/**
 * @class Ext.layout.container.Box
 * @extends Ext.layout.container.Container
 * <p>Base Class for HBoxLayout and VBoxLayout Classes. Generally it should not need to be used directly.</p>
 */

Ext.define('Ext.layout.container.Box', {

    /* Begin Definitions */

    alias: ['layout.box'],
    extend: 'Ext.layout.container.Container',
    alternateClassName: 'Ext.layout.BoxLayout',
    
    requires: [
        'Ext.layout.container.boxOverflow.None',
        'Ext.layout.container.boxOverflow.Menu',
        'Ext.layout.container.boxOverflow.Scroller',
        'Ext.util.Format',
        'Ext.dd.DragDropManager'
    ],

    /* End Definitions */

    /**
     * @cfg {Mixed} animate
     * <p>If truthy, child Component are <i>animated</i> into position whenever the Container
     * is layed out. If this option is numeric, it is used as the animation duration in milliseconds.</p>
     * <p>May be set as a property at any time.</p>
     */

    /**
     * @cfg {Object} defaultMargins
     * <p>If the individual contained items do not have a <tt>margins</tt>
     * property specified or margin specified via CSS, the default margins from this property will be
     * applied to each item.</p>
     * <br><p>This property may be specified as an object containing margins
     * to apply in the format:</p><pre><code>
{
    top: (top margin),
    right: (right margin),
    bottom: (bottom margin),
    left: (left margin)
}</code></pre>
     * <p>This property may also be specified as a string containing
     * space-separated, numeric margin values. The order of the sides associated
     * with each value matches the way CSS processes margin values:</p>
     * <div class="mdetail-params"><ul>
     * <li>If there is only one value, it applies to all sides.</li>
     * <li>If there are two values, the top and bottom borders are set to the
     * first value and the right and left are set to the second.</li>
     * <li>If there are three values, the top is set to the first value, the left
     * and right are set to the second, and the bottom is set to the third.</li>
     * <li>If there are four values, they apply to the top, right, bottom, and
     * left, respectively.</li>
     * </ul></div>
     * <p>Defaults to:</p><pre><code>
     * {top:0, right:0, bottom:0, left:0}
     * </code></pre>
     */
    defaultMargins: {
        top: 0,
        right: 0,
        bottom: 0,
        left: 0
    },

    /**
     * @cfg {String} padding
     * <p>Sets the padding to be applied to all child items managed by this layout.</p>
     * <p>This property must be specified as a string containing
     * space-separated, numeric padding values. The order of the sides associated
     * with each value matches the way CSS processes padding values:</p>
     * <div class="mdetail-params"><ul>
     * <li>If there is only one value, it applies to all sides.</li>
     * <li>If there are two values, the top and bottom borders are set to the
     * first value and the right and left are set to the second.</li>
     * <li>If there are three values, the top is set to the first value, the left
     * and right are set to the second, and the bottom is set to the third.</li>
     * <li>If there are four values, they apply to the top, right, bottom, and
     * left, respectively.</li>
     * </ul></div>
     * <p>Defaults to: <code>"0"</code></p>
     */
    padding: '0',
    // documented in subclasses
    pack: 'start',

    /**
     * @cfg {String} pack
     * Controls how the child items of the container are packed together. Acceptable configuration values
     * for this property are:
     * <div class="mdetail-params"><ul>
     * <li><b><tt>start</tt></b> : <b>Default</b><div class="sub-desc">child items are packed together at
     * <b>left</b> side of container</div></li>
     * <li><b><tt>center</tt></b> : <div class="sub-desc">child items are packed together at
     * <b>mid-width</b> of container</div></li>
     * <li><b><tt>end</tt></b> : <div class="sub-desc">child items are packed together at <b>right</b>
     * side of container</div></li>
     * </ul></div>
     */
    /**
     * @cfg {Number} flex
     * This configuration option is to be applied to <b>child <tt>items</tt></b> of the container managed
     * by this layout. Each child item with a <tt>flex</tt> property will be flexed <b>horizontally</b>
     * according to each item's <b>relative</b> <tt>flex</tt> value compared to the sum of all items with
     * a <tt>flex</tt> value specified.  Any child items that have either a <tt>flex = 0</tt> or
     * <tt>flex = undefined</tt> will not be 'flexed' (the initial size will not be changed).
     */

    type: 'box',
    scrollOffset: 0,
    itemCls: Ext.baseCSSPrefix + 'box-item',
    targetCls: Ext.baseCSSPrefix + 'box-layout-ct',
    innerCls: Ext.baseCSSPrefix + 'box-inner',

    bindToOwnerCtContainer: true,

    fixedLayout: false,
    
    // availableSpaceOffset is used to adjust the availableWidth, typically used
    // to reserve space for a scrollbar
    availableSpaceOffset: 0,
    
    // whether or not to reserve the availableSpaceOffset in layout calculations
    reserveOffset: true,
    
    /**
     * @cfg {Boolean} clearInnerCtOnLayout
     */
    clearInnerCtOnLayout: false,

    flexSortFn: function (a, b) {
        var maxParallelPrefix = 'max' + this.parallelPrefixCap,
            infiniteValue = Infinity;
        a = a.component[maxParallelPrefix] || infiniteValue;
        b = b.component[maxParallelPrefix] || infiniteValue;
        // IE 6/7 Don't like Infinity - Infinity...
        if (!isFinite(a) && !isFinite(b)) {
            return false;
        }
        return a - b;
    },

    // Sort into *descending* order.
    minSizeSortFn: function(a, b) {
        return b.available - a.available;
    },

    constructor: function(config) {
        var me = this;

        me.callParent(arguments);

        // The sort function needs access to properties in this, so must be bound.
        me.flexSortFn = Ext.Function.bind(me.flexSortFn, me);

        me.initOverflowHandler();
    },

    /**
     * @private
     * Returns the current size and positioning of the passed child item.
     * @param {Component} child The child Component to calculate the box for
     * @return {Object} Object containing box measurements for the child. Properties are left,top,width,height.
     */
    getChildBox: function(child) {
        child = child.el || this.owner.getComponent(child).el;
        return {
            left: child.getLeft(true),
            top: child.getTop(true),
            width: child.getWidth(),
            height: child.getHeight()
        };
    },

    /**
     * @private
     * Calculates the size and positioning of the passed child item.
     * @param {Component} child The child Component to calculate the box for
     * @return {Object} Object containing box measurements for the child. Properties are left,top,width,height.
     */
    calculateChildBox: function(child) {
        var me = this,
            boxes = me.calculateChildBoxes(me.getVisibleItems(), me.getLayoutTargetSize()).boxes,
            ln = boxes.length,
            i = 0;

        child = me.owner.getComponent(child);
        for (; i < ln; i++) {
            if (boxes[i].component === child) {
                return boxes[i];
            }
        }
    },

    /**
     * @private
     * Calculates the size and positioning of each item in the box. This iterates over all of the rendered,
     * visible items and returns a height, width, top and left for each, as well as a reference to each. Also
     * returns meta data such as maxSize which are useful when resizing layout wrappers such as this.innerCt.
     * @param {Array} visibleItems The array of all rendered, visible items to be calculated for
     * @param {Object} targetSize Object containing target size and height
     * @return {Object} Object containing box measurements for each child, plus meta data
     */
    calculateChildBoxes: function(visibleItems, targetSize) {
        var me = this,
            math = Math,
            mmax = math.max,
            infiniteValue = Infinity,
            undefinedValue,

            parallelPrefix = me.parallelPrefix,
            parallelPrefixCap = me.parallelPrefixCap,
            perpendicularPrefix = me.perpendicularPrefix,
            perpendicularPrefixCap = me.perpendicularPrefixCap,
            parallelMinString = 'min' + parallelPrefixCap,
            perpendicularMinString = 'min' + perpendicularPrefixCap,
            perpendicularMaxString = 'max' + perpendicularPrefixCap,

            parallelSize = targetSize[parallelPrefix] - me.scrollOffset,
            perpendicularSize = targetSize[perpendicularPrefix],
            padding = me.padding,
            parallelOffset = padding[me.parallelBefore],
            paddingParallel = parallelOffset + padding[me.parallelAfter],
            perpendicularOffset = padding[me.perpendicularLeftTop],
            paddingPerpendicular =  perpendicularOffset + padding[me.perpendicularRightBottom],
            availPerpendicularSize = mmax(0, perpendicularSize - paddingPerpendicular),

            isStart = me.pack == 'start',
            isCenter = me.pack == 'center',
            isEnd = me.pack == 'end',

            constrain = Ext.Number.constrain,
            visibleCount = visibleItems.length,
            nonFlexSize = 0,
            totalFlex = 0,
            desiredSize = 0,
            minimumSize = 0,
            maxSize = 0,
            boxes = [],
            minSizes = [],
            calculatedWidth,

            i, child, childParallel, childPerpendicular, childMargins, childSize, minParallel, tmpObj, shortfall, 
            tooNarrow, availableSpace, minSize, item, length, itemIndex, box, oldSize, newSize, reduction, diff, 
            flexedBoxes, remainingSpace, remainingFlex, flexedSize, parallelMargins, calcs, offset, 
            perpendicularMargins, stretchSize;

        //gather the total flex of all flexed items and the width taken up by fixed width items
        for (i = 0; i < visibleCount; i++) {
            child = visibleItems[i];
            childPerpendicular = child[perpendicularPrefix];
            me.layoutItem(child);
            childMargins = child.margins;
            parallelMargins = childMargins[me.parallelBefore] + childMargins[me.parallelAfter];

            // Create the box description object for this child item.
            tmpObj = {
                component: child,
                margins: childMargins
            };

            // flex and not 'auto' width
            if (child.flex) {
                totalFlex += child.flex;
                childParallel = undefinedValue;
            }
            // Not flexed or 'auto' width or undefined width
            else {
                if (!(child[parallelPrefix] && childPerpendicular)) {
                    childSize = child.getSize();
                }
                childParallel = child[parallelPrefix] || childSize[parallelPrefix];
                childPerpendicular = childPerpendicular || childSize[perpendicularPrefix];
            }

            nonFlexSize += parallelMargins + (childParallel || 0);
            desiredSize += parallelMargins + (child.flex ? child[parallelMinString] || 0 : childParallel);
            minimumSize += parallelMargins + (child[parallelMinString] || childParallel || 0);

            // Max height for align - force layout of non-laid out subcontainers without a numeric height
            if (typeof childPerpendicular != 'number') {
                // Clear any static sizing and revert to flow so we can get a proper measurement
                // child['set' + perpendicularPrefixCap](null);
                childPerpendicular = child['get' + perpendicularPrefixCap]();
            }

            // Track the maximum perpendicular size for use by the stretch and stretchmax align config values.
            maxSize = mmax(maxSize, childPerpendicular + childMargins[me.perpendicularLeftTop] + childMargins[me.perpendicularRightBottom]);

            tmpObj[parallelPrefix] = childParallel || undefinedValue;
            tmpObj[perpendicularPrefix] = childPerpendicular || undefinedValue;
            boxes.push(tmpObj);
        }
        shortfall = desiredSize - parallelSize;
        tooNarrow = minimumSize > parallelSize;

        //the space available to the flexed items
        availableSpace = mmax(0, parallelSize - nonFlexSize - paddingParallel - (me.reserveOffset ? me.availableSpaceOffset : 0));

        if (tooNarrow) {
            for (i = 0; i < visibleCount; i++) {
                box = boxes[i];
                minSize = visibleItems[i][parallelMinString] || visibleItems[i][parallelPrefix] || box[parallelPrefix];
                box.dirtySize = box.dirtySize || box[parallelPrefix] != minSize;
                box[parallelPrefix] = minSize;
            }
        }
        else {
            //all flexed items should be sized to their minimum size, other items should be shrunk down until
            //the shortfall has been accounted for
            if (shortfall > 0) {
                /*
                 * When we have a shortfall but are not tooNarrow, we need to shrink the width of each non-flexed item.
                 * Flexed items are immediately reduced to their minWidth and anything already at minWidth is ignored.
                 * The remaining items are collected into the minWidths array, which is later used to distribute the shortfall.
                 */
                for (i = 0; i < visibleCount; i++) {
                    item = visibleItems[i];
                    minSize = item[parallelMinString] || 0;

                    //shrink each non-flex tab by an equal amount to make them all fit. Flexed items are all
                    //shrunk to their minSize because they're flexible and should be the first to lose size
                    if (item.flex) {
                        box = boxes[i];
                        box.dirtySize = box.dirtySize || box[parallelPrefix] != minSize;
                        box[parallelPrefix] = minSize;
                    }
                    else {
                        minSizes.push({
                            minSize: minSize,
                            available: boxes[i][parallelPrefix] - minSize,
                            index: i
                        });
                    }
                }

                //sort by descending amount of width remaining before minWidth is reached
                Ext.Array.sort(minSizes, me.minSizeSortFn);

                /*
                 * Distribute the shortfall (difference between total desired size of all items and actual size available)
                 * between the non-flexed items. We try to distribute the shortfall evenly, but apply it to items with the
                 * smallest difference between their size and minSize first, so that if reducing the size by the average
                 * amount would make that item less than its minSize, we carry the remainder over to the next item.
                 */
                for (i = 0, length = minSizes.length; i < length; i++) {
                    itemIndex = minSizes[i].index;

                    if (itemIndex == undefinedValue) {
                        continue;
                    }
                    item = visibleItems[itemIndex];
                    minSize = minSizes[i].minSize;

                    box = boxes[itemIndex];
                    oldSize = box[parallelPrefix];
                    newSize = mmax(minSize, oldSize - math.ceil(shortfall / (length - i)));
                    reduction = oldSize - newSize;

                    box.dirtySize = box.dirtySize || box[parallelPrefix] != newSize;
                    box[parallelPrefix] = newSize;
                    shortfall -= reduction;
                }
            }
            else {
                remainingSpace = availableSpace;
                remainingFlex = totalFlex;
                flexedBoxes = [];

                // Create an array containing *just the flexed boxes* for allocation of remainingSpace
                for (i = 0; i < visibleCount; i++) {
                    child = visibleItems[i];
                    if (isStart && child.flex) {
                        flexedBoxes.push(boxes[Ext.Array.indexOf(visibleItems, child)]);
                    }
                }
                // The flexed boxes need to be sorted in ascending order of maxSize to work properly
                // so that unallocated space caused by maxWidth being less than flexed width
                // can be reallocated to subsequent flexed boxes.
                Ext.Array.sort(flexedBoxes, me.flexSortFn);

                // Calculate the size of each flexed item, and attempt to set it.
                for (i = 0; i < flexedBoxes.length; i++) {
                    calcs = flexedBoxes[i];
                    child = calcs.component;
                    childMargins = calcs.margins;

                    flexedSize = math.ceil((child.flex / remainingFlex) * remainingSpace);

                    // Implement maxSize and minSize check
                    flexedSize = Math.max(child['min' + parallelPrefixCap] || 0, math.min(child['max' + parallelPrefixCap] || infiniteValue, flexedSize));

                    // Remaining space has already had all parallel margins subtracted from it, so just subtract consumed size
                    remainingSpace -= flexedSize;
                    remainingFlex -= child.flex;

                    calcs.dirtySize = calcs.dirtySize || calcs[parallelPrefix] != flexedSize;
                    calcs[parallelPrefix] = flexedSize;
                }
            }
        }

        if (isCenter) {
            parallelOffset += availableSpace / 2;
        }
        else if (isEnd) {
            parallelOffset += availableSpace;
        }

        // Fix for left and right docked Components in a dock component layout. This is for docked Headers and docked Toolbars.
        // Older Microsoft browsers do not size a position:absolute element's width to match its content.
        // So in this case, in the updateInnerCtSize method we may need to adjust the size of the owning Container's element explicitly based upon
        // the discovered max width. So here we put a calculatedWidth property in the metadata to facilitate this.
        if (me.owner.dock && (Ext.isIE6 || Ext.isIE7 || Ext.isIEQuirks) && !me.owner.width && me.direction == 'vertical') {

            calculatedWidth = maxSize + me.owner.el.getPadding('lr') + me.owner.el.getBorderWidth('lr');
            if (me.owner.frameSize) {
                calculatedWidth += me.owner.frameSize.left + me.owner.frameSize.right;
            }
            // If the owning element is not sized, calculate the available width to center or stretch in based upon maxSize
            availPerpendicularSize = Math.min(availPerpendicularSize, targetSize.width = maxSize + padding.left + padding.right);
        }

        //finally, calculate the left and top position of each item
        for (i = 0; i < visibleCount; i++) {
            child = visibleItems[i];
            calcs = boxes[i];

            childMargins = calcs.margins;

            perpendicularMargins = childMargins[me.perpendicularLeftTop] + childMargins[me.perpendicularRightBottom];

            // Advance past the "before" margin
            parallelOffset += childMargins[me.parallelBefore];

            calcs[me.parallelBefore] = parallelOffset;
            calcs[me.perpendicularLeftTop] = perpendicularOffset + childMargins[me.perpendicularLeftTop];

            if (me.align == 'stretch') {
                stretchSize = constrain(availPerpendicularSize - perpendicularMargins, child[perpendicularMinString] || 0, child[perpendicularMaxString] || infiniteValue);
                calcs.dirtySize = calcs.dirtySize || calcs[perpendicularPrefix] != stretchSize;
                calcs[perpendicularPrefix] = stretchSize;
            }
            else if (me.align == 'stretchmax') {
                stretchSize = constrain(maxSize - perpendicularMargins, child[perpendicularMinString] || 0, child[perpendicularMaxString] || infiniteValue);
                calcs.dirtySize = calcs.dirtySize || calcs[perpendicularPrefix] != stretchSize;
                calcs[perpendicularPrefix] = stretchSize;
            }
            else if (me.align == me.alignCenteringString) {
                // When calculating a centered position within the content box of the innerCt, the width of the borders must be subtracted from
                // the size to yield the space available to center within.
                // The updateInnerCtSize method explicitly adds the border widths to the set size of the innerCt.
                diff = mmax(availPerpendicularSize, maxSize) - me.innerCt.getBorderWidth(me.perpendicularLT + me.perpendicularRB) - calcs[perpendicularPrefix];
                if (diff > 0) {
                    calcs[me.perpendicularLeftTop] = perpendicularOffset + Math.round(diff / 2);
                }
            }

            // Advance past the box size and the "after" margin
            parallelOffset += (calcs[parallelPrefix] || 0) + childMargins[me.parallelAfter];
        }

        return {
            boxes: boxes,
            meta : {
                calculatedWidth: calculatedWidth,
                maxSize: maxSize,
                nonFlexSize: nonFlexSize,
                desiredSize: desiredSize,
                minimumSize: minimumSize,
                shortfall: shortfall,
                tooNarrow: tooNarrow
            }
        };
    },
    
    onRemove: function(comp){
        this.callParent(arguments);
        if (this.overflowHandler) {
            this.overflowHandler.onRemove(comp);
        }
    },

    /**
     * @private
     */
    initOverflowHandler: function() {
        var handler = this.overflowHandler;

        if (typeof handler == 'string') {
            handler = {
                type: handler
            };
        }

        var handlerType = 'None';
        if (handler && handler.type !== undefined) {
            handlerType = handler.type;
        }

        var constructor = Ext.layout.container.boxOverflow[handlerType];
        if (constructor[this.type]) {
            constructor = constructor[this.type];
        }

        this.overflowHandler = Ext.create('Ext.layout.container.boxOverflow.' + handlerType, this, handler);
    },

    /**
     * @private
     * Runs the child box calculations and caches them in childBoxCache. Subclasses can used these cached values
     * when laying out
     */
    onLayout: function() {
        this.callParent();
        // Clear the innerCt size so it doesn't influence the child items.
        if (this.clearInnerCtOnLayout === true && this.adjustmentPass !== true) {
            this.innerCt.setSize(null, null);
        }

        var me = this,
            targetSize = me.getLayoutTargetSize(),
            items = me.getVisibleItems(),
            calcs = me.calculateChildBoxes(items, targetSize),
            boxes = calcs.boxes,
            meta = calcs.meta,
            handler, method, results;

        if (me.autoSize && calcs.meta.desiredSize) {
            targetSize[me.parallelPrefix] = calcs.meta.desiredSize;
        }

        //invoke the overflow handler, if one is configured
        if (meta.shortfall > 0) {
            handler = me.overflowHandler;
            method = meta.tooNarrow ? 'handleOverflow': 'clearOverflow';

            results = handler[method](calcs, targetSize);

            if (results) {
                if (results.targetSize) {
                    targetSize = results.targetSize;
                }

                if (results.recalculate) {
                    items = me.getVisibleItems(owner);
                    calcs = me.calculateChildBoxes(items, targetSize);
                    boxes = calcs.boxes;
                }
            }
        } else {
            me.overflowHandler.clearOverflow();
        }

        /**
         * @private
         * @property layoutTargetLastSize
         * @type Object
         * Private cache of the last measured size of the layout target. This should never be used except by
         * BoxLayout subclasses during their onLayout run.
         */
        me.layoutTargetLastSize = targetSize;

        /**
         * @private
         * @property childBoxCache
         * @type Array
         * Array of the last calculated height, width, top and left positions of each visible rendered component
         * within the Box layout.
         */
        me.childBoxCache = calcs;

        me.updateInnerCtSize(targetSize, calcs);
        me.updateChildBoxes(boxes);
        me.handleTargetOverflow(targetSize);
    },

    /**
     * Resizes and repositions each child component
     * @param {Array} boxes The box measurements
     */
    updateChildBoxes: function(boxes) {
        var me = this,
            i = 0,
            length = boxes.length,
            animQueue = [],
            dd = Ext.dd.DDM.getDDById(me.innerCt.id), // Any DD active on this layout's element (The BoxReorderer plugin does this.)
            oldBox, newBox, changed, comp, boxAnim, animCallback;

        for (; i < length; i++) {
            newBox = boxes[i];
            comp = newBox.component;

            // If a Component is being drag/dropped, skip positioning it.
            // Accomodate the BoxReorderer plugin: Its current dragEl must not be positioned by the layout
            if (dd && (dd.getDragEl() === comp.el.dom)) {
                continue;
            }

            changed = false;

            oldBox = me.getChildBox(comp);

            // If we are animating, we build up an array of Anim config objects, one for each
            // child Component which has any changed box properties. Those with unchanged
            // properties are not animated.
            if (me.animate) {
                // Animate may be a config object containing callback.
                animCallback = me.animate.callback || me.animate;
                boxAnim = {
                    layoutAnimation: true,  // Component Target handler must use set*Calculated*Size
                    target: comp,
                    from: {},
                    to: {},
                    listeners: {}
                };
                // Only set from and to properties when there's a change.
                // Perform as few Component setter methods as possible.
                // Temporarily set the property values that we are not animating
                // so that doComponentLayout does not auto-size them.
                if (!isNaN(newBox.width) && (newBox.width != oldBox.width)) {
                    changed = true;
                    // boxAnim.from.width = oldBox.width;
                    boxAnim.to.width = newBox.width;
                }
                if (!isNaN(newBox.height) && (newBox.height != oldBox.height)) {
                    changed = true;
                    // boxAnim.from.height = oldBox.height;
                    boxAnim.to.height = newBox.height;
                }
                if (!isNaN(newBox.left) && (newBox.left != oldBox.left)) {
                    changed = true;
                    // boxAnim.from.left = oldBox.left;
                    boxAnim.to.left = newBox.left;
                }
                if (!isNaN(newBox.top) && (newBox.top != oldBox.top)) {
                    changed = true;
                    // boxAnim.from.top = oldBox.top;
                    boxAnim.to.top = newBox.top;
                }
                if (changed) {
                    animQueue.push(boxAnim);
                }
            } else {
                if (newBox.dirtySize) {
                    if (newBox.width !== oldBox.width || newBox.height !== oldBox.height) {
                        me.setItemSize(comp, newBox.width, newBox.height);
                    }
                }
                // Don't set positions to NaN
                if (isNaN(newBox.left) || isNaN(newBox.top)) {
                    continue;
                }
                comp.setPosition(newBox.left, newBox.top);
            }
        }

        // Kick off any queued animations
        length = animQueue.length;
        if (length) {

            // A function which cleans up when a Component's animation is done.
            // The last one to finish calls the callback.
            var afterAnimate = function(anim) {
                // When we've animated all changed boxes into position, clear our busy flag and call the callback.
                length -= 1;
                if (!length) {
                    me.layoutBusy = false;
                    if (Ext.isFunction(animCallback)) {
                        animCallback();
                    }
                }
            };

            var beforeAnimate = function() {
                me.layoutBusy = true;
            };

            // Start each box animation off
            for (i = 0, length = animQueue.length; i < length; i++) {
                boxAnim = animQueue[i];

                // Clean up the Component after. Clean up the *layout* after the last animation finishes
                boxAnim.listeners.afteranimate = afterAnimate;

                // The layout is busy during animation, and may not be called, so set the flag when the first animation begins
                if (!i) {
                    boxAnim.listeners.beforeanimate = beforeAnimate;
                }
                if (me.animate.duration) {
                    boxAnim.duration = me.animate.duration;
                }
                comp = boxAnim.target;
                delete boxAnim.target;
                // Stop any currently running animation
                comp.stopAnimation();
                comp.animate(boxAnim);
            }
        }
    },

    /**
     * @private
     * Called by onRender just before the child components are sized and positioned. This resizes the innerCt
     * to make sure all child items fit within it. We call this before sizing the children because if our child
     * items are larger than the previous innerCt size the browser will insert scrollbars and then remove them
     * again immediately afterwards, giving a performance hit.
     * Subclasses should provide an implementation.
     * @param {Object} currentSize The current height and width of the innerCt
     * @param {Array} calculations The new box calculations of all items to be laid out
     */
    updateInnerCtSize: function(tSize, calcs) {
        var me = this,
            mmax = Math.max,
            align = me.align,
            padding = me.padding,
            width = tSize.width,
            height = tSize.height,
            meta = calcs.meta,
            innerCtWidth,
            innerCtHeight;

        if (me.direction == 'horizontal') {
            innerCtWidth = width;
            innerCtHeight = meta.maxSize + padding.top + padding.bottom + me.innerCt.getBorderWidth('tb');

            if (align == 'stretch') {
                innerCtHeight = height;
            }
            else if (align == 'middle') {
                innerCtHeight = mmax(height, innerCtHeight);
            }
        } else {
            innerCtHeight = height;
            innerCtWidth = meta.maxSize + padding.left + padding.right + me.innerCt.getBorderWidth('lr');

            if (align == 'stretch') {
                innerCtWidth = width;
            }
            else if (align == 'center') {
                innerCtWidth = mmax(width, innerCtWidth);
            }
        }
        me.getRenderTarget().setSize(innerCtWidth || undefined, innerCtHeight || undefined);

        // If a calculated width has been found (and this only happens for auto-width vertical docked Components in old Microsoft browsers)
        // then, if the Component has not assumed the size of its content, set it to do so.
        if (meta.calculatedWidth && me.owner.el.getWidth() > meta.calculatedWidth) {
            me.owner.el.setWidth(meta.calculatedWidth);
        }

        if (me.innerCt.dom.scrollTop) {
            me.innerCt.dom.scrollTop = 0;
        }
    },

    /**
     * @private
     * This should be called after onLayout of any BoxLayout subclass. If the target's overflow is not set to 'hidden',
     * we need to lay out a second time because the scrollbars may have modified the height and width of the layout
     * target. Having a Box layout inside such a target is therefore not recommended.
     * @param {Object} previousTargetSize The size and height of the layout target before we just laid out
     * @param {Ext.container.Container} container The container
     * @param {Ext.core.Element} target The target element
     * @return True if the layout overflowed, and was reflowed in a secondary onLayout call.
     */
    handleTargetOverflow: function(previousTargetSize) {
        var target = this.getTarget(),
            overflow = target.getStyle('overflow'),
            newTargetSize;

        if (overflow && overflow != 'hidden' && !this.adjustmentPass) {
            newTargetSize = this.getLayoutTargetSize();
            if (newTargetSize.width != previousTargetSize.width || newTargetSize.height != previousTargetSize.height) {
                this.adjustmentPass = true;
                this.onLayout();
                return true;
            }
        }

        delete this.adjustmentPass;
    },

    // private
    isValidParent : function(item, target, position) {
        // Note: Box layouts do not care about order within the innerCt element because it's an absolutely positioning layout
        // We only care whether the item is a direct child of the innerCt element.
        var itemEl = item.el ? item.el.dom : Ext.getDom(item);
        return (itemEl && this.innerCt && itemEl.parentNode === this.innerCt.dom) || false;
    },

    // Overridden method from AbstractContainer.
    // Used in the base AbstractLayout.beforeLayout method to render all items into.
    getRenderTarget: function() {
        if (!this.innerCt) {
            // the innerCt prevents wrapping and shuffling while the container is resizing
            this.innerCt = this.getTarget().createChild({
                cls: this.innerCls,
                role: 'presentation'
            });
            this.padding = Ext.util.Format.parseBox(this.padding);
        }
        return this.innerCt;
    },

    // private
    renderItem: function(item, target) {
        this.callParent(arguments);
        var me = this,
            itemEl = item.getEl(),
            style = itemEl.dom.style,
            margins = item.margins || item.margin;

        // Parse the item's margin/margins specification
        if (margins) {
            if (Ext.isString(margins) || Ext.isNumber(margins)) {
                margins = Ext.util.Format.parseBox(margins);
            } else {
                Ext.applyIf(margins, {top: 0, right: 0, bottom: 0, left: 0});
            }
        } else {
            margins = Ext.apply({}, me.defaultMargins);
        }

        // Add any before/after CSS margins to the configured margins, and zero the CSS margins
        margins.top    += itemEl.getMargin('t');
        margins.right  += itemEl.getMargin('r');
        margins.bottom += itemEl.getMargin('b');
        margins.left   += itemEl.getMargin('l');
        style.marginTop = style.marginRight = style.marginBottom = style.marginLeft = '0';

        // Item must reference calculated margins.
        item.margins = margins;
    },

    /**
     * @private
     */
    destroy: function() {
        Ext.destroy(this.overflowHandler);
        this.callParent(arguments);
    }
});