/*
 * Copyright 2005 the original author or authors.
 * 
 * Licensed 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
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * 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.wamblee.crawler.kiss;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import org.wamblee.conditions.Condition;
import org.wamblee.conditions.OrCondition;

/**
 * Parse the configuration of desired programs.
 */
public class ProgramConfigurationParser {

    private static final String ELEM_PROGRAM = "program";

    private static final String ELEM_PATTERN = "name";

    /**
     * Parses the condition used to match the desired programs.
     * 
     * @param aStream
     *            Input stream to parse from.
     * @return Condition.
     */
    Condition<Program> parse(InputStream aStream) {
        try {
            SAXReader reader = new SAXReader();
            Document document = reader.read(aStream);

            Element root = document.getRootElement();
            List<Condition<Program>> conditions = new ArrayList<Condition<Program>>();

            for (Iterator i = root.elementIterator(ELEM_PROGRAM); i.hasNext();) {
                Element program = (Element) i.next();
                String pattern = ".*" + program.element(ELEM_PATTERN).getText()
                        + ".*";
                conditions.add(new ProgramNameMatcher(pattern));
            }
            return new OrCondition<Program>(conditions);
        } catch (DocumentException e) {
            throw new RuntimeException("Error parsing program configuraiton", e);
        }
    }
}