package com.googlecode.struts2yuiplugin.components;



import com.googlecode.struts2yuiplugin.tools.YUITools;

import org.apache.struts2.components.UIBean;



/**

 * Delegatable implementation of an XHRComponent.  Provides common behaviour for evaluating the parameters

 */

public class XHRSupport implements XHRComponent {



    private static final String DEFAULT_METHOD = "GET";



    private OGNLEvaluator eval;



    private String callback;

    private String formId;

    private String href;

    private String method;



    public XHRSupport(OGNLEvaluator eval) {

        this.eval = eval;

    }



    /**

     * Adds the common XHR parameters to the UIBean

     * @param uiBean bean to be updated

     */

    public void evaluateParams(UIBean uiBean) {

        populateCallbackName(uiBean);

        populateMethod(uiBean);



        if (formId != null) {

            uiBean.addParameter("formId", eval.evaluateExpression(formId));

        }



        if (href != null) {

            uiBean.addParameter("href", eval.evaluateExpression(href));

        }

    }



    /**

     * Generate the javascript onclick callback name for this widget if not explictly specified.

     * The name is generated from the id but sanitized for javascript

     */

    private void populateCallbackName(UIBean uiBean) {

        String callbackName;

        if (callback != null) {

            callbackName = eval.evaluateExpression(callback);

            uiBean.addParameter("customCallback", true);

        } else {

            callbackName = YUITools.sanitizeForJavascript(uiBean.getId()+"Callback");

            uiBean.addParameter("customCallback", false);

        }

        uiBean.addParameter("callback", callbackName);

    }



    /** Populates the http method property */

    private void populateMethod(UIBean uiBean) {

        String methodName;

        if (method != null) {

            methodName = eval.evaluateExpression(method);

        } else {

            methodName = DEFAULT_METHOD;

        }

        uiBean.addParameter("method", methodName);

    }



    /** An alterative javascript callback function for the YUI Connection Manager's response */

    public void setCallback(String callback) {

        this.callback = callback;

    }



    /**

     * The ID Of the form to include in the request

     */

    public void setFormId(String formId) {

        this.formId = formId;

    }



    /**

     * If the href is provided the widget will send the request to the specified URL.

     */

    public void setHref(String href) {

        this.href = href;

    }



    /**

     * HTTP method to use when HREF is specified. Default is GET

     */

    public void setMethod(String method) {

        this.method = method;

    }

}