/*
 * Copyright (C) 2015-2016 Canonical, Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 3.
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */

#ifndef UNITY_WINDOWINPUTMONITOR_H
#define UNITY_WINDOWINPUTMONITOR_H

#include <QQuickItem>
#include <QList>
#include <QPointer>

#include "Timer.h"
#include "ElapsedTimer.h"

/**
  * Monitors input events received by the window holding this item and the Home (Win aka Super_L)
  * key presses.
  *
  * Additionally, this class monitors for generic touch events on the screen, to
  * help with hiding/revealing the mouse pointer.
 */
class WindowInputMonitor : public QQuickItem
{
    Q_OBJECT
public:

    WindowInputMonitor(QQuickItem *parent = 0);

    // for testing
    WindowInputMonitor(UnityUtil::AbstractTimer *timer,
            UnityUtil::AbstractElapsedTimer *elapsedTimer,
            QQuickItem *parent = 0);

    virtual ~WindowInputMonitor();

    bool eventFilter(QObject *watched, QEvent *event) override;

    void update(QEvent *event);

    const qint64 msecsWithoutTouches = 150;

Q_SIGNALS:
    /**
     * Emitted when the home key has been intentionally tapped
     *
     * It only says the home key has been activated if it has been tapped in isolation,
     * that is, without being accompanied by touches on the screen. Home key taps that
     * happen along with (or immediately after, or immediately before) touches on the
     * screen are considered to have happened unintentionally and are thus ignored.
     *
     * Rationale being that it's easy to accidentally hit the home key while performing
     * a swipe from a screen edge, for instance. That's particularly the case when the
     * home key is a capacitive key.
     */
    void homeKeyActivated();

    /**
     * Emitted when a touch begin event is detected
     */
    void touchBegun();

    /**
     * Emitted when a touch end event is detected
     * @param pos the position in screen coordinates
     */
    void touchEnded(const QPointF &pos);

private Q_SLOTS:
    void setupFilterOnWindow(QQuickWindow *window);
    void emitActivatedIfNoTouchesAround();

private:
    QPointer<QQuickWindow> m_filteredWindow;
    bool m_windowBeingTouched;
    UnityUtil::AbstractElapsedTimer *m_windowLastTouchedTimer;
    UnityUtil::AbstractTimer *m_activationTimer;

    // Qt::Keys that are mapped to our "home" key.
    QList<int> m_homeKeys{Qt::Key_Super_L, Qt::Key_HomePage};
    // Which Qt::Key from m_homeKeys is currently pressed.
    // 0 if none
    int m_pressedHomeKey{0};
};

#endif // UNITY_WINDOWINPUTMONITOR_H