/**
 * @class Ext.util.KeyNav
 * <p>Provides a convenient wrapper for normalized keyboard navigation.  KeyNav allows you to bind
 * navigation keys to function calls that will get called when the keys are pressed, providing an easy
 * way to implement custom navigation schemes for any UI component.</p>
 * <p>The following are all of the possible keys that can be implemented: enter, space, left, right, up, down, tab, esc,
 * pageUp, pageDown, del, backspace, home, end.  Usage:</p>
 <pre><code>
var nav = new Ext.util.KeyNav("my-element", {
    "left" : function(e){
        this.moveLeft(e.ctrlKey);
    },
    "right" : function(e){
        this.moveRight(e.ctrlKey);
    },
    "enter" : function(e){
        this.save();
    },
    scope : this
});
</code></pre>
 */
Ext.define('Ext.util.KeyNav', {
    
    alternateClassName: 'Ext.KeyNav',
    
    requires: ['Ext.util.KeyMap'],
    
    statics: {
        keyOptions: {
            left: 37,
            right: 39,
            up: 38,
            down: 40,
            space: 32,
            pageUp: 33,
            pageDown: 34,
            del: 46,
            backspace: 8,
            home: 36,
            end: 35,
            enter: 13,
            esc: 27,
            tab: 9
        }
    },

    /**
     * Creates new KeyNav.
     * @param {Mixed} el The element to bind to
     * @param {Object} config The config
     */
    constructor: function(el, config){
        this.setConfig(el, config || {});
    },
    
    /**
     * Sets up a configuration for the KeyNav.
     * @private
     * @param {Mixed} el The element to bind to
     * @param {Object}A configuration object as specified in the constructor.
     */
    setConfig: function(el, config) {
        if (this.map) {
            this.map.destroy();
        }
        
        var map = Ext.create('Ext.util.KeyMap', el, null, this.getKeyEvent('forceKeyDown' in config ? config.forceKeyDown : this.forceKeyDown)),
            keys = Ext.util.KeyNav.keyOptions,
            scope = config.scope || this,
            key;
        
        this.map = map;
        for (key in keys) {
            if (keys.hasOwnProperty(key)) {
                if (config[key]) {
                    map.addBinding({
                        scope: scope,
                        key: keys[key],
                        handler: Ext.Function.bind(this.handleEvent, scope, [config[key]], true),
                        defaultEventAction: config.defaultEventAction || this.defaultEventAction
                    });
                }
            }
        }
        
        map.disable();
        if (!config.disabled) {
            map.enable();
        }
    },
    
    /**
     * Method for filtering out the map argument
     * @private
     * @param {Ext.util.KeyMap} map
     * @param {Ext.EventObject} event
     * @param {Object} options Contains the handler to call
     */
    handleEvent: function(map, event, handler){
        return handler.call(this, event);
    },
    
    /**
     * @cfg {Boolean} disabled
     * True to disable this KeyNav instance (defaults to false)
     */
    disabled: false,
    
    /**
     * @cfg {String} defaultEventAction
     * The method to call on the {@link Ext.EventObject} after this KeyNav intercepts a key.  Valid values are
     * {@link Ext.EventObject#stopEvent}, {@link Ext.EventObject#preventDefault} and
     * {@link Ext.EventObject#stopPropagation} (defaults to 'stopEvent')
     */
    defaultEventAction: "stopEvent",
    
    /**
     * @cfg {Boolean} forceKeyDown
     * Handle the keydown event instead of keypress (defaults to false).  KeyNav automatically does this for IE since
     * IE does not propagate special keys on keypress, but setting this to true will force other browsers to also
     * handle keydown instead of keypress.
     */
    forceKeyDown: false,
    
    /**
     * Destroy this KeyNav (this is the same as calling disable).
     * @param {Boolean} removeEl True to remove the element associated with this KeyNav.
     */
    destroy: function(removeEl){
        this.map.destroy(removeEl);
        delete this.map;
    },

    /**
     * Enable this KeyNav
     */
    enable: function() {
        this.map.enable();
        this.disabled = false;
    },

    /**
     * Disable this KeyNav
     */
    disable: function() {
        this.map.disable();
        this.disabled = true;
    },
    
    /**
     * Convenience function for setting disabled/enabled by boolean.
     * @param {Boolean} disabled
     */
    setDisabled : function(disabled){
        this.map.setDisabled(disabled);
        this.disabled = disabled;
    },
    
    /**
     * Determines the event to bind to listen for keys. Depends on the {@link #forceKeyDown} setting,
     * as well as the useKeyDown option on the EventManager.
     * @return {String} The type of event to listen for.
     */
    getKeyEvent: function(forceKeyDown){
        return (forceKeyDown || Ext.EventManager.useKeyDown) ? 'keydown' : 'keypress';
    }
});