package com.googlecode.struts2yuiplugin.components;



import com.googlecode.struts2yuiplugin.tools.YUITools;

import com.opensymphony.xwork2.util.ValueStack;

import org.apache.struts2.views.annotations.StrutsTag;

import org.apache.struts2.views.annotations.StrutsTagAttribute;



import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;



/**

 * An anchor that can load the content of a target div via XHR

 */

@StrutsTag(name = "a", tldTagClass = "com.googlecode.struts2yuiplugin.views.jsp.ui.AnchorTag", description = "Renders an anchor tag with an onclick listener that performs an XHR")

public class Anchor extends ClosingYUIBean implements XHRComponent, OGNLEvaluator {



    public static final String OPEN_TEMPLATE = "yuianchor";

    public static final String TEMPLATE = OPEN_TEMPLATE +"-close";



    private XHRSupport xhrSupport;



    private String target;

    private String clickListener;



    public Anchor(ValueStack valueStack, HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) {

        super(valueStack, httpServletRequest, httpServletResponse);

        xhrSupport = new XHRSupport(this);

    }



    @Override

    public void evaluateParams() {

        super.evaluateParams();

        xhrSupport.evaluateParams(this);



        populateClickListenerName();

        if (target != null) {

            addParameter("target", evaluateExpression(target));

        }

    }



    public String getDefaultOpenTemplate() {

        return OPEN_TEMPLATE;

    }



    protected String getDefaultTemplate() {

        return TEMPLATE;

    }



    /**

     * Generate the javacscript click listener name if not explictly specified

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

     */

    private void populateClickListenerName() {

        String listenerName;

        if (clickListener != null) {

            listenerName = evaluateExpression(clickListener);

            addParameter("customClickListener", true);

        } else {

            listenerName = YUITools.sanitizeForJavascript(getId()+"Click");

            addParameter("customClickListener", false);

        }

        addParameter("clickListener", listenerName);

    }



    @StrutsTagAttribute(description = "Mandatory id attribute", required = true, rtexprvalue = true)

    public void setId(String id) {

        super.setId(id);

    }



    /**

     * The optional ID of the form to include in the request

     */

    @StrutsTagAttribute(description = "The ID of the form to include in the request", required = false)

    public void setFormId(String formId) {

        xhrSupport.setFormId(formId);

    }



    /**

     * If optional the href to send the request to.  I not provided, the form's action will used

     */

    @StrutsTagAttribute(description = "The URL to make the request to if other than the form's action", required = false, rtexprvalue = true)

    public void setHref(String href) {

        xhrSupport.setHref(href);

    }



    /**

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

     */

    @StrutsTagAttribute(description = "The HTTP method to use", required = false, defaultValue = "GET")

    public void setMethod(String method) {

        xhrSupport.setMethod(method);

    }



    /**

     * ID of the target div

     */

    @StrutsTagAttribute(description = "The ID of the target div to render the result", required = false)

    public void setTarget(String target) {

        this.target = target;

    }



    /**

     * The name of an alternative javascript callback for the YUI Connection Manager's response

     */

    @StrutsTagAttribute(description = "An alternative javascript callback for the YUI Connection Manager's response", required = false)

    public void setCallback(String callback) {

        xhrSupport.setCallback(callback);

    }



    /**

     * An alternateive javascript listener function for the click event

     */

    @StrutsTagAttribute(description = "An alternative listener for the click event", required = false)

    public void setClickListener(String listener) {

        this.clickListener = listener;

    }



    /**

     * Evaluates the OGNL expression

     *

     * @param expr OGNL expression.

     * @return the String value found.

     */

    public String evaluateExpression(String expr) {

        return super.findString(expr);

    }

}