/*
This file is part of Ext JS 4.2

Copyright (c) 2011-2013 Sencha Inc

Contact:  http://www.sencha.com/contact

GNU General Public License Usage
This file may be used under the terms of the GNU General Public License version 3.0 as
published by the Free Software Foundation and appearing in the file LICENSE included in the
packaging of this file.

Please review the following information to ensure the GNU General Public License version 3.0
requirements will be met: http://www.gnu.org/copyleft/gpl.html.

If you are unsure which license is appropriate for your use, please contact the sales department
at http://www.sencha.com/contact.

Build date: 2013-05-16 14:36:50 (f9be68accb407158ba2b1be2c226a6ce1f649314)
*/
/**
 * Private utility class for Ext.resizer.Resizer.
 * @private
 */
Ext.define('Ext.resizer.ResizeTracker', {
    extend: 'Ext.dd.DragTracker',
    dynamic: true,
    preserveRatio: false,

    // Default to no constraint
    constrainTo: null,
    
    proxyCls:  Ext.baseCSSPrefix + 'resizable-proxy',

    constructor: function(config) {
        var me = this,
            widthRatio, heightRatio,
            throttledResizeFn;

        if (!config.el) {
            if (config.target.isComponent) {
                me.el = config.target.getEl();
            } else {
                me.el = config.target;
            }
        }
        this.callParent(arguments);

        // Ensure that if we are preserving aspect ratio, the largest minimum is honoured
        if (me.preserveRatio && me.minWidth && me.minHeight) {
            widthRatio = me.minWidth / me.el.getWidth();
            heightRatio = me.minHeight / me.el.getHeight();

            // largest ratio of minimum:size must be preserved.
            // So if a 400x200 pixel image has
            // minWidth: 50, maxWidth: 50, the maxWidth will be 400 * (50/200)... that is 100
            if (heightRatio > widthRatio) {
                me.minWidth = me.el.getWidth() * heightRatio;
            } else {
                me.minHeight = me.el.getHeight() * widthRatio;
            }
        }

        // If configured as throttled, create an instance version of resize which calls
        // a throttled function to perform the resize operation.
        if (me.throttle) {
            throttledResizeFn = Ext.Function.createThrottled(function() {
                    Ext.resizer.ResizeTracker.prototype.resize.apply(me, arguments);
                }, me.throttle);

            me.resize = function(box, direction, atEnd) {
                if (atEnd) {
                    Ext.resizer.ResizeTracker.prototype.resize.apply(me, arguments);
                } else {
                    throttledResizeFn.apply(null, arguments);
                }
            };
        }
    },

    onBeforeStart: function(e) {
        // record the startBox
        this.startBox = this.target.getBox();
    },

    /**
     * @private
     * Returns the object that will be resized on every mousemove event.
     * If dynamic is false, this will be a proxy, otherwise it will be our actual target.
     */
    getDynamicTarget: function() {
        var me = this,
            target = me.target;
            
        if (me.dynamic) {
            return target;
        } else if (!me.proxy) {
            me.proxy = me.createProxy(target);
        }
        me.proxy.show();
        return me.proxy;
    },

    /**
     * Create a proxy for this resizer
     * @param {Ext.Component/Ext.Element} target The target
     * @return {Ext.Element} A proxy element
     */
    createProxy: function(target){
        var proxy,
            cls = this.proxyCls;

        if (target.isComponent) {
            proxy = target.getProxy().addCls(cls);
        } else {
            proxy = target.createProxy({
                tag: 'div',
                cls: cls,
                id: target.id + '-rzproxy'
            }, Ext.getBody());
        }
        proxy.removeCls(Ext.baseCSSPrefix + 'proxy-el');
        return proxy;
    },

    onStart: function(e) {
        // returns the Ext.ResizeHandle that the user started dragging
        this.activeResizeHandle = Ext.get(this.getDragTarget().id);

        // If we are using a proxy, ensure it is sized.
        if (!this.dynamic) {
            this.resize(this.startBox, {
                horizontal: 'none',
                vertical: 'none'
            });
        }
    },

    onDrag: function(e) {
        // dynamic resizing, update dimensions during resize
        if (this.dynamic || this.proxy) {
            this.updateDimensions(e);
        }
    },

    updateDimensions: function(e, atEnd) {
        var me = this,
            region = me.activeResizeHandle.region,
            offset = me.getOffset(me.constrainTo ? 'dragTarget' : null),
            box = me.startBox,
            ratio,
            widthAdjust = 0,
            heightAdjust = 0,
            snappedWidth,
            snappedHeight,
            adjustX = 0,
            adjustY = 0,
            dragRatio,
            horizDir = offset[0] < 0 ? 'right' : 'left',
            vertDir = offset[1] < 0 ? 'down' : 'up',
            oppositeCorner,
            axis, // 1 = x, 2 = y, 3 = x and y.
            newBox,
            newHeight, newWidth;

        region = me.convertRegionName(region);

        switch (region) {
            case 'south':
                heightAdjust = offset[1];
                axis = 2;
                break;
            case 'north':
                heightAdjust = -offset[1];
                adjustY = -heightAdjust;
                axis = 2;
                break;
            case 'east':
                widthAdjust = offset[0];
                axis = 1;
                break;
            case 'west':
                widthAdjust = -offset[0];
                adjustX = -widthAdjust;
                axis = 1;
                break;
            case 'northeast':
                heightAdjust = -offset[1];
                adjustY = -heightAdjust;
                widthAdjust = offset[0];
                oppositeCorner = [box.x, box.y + box.height];
                axis = 3;
                break;
            case 'southeast':
                heightAdjust = offset[1];
                widthAdjust = offset[0];
                oppositeCorner = [box.x, box.y];
                axis = 3;
                break;
            case 'southwest':
                widthAdjust = -offset[0];
                adjustX = -widthAdjust;
                heightAdjust = offset[1];
                oppositeCorner = [box.x + box.width, box.y];
                axis = 3;
                break;
            case 'northwest':
                heightAdjust = -offset[1];
                adjustY = -heightAdjust;
                widthAdjust = -offset[0];
                adjustX = -widthAdjust;
                oppositeCorner = [box.x + box.width, box.y + box.height];
                axis = 3;
                break;
        }

        newBox = {
            width: box.width + widthAdjust,
            height: box.height + heightAdjust,
            x: box.x + adjustX,
            y: box.y + adjustY
        };

        // Snap value between stops according to configured increments
        snappedWidth = Ext.Number.snap(newBox.width, me.widthIncrement);
        snappedHeight = Ext.Number.snap(newBox.height, me.heightIncrement);
        if (snappedWidth != newBox.width || snappedHeight != newBox.height){
            switch (region) {
                case 'northeast':
                    newBox.y -= snappedHeight - newBox.height;
                    break;
                case 'north':
                    newBox.y -= snappedHeight - newBox.height;
                    break;
                case 'southwest':
                    newBox.x -= snappedWidth - newBox.width;
                    break;
                case 'west':
                    newBox.x -= snappedWidth - newBox.width;
                    break;
                case 'northwest':
                    newBox.x -= snappedWidth - newBox.width;
                    newBox.y -= snappedHeight - newBox.height;
            }
            newBox.width = snappedWidth;
            newBox.height = snappedHeight;
        }

        // out of bounds
        if (newBox.width < me.minWidth || newBox.width > me.maxWidth) {
            newBox.width = Ext.Number.constrain(newBox.width, me.minWidth, me.maxWidth);

            // Re-adjust the X position if we were dragging the west side
            if (adjustX) {
                newBox.x = box.x + (box.width - newBox.width);
            }
        } else {
            me.lastX = newBox.x;
        }
        if (newBox.height < me.minHeight || newBox.height > me.maxHeight) {
            newBox.height = Ext.Number.constrain(newBox.height, me.minHeight, me.maxHeight);

            // Re-adjust the Y position if we were dragging the north side
            if (adjustY) {
                newBox.y = box.y + (box.height - newBox.height);
            }
        } else {
            me.lastY = newBox.y;
        }

        // If this is configured to preserve the aspect ratio, or they are dragging using the shift key
        if (me.preserveRatio || e.shiftKey) {
            ratio = me.startBox.width / me.startBox.height;

            // Calculate aspect ratio constrained values.
            newHeight = Math.min(Math.max(me.minHeight, newBox.width / ratio), me.maxHeight);
            newWidth = Math.min(Math.max(me.minWidth, newBox.height * ratio), me.maxWidth);

            // X axis: width-only change, height must obey
            if (axis == 1) {
                newBox.height = newHeight;
            }

            // Y axis: height-only change, width must obey
            else if (axis == 2) {
                newBox.width = newWidth;
            }

            // Corner drag.
            else {
                // Drag ratio is the ratio of the mouse point from the opposite corner.
                // Basically what edge we are dragging, a horizontal edge or a vertical edge.
                dragRatio = Math.abs(oppositeCorner[0] - this.lastXY[0]) / Math.abs(oppositeCorner[1] - this.lastXY[1]);

                // If drag ratio > aspect ratio then width is dominant and height must obey
                if (dragRatio > ratio) {
                    newBox.height = newHeight;
                } else {
                    newBox.width = newWidth;
                }

                // Handle dragging start coordinates
                if (region == 'northeast') {
                    newBox.y = box.y - (newBox.height - box.height);
                } else if (region == 'northwest') {
                    newBox.y = box.y - (newBox.height - box.height);
                    newBox.x = box.x - (newBox.width - box.width);
                } else if (region == 'southwest') {
                    newBox.x = box.x - (newBox.width - box.width);
                }
            }
        }

        if (heightAdjust === 0) {
            vertDir = 'none';
        }
        if (widthAdjust === 0) {
            horizDir = 'none';
        }
        me.resize(newBox, {
            horizontal: horizDir,
            vertical: vertDir
        }, atEnd);
    },

    getResizeTarget: function(atEnd) {
        return atEnd ? this.target : this.getDynamicTarget();
    },

    resize: function(box, direction, atEnd) {
        var me = this,
            target = me.getResizeTarget(atEnd);

        target.setBox(box);

        // update the originalTarget if it was wrapped, and the target passed in was the wrap el.
        if (me.originalTarget && (me.dynamic || atEnd)) {
            me.originalTarget.setBox(box);
        }
    },

    onEnd: function(e) {
        this.updateDimensions(e, true);
        if (this.proxy) {
            this.proxy.hide();
        }
    },

    convertRegionName: function(name) {
        return name;
    }
});
