/*
 * Created on Apr 13, 2004
 */
package net.bmllc.tags;

import java.io.Serializable;
import java.util.Collection;
import java.util.Iterator;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.TagSupport;

import net.bmllc.utils.StringTools;
import net.sf.njmvcopensource.utils.LabelValue;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * @author edgar
 *
 */
public class JavaScriptCollection extends TagSupport implements Serializable {

	private static Log log = LogFactory.getLog(JavaScriptCollection.class);

	/**
	 * output a javascript function to add elements of a collection
	 * to a select
	 */

	String id;
	public String getId() {
		return id;
	}
	public void setId(String string) {
		id = string;
	}

	String function;
	public String getFunction() {
		return function;
	}
	public void setFunction(String string) {
		function = string;
	}


	public JavaScriptCollection() {
		super();
	}

	/**
	 * output the javascript
	 */

	public int doStartTag() throws JspException {
		if (function == null) {
			return super.doStartTag();
		}
		if (id == null) {
			return super.doStartTag();
		}
		Collection c = (Collection) pageContext.findAttribute(id);
		if (c == null) {
			return super.doStartTag();
		}

		JspWriter out;
		try {
			out = pageContext.getOut();
		} catch (Exception e) {
			log.fatal("doStartTag: no JspWriter object", e);
			return super.doStartTag();
		}

		try {
			out.println("<script type='text/javascript'>");
			out.println("function " + getFunction() + "(fieldName, value) {");
			out.println("  if (fieldName == null) {");
			out.println("    alert('" + getFunction() + " has been invoked with a null fieldName');");
			out.println("    return;");
			out.println("  };");
			out.println("  var f = Struts_eval(fieldName, 0);");
			out.println("  if (f == null) {");
			out.println("    alert('field ' + fieldName + ' does not resolve');");
			out.println("    return;");
			out.println("  };");
			out.println("  if (f.options == null) {");
			out.println("    alert('field ' + fieldName + ' is not a select field');");
			out.println("    return;");
			out.println("  };");
			for (Iterator i = c.iterator(); i.hasNext();) {
				LabelValue lv = (LabelValue) i.next();
				if (lv == null) {
					continue;
				}
				out.println("  f.options[f.options.length] = new Option('" + StringTools.escape(lv.getLabel()) + "','" + StringTools.escape(lv.getValue()) + "');");
			}

			out.println("  if (value == null) return;");
			out.println("  for (i = 0; i < f.options.length; i++) {");
			out.println("    if (value == f.options[i].value) {");
			out.println("      f.options[i].selected=true");
			out.println("      break;");
			out.println("    }");
			out.println("  }");
			out.println("}");
			out.println("</script>");
		} 

		catch (Exception e) {
			log.fatal("doStartTag: io error writing javascript",e);
			return super.doStartTag();
		}

		return super.doStartTag();
	}

}