/****************************************************************************
**
** Copyright (C) 2019 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the manual tests of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:GPL-EXCEPT$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 as published by the Free Software
** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

import QtQuick 2.14
import Qt.labs.animation 1.0

Item {
    id: root
    objectName: "viewport"
    default property alias data: __contentItem.data
    property alias velocity: anim.velocity
    property alias contentX: __contentItem.x // sign is reversed compared to Flickable.contentX
    property alias contentY: __contentItem.y // sign is reversed compared to Flickable.contentY
    property alias contentWidth: __contentItem.width
    property alias contentHeight: __contentItem.height
    signal flickStarted
    signal flickEnded

    Item {
        id: __contentItem
        objectName: "__contentItem"
        width: childrenRect.width
        height: childrenRect.height

        BoundaryRule on x {
            id: xbr
            minimum: root.width - __contentItem.width
            maximum: 0
            minimumOvershoot: 100
            maximumOvershoot: 100
            overshootFilter: BoundaryRule.Peak
        }

        BoundaryRule on y {
            id: ybr
            minimum: root.height - __contentItem.height
            maximum: 0
            minimumOvershoot: 100
            maximumOvershoot: 100
            overshootFilter: BoundaryRule.Peak
        }

        DragHandler {
            id: dragHandler
            onActiveChanged:
                if (active) {
                    anim.stop()
                    root.flickStarted()
                } else {
                    var vel = centroid.velocity
                    if (xbr.returnToBounds())
                        vel.x = 0
                    if (ybr.returnToBounds())
                        vel.y = 0
                    if (vel.x !== 0 || vel.y !== 0)
                        anim.restart(vel)
                    else
                        root.flickEnded()
                }
        }
        WheelHandler {
            rotationScale: 15
            property: "x"
            orientation: Qt.Horizontal
            acceptedDevices: PointerDevice.Mouse | PointerDevice.TouchPad
            onActiveChanged:
                // emitting signals in both instances is redundant but hard to avoid
                // when the touchpad is flicking along both axes
                if (active) {
                    anim.stop()
                    root.flickStarted()
                } else {
                    xbr.returnToBounds()
                    root.flickEnded()
                }
        }
        WheelHandler {
            rotationScale: 15
            property: "y"
            orientation: Qt.Vertical
            acceptedDevices: PointerDevice.Mouse | PointerDevice.TouchPad
            onActiveChanged:
                if (active) {
                    anim.stop()
                    root.flickStarted()
                } else {
                    ybr.returnToBounds()
                    root.flickEnded()
                }
        }
        MomentumAnimation {
            id: anim
            target: __contentItem
            onStarted: root.flickStarted()
            onStopped: {
                xbr.returnToBounds()
                ybr.returnToBounds()
                root.flickEnded()
            }
        }
    }
}