/**
 * @class Ext.layout.CardLayout
 * @extends Ext.layout.FitLayout
 * 
This layout manages multiple child Components, each fitted to the Container, where only a single child Component can be
 * visible at any given time.  This layout style is most commonly used for wizards, tab implementations, etc.
 * This class is intended to be extended or created via the layout:'card' {@link Ext.Container#layout} config,
 * and should generally not need to be created directly via the new keyword.

 * 
The CardLayout's focal method is {@link #setActiveItem}.  Since only one panel is displayed at a time,
 * the only way to move from one Component to the next is by calling setActiveItem, passing the id or index of
 * the next panel to display.  The layout itself does not provide a user interface for handling this navigation,
 * so that functionality must be provided by the developer.

 * 
In the following example, a simplistic wizard setup is demonstrated.  A button bar is added
 * to the footer of the containing panel to provide navigation buttons.  The buttons will be handled by a
 * common navigation routine -- for this example, the implementation of that routine has been ommitted since
 * it can be any type of custom logic.  Note that other uses of a CardLayout (like a tab control) would require a
 * completely different implementation.  For serious implementations, a better approach would be to extend
 * CardLayout to provide the custom functionality needed.  Example usage:

 * 

var navHandler = function(direction){
    // This routine could contain business logic required to manage the navigation steps.
    // It would call setActiveItem as needed, manage navigation button state, handle any
    // branching logic that might be required, handle alternate actions like cancellation
    // or finalization, etc.  A complete wizard implementation could get pretty
    // sophisticated depending on the complexity required, and should probably be
    // done as a subclass of CardLayout in a real-world implementation.
};

var card = new Ext.Panel({
    title: 'Example Wizard',
    layout:'card',
    activeItem: 0, // make sure the active item is set on the container config!
    bodyStyle: 'padding:15px',
    defaults: {
        // applied to each contained panel
        border:false
    },
    // just an example of one possible navigation scheme, using buttons
    bbar: [
        {
            id: 'move-prev',
            text: 'Back',
            handler: navHandler.createDelegate(this, [-1]),
            disabled: true
        },
        '->', // greedy spacer so that the buttons are aligned to each side
        {
            id: 'move-next',
            text: 'Next',
            handler: navHandler.createDelegate(this, [1])
        }
    ],
    // the panels (or "cards") within the layout
    items: [{
        id: 'card-0',
        html: '<h1>Welcome to the Wizard!</h1><p>Step 1 of 3</p>'
    },{
        id: 'card-1',
        html: '<p>Step 2 of 3</p>'
    },{
        id: 'card-2',
        html: '<h1>Congratulations!</h1><p>Step 3 of 3 - Complete</p>'
    }]
});

 */
Ext.layout.CardLayout = Ext.extend(Ext.layout.FitLayout, {
    
/**
     * @cfg {Boolean} deferredRender
     * True to render each contained item at the time it becomes active, false to render all contained items
     * as soon as the layout is rendered (defaults to false).  If there is a significant amount of content or
     * a lot of heavy controls being rendered into panels that are not displayed by default, setting this to
     * true might improve performance.
     */
    deferredRender : false,
    
    
/**
     * @cfg {Boolean} layoutOnCardChange
     * True to force a layout of the active item when the active card is changed. Defaults to false.
     */
    layoutOnCardChange : false,

    
/**
     * @cfg {Boolean} renderHidden @hide
     */
    // private
    renderHidden : true,
    
    constructor: function(config){
        Ext.layout.CardLayout.superclass.constructor.call(this, config);
        this.forceLayout = (this.deferredRender === false);
    },

    
/**
     * Sets the active (visible) item in the layout.
     * @param {String/Number} item The string component id or numeric index of the item to activate
     */
    setActiveItem : function(item){
        item = this.container.getComponent(item);
        if(this.activeItem != item){
            if(this.activeItem){
                this.activeItem.hide();
            }
            this.activeItem = item;
            item.show();
            this.container.doLayout();
            if(this.layoutOnCardChange && item.doLayout){
                item.doLayout();
            }
        }
    },

    // private
    renderAll : function(ct, target){
        if(this.deferredRender){
            this.renderItem(this.activeItem, undefined, target);
        }else{
            Ext.layout.CardLayout.superclass.renderAll.call(this, ct, target);
        }
    }
});
Ext.Container.LAYOUTS['card'] = Ext.layout.CardLayout;