package org.argeo.slc.rpmfactory.core;

import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeSet;

import org.apache.commons.io.FilenameUtils;
import org.apache.commons.io.IOUtils;
import org.apache.commons.io.LineIterator;
import org.argeo.api.cms.CmsLog;
import org.argeo.slc.SlcException;

/**
 * Reads the output of a 'yum list all' command and interpret the list of
 * packages.
 */
public class YumListParser implements RpmPackageSet {
	private final static CmsLog log = CmsLog.getLog(YumListParser.class);

	private Set<String> installed = new TreeSet<String>();
	/** Not installed but available */
	private Set<String> installable = new TreeSet<String>();

	private Path yumListOutput;

	public void init() {
		if (yumListOutput != null) {
			try (InputStream in = Files.newInputStream(yumListOutput)) {
				load(in);
				if (log.isDebugEnabled())
					log.debug(installed.size() + " installed, " + installable.size() + " installable, from "
							+ yumListOutput);
			} catch (IOException e) {
				throw new SlcException("Cannot initialize yum list parser", e);
			}
		}
	}

	public Boolean contains(String packageName) {
		if (installed.contains(packageName))
			return true;
		else
			return installable.contains(packageName);
	}

	protected void load(InputStream in) throws IOException {
		Boolean readingInstalled = false;
		Boolean readingAvailable = false;
		LineIterator it = IOUtils.lineIterator(in, "UTF-8");
		while (it.hasNext()) {
			String line = it.nextLine();
			if (line.trim().equals("Installed Packages")) {
				readingInstalled = true;
			} else if (line.trim().equals("Available Packages")) {
				readingAvailable = true;
				readingInstalled = false;
			} else if (readingAvailable) {
				if (Character.isLetterOrDigit(line.charAt(0))) {
					installable.add(extractRpmName(line));
				}
			} else if (readingInstalled) {
				if (Character.isLetterOrDigit(line.charAt(0))) {
					installed.add(extractRpmName(line));
				}
			}
		}
	}

	protected String extractRpmName(String line) {
		StringTokenizer st = new StringTokenizer(line, " \t");
		String packageName = st.nextToken();
		// consider the arch as an extension
		return FilenameUtils.getBaseName(packageName);
		// return packageName.split("\\.")[0];
	}

	public Set<String> getInstalled() {
		return installed;
	}

	public Set<String> getInstallable() {
		return installable;
	}

	public void setYumListOutput(Path yumListOutput) {
		this.yumListOutput = yumListOutput;
	}

}