/*
 * Copyright (C) 2012 SeqWare
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package net.sourceforge.seqware.pipeline.workflowV2;

import java.io.IOException;
import java.net.URL;
import java.net.URLClassLoader;
import net.sourceforge.seqware.common.util.Log;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;

/**
 * <p>
 * WorkflowClassFinder class.
 * </p>
 * 
 * @author boconnor
 * @version $Id: $Id
 */
public class WorkflowClassFinder {

    private static final String FOLDERS_SEPARATOR_AS_STRING = System.getProperty("file.separator");

    private final ResourcePatternResolver resourceResolver;

    /**
     * <p>
     * Constructor for WorkflowClassFinder.
     * </p>
     */
    public WorkflowClassFinder() {
        this.resourceResolver = new PathMatchingResourcePatternResolver(Thread.currentThread().getContextClassLoader());
    }

    /**
     * find the first .class in the clazzPath
     * 
     * This has been modified to locate a specific class. The name of the method is now totally misleading. We are loading a specific class.
     * 
     * @param clazzPath
     * @return
     */
    public Class<?> findFirstWorkflowClass(String clazzPath) {
        String classWithoutJava = clazzPath.substring(0, clazzPath.length() - 5);
        String classPathWithoutClass = clazzPath.substring(0, clazzPath.lastIndexOf("classes") + 8);
        clazzPath = classPathWithoutClass;

        String candidateClassesLocationPattern = "file:" + clazzPath + "**" + FOLDERS_SEPARATOR_AS_STRING + "*.class";
        Resource[] resources = null;

        try {
            resources = resourceResolver.getResources(candidateClassesLocationPattern);
        } catch (IOException e) {
            throw new RuntimeException("An I/O problem occurs when trying to resolve " + "ressources matching the pattern : "
                    + candidateClassesLocationPattern, e);

        }
        for (Resource resource : resources) {
            try {
                // seqware-1904 ignore private classes
                if (resource.getFilename().contains("$")) {
                    continue;
                }
                // get the path
                String path = resource.getFile().getPath();
                String qPath = path.substring(classPathWithoutClass.length(), path.length() - ".class".length());
                qPath = qPath.replaceAll(FOLDERS_SEPARATOR_AS_STRING, ".");

                if (!path.contains(classWithoutJava)) {
                    continue;
                }

                URL url = new URL("file://" + clazzPath);
                URL[] urls = new URL[] { url };
                ClassLoader cl = new URLClassLoader(urls);
                Class<?> cls = cl.loadClass(qPath);
                Log.info("CLASS LOADED " + qPath);
                return cls;

            } catch (IOException | ClassNotFoundException ex) {
                Log.error(ex, ex);
            }
        }
        return null;

    }

}