/*
 * Copyright (C) 2014 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/>.
 *
 * Authors: Michael Zanetti <michael.zanetti@canonical.com>
 */

import QtQuick 2.3
import Ubuntu.Components 1.1

MouseArea {
    id: root
    anchors.fill: target
    anchors.margins: -resizeHandleWidth

    // The target item managed by this. Must be a parent or a sibling
    // The area will anchor to it and manage move and resize events
    property var target: null
    property int resizeHandleWidth: 0
    property int minWidth: 0
    property int minHeight: 0

    QtObject {
        id: priv
        readonly property int windowWidth: root.width - root.resizeHandleWidth * 2
        readonly property int windowHeight: root.height - resizeHandleWidth * 2

        property var startPoint
        property int startWidth
        property int startHeight

        property bool resizeTop: false
        property bool resizeBottom: false
        property bool resizeLeft: false
        property bool resizeRight: false

    }

    onPressed: {
        priv.startPoint = mapToItem(null, Qt.point(mouse.x, mouse.y)).x;
        priv.startWidth = root.width;
        priv.startHeight = root.height;
        priv.resizeTop = mouseY < root.resizeHandleWidth;
        priv.resizeBottom = mouseY > (root.height - root.resizeHandleWidth);
        priv.resizeLeft = mouseX < root.resizeHandleWidth;
        priv.resizeRight = mouseX > (root.width - root.resizeHandleWidth);
    }

    onPositionChanged: {
        var currentPoint = mapToItem(null, Qt.point(mouse.x, mouse.y)).x;
        var mouseDiff = Qt.point(currentPoint.x - priv.startPoint.x, currentPoint.y - priv.startPoint.y);
        var moveDiff = Qt.point(0, 0);
        var sizeDiff = Qt.point(0, 0);
        if (priv.resizeTop || priv.resizeBottom || priv.resizeLeft || priv.resizeRight) {
            if (priv.resizeTop) {
                moveDiff.y += mouseDiff.y;
                sizeDiff.y += -mouseDiff.y;
            } else if (priv.resizeBottom) {
                sizeDiff.y += mouse.y - priv.startPoint.y;
                priv.startPoint.y = mouse.y
            }
            if (priv.resizeLeft) {
                moveDiff.x += mouseDiff.x;
                sizeDiff.x += -mouseDiff.x;
            } else if (priv.resizeRight) {
                sizeDiff.x += mouse.x - priv.startPoint.x;
                priv.startPoint.x = mouse.x
            }
            if (priv.windowWidth + sizeDiff.x < root.minWidth) {
                sizeDiff.x = root.minWidth - priv.windowWidth;
                moveDiff.x = moveDiff.x == 0 ? 0 : -sizeDiff.x;
            }
            if (priv.windowHeight + sizeDiff.y < root.minHeight) {
                sizeDiff.y = root.minHeight - priv.windowHeight;
                moveDiff.y = moveDiff.y == 0 ? 0 : -sizeDiff.y;
            }

            target.x += moveDiff.x;
            target.y += moveDiff.y;
            target.width += sizeDiff.x;
            target.height += sizeDiff.y;
        } else {
            target.x += mouseDiff.x;
            target.y += mouseDiff.y;
        }
    }
}