package eu.dnetlib.download.plugin;

import java.io.File;
import java.io.FileFilter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

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

// TODO: Auto-generated Javadoc
/**
 * The Class PathRetreiver.
 */
public class PathRetreiver {

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

	/** The instance. */
	private static PathRetreiver instance;

	/**
	 * Gets the single instance of PathRetreiver.
	 *
	 * @param base_path
	 *            the base_path
	 * @return single instance of PathRetreiver
	 */
	public static PathRetreiver getInstance(final String base_path) {
		if (instance == null) {
			instance = new PathRetreiver();
			instance.setBase_path(base_path);
		}
		return instance;
	}

	/** The base_path. */
	private String base_path;

	/** The values. */
	private List<InfoPath> values;

	/**
	 * Bootstrap.
	 */
	private void bootstrap() {
		values = new ArrayList<InfoPath>();
		File basePath = new File(this.base_path);
		File[] selectedFiles = basePath.listFiles(new FileFilter() {

			@Override
			public boolean accept(final File pathname) {
				return pathname.isDirectory();
			}
		});

		for (File f : selectedFiles) {
			String lower = StringUtils.substringAfter(StringUtils.substringBefore(f.getName(), "_"), "PMC");
			String upper = StringUtils.substringAfter(StringUtils.substringAfter(f.getName(), "_"), "PMC");
			String path = f.getPath();
			InfoPath i = new InfoPath();
			i.setLower(Integer.parseInt(lower));
			i.setUpper(Integer.parseInt(upper));
			i.setPath(path);
			values.add(i);
		}

		Collections.sort(values, new Comparator<InfoPath>() {

			@Override
			public int compare(final InfoPath o1, final InfoPath o2) {
				if (o1.getLower() < o2.getLower()) return -1;
				else if (o1.getLower() < o2.getLower()) return 0;
				else return 1;
			}
		});
		if (log.isDebugEnabled()) {
			for (InfoPath p : values) {
				log.debug(String.format("%s -- %s : %s", p.getLower(), p.getUpper(), p.getPath()));
			}
		}

	}

	/**
	 * Gets the path for pmcid.
	 *
	 * @param pmcID
	 *            the pmc id
	 * @return the path for pmcid
	 */
	public String getPathForPMCID(final int pmcID) {
		if (values == null) {
			bootstrap();
		}
		for (int i = 0; i < values.size(); i++) {
			if (pmcID < values.get(i).getLower()) {
				if (i == 0) return null;
				String currentPath = values.get(i - 1).getPath() + "/" + pmcID + ".xml";
				File f = new File(currentPath);
				log.debug(String.format("try to search in path %s", currentPath));
				String s = null;
				if (f.exists()) {
					s = f.getPath();
					log.debug(String.format("found in %s", s));
				} else {
					log.debug(String.format("not found in %s", s));
				}
				return s;

			}
		}
		log.debug(String.format("PMC with ID: %s not found", pmcID));
		return null;
	}

	/**
	 * Sets the base_path.
	 *
	 * @param base_path
	 *            the new base_path
	 */
	public void setBase_path(final String base_path) {
		this.base_path = base_path;
	}

	/**
	 * Gets the base_path.
	 *
	 * @return the base_path
	 */
	public String getBase_path() {
		return this.base_path;
	}
}