/*
 *   Copyright (C) 2012, 2013, 2014, 2015 Ivan Cukic <ivan.cukic(at)kde.org>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License version 2,
 *   or (at your option) any later version, 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 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.
 */

// Self
#include "activitymodel.h"

// Qt
#include <QByteArray>
#include <QDBusPendingCall>
#include <QDBusPendingCallWatcher>
#include <QDebug>
#include <QHash>
#include <QIcon>
#include <QList>
#include <QFutureWatcher>
#include <QModelIndex>

// KDE
#include <kconfig.h>
#include <kconfiggroup.h>
#include <kdirwatch.h>

// Boost
#include <boost/range/algorithm/find_if.hpp>
#include <boost/range/algorithm/binary_search.hpp>
#include <boost/range/adaptor/filtered.hpp>
#include <boost/optional.hpp>

// Local
#include "utils/remove_if.h"
#define ENABLE_QJSVALUE_CONTINUATION
#include "utils/continue_with.h"
#include "utils/model_updaters.h"

using kamd::utils::continue_with;


namespace KActivities {
namespace Imports {

class ActivityModel::Private {
public:
    DECLARE_RAII_MODEL_UPDATERS(ActivityModel)

    /**
     * Returns whether the the activity has a desired state.
     * If the state is 0, returns true
     */
    template <typename T>
    static inline bool matchingState(InfoPtr activity,
                                     T states)
    {
        // Are we filtering activities on their states?
        if (!states.empty()
            && !boost::binary_search(states, activity->state())) {
            return false;
        }

        return true;
    }

    /**
     * Searches for the activity.
     * Returns an option(index, iterator) for the found activity.
     */
    template <typename _Container>
    static inline
    boost::optional<
        std::pair<unsigned int, typename _Container::const_iterator>
    >
    activityPosition(const _Container &container, const QString &activityId)
    {
        using ActivityPosition =
                decltype(activityPosition(container, activityId));
        using ContainerElement =
                typename _Container::value_type;

        auto position = boost::find_if(container,
            [&] (const ContainerElement &activity) {
                return activity->id() == activityId;
            }
        );

        return (position != container.end()) ?
            ActivityPosition(
                std::make_pair(position - container.begin(), position)
            ) :
            ActivityPosition();
    }

    /**
     * Notifies the model that an activity was updated
     */
    template <typename _Model, typename _Container>
    static inline
    void emitActivityUpdated(_Model *model,
                             const _Container &container,
                             QObject *activityInfo, int role)
    {
        const auto activity = static_cast<Info*> (activityInfo);
        emitActivityUpdated(model, container, activity->id(), role);
    }

    /**
     * Notifies the model that an activity was updated
     */
    template <typename _Model, typename _Container>
    static inline
    void emitActivityUpdated(_Model *model,
                             const _Container &container,
                             const QString &activity, int role)
    {
        auto position = Private::activityPosition(container, activity);

        if (position) {
            emit model->dataChanged(
                model->index(position->first),
                model->index(position->first),
                role == Qt::DecorationRole ?
                    QVector<int> {role, ActivityModel::ActivityIcon} :
                    QVector<int> {role}
            );
        }
    }

    class BackgroundCache {
    public:
        BackgroundCache()
            : initialized(false)
            , plasmaConfig("plasma-org.kde.plasma.desktop-appletsrc")
        {
            using namespace std::placeholders;

            const auto configFile = QStandardPaths::writableLocation(
                                        QStandardPaths::GenericConfigLocation) +
                                    QLatin1Char('/') + plasmaConfig.name();

            KDirWatch::self()->addFile(configFile);

            connect(KDirWatch::self(), &KDirWatch::dirty,
                    std::bind(&BackgroundCache::settingsFileChanged, this, _1));
            connect(KDirWatch::self(), &KDirWatch::created,
                    std::bind(&BackgroundCache::settingsFileChanged, this, _1));
        }

        void settingsFileChanged(const QString &file)
        {
            if (!file.endsWith(plasmaConfig.name())) return;

            plasmaConfig.reparseConfiguration();

            if (initialized) {
                reload(false);
            }
        }

        void subscribe(ActivityModel *model)
        {
            if (!initialized) {
                reload(true);
            }

            models << model;
        }

        void unsubscribe(ActivityModel *model)
        {
            models.removeAll(model);

            if (models.isEmpty()) {
                initialized = false;
                forActivity.clear();
            }
        }

        QString backgroundFromConfig(const KConfigGroup &config) const
        {
            auto wallpaperPlugin = config.readEntry("wallpaperplugin");
            auto wallpaperConfig = config.group("Wallpaper").group(wallpaperPlugin).group("General");

            if (wallpaperConfig.hasKey("Image")) {
                // Trying for the wallpaper
                auto wallpaper = wallpaperConfig.readEntry("Image", QString());
                if (!wallpaper.isEmpty()) {
                    return wallpaper;
                }
            }
            if (wallpaperConfig.hasKey("Color")) {
                auto backgroundColor = wallpaperConfig.readEntry("Color", QColor(0, 0, 0));
                return backgroundColor.name();
            }

            return QString();
        }

        void reload(bool fullReload)
        {
            QHash<QString, QString> newBackgrounds;

            if (fullReload) {
                forActivity.clear();
            }

            QStringList changedBackgrounds;

            for (const auto &cont: plasmaConfigContainments().groupList()) {

                auto config = plasmaConfigContainments().group(cont);
                auto activityId = config.readEntry("activityId", QString());

                // Ignore if it has no assigned activity
                if (activityId.isEmpty()) continue;

                // Ignore if we have already found the background
                if (newBackgrounds.contains(activityId) &&
                    newBackgrounds[activityId][0] != '#') continue;

                auto newBackground = backgroundFromConfig(config);

                if (forActivity[activityId] != newBackground) {
                    changedBackgrounds << activityId;
                    if (!newBackground.isEmpty()) {
                        newBackgrounds[activityId] = newBackground;
                    }
                }
            }

            initialized = true;

            if (!changedBackgrounds.isEmpty()) {
                forActivity = newBackgrounds;

                for (auto model: models) {
                    model->backgroundsUpdated(changedBackgrounds);
                }
            }
        }

        KConfigGroup plasmaConfigContainments() {
            return plasmaConfig.group("Containments");
        }

        QHash<QString, QString> forActivity;
        QList<ActivityModel*> models;

        bool initialized;
        KConfig plasmaConfig;

    };

    static BackgroundCache &backgrounds()
    {
        // If you convert this to a shared pointer,
        // fix the connections to KDirWatcher
        static BackgroundCache cache;
        return cache;
    }
};


ActivityModel::ActivityModel(QObject *parent)
    : QAbstractListModel(parent)
{
    // Initializing role names for qml
    connect(&m_service, &Consumer::serviceStatusChanged,
            this,       &ActivityModel::setServiceStatus);

    connect(&m_service, SIGNAL(activityAdded(QString)),
            this,       SLOT(onActivityAdded(QString)));
    connect(&m_service, SIGNAL(activityRemoved(QString)),
            this,       SLOT(onActivityRemoved(QString)));
    connect(&m_service, SIGNAL(currentActivityChanged(QString)),
            this,       SLOT(onCurrentActivityChanged(QString)));

    setServiceStatus(m_service.serviceStatus());

    Private::backgrounds().subscribe(this);
}

ActivityModel::~ActivityModel()
{
    Private::backgrounds().unsubscribe(this);
}

QHash<int, QByteArray> ActivityModel::roleNames() const
{
    return {
        {Qt::DisplayRole,     "name"},
        {Qt::DecorationRole,  "icon"},

        {ActivityState,       "state"},
        {ActivityId,          "id"},
        {ActivityIcon,        "iconSource"},
        {ActivityDescription, "description"},
        {ActivityBackground,  "background"},
        {ActivityCurrent,     "current"}
    };
}


void ActivityModel::setServiceStatus(Consumer::ServiceStatus)
{
    replaceActivities(m_service.activities());
}

void ActivityModel::replaceActivities(const QStringList &activities)
{
    // qDebug() << m_shownStatesString << "New list of activities: "
    //          << activities;
    // qDebug() << m_shownStatesString << " -- RESET MODEL -- ";

    Private::model_reset m(this);

    m_knownActivities.clear();
    m_shownActivities.clear();

    for (const QString &activity: activities) {
        onActivityAdded(activity, false);
    }
}

void ActivityModel::onActivityAdded(const QString &id, bool notifyClients)
{
    auto info = registerActivity(id);

    // qDebug() << m_shownStatesString << "Added a new activity:" << info->id()
    //          << " " << info->name();

    showActivity(info, notifyClients);
}

void ActivityModel::onActivityRemoved(const QString &id)
{
    // qDebug() << m_shownStatesString << "Removed an activity:" << id;

    hideActivity(id);
    unregisterActivity(id);
}

void ActivityModel::onCurrentActivityChanged(const QString &id)
{
    Q_UNUSED(id);

    for (const auto &activity: m_shownActivities) {
        Private::emitActivityUpdated(this, m_shownActivities, activity->id(),
                                     ActivityCurrent);
    }
}

ActivityModel::InfoPtr ActivityModel::registerActivity(const QString &id)
{
    auto position = Private::activityPosition(m_knownActivities, id);

    // qDebug() << m_shownStatesString << "Registering activity: " << id
    //          << " new? not " << (bool)position;

    if (position) {
        return *(position->second);

    } else {
        auto activityInfo = std::make_shared<Info>(id);

        auto ptr = activityInfo.get();

        connect(ptr,  &Info::nameChanged,
                this, &ActivityModel::onActivityNameChanged);
        connect(ptr,  &Info::descriptionChanged,
                this, &ActivityModel::onActivityDescriptionChanged);
        connect(ptr,  &Info::iconChanged,
                this, &ActivityModel::onActivityIconChanged);
        connect(ptr,  &Info::stateChanged,
                this, &ActivityModel::onActivityStateChanged);

        m_knownActivities.insert(InfoPtr(activityInfo));

        return activityInfo;
    }
}

void ActivityModel::unregisterActivity(const QString &id)
{
    // qDebug() << m_shownStatesString << "Deregistering activity: " << id;

    auto position = Private::activityPosition(m_knownActivities, id);

    if (position) {
        if (auto shown = Private::activityPosition(m_shownActivities, id)) {
            Private::model_remove(this, QModelIndex(), shown->first,
                                  shown->first);
            m_shownActivities.erase(shown->second);
        }

        m_knownActivities.erase(position->second);
    }
}

void ActivityModel::showActivity(InfoPtr activityInfo, bool notifyClients)
{
    // Should it really be shown?
    if (!Private::matchingState(activityInfo, m_shownStates)) return;

    // Is it already shown?
    if (boost::binary_search(m_shownActivities, activityInfo,
                             InfoPtrComparator())) return;

    auto registeredPosition
        = Private::activityPosition(m_knownActivities, activityInfo->id());

    if (!registeredPosition) {
        qDebug() << "Got a request to show an unknown activity, ignoring";
        return;
    }

    auto activityInfoPtr = *(registeredPosition->second);

    // qDebug() << m_shownStatesString << "Setting activity visibility to true:"
    //     << activityInfoPtr->id() << activityInfoPtr->name();

    auto position = m_shownActivities.insert(activityInfoPtr);

    if (notifyClients) {
        unsigned int index =
            (position.second ? position.first : m_shownActivities.end())
            - m_shownActivities.begin();

        // qDebug() << m_shownStatesString << " -- MODEL INSERT -- " << index;
        Private::model_insert(this, QModelIndex(), index, index);
    }
}

void ActivityModel::hideActivity(const QString &id)
{
    auto position = Private::activityPosition(m_shownActivities, id);

    // qDebug() << m_shownStatesString
    //          << "Setting activity visibility to false: " << id;

    if (position) {
        // qDebug() << m_shownStatesString << " -- MODEL REMOVE -- "
        //          << position->first;
        Private::model_remove(this, QModelIndex(),
            position->first, position->first);
        m_shownActivities.erase(position->second);
    }
}

#define CREATE_SIGNAL_EMITTER(What, Role)                                      \
    void ActivityModel::onActivity##What##Changed(const QString &)             \
    {                                                                          \
        Private::emitActivityUpdated(this, m_shownActivities, sender(), Role); \
    }

CREATE_SIGNAL_EMITTER(Name, Qt::DisplayRole)
CREATE_SIGNAL_EMITTER(Description, ActivityDescription)
CREATE_SIGNAL_EMITTER(Icon, Qt::DecorationRole)

#undef CREATE_SIGNAL_EMITTER

void ActivityModel::onActivityStateChanged(Info::State state)
{
    if (m_shownStates.empty()) {
        Private::emitActivityUpdated(this, m_shownActivities, sender(),
                                     ActivityState);

    } else {
        auto info = findActivity(sender());

        if (!info) {
            return;
        }

        if (boost::binary_search(m_shownStates, state)) {
            showActivity(info, true);
        } else {
            hideActivity(info->id());
        }
    }
}

void ActivityModel::backgroundsUpdated(const QStringList &activities)
{
    for (const auto &activity: activities) {
        Private::emitActivityUpdated(this, m_shownActivities, activity,
                                     ActivityBackground);
    }
}

void ActivityModel::setShownStates(const QString &states)
{
    m_shownStates.clear();
    m_shownStatesString = states;

    for (const auto &state: states.split(',')) {
        if (state == QStringLiteral("Running")) {
            m_shownStates.insert(Running);

        } else if (state == QStringLiteral("Starting")) {
            m_shownStates.insert(Starting);

        } else if (state == QStringLiteral("Stopped")) {
            m_shownStates.insert(Stopped);

        } else if (state == QStringLiteral("Stopping")) {
            m_shownStates.insert(Stopping);

        }
    }

    replaceActivities(m_service.activities());

    emit shownStatesChanged(states);
}

QString ActivityModel::shownStates() const
{
    return m_shownStatesString;
}

int ActivityModel::rowCount(const QModelIndex &parent) const
{
    Q_UNUSED(parent);

    return m_shownActivities.size();
}

QVariant ActivityModel::data(const QModelIndex &index, int role) const
{
    const int row = index.row();
    const auto &item = *(m_shownActivities.cbegin() + row);

    switch (role) {
    case Qt::DisplayRole:
        return item->name();

    case Qt::DecorationRole:
        return QIcon::fromTheme(data(index, ActivityIcon).toString());

    case ActivityId:
        return item->id();

    case ActivityState:
        return item->state();

    case ActivityIcon:
        {
            const QString &icon = item->icon();

            // We need a default icon for activities
            return icon.isEmpty() ? "preferences-activities" : icon;
        }

    case ActivityDescription:
        return item->description();

    case ActivityCurrent:
        return m_service.currentActivity() == item->id();

    case ActivityBackground:
        return Private::backgrounds().forActivity[item->id()];

    default:
        return QVariant();
    }
}

QVariant ActivityModel::headerData(int section, Qt::Orientation orientation,
                                   int role) const
{
    Q_UNUSED(section);
    Q_UNUSED(orientation);
    Q_UNUSED(role);

    return QVariant();
}

ActivityModel::InfoPtr ActivityModel::findActivity(QObject *ptr) const
{
    auto info = boost::find_if(m_knownActivities, [ptr] (const InfoPtr &info) {
            return ptr == info.get();
        });

    if (info == m_knownActivities.end()) {
        return nullptr;
    } else {
        return *info;
    }
}

// QFuture<void> Controller::setActivityWhat(id, value)
#define CREATE_SETTER(What)                                                    \
    void ActivityModel::setActivity##What(                                     \
        const QString &id, const QString &value, const QJSValue &callback)     \
    {                                                                          \
        continue_with(m_service.setActivity##What(id, value), callback);       \
    }

CREATE_SETTER(Name)
CREATE_SETTER(Description)
CREATE_SETTER(Icon)

#undef CREATE_SETTER

// QFuture<bool> Controller::setCurrentActivity(id)
void ActivityModel::setCurrentActivity(const QString &id,
                                       const QJSValue &callback)
{
    continue_with(m_service.setCurrentActivity(id), callback);
}

// QFuture<QString> Controller::addActivity(name)
void ActivityModel::addActivity(const QString &name, const QJSValue &callback)
{
    continue_with(m_service.addActivity(name), callback);
}

// QFuture<void> Controller::removeActivity(id)
void ActivityModel::removeActivity(const QString &id, const QJSValue &callback)
{
    continue_with(m_service.removeActivity(id), callback);
}

// QFuture<void> Controller::stopActivity(id)
void ActivityModel::stopActivity(const QString &id, const QJSValue &callback)
{
    continue_with(m_service.stopActivity(id), callback);
}

// QFuture<void> Controller::startActivity(id)
void ActivityModel::startActivity(const QString &id, const QJSValue &callback)
{
    continue_with(m_service.startActivity(id), callback);
}

} // namespace Imports
} // namespace KActivities

// #include "activitymodel.moc"

