/**
 * Licensed to Apereo under one or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information regarding copyright ownership. Apereo
 * licenses this file to you under the Apache License, Version 2.0 (the "License"); you may not use
 * this file except in compliance with the License. You may obtain a copy of the License at the
 * following location:
 *
 * <p>http://www.apache.org/licenses/LICENSE-2.0
 *
 * <p>Unless required by applicable law or agreed to in writing, software distributed under the
 * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied. See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apereo.portal.io;

import org.danann.cernunnos.EntityConfig;
import org.danann.cernunnos.Formula;
import org.danann.cernunnos.Phrase;
import org.danann.cernunnos.Reagent;
import org.danann.cernunnos.ReagentType;
import org.danann.cernunnos.SimpleFormula;
import org.danann.cernunnos.SimpleReagent;
import org.danann.cernunnos.TaskRequest;
import org.danann.cernunnos.TaskResponse;
import org.dom4j.Element;

public class DefaultUsernamePhrase implements Phrase {

    // Instance Members.
    private Phrase element;

    /*
     * Public API.
     */

    public static final Reagent ELEMENT =
            new SimpleReagent(
                    "ELEMENT",
                    "descendant-or-self::text()",
                    ReagentType.PHRASE,
                    Element.class,
                    "Element representing a default user or null.");

    public Formula getFormula() {
        Reagent[] reagents = new Reagent[] {ELEMENT};
        return new SimpleFormula(DefaultUsernamePhrase.class, reagents);
    }

    public void init(EntityConfig config) {

        // Instance Members.
        this.element = (Phrase) config.getValue(ELEMENT);
    }

    public Object evaluate(TaskRequest req, TaskResponse res) {

        String rslt = null;

        Element e = (Element) element.evaluate(req, res);
        if (e != null) {
            rslt = e.getText();
        }

        return rslt;
    }
}
