/* This file is part of the KDE libraries
   Copyright (C) 2000 Torben Weis <weis@kde.org>
   Copyright (C) 2006 David Faure <faure@kde.org>

   This library 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 library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with this library; see the file COPYING.LIB.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.
*/

#include "kservicetypetrader.h"

#include "ksycoca.h"
#include "ksycoca_p.h"
#include "ktraderparsetree_p.h"
#include <kservicetypeprofile.h>
#include "kservicetype.h"
#include "kservicetypefactory_p.h"
#include "kservicefactory_p.h"

#include <QDebug>

using namespace KTraderParse;

// --------------------------------------------------

namespace KServiceTypeProfile
{
KServiceOfferList sortServiceTypeOffers(const KServiceOfferList &list, const QString &servicetype);
}

class KServiceTypeTraderSingleton
{
public:
    KServiceTypeTrader instance;
};

Q_GLOBAL_STATIC(KServiceTypeTraderSingleton, s_globalServiceTypeTrader)

KServiceTypeTrader *KServiceTypeTrader::self()
{
    return &s_globalServiceTypeTrader()->instance;
}

KServiceTypeTrader::KServiceTypeTrader()
    : d(0)
{
}

KServiceTypeTrader::~KServiceTypeTrader()
{
}

// shared with KMimeTypeTrader
void KServiceTypeTrader::applyConstraints(KService::List &lst,
        const QString &constraint)
{
    if (lst.isEmpty() || constraint.isEmpty()) {
        return;
    }

    const ParseTreeBase::Ptr constr = parseConstraints(constraint);   // for ownership
    const ParseTreeBase *pConstraintTree = constr.data(); // for speed

    if (!constr) { // parse error
        lst.clear();
    } else {
        // Find all services matching the constraint
        // and remove the other ones
        KService::List::iterator it = lst.begin();
        while (it != lst.end()) {
            if (matchConstraint(pConstraintTree, (*it), lst) != 1) {
                it = lst.erase(it);
            } else {
                ++it;
            }
        }
    }
}

#if 0
static void dumpOfferList(const KServiceOfferList &offers)
{
    // qDebug() << "Sorted list:";
    OfferList::Iterator itOff = offers.begin();
    for (; itOff != offers.end(); ++itOff)
        // qDebug() << (*itOff).service()->name() << " allow-as-default=" << (*itOff).allowAsDefault() << " preference=" << (*itOff).preference();
    }
#endif

KServiceOfferList KServiceTypeTrader::weightedOffers(const QString &serviceType)   // static, internal
{
    //qDebug() << "KServiceTypeTrader::weightedOffers( " << serviceType << " )";

    KSycoca::self()->ensureCacheValid();
    KServiceType::Ptr servTypePtr = KSycocaPrivate::self()->serviceTypeFactory()->findServiceTypeByName(serviceType);
    if (!servTypePtr) {
        qWarning() << "KServiceTypeTrader: serviceType" << serviceType << "not found";
        return KServiceOfferList();
    }
    if (servTypePtr->serviceOffersOffset() == -1) {  // no offers in ksycoca
        return KServiceOfferList();
    }

    // First, get all offers known to ksycoca.
    const KServiceOfferList services = KSycocaPrivate::self()->serviceFactory()->offers(servTypePtr->offset(), servTypePtr->serviceOffersOffset());

    const KServiceOfferList offers = KServiceTypeProfile::sortServiceTypeOffers(services, serviceType);
    //qDebug() << "Found profile: " << offers.count() << " offers";

#if 0
    dumpOfferList(offers);
#endif

    return offers;
}

KService::List KServiceTypeTrader::defaultOffers(const QString &serviceType,
        const QString &constraint) const
{
    KSycoca::self()->ensureCacheValid();
    KServiceType::Ptr servTypePtr = KSycocaPrivate::self()->serviceTypeFactory()->findServiceTypeByName(serviceType);
    if (!servTypePtr) {
        qWarning() << "KServiceTypeTrader: serviceType" << serviceType << "not found";
        return KService::List();
    }
    if (servTypePtr->serviceOffersOffset() == -1) {
        return KService::List();
    }

    KService::List lst =
        KSycocaPrivate::self()->serviceFactory()->serviceOffers(servTypePtr->offset(), servTypePtr->serviceOffersOffset());

    applyConstraints(lst, constraint);

    //qDebug() << "query for serviceType " << serviceType << constraint
    //             << " : returning " << lst.count() << " offers" << endl;
    return lst;
}

KService::List KServiceTypeTrader::query(const QString &serviceType,
        const QString &constraint) const
{
    if (!KServiceTypeProfile::hasProfile(serviceType)) {
        // Fast path: skip the profile stuff if there's none (to avoid kservice->serviceoffer->kservice)
        // The ordering according to initial preferences is done by kbuildsycoca
        return defaultOffers(serviceType, constraint);
    }

    KService::List lst;
    // Get all services of this service type.
    const KServiceOfferList offers = weightedOffers(serviceType);

    // Now extract only the services; the weighting was only used for sorting.
    KServiceOfferList::const_iterator itOff = offers.begin();
    for (; itOff != offers.end(); ++itOff) {
        lst.append((*itOff).service());
    }

    applyConstraints(lst, constraint);

    //qDebug() << "query for serviceType " << serviceType << constraint
    //             << " : returning " << lst.count() << " offers" << endl;
    return lst;
}

KService::Ptr KServiceTypeTrader::preferredService(const QString &serviceType) const
{
    const KServiceOfferList offers = weightedOffers(serviceType);

    KServiceOfferList::const_iterator itOff = offers.begin();
    // Look for the first one that is allowed as default.
    // Since the allowed-as-default are first anyway, we only have
    // to look at the first one to know.
    if (itOff != offers.end() && (*itOff).allowAsDefault()) {
        return (*itOff).service();
    }

    //qDebug() << "No offers, or none allowed as default";
    return KService::Ptr();
}
