrollToAnchor()). When the user clicks on a hyperlink, the

    browser will call setSource() itself, with the link's \c href

    value as argument. You can track the current source by connetion

    to the sourceChanged() signal.

    Q3TextBrowser provides backward() and forward() slots which you can

    use to implement Back and Forward buttons. The home() slot sets

    the text to the very first document displayed. The linkClicked()

    signal is emitted when the user clicks a link.

    By using Q3TextEdit::setMimeSourceFactory() you can provide your

    own subclass of Q3MimeSourceFactory. This makes it possible to

    access data from anywhere, for example from a network or from a

    database. See Q3MimeSourceFactory::data() for details.

    If you intend using the mime factory to read the data directly

    from the file system, you may have to specify the encoding for the

    file extension you are using. For example:

    \snippet doc/src/snippets/code/src_qt3support_text_q3textbrowser.cpp 0

    This is to ensure that the factory is able to resolve the document

    names.

    Q3TextBrowser interprets the tags it processes in accordance with

    the default style sheet. Change the style sheet with

    \l{setStyleSheet()}; see QStyleSheet for details.

    If you want to provide your users with editable rich text use

    Q3TextEdit. If you want a text browser without hypertext navigation

    use Q3TextEdit, and use Q3TextEdit::setReadOnly() to disable

    editing. If you just need to display a small piece of rich text

    use QSimpleRichText or QLabel.

*/

class Q3TextBrowserData

{

public:

    Q3TextBrowserData():textOrSourceChanged(false) {}

    QStack<QString> stack;

    QStack<QString> forwardStack;

    QString home;

    QString curmain;

    QString curmark;

    /*flag necessary to give the linkClicked() signal some meaningful

      semantics when somebody connected to it calls setText() or

      setSource() */

    bool textOrSourceChanged;

};

/*!

    Constructs an empty Q3TextBrowser called \a name, with parent \a

    parent.

*/

Q3TextBrowser::Q3TextBrowser(QWidget *parent, const char *name)

    : Q3TextEdit(parent, name)

{

    setReadOnly(true);

    d = new Q3TextBrowserData;

    viewport()->setMouseTracking(true);

}

/*!

    \internal

*/

Q3TextBrowser::~Q3TextBrowser()

{

    delete d;

}

/*!

    \property Q3TextBrowser::source

    \brief the name of the displayed document.

    This is a an empty string if no document is displayed or if the

    source is unknown.

    Setting this property uses the mimeSourceFactory() to lookup the

    named document. It also checks for optional anchors and scrolls

    the document accordingly.

    If the first tag in the document is \c{<qt type=detail>}, the

    document is displayed as a popup rather than as new document in

    the browser window itself. Otherwise, the document is displayed

    normally in the text browser with the text set to the contents of

    the named document with setText().

    If you are using the filesystem access capabilities of the mime

    source factory, you must ensure that the factory knows about the

    encoding of specified files; otherwise no data will be available.

    The default factory handles a couple of common file extensions

    such as \c *.html and \c *.txt with reasonable defaults. See

    Q3MimeSourceFactory::data() for details.

*/

QString Q3TextBrowser::source() const

{

    if (d->stack.isEmpty())

        return QString();

    else

        return d->stack.top();

}

/*!

    Reloads the current set source.

*/

void Q3TextBrowser::reload()

{

    QString s = d->curmain;

    d->curmain = QLatin1String("");

    setSource(s);

}

void Q3TextBrowser::setSource(const QString& name)

{

#ifndef QT_NO_CURSOR

    if (isVisible())

        qApp->setOverrideCursor(Qt::WaitCursor);

#endif

    d->textOrSourceChanged = true;

    QString source = name;

    QString mark;

    int hash = name.indexOf(QLatin1Char('#'));

    if (hash != -1) {

        source = name.left(hash);

        mark = name.mid(hash+1);

    }

    if (source.left(5) == QLatin1String("file:"))

        source = source.mid(6);

    QString url = mimeSourceFactory()->makeAbsolute(source, context());

    QString txt;

    bool dosettext = false;

    if (!source.isEmpty() && url != d->curmain) {

        const QMimeSource* m =

                    mimeSourceFactory()->data(source, context());

        if (!m){

            qWarning("Q3TextBrowser: no mimesource for %s", source.latin1());

        }

        else {

            if (!Q3TextDrag::decode(m, txt)) {

                qWarning("Q3TextBrowser: cannot decode %s", source.latin1());

            }

        }

        if (isVisible()) {

            QString firstTag = txt.left(txt.indexOf(QLatin1Char('>')) + 1);

            if (firstTag.left(3) == QLatin1String("<qt") && firstTag.contains(QLatin1String("type")) && firstTag.contains(QLatin1String("detail"))) {

                popupDetail(txt, QCursor::pos());

#ifndef QT_NO_CURSOR

                qApp->restoreOverrideCursor();

#endif

                return;

            }

        }

        d->curmain = url;

        dosettext = true;

    }

    d->curmark = mark;

    if (!mark.isEmpty()) {

        url += QLatin1Char('#');

        url += mark;

    }

    if (d->home.count() == 0)

        d->home = url;

    if (d->stack.isEmpty() || d->stack.top() != url)

        d->stack.push(url);

    int stackCount = (int)d->stack.count();

    if (d->stack.top() == url)

        stackCount--;

    emit backwardAvailable(stackCount > 0);

    stackCount = (int)d->forwardStack.count();

    if (d->forwardStack.isEmpty() || d->forwardStack.top() == url)

        stackCount--;

    emit forwardAvailable(stackCount > 0);

    if (dosettext)

        Q3TextEdit::setText(txt, url);

    if (!mark.isEmpty())

        scrollToAnchor(mark);

    else

        setContentsPos(0, 0);

#ifndef QT_NO_CURSOR

    if (isVisible())

        qApp->restoreOverrideCursor();

#endif

    emit sourceChanged(url);

}

/*!

    \fn void Q3TextBrowser::backwardAvailable(bool available)

    This signal is emitted when the availability of backward()

    changes. \a available is false when the user is at home();

    otherwise it is true.

*/

/*!

    \fn void Q3TextBrowser::forwardAvailable(bool available)

    This signal is emitted when the availability of forward() changes.

    \a available is true after the user navigates backward() and false

    when the user navigates or goes forward().

*/

/*!

    \fn void Q3TextBrowser::sourceChanged(const QString& src)

    This signal is emitted when the mime source has changed, \a src

    being the new source.

    Source changes happen both programmatically when calling

    setSource(), forward(), backword() or home() or when the user

    clicks on links or presses the equivalent key sequences.

*/

/*!  \fn void Q3TextBrowser::highlighted (const QString &link)

    This signal is emitted when the user has selected but not

    activated a link in the document. \a link is the value of the \c

    href i.e. the name of the target document.

*/

/*!

    \fn void Q3TextBrowser::linkClicked(const QString& link)

    This signal is emitted when the user clicks a link. The \a link is

    the value of the \c href i.e. the name of the target document.

    The \a link will be the absolute location of the document, based

    on the value of the anchor's href tag and the current context of

    the document.

    \sa anchorClicked()

*/

/*!

    \fn void Q3TextBrowser::anchorClicked(const QString& name, const QString &link)

    This signal is emitted when the user clicks an anchor. The \a link is

    the value of the \c href i.e. the name of the target document.  The \a name

    is the name of the anchor.

    \sa linkClicked()

*/

/*!

    Changes the document displayed to the previous document in the

    list of documents built by navigating links. Does nothing if there

    is no previous document.

    \sa forward(), backwardAvailable()

*/

void Q3TextBrowser::backward()

{

    if (d->stack.count() <= 1)

        return;

    d->forwardStack.push(d->stack.pop());

    setSource(d->stack.pop());

    emit forwardAvailable(true);

}

/*!

    Changes the document displayed to the next document in the list of

    documents built by navigating links. Does nothing if there is no

    next document.

    \sa backward(), forwardAvailable()

*/

void Q3TextBrowser::forward()

{

    if (d->forwardStack.isEmpty())

        return;

    setSource(d->forwardStack.pop());

    emit forwardAvailable(!d->forwardStack.isEmpty());

}

/*!

    Changes the document displayed to be the first document the

    browser displayed.

*/

void Q3TextBrowser::home()

{

    if (!d->home.isNull())

        setSource(d->home);

}

/*!

    The event \a e is used to provide the following keyboard shortcuts:

    \table

    \header \i Keypress            \i Action

    \row \i Alt+Left Arrow  \i \l backward()

    \row \i Alt+Right Arrow \i \l forward()

    \row \i Alt+Up Arrow    \i \l home()

    \endtable

*/

void Q3TextBrowser::keyPressEvent(QKeyEvent * e)

{

    if (e->state() & Qt::AltButton) {

        switch (e->key()) {

        case Qt::Key_Right:

            forward();

            return;

        case Qt::Key_Left:

            backward();

            return;

        case Qt::Key_Up:

            home();

            return;

        }

    }

    Q3TextEdit::keyPressEvent(e);

}

class QTextDetailPopup : public QWidget

{

public:

    QTextDetailPopup()

        : QWidget (0, "automatic QText detail widget", Qt::WType_Popup)

    {

	setAttribute(Qt::WA_DeleteOnClose, true);

    }

protected:

    void mousePressEvent(QMouseEvent *)

    {

        close();

    }

};

void Q3TextBrowser::popupDetail(const QString& contents, const QPoint& pos)

{

    const int shadowWidth = 6;   // also used as '5' and '6' and even '8' below

    const int vMargin = 8;

    const int hMargin = 12;

    QWidget* popup = new QTextDetailPopup;

    popup->setAttribute(Qt::WA_NoSystemBackground, true);

    Q3SimpleRichText* doc = new Q3SimpleRichText(contents, popup->font());

    doc->adjustSize();

    QRect r(0, 0, doc->width(), doc->height());

    int w = r.width() + 2*hMargin;

    int h = r.height() + 2*vMargin;

    popup->resize(w + shadowWidth, h + shadowWidth);

    // okay, now to find a suitable location

    //###### we need a global fancy popup positioning somewhere

    popup->move(pos - popup->rect().center());

    if (popup->geometry().right() > QApplication::desktop()->width())

        popup->move(QApplication::desktop()->width() - popup->width(),

                     popup->y());

    if (popup->geometry().bottom() > QApplication::desktop()->height())

        popup->move(popup->x(),

                     QApplication::desktop()->height() - popup->height());

    if (popup->x() < 0)

        popup->move(0, popup->y());

    if (popup->y() < 0)

        popup->move(popup->x(), 0);

    popup->show();

    // now for super-clever shadow stuff.  super-clever mostly in

    // how many window system problems it skirts around.

    QPainter p(popup);

    p.setPen(QApplication::palette().color(QPalette::Active, QPalette::WindowText));

    p.drawRect(0, 0, w, h);

    p.setPen(QApplication::palette().color(QPalette::Active, QPalette::Mid));

    p.setBrush(QColor(255, 255, 240));

    p.drawRect(1, 1, w-2, h-2);

    p.setPen(Qt::black);

    doc->draw(&p, hMargin, vMargin, r, popup->palette(), 0);

    delete doc;

    p.drawPoint(w + 5, 6);

    p.drawLine(w + 3, 6,

                w + 5, 8);

    p.drawLine(w + 1, 6,

                w + 5, 10);

    int i;

    for(i=7; i < h; i += 2)

        p.drawLine(w, i,

                    w + 5, i + 5);

    for(i = w - i + h; i > 6; i -= 2)

        p.drawLine(i, h,

                    i + 5, h + 5);

    for(; i > 0 ; i -= 2)

        p.drawLine(6, h + 6 - i,

                    i + 5, h + 5);

}

/*!

    \fn void Q3TextBrowser::setText(const QString &txt)

    \overload

    Sets the text to \a txt.

*/

/*!

    \reimp

*/

void Q3TextBrowser::setText(const QString &txt, const QString &context)

{

    d->textOrSourceChanged = true;

    d->curmark = QLatin1String("");

    d->curmain = QLatin1String("");

    Q3TextEdit::setText(txt, context);

}

void Q3TextBrowser::emitHighlighted(const QString &s)

{

    emit highlighted(s);

}

void Q3TextBrowser::emitLinkClicked(const QString &s)

{

    d->textOrSourceChanged = false;

    emit linkClicked(s);

    if (!d->textOrSourceChanged)

        setSource(s);

}

QT_END_NAMESPACE

#endif  // QT_NO_TEXTBROWSER