/**
+ * @class Ext.state.Provider
+ * <p>Abstract base class for state provider implementations. The provider is responsible
+ * for setting values and extracting values to/from the underlying storage source. The
+ * storage source can vary and the details should be implemented in a subclass. For example
+ * a provider could use a server side database or the browser localstorage where supported.</p>
+ *
+ * <p>This class provides methods for encoding and decoding <b>typed</b> variables including
+ * dates and defines the Provider interface. By default these methods put the value and the
+ * type information into a delimited string that can be stored. These should be overridden in
+ * a subclass if you want to change the format of the encoded value and subsequent decoding.</p>
+ */
+Ext.define('Ext.state.Provider', {
+ mixins: {
+ observable: 'Ext.util.Observable'
+ },
+
+ /**
+ * @cfg {String} prefix A string to prefix to items stored in the underlying state store.
+ * Defaults to <tt>'ext-'</tt>
+ */
+ prefix: 'ext-',
+
+ constructor : function(config){
+ config = config || {};
+ var me = this;
+ Ext.apply(me, config);
+ /**
+ * @event statechange
+ * Fires when a state change occurs.
+ * @param {Provider} this This state provider
+ * @param {String} key The state key which was changed
+ * @param {String} value The encoded value for the state
+ */
+ me.addEvents("statechange");
+ me.state = {};
+ me.mixins.observable.constructor.call(me);
+ },
+
+ /**
+ * Returns the current value for a key
+ * @param {String} name The key name
+ * @param {Mixed} defaultValue A default value to return if the key's value is not found
+ * @return {Mixed} The state data
+ */
+ get : function(name, defaultValue){
+ return typeof this.state[name] == "undefined" ?
+ defaultValue : this.state[name];
+ },
+
+ /**
+ * Clears a value from the state
+ * @param {String} name The key name
+ */
+ clear : function(name){
+ var me = this;
+ delete me.state[name];
+ me.fireEvent("statechange", me, name, null);
+ },
+
+ /**
+ * Sets the value for a key
+ * @param {String} name The key name
+ * @param {Mixed} value The value to set
+ */
+ set : function(name, value){
+ var me = this;
+ me.state[name] = value;
+ me.fireEvent("statechange", me, name, value);
+ },
+
+ /**
+ * Decodes a string previously encoded with {@link #encodeValue}.
+ * @param {String} value The value to decode
+ * @return {Mixed} The decoded value
+ */
+ decodeValue : function(value){
+
+ // a -> Array
+ // n -> Number
+ // d -> Date
+ // b -> Boolean
+ // s -> String
+ // o -> Object
+ // -> Empty (null)
+
+ var me = this,
+ re = /^(a|n|d|b|s|o|e)\:(.*)$/,
+ matches = re.exec(unescape(value)),
+ all,
+ type,
+ value,
+ keyValue;
+
+ if(!matches || !matches[1]){
+ return; // non state
+ }
+
+ type = matches[1];
+ value = matches[2];
+ switch (type) {
+ case 'e':
+ return null;
+ case 'n':
+ return parseFloat(value);
+ case 'd':
+ return new Date(Date.parse(value));
+ case 'b':
+ return (value == '1');
+ case 'a':
+ all = [];
+ if(value != ''){
+ Ext.each(value.split('^'), function(val){
+ all.push(me.decodeValue(val));
+ }, me);
+ }
+ return all;
+ case 'o':
+ all = {};
+ if(value != ''){
+ Ext.each(value.split('^'), function(val){
+ keyValue = val.split('=');
+ all[keyValue[0]] = me.decodeValue(keyValue[1]);
+ }, me);
+ }
+ return all;
+ default:
+ return value;
+ }
+ },
+
+ /**
+ * Encodes a value including type information. Decode with {@link #decodeValue}.
+ * @param {Mixed} value The value to encode
+ * @return {String} The encoded value
+ */
+ encodeValue : function(value){
+ var flat = '',
+ i = 0,
+ enc,
+ len,
+ key;
+
+ if (value == null) {
+ return 'e:1';
+ } else if(typeof value == 'number') {
+ enc = 'n:' + value;
+ } else if(typeof value == 'boolean') {
+ enc = 'b:' + (value ? '1' : '0');
+ } else if(Ext.isDate(value)) {
+ enc = 'd:' + value.toGMTString();
+ } else if(Ext.isArray(value)) {
+ for (len = value.length; i < len; i++) {
+ flat += this.encodeValue(value[i]);
+ if (i != len - 1) {
+ flat += '^';
+ }
+ }
+ enc = 'a:' + flat;
+ } else if (typeof value == 'object') {
+ for (key in value) {
+ if (typeof value[key] != 'function' && value[key] !== undefined) {
+ flat += key + '=' + this.encodeValue(value[key]) + '^';
+ }
+ }
+ enc = 'o:' + flat.substring(0, flat.length-1);
+ } else {
+ enc = 's:' + value;
+ }
+ return escape(enc);
+ }
+});