HelpViewer.cpp

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/*
        Aseba - an event-based framework for distributed robot control
        Copyright (C) 2007--2012:
                Stephane Magnenat <stephane at magnenat dot net>
                (http://stephane.magnenat.net)
                and other contributors, see authors.txt for details
        
        This program is free software: you can redistribute it and/or modify
        it under the terms of the GNU Lesser General Public License as published
        by the Free Software Foundation, version 3 of the License.
        
        This program is distributed in the hope that it will be useful,
        but WITHOUT ANY WARRANTY; without even the implied warranty of
        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        GNU Lesser General Public License for more details.
        
        You should have received a copy of the GNU Lesser General Public License
        along with this program. If not, see <http://www.gnu.org/licenses/>.
*/

#include "HelpViewer.h"

#include <QtHelp/QHelpContentWidget>
#include <QCoreApplication>
#include <QDir>
#include <QHBoxLayout>
#include <QVBoxLayout>
#include <QSplitter>
#include <QFile>
#include <QIODevice>
#include <QUrl>
#include <QVariant>
#include <QSettings>
#include <QDesktopServices>
#include <QMessageBox>

#include <QDebug>

#include <HelpViewer.moc>

namespace Aseba
{
        const QString HelpViewer::DEFAULT_LANGUAGE = "en";

        HelpViewer::HelpViewer(QWidget* parent):
                QWidget(parent),
                tmpHelpSubDir(QString("aseba-studio-%1").arg(QCoreApplication::applicationPid())),
                tmpHelpFileNameHC(QDir::temp().filePath(tmpHelpSubDir + "/aseba-doc.qhc")),
                tmpHelpFileNameCH(QDir::temp().filePath(tmpHelpSubDir + "/aseba-doc.qch"))
        {
                // expanding help files into tmp
                QDir::temp().mkdir(tmpHelpSubDir);
                QFile(":aseba-doc.qhc").copy(tmpHelpFileNameHC);
                QFile(":aseba-doc.qch").copy(tmpHelpFileNameCH);
                
                // open files from tmp
                helpEngine = new QHelpEngine(tmpHelpFileNameHC, this);
                if (helpEngine->setupData() == false)
                {
                        helpFound = false;
                        QString message = tr("The help file %0 was not loaded successfully. " \
                                "The error was: %1." \
                                "The help file should be available in the temporary directory of your system. " \
                                "Please check your installation, or report a bug.").arg(tmpHelpFileNameHC).arg(helpEngine->error());
                        QMessageBox::warning(this, tr("Help file not found"), message);
                }
                else
                        helpFound = true;

                // navigation buttons
                previous = new QPushButton(tr("Previous"));
                previous->setEnabled(false);
                next = new QPushButton(tr("Next"));
                next->setEnabled(false);
                home = new QPushButton(tr("Home"));
                QHBoxLayout* buttonLayout = new QHBoxLayout();
                buttonLayout->addWidget(previous);
                buttonLayout->addWidget(home);
                buttonLayout->addWidget(next);
                buttonLayout->addStretch();

                // QTextBrower
                viewer = new HelpBrowser(helpEngine);

                // set default language
                setLanguage();

                // help layout
                QSplitter *helpSplitter = new QSplitter(Qt::Horizontal);
                helpSplitter->addWidget(helpEngine->contentWidget());
                helpSplitter->addWidget(viewer);
                helpSplitter->setStretchFactor(helpSplitter->indexOf(viewer), 1);

                // main layout
                QVBoxLayout* mainLayout = new QVBoxLayout();
                mainLayout->addLayout(buttonLayout);
                //mainLayout->addWidget(viewer);
                mainLayout->addWidget(helpSplitter);

                setLayout(mainLayout);

                // connect
                connect(previous, SIGNAL(clicked()), this, SLOT(previousClicked()));
                connect(next, SIGNAL(clicked()), this, SLOT(nextClicked()));
                connect(home, SIGNAL(clicked()), this, SLOT(homeClicked()));
                connect(viewer, SIGNAL(backwardAvailable(bool)), this, SLOT(backwardAvailable(bool)));
                connect(viewer, SIGNAL(forwardAvailable(bool)), this, SLOT(forwardAvailable(bool)));
                connect(helpEngine->contentWidget(), SIGNAL(linkActivated(const QUrl&)), viewer, SLOT(setSource(const QUrl&)));

                // restore window state, if available
                if (readSettings() == false)
                        resize(800, 500);

                setWindowTitle(tr("Aseba Studio Help"));
        }

        HelpViewer::~HelpViewer()
        {
                writeSettings();
                // remove help files from tmp
                QFile(tmpHelpFileNameHC).remove();
                QFile(tmpHelpFileNameCH).remove();
                QDir::temp().rmdir(tmpHelpSubDir);
        }

        void HelpViewer::setLanguage(const QString& lang)
        {
                if (!helpFound)
                        return;

                // check if the language is part of the existing filters
                if (selectLanguage(lang) == false)
                {
                        // rollback to default language
                        QString message = tr("The help filter for the langauge \"%0\" has not been found. " \
                                             "Falling back to the default language (%1). " \
                                             "This is probably a bug, please report it.").arg(lang).arg(DEFAULT_LANGUAGE);
                        QMessageBox::warning(this, tr("Help filter not found"), message);
                        helpEngine->setCurrentFilter(DEFAULT_LANGUAGE);
                        this->language = DEFAULT_LANGUAGE;
                }
        }
        
        bool HelpViewer::selectLanguage(const QString& reqLang)
        {
                const QStringList& langList(helpEngine->customFilters());
                for (QStringList::const_iterator it = langList.constBegin(); it != langList.constEnd(); ++it)
                {
                        const QString& availableLang(*it);
                        if (reqLang.startsWith(availableLang))
                        {
                                helpEngine->setCurrentFilter(availableLang);
                                this->language = availableLang;
                                return true;
                        }
                }
                return false;
        }

        void HelpViewer::showHelp(helpType type)
        {
                if (!helpFound)
                {
                        this->show();   // show anyway, but will be blank
                        return;
                }

                QString filename = "qthelp:///doc/doc/" + this->language + "_";
                switch (type)
                {
                        // help files generated by the wikidot parser
                        case HelpViewer::USERMANUAL:
                                filename += "asebausermanual.html";
                                break;
                        case HelpViewer::STUDIO:
                                filename += "asebastudio.html";
                                break;
                        case HelpViewer::LANGUAGE:
                                filename += "asebalanguage.html";
                                break;
                }

                QUrl result = helpEngine->findFile(QUrl(filename));
                viewer->setSource(result);
                viewer->setWindowTitle(tr("Aseba Studio Help"));
                this->show();
        }

        bool HelpViewer::readSettings()
        {
                bool result;

                QSettings settings;
                result = restoreGeometry(settings.value("HelpViewer/geometry").toByteArray());
                move(settings.value("HelpViewer/position").toPoint());
                return result;
        }

        void HelpViewer::writeSettings()
        {
                QSettings settings;
                settings.setValue("HelpViewer/geometry", saveGeometry());
                settings.setValue("HelpViewer/position", pos());
        }


        void HelpViewer::previousClicked()
        {
                viewer->backward();
        }

        void HelpViewer::backwardAvailable(bool state)
        {
                previous->setEnabled(state);
        }

        void HelpViewer::nextClicked()
        {
                viewer->forward();
        }

        void HelpViewer::forwardAvailable(bool state)
        {
                next->setEnabled(state);
        }

        void HelpViewer::homeClicked()
        {
                showHelp(HelpViewer::USERMANUAL);
        }


        HelpBrowser::HelpBrowser(QHelpEngine* helpEngine, QWidget* parent):
                QTextBrowser(parent), helpEngine(helpEngine)
        {
                setReadOnly(true);
        }

        void HelpBrowser::setSource(const QUrl &url)
        {
                if (url.scheme() == "http")
                {
                        QDesktopServices::openUrl(url);
                }
                else
                        QTextBrowser::setSource(url);
        }

        QVariant HelpBrowser::loadResource(int type, const QUrl& url)
        {
                //qDebug() << "Loading " << url;

                // from Qt Quarterly 28:
                // "Using QtHelp to Lend a Helping Hand"
                if (url.scheme() == "qthelp")
                        return QVariant(helpEngine->fileData(url));
                else
                        return QTextBrowser::loadResource(type, url);
        }
}