/**
 * @class Ext.direct.RemotingProvider
 * @extends Ext.direct.JsonProvider
 * 
 * <p>The {@link Ext.direct.RemotingProvider RemotingProvider} exposes access to
 * server side methods on the client (a remote procedure call (RPC) type of
 * connection where the client can initiate a procedure on the server).</p>
 * 
 * <p>This allows for code to be organized in a fashion that is maintainable,
 * while providing a clear path between client and server, something that is
 * not always apparent when using URLs.</p>
 * 
 * <p>To accomplish this the server-side needs to describe what classes and methods
 * are available on the client-side. This configuration will typically be
 * outputted by the server-side Ext.Direct stack when the API description is built.</p>
 */
Ext.define('Ext.direct.RemotingProvider', {
    
    /* Begin Definitions */
   
    alias: 'direct.remotingprovider',
    
    extend: 'Ext.direct.JsonProvider', 
    
    requires: [
        'Ext.util.MixedCollection', 
        'Ext.util.DelayedTask', 
        'Ext.direct.Transaction',
        'Ext.direct.RemotingMethod'
    ],
   
    /* End Definitions */
   
   /**
     * @cfg {Object} actions
     * Object literal defining the server side actions and methods. For example, if
     * the Provider is configured with:
     * <pre><code>
"actions":{ // each property within the 'actions' object represents a server side Class 
    "TestAction":[ // array of methods within each server side Class to be   
    {              // stubbed out on client
        "name":"doEcho", 
        "len":1            
    },{
        "name":"multiply",// name of method
        "len":2           // The number of parameters that will be used to create an
                          // array of data to send to the server side function.
                          // Ensure the server sends back a Number, not a String. 
    },{
        "name":"doForm",
        "formHandler":true, // direct the client to use specialized form handling method 
        "len":1
    }]
}
     * </code></pre>
     * <p>Note that a Store is not required, a server method can be called at any time.
     * In the following example a <b>client side</b> handler is used to call the
     * server side method "multiply" in the server-side "TestAction" Class:</p>
     * <pre><code>
TestAction.multiply(
    2, 4, // pass two arguments to server, so specify len=2
    // callback function after the server is called
    // result: the result returned by the server
    //      e: Ext.direct.RemotingEvent object
    function(result, e){
        var t = e.getTransaction();
        var action = t.action; // server side Class called
        var method = t.method; // server side method called
        if(e.status){
            var answer = Ext.encode(result); // 8
    
        }else{
            var msg = e.message; // failure message
        }
    }
);
     * </code></pre>
     * In the example above, the server side "multiply" function will be passed two
     * arguments (2 and 4).  The "multiply" method should return the value 8 which will be
     * available as the <tt>result</tt> in the example above. 
     */
    
    /**
     * @cfg {String/Object} namespace
     * Namespace for the Remoting Provider (defaults to the browser global scope of <i>window</i>).
     * Explicitly specify the namespace Object, or specify a String to have a
     * {@link Ext#namespace namespace created} implicitly.
     */
    
    /**
     * @cfg {String} url
     * <b>Required</b>. The url to connect to the {@link Ext.direct.Manager} server-side router. 
     */
    
    /**
     * @cfg {String} enableUrlEncode
     * Specify which param will hold the arguments for the method.
     * Defaults to <tt>'data'</tt>.
     */
    
    /**
     * @cfg {Number/Boolean} enableBuffer
     * <p><tt>true</tt> or <tt>false</tt> to enable or disable combining of method
     * calls. If a number is specified this is the amount of time in milliseconds
     * to wait before sending a batched request (defaults to <tt>10</tt>).</p>
     * <br><p>Calls which are received within the specified timeframe will be
     * concatenated together and sent in a single request, optimizing the
     * application by reducing the amount of round trips that have to be made
     * to the server.</p>
     */
    enableBuffer: 10,
    
    /**
     * @cfg {Number} maxRetries
     * Number of times to re-attempt delivery on failure of a call. Defaults to <tt>1</tt>.
     */
    maxRetries: 1,
    
    /**
     * @cfg {Number} timeout
     * The timeout to use for each request. Defaults to <tt>undefined</tt>.
     */
    timeout: undefined,
    
    constructor : function(config){
        var me = this;
        me.callParent(arguments);
        me.addEvents(
            /**
             * @event beforecall
             * Fires immediately before the client-side sends off the RPC call.
             * By returning false from an event handler you can prevent the call from
             * executing.
             * @param {Ext.direct.RemotingProvider} provider
             * @param {Ext.direct.Transaction} transaction
             * @param {Object} meta The meta data
             */            
            'beforecall',            
            /**
             * @event call
             * Fires immediately after the request to the server-side is sent. This does
             * NOT fire after the response has come back from the call.
             * @param {Ext.direct.RemotingProvider} provider
             * @param {Ext.direct.Transaction} transaction
             * @param {Object} meta The meta data
             */            
            'call'
        );
        me.namespace = (Ext.isString(me.namespace)) ? Ext.ns(me.namespace) : me.namespace || window;
        me.transactions = Ext.create('Ext.util.MixedCollection');
        me.callBuffer = [];
    },
    
    /**
     * Initialize the API
     * @private
     */
    initAPI : function(){
        var actions = this.actions,
            namespace = this.namespace,
            action,
            cls,
            methods,
            i,
            len,
            method;
            
        for (action in actions) {
            cls = namespace[action];
            if (!cls) {
                cls = namespace[action] = {};
            }
            methods = actions[action];
            
            for (i = 0, len = methods.length; i < len; ++i) {
                method = Ext.create('Ext.direct.RemotingMethod', methods[i]);
                cls[method.name] = this.createHandler(action, method);
            }
        }
    },
    
    /**
     * Create a handler function for a direct call.
     * @private
     * @param {String} action The action the call is for
     * @param {Object} method The details of the method
     * @return {Function} A JS function that will kick off the call
     */
    createHandler : function(action, method){
        var me = this,
            handler;
        
        if (!method.formHandler) {
            handler = function(){
                me.configureRequest(action, method, Array.prototype.slice.call(arguments, 0));
            };
        } else {
            handler = function(form, callback, scope){
                me.configureFormRequest(action, method, form, callback, scope);
            };
        }
        handler.directCfg = {
            action: action,
            method: method
        };
        return handler;
    },
    
    // inherit docs
    isConnected: function(){
        return !!this.connected;
    },

    // inherit docs
    connect: function(){
        var me = this;
        
        if (me.url) {
            me.initAPI();
            me.connected = true;
            me.fireEvent('connect', me);
        } else if(!me.url) {
            //<debug>
            Ext.Error.raise('Error initializing RemotingProvider, no url configured.');
            //</debug>
        }
    },

    // inherit docs
    disconnect: function(){
        var me = this;
        
        if (me.connected) {
            me.connected = false;
            me.fireEvent('disconnect', me);
        }
    },
    
    /**
     * Run any callbacks related to the transaction.
     * @private
     * @param {Ext.direct.Transaction} transaction The transaction
     * @param {Ext.direct.Event} event The event
     */
    runCallback: function(transaction, event){
        var funcName = event.status ? 'success' : 'failure',
            callback,
            result;
        
        if (transaction && transaction.callback) {
            callback = transaction.callback;
            result = Ext.isDefined(event.result) ? event.result : event.data;
        
            if (Ext.isFunction(callback)) {
                callback(result, event);
            } else {
                Ext.callback(callback[funcName], callback.scope, [result, event]);
                Ext.callback(callback.callback, callback.scope, [result, event]);
            }
        }
    },
    
    /**
     * React to the ajax request being completed
     * @private
     */
    onData: function(options, success, response){
        var me = this,
            i = 0,
            len,
            events,
            event,
            transaction,
            transactions;
            
        if (success) {
            events = me.createEvents(response);
            for (len = events.length; i < len; ++i) {
                event = events[i];
                transaction = me.getTransaction(event);
                me.fireEvent('data', me, event);
                if (transaction) {
                    me.runCallback(transaction, event, true);
                    Ext.direct.Manager.removeTransaction(transaction);
                }
            }
        } else {
            transactions = [].concat(options.transaction);
            for (len = transactions.length; i < len; ++i) {
                transaction = me.getTransaction(transactions[i]);
                if (transaction && transaction.retryCount < me.maxRetries) {
                    transaction.retry();
                } else {
                    event = Ext.create('Ext.direct.ExceptionEvent', {
                        data: null,
                        transaction: transaction,
                        code: Ext.direct.Manager.self.exceptions.TRANSPORT,
                        message: 'Unable to connect to the server.',
                        xhr: response
                    });
                    me.fireEvent('data', me, event);
                    if (transaction) {
                        me.runCallback(transaction, event, false);
                        Ext.direct.Manager.removeTransaction(transaction);
                    }
                }
            }
        }
    },
    
    /**
     * Get transaction from XHR options
     * @private
     * @param {Object} options The options sent to the Ajax request
     * @return {Ext.direct.Transaction} The transaction, null if not found
     */
    getTransaction: function(options){
        return options && options.tid ? Ext.direct.Manager.getTransaction(options.tid) : null;
    },
    
    /**
     * Configure a direct request
     * @private
     * @param {String} action The action being executed
     * @param {Object} method The being executed
     */
    configureRequest: function(action, method, args){
        var me = this,
            callData = method.getCallData(args),
            data = callData.data, 
            callback = callData.callback, 
            scope = callData.scope,
            transaction;

        transaction = Ext.create('Ext.direct.Transaction', {
            provider: me,
            args: args,
            action: action,
            method: method.name,
            data: data,
            callback: scope && Ext.isFunction(callback) ? Ext.Function.bind(callback, scope) : callback
        });

        if (me.fireEvent('beforecall', me, transaction, method) !== false) {
            Ext.direct.Manager.addTransaction(transaction);
            me.queueTransaction(transaction);
            me.fireEvent('call', me, transaction, method);
        }
    },
    
    /**
     * Gets the Ajax call info for a transaction
     * @private
     * @param {Ext.direct.Transaction} transaction The transaction
     * @return {Object} The call params
     */
    getCallData: function(transaction){
        return {
            action: transaction.action,
            method: transaction.method,
            data: transaction.data,
            type: 'rpc',
            tid: transaction.id
        };
    },
    
    /**
     * Sends a request to the server
     * @private
     * @param {Object/Array} data The data to send
     */
    sendRequest : function(data){
        var me = this,
            request = {
                url: me.url,
                callback: me.onData,
                scope: me,
                transaction: data,
                timeout: me.timeout
            }, callData,
            enableUrlEncode = me.enableUrlEncode,
            i = 0,
            len,
            params;
            

        if (Ext.isArray(data)) {
            callData = [];
            for (len = data.length; i < len; ++i) {
                callData.push(me.getCallData(data[i]));
            }
        } else {
            callData = me.getCallData(data);
        }

        if (enableUrlEncode) {
            params = {};
            params[Ext.isString(enableUrlEncode) ? enableUrlEncode : 'data'] = Ext.encode(callData);
            request.params = params;
        } else {
            request.jsonData = callData;
        }
        Ext.Ajax.request(request);
    },
    
    /**
     * Add a new transaction to the queue
     * @private
     * @param {Ext.direct.Transaction} transaction The transaction
     */
    queueTransaction: function(transaction){
        var me = this,
            enableBuffer = me.enableBuffer;
        
        if (transaction.form) {
            me.sendFormRequest(transaction);
            return;
        }
        
        me.callBuffer.push(transaction);
        if (enableBuffer) {
            if (!me.callTask) {
                me.callTask = Ext.create('Ext.util.DelayedTask', me.combineAndSend, me);
            }
            me.callTask.delay(Ext.isNumber(enableBuffer) ? enableBuffer : 10);
        } else {
            me.combineAndSend();
        }
    },
    
    /**
     * Combine any buffered requests and send them off
     * @private
     */
    combineAndSend : function(){
        var buffer = this.callBuffer,
            len = buffer.length;
            
        if (len > 0) {
            this.sendRequest(len == 1 ? buffer[0] : buffer);
            this.callBuffer = [];
        }
    },
    
    /**
     * Configure a form submission request
     * @private
     * @param {String} action The action being executed
     * @param {Object} method The method being executed
     * @param {HTMLElement} form The form being submitted
     * @param {Function} callback (optional) A callback to run after the form submits
     * @param {Object} scope A scope to execute the callback in
     */
    configureFormRequest : function(action, method, form, callback, scope){
        var me = this,
            transaction = Ext.create('Ext.direct.Transaction', {
                provider: me,
                action: action,
                method: method.name,
                args: [form, callback, scope],
                callback: scope && Ext.isFunction(callback) ? Ext.Function.bind(callback, scope) : callback,
                isForm: true
            }),
            isUpload,
            params;

        if (me.fireEvent('beforecall', me, transaction, method) !== false) {
            Ext.direct.Manager.addTransaction(transaction);
            isUpload = String(form.getAttribute("enctype")).toLowerCase() == 'multipart/form-data';
            
            params = {
                extTID: transaction.id,
                extAction: action,
                extMethod: method.name,
                extType: 'rpc',
                extUpload: String(isUpload)
            };
            
            // change made from typeof callback check to callback.params
            // to support addl param passing in DirectSubmit EAC 6/2
            Ext.apply(transaction, {
                form: Ext.getDom(form),
                isUpload: isUpload,
                params: callback && Ext.isObject(callback.params) ? Ext.apply(params, callback.params) : params
            });
            me.fireEvent('call', me, transaction, method);
            me.sendFormRequest(transaction);
        }
    },
    
    /**
     * Sends a form request
     * @private
     * @param {Ext.direct.Transaction} transaction The transaction to send
     */
    sendFormRequest: function(transaction){
        Ext.Ajax.request({
            url: this.url,
            params: transaction.params,
            callback: this.onData,
            scope: this,
            form: transaction.form,
            isUpload: transaction.isUpload,
            transaction: transaction
        });
    }
    
});
