trotzig/diffux

define([
    "../core",
    "./var/nonce",
    "./var/rquery",
    "../ajax"
], function( jQuery, nonce, rquery ) {

var oldCallbacks = [],
    rjsonp = /(=)\?(?=&|$)|\?\?/;

// Default jsonp settings
jQuery.ajaxSetup({
    jsonp: "callback",
    jsonpCallback: function() {
        var callback = oldCallbacks.pop() || ( jQuery.expando + "_" + ( nonce++ ) );
        this[ callback ] = true;
        return callback;
    }
});

// Detect, normalize options and install callbacks for jsonp requests
jQuery.ajaxPrefilter( "json jsonp", function( s, originalSettings, jqXHR ) {

    var callbackName, overwritten, responseContainer,
        jsonProp = s.jsonp !== false && ( rjsonp.test( s.url ) ?
            "url" :
            typeof s.data === "string" && !( s.contentType || "" ).indexOf("application/x-www-form-urlencoded") && rjsonp.test( s.data ) && "data"
        );

    // Handle iff the expected data type is "jsonp" or we have a parameter to set
    if ( jsonProp || s.dataTypes[ 0 ] === "jsonp" ) {

        // Get callback name, remembering preexisting value associated with it
        callbackName = s.jsonpCallback = jQuery.isFunction( s.jsonpCallback ) ?
            s.jsonpCallback() :
            s.jsonpCallback;

        // Insert callback into url or form data
        if ( jsonProp ) {
            s[ jsonProp ] = s[ jsonProp ].replace( rjsonp, "$1" + callbackName );
        } else if ( s.jsonp !== false ) {
            s.url += ( rquery.test( s.url ) ? "&" : "?" ) + s.jsonp + "=" + callbackName;
        }

        // Use data converter to retrieve json after script execution
        s.converters["script json"] = function() {
            if ( !responseContainer ) {
                jQuery.error( callbackName + " was not called" );
            }
            return responseContainer[ 0 ];
        };

        // force json dataType
        s.dataTypes[ 0 ] = "json";

        // Install callback
        overwritten = window[ callbackName ];
        window[ callbackName ] = function() {
            responseContainer = arguments;
        };

        // Clean-up function (fires after converters)
        jqXHR.always(function() {
            // Restore preexisting value
            window[ callbackName ] = overwritten;

            // Save back as free
            if ( s[ callbackName ] ) {
                // make sure that re-using the options doesn't screw things around
                s.jsonpCallback = originalSettings.jsonpCallback;

                // save the callback name for future use
                oldCallbacks.push( callbackName );
            }

            // Call if it was a function and we have a response
            if ( responseContainer && jQuery.isFunction( overwritten ) ) {
                overwritten( responseContainer[ 0 ] );
            }

            responseContainer = overwritten = undefined;
        });

        // Delegate to script
        return "script";
    }
});

});