path: root/dozentenmodul/src/main/java/org/openslx/dozmod/gui/configurator/NetrulesConfigurator.java

package org.openslx.dozmod.gui.configurator;

import java.awt.Color;
import java.awt.Insets;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.EventListener;
import java.util.EventObject;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

import javax.swing.BorderFactory;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextPane;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.event.EventListenerList;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultStyledDocument;
import javax.swing.text.SimpleAttributeSet;
import javax.swing.text.StyleConstants;

import org.apache.log4j.Logger;
import org.openslx.bwlp.thrift.iface.NetDirection;
import org.openslx.bwlp.thrift.iface.NetRule;
import org.openslx.dozmod.gui.Gui;
import org.openslx.dozmod.gui.control.WordWrapLabel;
import org.openslx.dozmod.gui.helper.GridManager;
import org.openslx.dozmod.gui.helper.MessageType;
import org.openslx.dozmod.gui.helper.TextChangeListener;
import org.openslx.util.Util;

/**
 * Widget for netrules configuration of lectures
 */
public class NetrulesConfigurator extends NetrulesConfiguratorLayout {

	private static final long serialVersionUID = -3497629601818983994L;
	private final static Logger LOGGER = Logger
			.getLogger(NetrulesConfigurator.class);

	private String originalRawRuleText = null;
	/**
	 * Character defining how the rules are parsed, e.g. for whitespace \\s
	 * Example: "8.8.8.8 80 in" would be split in -hostname "8.8.8.8" -port "80"
	 * -direction "in"
	 */
	private static final String FIELD_DELIMITER = "\\s+";
	
	private static final Color FOREGROUND_TEXT_COLOR;
	
	static {
		Color fgOrigColor = UIManager.getDefaults().getColor("ColorChooser.foreground");
		if (fgOrigColor == null) {
			// use black as fallback
			fgOrigColor = Color.BLACK;
		}
		FOREGROUND_TEXT_COLOR = fgOrigColor;
	}

	public NetrulesConfigurator() {
		super();

		final TextChangeListener docListener = new TextChangeListener() {
			@Override
			public void changed() {
				fireNetrulesConfigurationChangeEvent(new NetrulesConfigurationChangeEvent(NetrulesConfigurator.this));
			}
		};
		final SimpleAttributeSet as = new SimpleAttributeSet();
		StyleConstants.setForeground(as, FOREGROUND_TEXT_COLOR);
		tpNetworkRules.getDocument().addDocumentListener(docListener);
		tpNetworkRules.addKeyListener(new KeyAdapter() {
			@Override
			public void keyTyped(KeyEvent e) {
				SwingUtilities.invokeLater(new Runnable() {
					@Override
					public void run() {
						int pos = tpNetworkRules.getCaretPosition();
						if (pos < 0) {
							return;
						}
						// Odd: On windows, getText() returns the text with CRLF line breaks,
						// regardless of what you put into the text box.
						// The offsets passed to setCharAttrs() below and the caret position
						// you get from getCaretPosition() however have to adhere to the
						// text version with just LF, exactly how we created the document.
						String text = tpNetworkRules.getText().replace("\r", "");
						if (pos >= text.length()) {
							return;
						}
						int start = text.lastIndexOf('\n', pos == 0 ? 0 : pos - 1);
						int end = text.indexOf('\n', pos);
						if (start == -1) {
							start = 0;
						}
						if (end == -1) {
							end = text.length() - 1;
						}
						if (end <= start) {
							return;
						}
						tpNetworkRules.getStyledDocument().setCharacterAttributes(start, end - start, as, true);
					}
				});
			}
		});
	}

	public boolean hasChanged() {
		return !originalRawRuleText.equalsIgnoreCase(tpNetworkRules.getText());
	}

	/**
	 * Gets the state of the widget as a list of netrules. Internally it first
	 * transforms the input text in a list of netrules.
	 * 
	 * @return the list of rules as parsed by parseNetRules()
	 */
	public List<NetRule> getState(boolean silent) {
		// cleanup the TextPane for network rules if needed
		return parseNetRules(silent);
	}

	/**
	 * Sets the state of this widget to the given list of netrules. This will
	 * internally transform the list to its string representation
	 * 
	 * @param netrules
	 *            as a list of NetRule to set the state to
	 */
	public void setState(final List<NetRule> netrules) {
		// setText() blanks the text area if null is given, so no null checks
		originalRawRuleText = decodeNetRulesToText(netrules);
		this.tpNetworkRules.setText(originalRawRuleText);
	}

	/**
	 * "Decodes" the given list of NetRule to a single String. This should be
	 * used to set the text in the TextPane for the network rules
	 * 
	 * @param netRulesList
	 *            list of NetRule to decode
	 * @return String representation of the list of rules
	 */
	public static String decodeNetRulesToText(final List<NetRule> netRulesList) {
		if (netRulesList == null || netRulesList.isEmpty())
			return "";

		String decodedRules = "";
		Iterator<NetRule> it = netRulesList.iterator();
		while (it.hasNext()) {
			String currentLine = "";
			NetRule currentRule = it.next();
			// simple test for validity (since this comes from the server it
			// should be correct anyways)
			if (currentRule.host.isEmpty() || currentRule.port > 65535) {
				LOGGER.error("Invalid rule! Ignoring: " + currentRule.host
						+ ":" + currentRule.port);
				continue;
			}
			currentLine += currentRule.host + " \t ";
			currentLine += currentRule.port + " \t ";
			currentLine += currentRule.direction.name();
			decodedRules += currentLine
					+ (it.hasNext() ? "\n" : "");
		}
		return decodedRules;
	}

	/**
	 * Parses the given rawNetRules String to a list of NetRule
	 * 
	 * @param rawNetRules
	 *            the raw text to be parsed
	 * @return list of netrules if successful. If any errors occured while
	 *         parsing, null is returned.
	 */
	public List<NetRule> parseNetRules(boolean silent) {
		String rawNetRules = tpNetworkRules.getText().trim();
		List<NetRule> rulesList = new ArrayList<NetRule>();
		if (rawNetRules.isEmpty()) {
			return rulesList;
		}

		// split it line by line
		boolean invalid = false; // True if the rules are invalid and null should be returned
		DefaultStyledDocument newdoc = null;
		if (!silent) {
			newdoc = new DefaultStyledDocument(); // Used to build new document with colors
		}
		StringBuilder errors = new StringBuilder(); // Error messages to show (if not silent)
		int lineNo = 0; // Show line numbers in error messages
		Set<String> warnedHosts = new HashSet<>(); // Ask only once about each unknown host
		for (String ruleLine : rawNetRules.split("[\r\n]+")) {
			if (silent && invalid)
				return null;
			Color lineColor = null;
			LOGGER.debug("Parsing rule: " + ruleLine);
			// split the fields and check if we have 3 as expected.
			String[] fields = ruleLine.trim().split(FIELD_DELIMITER);
			if (fields.length != 3) {
				lineNo += addLine(newdoc, ruleLine, Color.RED, true);
				// log numbers for fields independently...
				LOGGER.debug("Invalid number of fields! Expected 3, got: " + fields.length);
				if (fields.length > 3) {
					errors.append("Zeile " + lineNo + ": Zu viele Felder.\n");
				} else {
					errors.append("Zeile " + lineNo + ": Zu wenig Felder.\n");
				}
				invalid = true;
				continue;
			}
			// Have 3 fields, pretty up
			String ruleDirection = fields[2].toUpperCase();
			ruleLine = fields[0] + " \t " + fields[1] + " \t " + ruleDirection;

			// start to check fields one by one from the last to the first ....
			// check net direction: accept either 'in' or 'out' (case
			// insensitive)
			// TODO support combined 'in/out' rules
			if (!ruleDirection.equals("IN") && !ruleDirection.equals("OUT")) {
				lineNo += addLine(newdoc, ruleLine, Color.RED, true);
				LOGGER.debug("Invalid net direction! Expected 'in' or out'. Got: " + ruleDirection);
				errors.append("Zeile " + lineNo + ": Ungültige Richtung. Bitte nutzen Sie 'IN' bzw. 'OUT'.\n");
				invalid = true;
				continue;
			}
			// check port: accept if >= 0 and <= 65535
			int port = Util.parseInt(fields[1], -1);

			// port = 0 means match only host (all protocols and ports)
			if (port < 0 || port > 65535) {
				lineNo += addLine(newdoc, ruleLine, Color.RED, true);
				LOGGER.debug("Invalid port! Got: " + port);
				errors.append("Zeile " + lineNo + ": Ungültiger Port. Gültiger Bereich ist 0-65535.\n");
				invalid = true;
				continue;
			}
			// check hostname: bit more to do here
			// for IPs and/or resolvable hostnames we make use of java.net's
			// InetAddress.getByName() method which checks the validity of
			// an IP-Address represented by a string or if the given hostname
			// is resolvable. If any of these happen, we have a valid hostname.
			// Non-resolvable hostnames are handled differently, see after the
			// try/catch-block
			InetAddress ruleHost = null;
			try {
				// TODO: Find a way to reliably set a timeout (external DNS library?)
				// Otherwise just remove this check
				ruleHost = InetAddress.getByName(fields[0]);
			} catch (UnknownHostException e) {
				// might be good to see this exception in the log file
				// LOGGER.debug("Invalid hostname (java.net): ", e);
			}
			if (ruleHost == null) {
				// either invalid IP-Address or an invalid resolvable hostname
				// however it might also be a non-resolvable hostname that would
				// be valid in the actual pool-rooms, so lets check its syntax
				// according to: http://tools.ietf.org/html/rfc1034#section-3.1
				LOGGER.debug("Invalid host/IP! Got: " + fields[0]);
				String checkRes = checkHostnameSimple(fields[0]);
				if (checkRes == null) {
					if (!silent
							&& !warnedHosts.contains(fields[0])
							&& !Gui.showMessageBox("Konnte '" + fields[0]
									+ "' nicht auflösen. Wollen Sie diesen Hostnamen trotzdem verwenden?",
									MessageType.WARNING_RETRY, null, null)) {
						invalid = true;
					}
					warnedHosts.add(fields[0]);
					lineColor = Color.ORANGE;
				} else {
					lineNo += addLine(newdoc, ruleLine, Color.RED, true);
					errors.append("Zeile " + lineNo + ": " + checkRes + "\n");
					invalid = true;
					continue;
				}
			}
			// Made it to here - line is valid
			lineNo += addLine(newdoc, ruleLine, lineColor, false);
			rulesList.add(new NetRule(NetDirection.valueOf(ruleDirection), fields[0], port));
		}
		if (!silent && errors.length() != 0) {
			Gui.showMessageBox("Fehler beim Auswerten der angegebenen Netzwerkregeln.\n\n" + errors.toString()
					+ "\nBitte geben Sie die Regeln zeilenweise im Format\n"
					+ "<host> <port> <IN|OUT>\n"
					+ "an.",
					MessageType.ERROR, null, null);
		}
		if (newdoc != null) {
			tpNetworkRules.setDocument(newdoc);
		}
		if (invalid) {
			return null;
		}
		// Success
		return rulesList;
	}

	private int addLine(DefaultStyledDocument doc, String line, Color color, boolean bold) {
		if (doc == null)
			return 0;
		if (color == null) {
			color = FOREGROUND_TEXT_COLOR;
		}
		SimpleAttributeSet attrs = new SimpleAttributeSet();
		StyleConstants.setForeground(attrs, color);
		StyleConstants.setBold(attrs, bold);
		try {
			doc.insertString(doc.getLength(), line + "\n", attrs);
		} catch (BadLocationException e) {
			LOGGER.warn("Cannot append to new textbox document", e);
		}
		return 1;
	}

	/**
	 * Very simple hostname check for the given String. This will only check for
	 * some requirements of valid hostnames as stated in
	 * http://tools.ietf.org/html/rfc1034#section-3.1 To recap: max length of
	 * the whole hostname must be < 254 ASCII characters, all domain labels
	 * (between two dots) must be between 1 and 63 chars long and domain labels
	 * can only contain digits, letters and hyphen. (Note: we also accept
	 * forward slash to accept subnets!)
	 * 
	 * @param hostname the hostname to check for syntactical validity
	 * @return null if valid, error string otherwise
	 */
	private String checkHostnameSimple(final String hostname) {
		if (hostname.length() > 254) {
			return "Hostname ist zu lang.";
		}
		// split by '.' to get domain levels
		boolean allNumeric = true;
		String[] domainLabels = hostname.split("\\.");
		for (String domainLabel : domainLabels) {
			if (domainLabel.length() > 63) {
				// fail since domain level should be max 63 chars
				return "Domain-Ebene '" + domainLabel + "' länger als 63 Zeichen.";
			}
			if (Util.parseInt(domainLabel, -1) == -1) {
				allNumeric = false;
			}
			// checking for valid chars is pointless with punycode
		}
		if (allNumeric && domainLabels.length != 4) {
			return "Unvollständige IP-Adresse.";
		}
		return null;
	}

	/**
	 * Custom event mechanism to detect changes to the netrules list (Mostly
	 * needed for the reactToChange() stuff in LectureDetailsWindow)
	 */
	protected EventListenerList listenerList = new EventListenerList();

	public class NetrulesConfigurationChangeEvent extends EventObject {

		private static final long serialVersionUID = -8779550754760035845L;

		public NetrulesConfigurationChangeEvent(Object source) {
			super(source);
		}
	}

	public interface NetrulesConfigurationChangeEventListener extends
			EventListener {
		public void stateChanged(NetrulesConfigurationChangeEvent event);
	}

	public void addNetrulesConfigurationChangeEventListener(
			NetrulesConfigurationChangeEventListener listener) {
		listenerList.add(NetrulesConfigurationChangeEventListener.class,
				listener);
	}

	public void removeNetrulesConfigurationChangeEventListener(
			NetrulesConfigurationChangeEventListener listener) {
		listenerList.remove(NetrulesConfigurationChangeEventListener.class,
				listener);
	}

	void fireNetrulesConfigurationChangeEvent(
			NetrulesConfigurationChangeEvent evt) {
		Object[] listeners = listenerList.getListenerList();
		for (int i = 0; i < listeners.length; i++) {
			if (listeners[i] == NetrulesConfigurationChangeEventListener.class) {
				((NetrulesConfigurationChangeEventListener) listeners[i + 1])
						.stateChanged(evt);
			}
		}
	}
}

/**
 * Internal layout class for this widget
 */
class NetrulesConfiguratorLayout extends JPanel {

	private static final long serialVersionUID = 5266120380443817325L;
	private final static String txtNetworkOptionsTitle = "Netzwerk Einstellungen";
	private final static String txtNetworkOptionsDesc = "Wenn Sie den Internetzugriff deaktiviert haben,"
			+ " können Sie hier Ausnahmen definieren (Whitelist)."
			+ " Bitte definieren Sie Ihre Regeln im Format\n<host> <port> <in|out>.\n"
			+ "Sie können Port 0 angeben, was sämtlichen TCP und UDP Ports eines Hosts entspricht.\n\n"
			+ "Wenn Sie Internetzugriff aktivieren, hat diese Liste den gegenteiligen Effekt";
	private final static String txtNetworkRulesTitle = "Netzwerkregeln";

	private final JPanel pnlNetworkOptions;
	protected final JTextPane tpNetworkRules;

	public NetrulesConfiguratorLayout() {

		GridManager grid = new GridManager(this, 1, true,
				new Insets(5, 5, 5, 5));

		// middle panel for network rules
		pnlNetworkOptions = new JPanel();
		GridManager gridNetworkOptions = new GridManager(pnlNetworkOptions, 1,
				true, new Insets(2, 2, 2, 2));
		pnlNetworkOptions.setBorder(BorderFactory
				.createTitledBorder(txtNetworkOptionsTitle));
		tpNetworkRules = new JTextPane();

		JScrollPane scpNetworkRules = new JScrollPane(tpNetworkRules,
				JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
				JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
		pnlNetworkOptions.setBorder(BorderFactory
				.createTitledBorder(txtNetworkRulesTitle));
		gridNetworkOptions
				.add(new WordWrapLabel(txtNetworkOptionsDesc))
				.fill(true, false).expand(true, false);
		gridNetworkOptions.nextRow();
		gridNetworkOptions.add(scpNetworkRules).fill(true, true)
				.expand(true, true);
		gridNetworkOptions.finish(false);

		// build the final grid
		grid.add(pnlNetworkOptions).fill(true, true).expand(true, true);
		grid.finish(false);
	}
}