/*
 *   Copyright (C) 2005 by Aaron Seigo <aseigo@kde.org>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Library General Public License version 2 as
 *   published by the Free Software Foundation
 *
 *   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 General Public License for more details
 *
 *   You should have received a copy of the GNU Library General Public
 *   License along with this program; if not, write to the
 *   Free Software Foundation, Inc.,
 *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include "applet.h"

#include <QApplication>
#include <QEvent>
#include <QList>
#include <QPainter>
#include <QSize>
#include <QTimer>

#include <KDialog>
#include <KPluginInfo>
#include <KStandardDirs>
#include <KService>
#include <KServiceTypeTrader>

#include "plasma/corona.h"
#include "plasma/dataenginemanager.h"
#include "plasma/package.h"
#include "plasma/packages_p.h"
#include "plasma/plasma.h"
#include "plasma/scriptengine.h"
#include "plasma/svg.h"

#include "plasma/widgets/widget.h"
#include "plasma/widgets/lineedit.h"
#include "plasma/widgets/vboxlayout.h"

namespace Plasma
{

class Applet::Private
{
public:
    Private(KService::Ptr service, int uniqueID)
        : appletId(uniqueID),
          globalConfig(0),
          appletConfig(0),
          appletDescription(service),
          package(0),
          background(0),
          failureText(0),
          scriptEngine(0),
          immutable(false),
          hasConfigurationInterface(false),
          failed(false)
    {
        if (appletId == 0) {
            appletId = nextId();
        }

        if (appletId > s_maxAppletId) {
            s_maxAppletId = appletId;
        }
    }

    ~Private()
    {
        foreach ( const QString& engine, loadedEngines ) {
            DataEngineManager::self()->unloadDataEngine( engine );
        }
        delete background;
        delete package;
    }

    void init(Applet* applet)
    {
        if (!appletDescription.isValid()) {
            applet->setFailedToLaunch(true);
        }

        QString language = appletDescription.property("X-Plasma-Language").toString();

        // we have a scripted plasmoid
        if (!language.isEmpty()) {
            // find where the Package is
            QString path = KStandardDirs::locate("appdata",
                                                 "plasmoids/" +
                                                 appletDescription.pluginName());

            if (!path.isEmpty()) {
                // create the package and see if we have something real
                package = new Package(path,
                                      appletDescription.pluginName(),
                                      PlasmoidStructure());
                if (package->isValid()) {
                    // now we try and set up the script engine.
                    // it will be parented to this applet and so will get
                    // deleted when the applet does

                    scriptEngine = ScriptEngine::load(language, applet);
                    if (!scriptEngine) {
                        delete package;
                        package = 0;
                    }
                } else {
                    delete package;
                    package = 0;
                }

                if (!package) {
                    applet->setFailedToLaunch(true);
                }
            }
        }

        applet->setImmutable(applet->globalConfig().isImmutable() ||
                             applet->config().isImmutable());
    }

    static uint nextId()
    {
        ++s_maxAppletId;
        return s_maxAppletId;
    }

    //TODO: examine the usage of memory here; there's a pretty large
    //      number of members at this point.
    uint appletId;
    KSharedConfig::Ptr globalConfig;
    KSharedConfig::Ptr appletConfig;
    KPluginInfo appletDescription;
    Package* package;
    QList<QObject*> watchedForFocus;
    QStringList loadedEngines;
    static uint s_maxAppletId;
    Plasma::Svg *background;
    Plasma::LineEdit *failureText;
    ScriptEngine* scriptEngine;
    bool immutable : 1;
    bool hasConfigurationInterface : 1;
    bool failed : 1;
};

uint Applet::Private::s_maxAppletId = 0;

Applet::Applet(QGraphicsItem *parent,
               const QString& serviceID,
               uint appletId)
    : QObject(0),
      Widget(parent),
      d(new Private(KService::serviceByStorageId(serviceID), appletId))
{
    d->init(this);
}

Applet::Applet(QObject* parent, const QStringList& args)
    : QObject(parent),
      Widget(0),
      d(new Private(KService::serviceByStorageId(args.count() > 0 ? args[0] : QString()),
                    args.count() > 1 ? args[1].toInt() : 0))
{
    d->init(this);
    // the brain damage seen in the initialization list is due to the 
    // inflexibility of KService::createInstance
}

Applet::~Applet()
{
    needsFocus( false );
    delete d;
}

KConfigGroup Applet::config() const
{
    if (!d->appletConfig) {
        QString file = KStandardDirs::locateLocal( "appdata",
                                                   "applets/" + instanceName() + "rc",
                                                   true );
        d->appletConfig = KSharedConfig::openConfig( file );
    }

    return KConfigGroup(d->appletConfig, "General");
}

KConfigGroup Applet::config(const QString& group) const
{
    KConfigGroup cg = config();
    cg.changeGroup(instanceName() + '-' + group);
    return cg;
}

KConfigGroup Applet::globalConfig() const
{
    if ( !d->globalConfig ) {
        QString file = KStandardDirs::locateLocal( "config", "plasma_" + globalName() + "rc" );
        d->globalConfig = KSharedConfig::openConfig( file );
    }

    return KConfigGroup(d->globalConfig, "General");
}

DataEngine* Applet::dataEngine(const QString& name) const
{
    int index = d->loadedEngines.indexOf(name);
    if (index != -1) {
        return DataEngineManager::self()->dataEngine(name);
    }

    DataEngine* engine = DataEngineManager::self()->loadDataEngine(name);
    if (engine->isValid()) {
        d->loadedEngines.append(name);
    }

    return engine;
}

const Package* Applet::package() const
{
    return d->package;
}

void Applet::constraintsUpdated()
{
    kDebug() << "Applet::constraintsUpdate(): constraints are FormFactor: " << formFactor() << ", Location: " << location() << endl;
}

QString Applet::name() const
{
    if (!d->appletDescription.isValid()) {
        return i18n("Unknown Applet");
    }

    return d->appletDescription.name();
}

QString Applet::icon() const
{
    if (!d->appletDescription.isValid()) {
        return QString();
    }

    return d->appletDescription.icon();
}

QString Applet::category() const
{
    if (!d->appletDescription.isValid()) {
        return i18n("Misc");
    }

    return d->appletDescription.property("X-KDE-PluginInfo-Category").toString();
}

QString Applet::category(const KPluginInfo& applet)
{
    return applet.property("X-KDE-PluginInfo-Category").toString();
}

QString Applet::category(const QString& appletName)
{
    if (appletName.isEmpty()) {
        return QString();
    }

    QString constraint = QString("[X-KDE-PluginInfo-Name] == '%1'").arg(appletName);
    KService::List offers = KServiceTypeTrader::self()->query("Plasma/Applet", constraint);

    if (offers.isEmpty()) {
        return QString();
    }

    return offers.first()->property("X-KDE-PluginInfo-Category").toString();
}

bool Applet::isImmutable() const
{
    return d->immutable;
}

void Applet::setImmutable(bool immutable)
{
    d->immutable = immutable;
    QGraphicsItem::GraphicsItemFlags f = flags();
    if (immutable) {
        f ^= QGraphicsItem::ItemIsMovable;
    } else if (!scene() || !static_cast<Corona*>(scene())->isImmutable()) {
        f |= QGraphicsItem::ItemIsMovable;
    }
    setFlags(f);
}

bool Applet::drawStandardBackground()
{
    return d->background != 0;
}

void Applet::setDrawStandardBackground(bool drawBackground)
{
    if (drawBackground) {
        if (!d->background) {
            d->background = new Plasma::Svg("widgets/background");
        }
    } else {
        delete d->background;
        d->background = 0;
    }
}

bool Applet::failedToLaunch() const
{
    return d->failed;
}

QString visibleFailureText(const QString& reason)
{
    QString text;

    if (reason.isEmpty()) {
        text = i18n("This object could not be created.");
    } else {
        text = i18n("This object could not be created for the following reason:<p>%1</p>", reason);
    }

    return text;
}

void Applet::setFailedToLaunch(bool failed, const QString& reason)
{
    if (d->failed == failed) {
        if (d->failureText) {
            d->failureText->setHtml(visibleFailureText(reason));
        }
        return;
    }

    d->failed = failed;

    qDeleteAll(QGraphicsItem::children());
    delete layout();

    if (failed) {
        setDrawStandardBackground(failed || d->background != 0);
        Layout* failureLayout = new VBoxLayout(this);
        d->failureText = new LineEdit(this, scene());
        d->failureText->setFlags(0);
        d->failureText->setHtml(visibleFailureText(reason));
        failureLayout->addItem(d->failureText);
    } else {
        d->failureText = 0;
    }

    update();
}

int Applet::type() const
{
    return Type;
}

QRectF Applet::boundingRect () const
{
    if (d->scriptEngine) {
        return QRectF(QPointF(0, 0), d->scriptEngine->size());
    }

    //FIXME: this should be big enough to allow for the failure text?
    return QRectF(300, 300, 300, 300);
}

void Applet::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    if (d->background) {
        d->background->resize(boundingRect().size());
        d->background->paint(painter, boundingRect());
    }

    if (d->failed) {
        return;
    }

    paintInterface(painter, option, widget);

    //TODO: interface overlays on hover
}

void Applet::paintInterface(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    Q_UNUSED(widget)

    if (d->scriptEngine) {
        d->scriptEngine->paintInterface(painter, option);
    }
}

FormFactor Applet::formFactor() const
{
    if (!scene()) {
        return Plasma::Planar;
    }

    return static_cast<Corona*>(scene())->formFactor();
}

Location Applet::location() const
{
    if (!scene()) {
        return Plasma::Desktop;
    }

    return static_cast<Corona*>(scene())->location();
}

QString Applet::globalName() const
{
    if (!d->appletDescription.isValid()) {
        return QString();
    }

    return d->appletDescription.service()->library();
}

QString Applet::instanceName() const
{
    if (!d->appletDescription.isValid()) {
        return QString();
    }

    return d->appletDescription.service()->library() + QString::number( d->appletId );
}

void Applet::watchForFocus(QObject *widget, bool watch)
{
    if ( !widget ) {
        return;
    }

    int index = d->watchedForFocus.indexOf(widget);
    if ( watch ) {
        if ( index == -1 ) {
            d->watchedForFocus.append( widget );
            widget->installEventFilter( this );
        }
    } else if ( index != -1 ) {
        d->watchedForFocus.removeAt( index );
        widget->removeEventFilter( this );
    }
}

void Applet::needsFocus(bool focus)
{
    if (focus == QGraphicsItem::hasFocus()) {
        return;
    }

    emit requestFocus(focus);
}

bool Applet::hasConfigurationInterface()
{
    return d->hasConfigurationInterface;
}

void Applet::setHasConfigurationInterface(bool hasInterface)
{
    d->hasConfigurationInterface = hasInterface;
}

bool Applet::eventFilter( QObject *o, QEvent * e )
{
    if ( !d->watchedForFocus.contains( o ) )
    {
        if ( e->type() == QEvent::MouseButtonRelease ||
             e->type() == QEvent::FocusIn ) {
            needsFocus( true );
        } else if ( e->type() == QEvent::FocusOut ) {
            needsFocus( false );
        }
    }

    return QObject::eventFilter(o, e);
}

void Applet::showConfigurationInterface()
{
}

KPluginInfo::List Applet::knownApplets(const QString &category,
                                       const QString &parentApp)
{
    QString constraint;

    if (parentApp.isEmpty()) {
        constraint.append("not exist [X-KDE-ParentApp]");
    } else {
        constraint.append("[X-KDE-ParentApp] == '").append(parentApp).append("'");
    }

    if (!category.isEmpty()) {
        if (!constraint.isEmpty()) {
            constraint.append(" and ");
        }

        constraint.append("[X-KDE-PluginInfo-Category] == '").append(category).append("'");
        if (category == "Misc") {
            constraint.append(" or (not exist [X-KDE-PluginInfo-Category] or [X-KDE-PluginInfo-Category] == '')");
        }
    }

    KService::List offers = KServiceTypeTrader::self()->query("Plasma/Applet", constraint);
    //kDebug() << "Applet::knownApplets constraint was '" << constraint << "' which got us " << offers.count() << " matches" << endl;
    return KPluginInfo::fromServices(offers);
}

QStringList Applet::knownCategories(const QString &parentApp)
{
    QString constraint = "exist [X-KDE-PluginInfo-Category]";

    if (parentApp.isEmpty()) {
        constraint.append(" and not exist [X-KDE-ParentApp]");
    } else {
        constraint.append(" and [X-KDE-ParentApp] == '").append(parentApp).append("'");
    }

    KService::List offers = KServiceTypeTrader::self()->query("Plasma/Applet", constraint);
    QStringList categories;
    foreach (KService::Ptr applet, offers) {
        QString appletCategory = applet->property("X-KDE-PluginInfo-Category").toString();
        kDebug() << "   and we have " << appletCategory << endl;
        if (appletCategory.isEmpty()) {
            if (!categories.contains(i18n("Misc"))) {
                categories << i18n("Misc");
            }
        } else  if (!categories.contains(appletCategory)) {
            categories << appletCategory;
        }
    }

    categories.sort();
    return categories;
}

Applet* Applet::loadApplet(const QString& appletName, uint appletId, const QStringList& args)
{
    if (appletName.isEmpty()) {
        return 0;
    }

    QString constraint = QString("[X-KDE-PluginInfo-Name] == '%1'").arg(appletName);
    KService::List offers = KServiceTypeTrader::self()->query("Plasma/Applet", constraint);

    if (offers.isEmpty()) {
        //TODO: what would be -really- cool is offer to try and download the applet
        //      from the network at this point
        kDebug() << "Applet::loadApplet: offers is empty for \"" << appletName << "\"" << endl;
        return 0;
    }

    if (appletId == 0) {
        appletId = Private::nextId();
    }

    QStringList allArgs;
    QString id;
    id.setNum(appletId);
    allArgs << offers.first()->storageId() << id << args;
    Applet* applet = KService::createInstance<Plasma::Applet>(offers.first(), 0, allArgs);

    if (!applet) {
        kDebug() << "Couldn't load applet \"" << appletName << "\"!" << endl;
    }

    return applet;
}

Applet* Applet::loadApplet(const KPluginInfo& info, uint appletId, const QStringList& args)
{
    if (!info.isValid()) {
        return 0;
    }

    return loadApplet(info.pluginName(), appletId, args);
}

} // Plasma namespace

#include "applet.moc"