package org.openslx.dnbd3;

import java.io.DataOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.filter.Filters;
import org.jdom2.input.SAXBuilder;
import org.jdom2.xpath.XPathExpression;
import org.jdom2.xpath.XPathFactory;
import org.newsclub.net.unix.AFUNIXSocket;
import org.newsclub.net.unix.AFUNIXSocketAddress;

public class DNBD3Server {

	private final String UNIXSOCK = "/run/dnbd3-server.sock";

	private static final int CMDSTOP = 0;
	private static final int CMDRELOAD = 1;
	private static final int CMDINFO = 2;

	public void doReload() throws IOException {
		AFUNIXSocket sock = connect();
		sendCommand(sock, CMDRELOAD);
		sock.close();
	}

	public void doShutdown() throws IOException {
		AFUNIXSocket sock = connect();
		sendCommand(sock, CMDSTOP);
		sock.close();
	}

	public List<DNBD3Image> getImages() throws IOException {
		List<DNBD3Image> images = new ArrayList<DNBD3Image>();
		AFUNIXSocket sock = connect();
		sendCommand(sock, CMDINFO);

		try {
			String atime, vid, rid, file;
			InputStream is = sock.getInputStream();
			SAXBuilder builder = new SAXBuilder();
			Document document = (Document) builder.build(is);
			XPathFactory xpfac = XPathFactory.instance();
			XPathExpression<Element> xp;
			xp = xpfac.compile("//dnbd3-server/images/image", Filters.element());
			for (Element e : xp.evaluate(document)) {
				atime = e.getAttributeValue("atime");
				vid = e.getAttributeValue("vid");
				rid = e.getAttributeValue("rid");
				file = e.getAttributeValue("file");
				images.add(new DNBD3Image(atime, vid, rid, file));
			}
			is.close();

		} catch (JDOMException ex) {
			ex.printStackTrace();
		}

		sock.close();
		return images;
	}

	public List<DNBD3Client> getClients() throws IOException {
		List<DNBD3Client> clients = new ArrayList<DNBD3Client>();
		AFUNIXSocket sock = connect();
		sendCommand(sock, CMDINFO);

		try {
			String ip, image;
			InputStream is = sock.getInputStream();
			SAXBuilder builder = new SAXBuilder();
			Document document = (Document) builder.build(is);
			XPathFactory xpfac = XPathFactory.instance();
			XPathExpression<Element> xp;
			xp = xpfac.compile("//dnbd3-server/clients/client", Filters.element());
			for (Element e : xp.evaluate(document)) {
				ip = e.getAttributeValue("ip");
				image = e.getAttributeValue("file");
				clients.add(new DNBD3Client(ip, image));
			}
			is.close();

		} catch (JDOMException ex) {
			ex.printStackTrace();
		}

		sock.close();
		return clients;
	}

////////////////////////////////////////////////////////////////////////////////

	private AFUNIXSocket connect() throws IOException {
		AFUNIXSocket sock = null;
		File socketFile = new File(UNIXSOCK);
		sock = AFUNIXSocket.newInstance();
		sock.connect(new AFUNIXSocketAddress(socketFile));
		return sock;
	}

	private void sendCommand(AFUNIXSocket sock, int cmd) throws IOException {
		OutputStream os = sock.getOutputStream();
		DataOutputStream dos = new DataOutputStream(os);
		dos.writeInt(cmd);
		os.close();
	}

}