/*
 *   SPDX-FileCopyrightText: 2010-2016 Ivan Cukic <ivan.cukic@kde.org>
 *
 *   SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */

// Self
#include "Resources.h"
#include "Resources_p.h"

// Qt
#include <QDBusConnection>
#include <QMutex>
#include <QMutexLocker>
#include <QThread>

// KDE
#include <kwindowsystem.h>

// Utils
#include <utils/d_ptr_implementation.h>
#include <utils/remove_if.h>

// System
#include <time.h>

// Local
#include "Activities.h"
#include "Application.h"
#include "common/dbus/common.h"
#include "resourcesadaptor.h"

Resources::Private::Private(Resources *parent)
    : QThread(parent)
    , focussedWindow(0)
    , q(parent)
{
}

Resources::Private::~Private()
{
    requestInterruption();
    wait(1500); // Enough time for the sleep(1) + processing in run()
}

namespace
{
EventList events;
QMutex events_mutex;
}

void Resources::Private::run()
{
    while (!isInterruptionRequested()) {
        // initial delay before processing the events
        sleep(1);

        EventList currentEvents;

        {
            QMutexLocker locker(&events_mutex);

            if (events.count() == 0) {
                return;
            }

            std::swap(currentEvents, events);
        }

        emit q->ProcessedResourceEvents(currentEvents);
    }
}

void Resources::Private::insertEvent(const Event &newEvent)
{
    if (lastEvent == newEvent) {
        return;
    }

    lastEvent = newEvent;

    {
        QMutexLocker locker(&events_mutex);
        events << newEvent;
    }

    emit q->RegisteredResourceEvent(newEvent);
}

void Resources::Private::addEvent(const QString &application, WId wid, const QString &uri, int type)
{
    Event newEvent(application, wid, uri, type);
    addEvent(newEvent);
}

void Resources::Private::addEvent(const Event &newEvent)
{
    // And now, for something completely delayed
    {
        QMutexLocker locker(&events_mutex);

        // Deleting previously registered Accessed events if
        // the current one has the same application and uri
        if (newEvent.type != Event::Accessed) {
            kamd::utils::remove_if(events, [&newEvent](const Event &event) -> bool {
                return event.application == newEvent.application && event.uri == newEvent.uri;
            });
        }
    }

    // Process the windowing
    // Essentially, this is the brain of SLC. We need to track the
    // window focus changes to be able to generate the potential
    // missing events like FocussedOut before Closed and similar.
    // So, there is no point in having the same logic in SLC plugin
    // as well.

    if (newEvent.wid != 0) {
        WindowData &window = windows[newEvent.wid];
        const QString &uri = newEvent.uri;

        window.application = newEvent.application;

        switch (newEvent.type) {
        case Event::Opened:
            insertEvent(newEvent);

            if (window.focussedResource.isEmpty()) {
                // This window haven't had anything focused,
                // assuming the new document is focused

                window.focussedResource = newEvent.uri;
                insertEvent(newEvent.deriveWithType(Event::FocussedIn));
            }

            break;

        case Event::FocussedIn:

            if (!window.resources.contains(uri)) {
                // This window did not contain this resource before,
                // sending Opened event

                insertEvent(newEvent.deriveWithType(Event::Opened));
            }

            window.focussedResource = newEvent.uri;
            insertEvent(newEvent);

            break;

        case Event::Closed:

            if (window.focussedResource == uri) {
                // If we are closing a document that is in focus,
                // release focus first

                insertEvent(newEvent.deriveWithType(Event::FocussedOut));
                window.focussedResource.clear();
            }

            insertEvent(newEvent);

            break;

        case Event::FocussedOut:

            if (window.focussedResource == uri) {
                window.focussedResource.clear();
            }

            insertEvent(newEvent);

            break;

        default:
            insertEvent(newEvent);
            break;
        }

    } else {
        // If we haven't got a window, just pass the event on,
        // but only if it is not a focus event
        if (newEvent.type != Event::FocussedIn && newEvent.type != Event::FocussedOut) {
            insertEvent(newEvent);
        }
    }

    start();
}

void Resources::Private::windowClosed(WId windowId)
{
    // Testing whether the window is a registered one

    if (!windows.contains(windowId)) {
        return;
    }

    if (focussedWindow == windowId) {
        focussedWindow = 0;
    }

    // Closing all the resources that the window registered

    for (const QString &uri : windows[windowId].resources) {
        q->RegisterResourceEvent(windows[windowId].application, windowId, uri, Event::Closed);
    }

    windows.remove(windowId);
}

void Resources::Private::activeWindowChanged(WId windowId)
{
    // If the focused window has changed, we need to create a
    // FocussedOut event for the resource it contains,
    // and FocussedIn for the resource of the new active window.
    // The windows can do this manually, but if they are
    // SDI, we can do it on our own.

    if (windowId == focussedWindow) {
        return;
    }

    if (windows.contains(focussedWindow)) {
        const WindowData &data = windows[focussedWindow];

        if (!data.focussedResource.isEmpty()) {
            insertEvent(Event(data.application, focussedWindow, data.focussedResource, Event::FocussedOut));
        }
    }

    focussedWindow = windowId;

    if (windows.contains(focussedWindow)) {
        const WindowData &data = windows[focussedWindow];

        if (!data.focussedResource.isEmpty()) {
            insertEvent(Event(data.application, windowId, data.focussedResource, Event::FocussedIn));
        }
    }
}

Resources::Resources(QObject *parent)
    : Module(QStringLiteral("resources"), parent)
    , d(this)
{
    qRegisterMetaType<Event>("Event");
    qRegisterMetaType<EventList>("EventList");
    qRegisterMetaType<WId>("WId");

    new ResourcesAdaptor(this);
    QDBusConnection::sessionBus().registerObject(KAMD_DBUS_OBJECT_PATH("Resources"), this);

    connect(KWindowSystem::self(), &KWindowSystem::windowRemoved, d.operator->(), &Resources::Private::windowClosed);
    connect(KWindowSystem::self(), &KWindowSystem::activeWindowChanged, d.operator->(), &Resources::Private::activeWindowChanged);
}

Resources::~Resources()
{
}

void Resources::RegisterResourceEvent(const QString &application, uint _windowId, const QString &uri, uint event)
{
    if (event > Event::LastEventType || uri.isEmpty() || application.isEmpty()) {
        return;
    }

    WId windowId = (WId)_windowId;

    d->addEvent(application, windowId, uri, (Event::Type)event);
}

void Resources::RegisterResourceMimetype(const QString &uri, const QString &mimetype)
{
    if (!mimetype.isEmpty()) {
        return;
    }

    emit RegisteredResourceMimetype(uri, mimetype);
}

void Resources::RegisterResourceTitle(const QString &uri, const QString &title)
{
    // A dirty sanity check for the title
    if (title.length() < 3) {
        return;
    }

    emit RegisteredResourceTitle(uri, title);
}
