/**************************************************************************
**
** This file is part of Qt Creator
**
** Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).
**
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** Commercial Usage
**
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at http://qt.nokia.com/contact.
**
**************************************************************************/

#include "centralwidget.h"
#include "helpmanager.h"
#include "helpviewer.h"
#include "topicchooser.h"

#include <QtCore/QEvent>
#include <QtCore/QTimer>

#include <QtGui/QMenu>
#include <QtGui/QLabel>
#include <QtGui/QLayout>
#include <QtGui/QPrinter>
#include <QtGui/QLineEdit>
#include <QtGui/QCheckBox>
#include <QtGui/QTabBar>
#include <QtGui/QTabWidget>
#include <QtGui/QToolButton>
#include <QtGui/QMouseEvent>
#include <QtGui/QFocusEvent>
#include <QtGui/QMainWindow>
#include <QtGui/QSpacerItem>
#include <QtGui/QTextCursor>
#include <QtGui/QPrintDialog>
#include <QtGui/QApplication>
#include <QtGui/QTextDocumentFragment>
#include <QtGui/QPrintPreviewDialog>
#include <QtGui/QPageSetupDialog>

#include <QtHelp/QHelpEngineCore>

#include <coreplugin/coreconstants.h>

using namespace Help::Internal;

namespace {
    HelpViewer* helpViewerFromTabPosition(const QTabWidget *widget,
        const QPoint &point)
    {
        QTabBar *tabBar = qFindChild<QTabBar*>(widget);
        for (int i = 0; i < tabBar->count(); ++i) {
            if (tabBar->tabRect(i).contains(point))
                return qobject_cast<HelpViewer*>(widget->widget(i));
        }
        return 0;
    }
    Help::Internal::CentralWidget *staticCentralWidget = 0;
}

CentralWidget::CentralWidget(QWidget *parent)
    : QWidget(parent)
    , findBar(0)
    , tabWidget(0)
    , printer(0)
{
    lastTabPage = 0;
    globalActionList.clear();

    tabWidget = new QTabWidget;
    tabWidget->setDocumentMode(true);
    tabWidget->setMovable(true);
    connect(tabWidget, SIGNAL(tabCloseRequested(int)), this, SLOT(closeTab(int)));
    connect(tabWidget, SIGNAL(currentChanged(int)), this,
        SLOT(currentPageChanged(int)));

    QToolButton *newTabButton = new QToolButton(this);
    newTabButton->setAutoRaise(true);
    newTabButton->setToolTip(tr("Add new page"));
    newTabButton->setIcon(QIcon(
#ifdef Q_OS_MAC
        QLatin1String(":/trolltech/assistant/images/mac/addtab.png")));
#else
        QLatin1String(":/trolltech/assistant/images/win/addtab.png")));
#endif

    tabWidget->setCornerWidget(newTabButton, Qt::TopLeftCorner);
    connect(newTabButton, SIGNAL(clicked()), this, SLOT(newTab()));

    QVBoxLayout *vboxLayout = new QVBoxLayout(this);
    vboxLayout->setMargin(0);
    vboxLayout->addWidget(tabWidget);

    QTabBar *tabBar = qFindChild<QTabBar*>(tabWidget);
    if (tabBar) {
        tabBar->installEventFilter(this);
        tabBar->setContextMenuPolicy(Qt::CustomContextMenu);
        connect(tabBar, SIGNAL(customContextMenuRequested(QPoint)), this,
            SLOT(showTabBarContextMenu(QPoint)));
    }

    staticCentralWidget = this;
}

CentralWidget::~CentralWidget()
{
#ifndef QT_NO_PRINTER
    delete printer;
#endif

    QString zoomCount;
    QString currentPages;
    for (int i = 0; i < tabWidget->count(); ++i) {
        HelpViewer *viewer = qobject_cast<HelpViewer*>(tabWidget->widget(i));
        if (viewer && viewer->source().isValid()) {
            currentPages += (viewer->source().toString() + QLatin1Char('|'));
            zoomCount += QString::number(viewer->zoom()) + QLatin1Char('|');
        }
    }

    QHelpEngineCore *engine = &HelpManager::helpEngineCore();
    engine->setCustomValue(QLatin1String("LastTabPage"), lastTabPage);
    engine->setCustomValue(QLatin1String("LastShownPages"), currentPages);
    engine->setCustomValue(QLatin1String("LastShownPagesZoom"), zoomCount);
}

CentralWidget *CentralWidget::instance()
{
    return staticCentralWidget;
}

void CentralWidget::newTab()
{
    HelpViewer* viewer = currentHelpViewer();
#if !defined(QT_NO_WEBKIT)
    if (viewer && viewer->hasLoadFinished())
#else
    if (viewer)
#endif
        setSourceInNewTab(viewer->source());
}

void CentralWidget::zoomIn()
{
    HelpViewer* viewer = currentHelpViewer();
    if (viewer)
        viewer->zoomIn();
}

void CentralWidget::zoomOut()
{
    HelpViewer* viewer = currentHelpViewer();
    if (viewer)
        viewer->zoomOut();
}

void CentralWidget::nextPage()
{
    int index = tabWidget->currentIndex() + 1;
    if (index >= tabWidget->count())
        index = 0;
    tabWidget->setCurrentIndex(index);
}

void CentralWidget::resetZoom()
{
    HelpViewer* viewer = currentHelpViewer();
    if (viewer)
        viewer->resetZoom();
}

void CentralWidget::previousPage()
{
    int index = tabWidget->currentIndex() -1;
    if (index < 0)
        index = tabWidget->count() -1;
    tabWidget->setCurrentIndex(index);
}

void CentralWidget::closeTab()
{
    closeTab(tabWidget->currentIndex());
}

void CentralWidget::closeTab(int index)
{
    HelpViewer* viewer = helpViewerAtIndex(index);
    if (!viewer || tabWidget->count() == 1)
        return;

    emit viewerAboutToBeRemoved(index);
    tabWidget->removeTab(index);
    emit viewerRemoved(index);
    QTimer::singleShot(0, viewer, SLOT(deleteLater()));
}

void CentralWidget::setSource(const QUrl &url)
{
    HelpViewer* viewer = currentHelpViewer();
    HelpViewer* lastViewer =
        qobject_cast<HelpViewer*>(tabWidget->widget(lastTabPage));

    if (!viewer && !lastViewer) {
        viewer = new HelpViewer(this, this);
        viewer->installEventFilter(this);
        lastTabPage = tabWidget->addTab(viewer, QString());
        tabWidget->setCurrentIndex(lastTabPage);
        connectSignals();
        qApp->processEvents();
    } else {
        viewer = lastViewer;
    }

    viewer->setSource(url);
    currentPageChanged(lastTabPage);
    viewer->setFocus(Qt::OtherFocusReason);
    tabWidget->setCurrentIndex(lastTabPage);
    tabWidget->setTabText(lastTabPage, quoteTabTitle(viewer->documentTitle()));
}

void CentralWidget::setLastShownPages()
{
    const QHelpEngineCore &engine = HelpManager::helpEngineCore();
    QString value = engine.customValue(QLatin1String("LastShownPages"),
        QString()).toString();
    const QStringList lastShownPageList = value.split(QLatin1Char('|'),
        QString::SkipEmptyParts);
    const int pageCount = lastShownPageList.count();

    QString homePage = engine.customValue(QLatin1String("DefaultHomePage"),
        QLatin1String("about:blank")).toString();

    int option = engine.customValue(QLatin1String("StartOption"), 2).toInt();
    if (option == 0 || option == 1 || pageCount <= 0) {
        if (option == 0) {
            homePage = engine.customValue(QLatin1String("HomePage"),
                homePage).toString();
        } else if (option == 1) {
            homePage = QLatin1String("about:blank");
        }
        setSource(homePage);
        return;
    }

    value = engine.customValue(QLatin1String("LastShownPagesZoom"),
        QString()).toString();
    QVector<QString> zoomVector = value.split(QLatin1Char('|'),
        QString::SkipEmptyParts).toVector();

    const int zoomCount = zoomVector.count();
    zoomVector.insert(zoomCount, pageCount - zoomCount, QLatin1String("0"));

    QVector<QString>::const_iterator zIt = zoomVector.constBegin();
    QStringList::const_iterator it = lastShownPageList.constBegin();
    for (; it != lastShownPageList.constEnd(); ++it, ++zIt)
        setSourceInNewTab((*it), (*zIt).toInt());

    int tab = engine.customValue(QLatin1String("LastTabPage"), 0).toInt();
    tabWidget->setCurrentIndex(tab);
}

bool CentralWidget::hasSelection() const
{
    const HelpViewer* viewer = currentHelpViewer();
    return viewer ? viewer->hasSelection() : false;
}

QUrl CentralWidget::currentSource() const
{
    const HelpViewer* viewer = currentHelpViewer();
    if (viewer)
        return viewer->source();

    return QUrl();
}

QString CentralWidget::currentTitle() const
{
    const HelpViewer* viewer = currentHelpViewer();
    if (viewer)
        return viewer->documentTitle();

    return QString();
}

void CentralWidget::initPrinter()
{
#ifndef QT_NO_PRINTER
    if (!printer)
        printer = new QPrinter(QPrinter::HighResolution);
#endif
}

void CentralWidget::print()
{
#ifndef QT_NO_PRINTER
    HelpViewer* viewer = currentHelpViewer();
    if (!viewer)
        return;

    initPrinter();

    QPrintDialog *dlg = new QPrintDialog(printer, this);
#if defined(QT_NO_WEBKIT)
    if (viewer->textCursor().hasSelection())
        dlg->addEnabledOption(QAbstractPrintDialog::PrintSelection);
#endif
    dlg->addEnabledOption(QAbstractPrintDialog::PrintPageRange);
    dlg->addEnabledOption(QAbstractPrintDialog::PrintCollateCopies);
    dlg->setWindowTitle(tr("Print Document"));
    if (dlg->exec() == QDialog::Accepted) {
        viewer->print(printer);
    }
    delete dlg;
#endif
}

void CentralWidget::printPreview()
{
#ifndef QT_NO_PRINTER
    initPrinter();
    QPrintPreviewDialog preview(printer, this);
    connect(&preview, SIGNAL(paintRequested(QPrinter*)),
        SLOT(printPreview(QPrinter*)));
    preview.exec();
#endif
}

void CentralWidget::printPreview(QPrinter *p)
{
#ifndef QT_NO_PRINTER
    HelpViewer *viewer = currentHelpViewer();
    if (viewer)
        viewer->print(p);
#else
    Q_UNUSED(p)
#endif
}

void CentralWidget::pageSetup()
{
#ifndef QT_NO_PRINTER
    initPrinter();
    QPageSetupDialog dlg(printer);
    dlg.exec();
#endif
}

void CentralWidget::home()
{
    HelpViewer* viewer = currentHelpViewer();
    if (viewer)
        viewer->home();
}

bool CentralWidget::isForwardAvailable() const
{
    const HelpViewer* viewer = currentHelpViewer();
    if (viewer)
        return viewer->isForwardAvailable();

    return false;
}

void CentralWidget::forward()
{
    HelpViewer* viewer = currentHelpViewer();
    if (viewer)
        viewer->forward();
}

bool CentralWidget::isBackwardAvailable() const
{
    const HelpViewer* viewer = currentHelpViewer();
    if (viewer)
        return viewer->isBackwardAvailable();

    return false;
}

void CentralWidget::backward()
{
    HelpViewer* viewer = currentHelpViewer();
    if (viewer)
        viewer->backward();
}


QList<QAction*> CentralWidget::globalActions() const
{
    return globalActionList;
}

void CentralWidget::setGlobalActions(const QList<QAction*> &actions)
{
    globalActionList = actions;
}

void CentralWidget::setSourceInNewTab(const QUrl &url, int zoom)
{
    HelpViewer* viewer = new HelpViewer(this, this);
    viewer->installEventFilter(this);
    viewer->setZoom(zoom);
    viewer->setSource(url);
    viewer->setFocus(Qt::OtherFocusReason);

#if defined(QT_NO_WEBKIT)
    QFont font = viewer->font();
    font.setPointSize(font.pointSize() + int(zoom));
    viewer->setFont(font);
#endif

    tabWidget->setCurrentIndex(tabWidget->addTab(viewer,
        quoteTabTitle(viewer->documentTitle())));

    connectSignals();
}

HelpViewer *CentralWidget::newEmptyTab()
{
    HelpViewer* viewer = new HelpViewer(this, this);
    viewer->installEventFilter(this);
    viewer->setFocus(Qt::OtherFocusReason);
#if defined(QT_NO_WEBKIT)
    viewer->setDocumentTitle(tr("unknown"));
#endif
    tabWidget->setCurrentIndex(tabWidget->addTab(viewer, tr("unknown")));

    connectSignals();
    return viewer;
}

void CentralWidget::connectSignals()
{
    const HelpViewer* viewer = currentHelpViewer();
    if (viewer) {
        connect(viewer, SIGNAL(copyAvailable(bool)), this,
            SIGNAL(copyAvailable(bool)));
        connect(viewer, SIGNAL(forwardAvailable(bool)), this,
            SIGNAL(forwardAvailable(bool)));
        connect(viewer, SIGNAL(backwardAvailable(bool)), this,
            SIGNAL(backwardAvailable(bool)));
        connect(viewer, SIGNAL(sourceChanged(QUrl)), this,
            SIGNAL(sourceChanged(QUrl)));
        connect(viewer, SIGNAL(highlighted(QString)), this,
            SIGNAL(highlighted(QString)));
        connect(viewer, SIGNAL(sourceChanged(QUrl)), this,
            SLOT(setTabTitle(QUrl)));
    }
}

HelpViewer *CentralWidget::helpViewerAtIndex(int index) const
{
    return qobject_cast<HelpViewer*>(tabWidget->widget(index));
}

int CentralWidget::indexOf(HelpViewer *viewer) const
{
    if (!viewer)
        return -1;
    return tabWidget->indexOf(viewer);
}

HelpViewer *CentralWidget::currentHelpViewer() const
{
    return qobject_cast<HelpViewer*>(tabWidget->currentWidget());
}

void CentralWidget::activateTab(bool onlyHelpViewer)
{
    if (currentHelpViewer()) {
        currentHelpViewer()->setFocus();
    } else {
        int idx = 0;
        if (onlyHelpViewer)
            idx = lastTabPage;
        tabWidget->setCurrentIndex(idx);
        tabWidget->currentWidget()->setFocus();
    }
}

void CentralWidget::setTabTitle(const QUrl& url)
{
    Q_UNUSED(url)
#if !defined(QT_NO_WEBKIT)
        QTabBar *tabBar = qFindChild<QTabBar*>(tabWidget);
        for (int i = 0; i < tabBar->count(); ++i) {
            HelpViewer* view = qobject_cast<HelpViewer*>(tabWidget->widget(i));
            if (view) {
                tabWidget->setTabText(i,
                    quoteTabTitle(view->documentTitle().trimmed()));
            }
        }
#else
    if (HelpViewer* viewer = currentHelpViewer()) {
        tabWidget->setTabText(lastTabPage,
            quoteTabTitle(viewer->documentTitle().trimmed()));
    }
#endif
}

void CentralWidget::currentPageChanged(int index)
{
    lastTabPage = index;

    tabWidget->setTabsClosable(tabWidget->count() > 1);
    tabWidget->cornerWidget(Qt::TopLeftCorner)->setEnabled(true);

     emit currentViewerChanged(index);
}

void CentralWidget::showTabBarContextMenu(const QPoint &point)
{
    HelpViewer* viewer = helpViewerFromTabPosition(tabWidget, point);
    if (!viewer)
        return;

    QTabBar *tabBar = qFindChild<QTabBar*>(tabWidget);

    QMenu menu(QLatin1String(""), tabBar);
    QAction *newPage = menu.addAction(tr("Add New Page"));

    bool enableAction = tabBar->count() > 1;
    QAction *closePage = menu.addAction(tr("Close This Page"));
    closePage->setEnabled(enableAction);

    QAction *closePages = menu.addAction(tr("Close Other Pages"));
    closePages->setEnabled(enableAction);

    menu.addSeparator();

    QAction *newBookmark = menu.addAction(tr("Add Bookmark for this Page..."));
    const QString &url = viewer->source().toString();
    if (url.isEmpty() || url == QLatin1String("about:blank"))
        newBookmark->setEnabled(false);

    QAction *pickedAction = menu.exec(tabBar->mapToGlobal(point));
    if (pickedAction == newPage)
        setSourceInNewTab(viewer->source());

    if (pickedAction == closePage) {
        tabWidget->removeTab(tabWidget->indexOf(viewer));
        QTimer::singleShot(0, viewer, SLOT(deleteLater()));
    }

    if (pickedAction == closePages) {
        int currentPage = tabWidget->indexOf(viewer);
        for (int i = tabBar->count() -1; i >= 0; --i) {
            viewer = qobject_cast<HelpViewer*>(tabWidget->widget(i));
            if (i != currentPage && viewer) {
                tabWidget->removeTab(i);
                QTimer::singleShot(0, viewer, SLOT(deleteLater()));

                if (i < currentPage)
                    --currentPage;
            }
        }
    }

    if (pickedAction == newBookmark)
        emit addNewBookmark(viewer->documentTitle(), url);
}

// If we have a current help viewer then this is the 'focus proxy', otherwise
// it's the tab widget itself. This is needed, so an embedding program can just
// set the focus to the central widget and it does TheRightThing(TM)
void CentralWidget::focusInEvent(QFocusEvent * /* event */)
{
    QObject *receiver = tabWidget;
    if (currentHelpViewer())
        receiver = currentHelpViewer();

    QTimer::singleShot(1, receiver, SLOT(setFocus()));
}

bool CentralWidget::eventFilter(QObject *object, QEvent *e)
{
    if (e->type() == QEvent::KeyPress){
        if ((static_cast<QKeyEvent*>(e))->key() == Qt::Key_Backspace) {
            HelpViewer *viewer = currentHelpViewer();
            if (viewer == object) {
                if (viewer->isBackwardAvailable()) {
#if !defined(QT_NO_WEBKIT)
                    // this helps in case there is an html <input> field
                    if (!viewer->hasFocus())
#endif
                        viewer->backward();
                }
                return true;
            }
        }
    }

    if (qobject_cast<QTabBar*>(object)) {
        bool dblClick = e->type() == QEvent::MouseButtonDblClick;
        if((e->type() == QEvent::MouseButtonRelease) || dblClick) {
            if (tabWidget->count() <= 1)
                return QWidget::eventFilter(object, e);

            QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(e);
            HelpViewer *viewer = helpViewerFromTabPosition(tabWidget,
                mouseEvent->pos());

            if (viewer) {
                if ((mouseEvent->button() == Qt::MidButton) || dblClick) {
                    tabWidget->removeTab(tabWidget->indexOf(viewer));
                    QTimer::singleShot(0, viewer, SLOT(deleteLater()));
                    currentPageChanged(tabWidget->currentIndex());
                    return true;
                }
            }
        }
    }
    return QWidget::eventFilter(object, e);
}

bool CentralWidget::find(const QString &txt, QTextDocument::FindFlags findFlags,
    bool incremental)
{
    HelpViewer* viewer = currentHelpViewer();

#if !defined(QT_NO_WEBKIT)
    Q_UNUSED(incremental)
    if (viewer) {
        QWebPage::FindFlags options = QWebPage::FindWrapsAroundDocument;
        if (findFlags & QTextDocument::FindBackward)
            options |= QWebPage::FindBackward;
        if (findFlags & QTextDocument::FindCaseSensitively)
            options |= QWebPage::FindCaseSensitively;

        bool found = viewer->findText(txt, options);
        options = QWebPage::HighlightAllOccurrences;
        viewer->findText(QLatin1String(""), options); // clear first
        viewer->findText(txt, options); // force highlighting of all other matches
        return found;
    }
    return false;
#else
    QTextCursor cursor;
    QTextDocument *doc = 0;
    QTextBrowser *browser = 0;

    if (viewer) {
        doc = viewer->document();
        cursor = viewer->textCursor();
        browser = qobject_cast<QTextBrowser*>(viewer);
    }
    /*
    if (tabWidget->currentWidget() == m_searchWidget) {
        QTextBrowser* browser = qFindChild<QTextBrowser*>(m_searchWidget);
        if (browser) {
            doc = browser->document();
            cursor = browser->textCursor();
        }
    }
    */
    if (!browser || !doc || cursor.isNull())
        return false;
    if (incremental)
        cursor.setPosition(cursor.selectionStart());

    QTextCursor found = doc->find(txt, cursor, findFlags);
    if (found.isNull()) {
        if ((findFlags&QTextDocument::FindBackward) == 0)
            cursor.movePosition(QTextCursor::Start);
        else
            cursor.movePosition(QTextCursor::End);
        found = doc->find(txt, cursor, findFlags);
        if (found.isNull()) {
            return false;
        }
    }
    if (!found.isNull()) {
        viewer->setTextCursor(found);
    }
    return true;
#endif
}

void CentralWidget::showTopicChooser(const QMap<QString, QUrl> &links,
    const QString &keyword)
{
    TopicChooser tc(this, keyword, links);
    if (tc.exec() == QDialog::Accepted)
        setSource(tc.link());
}

void CentralWidget::copy()
{
    HelpViewer* viewer = currentHelpViewer();
    if (viewer)
        viewer->copy();
}

void CentralWidget::activateTab(int index)
{
    tabWidget->setCurrentIndex(index);
}

QString CentralWidget::quoteTabTitle(const QString &title) const
{
    QString s = title;
    return s.replace(QLatin1Char('&'), QLatin1String("&&"));
}