// In order to get this to work as an applet, I've had to bust the
// internal security!  You can't make them much richer than that...

import java.awt.*;
import java.awt.event.*;
import java.util.zip.*;
import java.io.*;
import java.net.*;
import java.util.*;
import java.text.DateFormat;

public class Search extends java.applet.Applet {
  public String getAppletInfo() {
    return "Applet to search the FEISTFANS-L archive";
  }

  public void init() {
    try {
      // Hard coded!  *sigh*
      base = new URL("http://www.cs.man.ac.uk/~fellowsd/REF/");
    } catch (MalformedURLException e) {
      // Ignore - it won't happen!
    }
    buildUI();
  }
  public synchronized void destroy() {
    if (getSearcher() != null) {
      getSearcher().stop();
    }
  }
  public synchronized void start() {
    if (getSearcher() != null) {
      getSearcher().resume();
    }
  }
  public synchronized void stop() {
    if (getSearcher() != null) {
      getSearcher().suspend();
    }
  }

  public TextField searchPattern;
  public TextArea  results;
  public Label     amWorking, whichArchive;
  public boolean   showHeaders;

  public void setShow(boolean flag) {
    showHeaders = flag;
  }

  public class Button_Search implements ActionListener {
    Search s;
    public Button_Search(Search s) {
      this.s = s;
    }
    public void actionPerformed(ActionEvent e) {
      s.searchPattern.requestFocus();
      s.results.setText("");
      s.search(s.searchPattern.getText());
    }
  }
  public class Button_Clear implements ActionListener {
    Search s;
    public Button_Clear(Search s) {
      this.s = s;
    }
    public void actionPerformed(ActionEvent e) {
      s.killSearcher();
      s.results.setText("");
      s.searchPattern.setText("");
      s.searchPattern.requestFocus();
    }
  }
  public class Checkbox_Flag implements ItemListener {
    Search s;
    public Checkbox_Flag(Search s) {
      this.s = s;
    }
    public void itemStateChanged(ItemEvent e) {
      s.setShow(((Checkbox)(e.getSource())).getState());
    }
  }

  public void buildUI() {
    this.setLayout( new BorderLayout());
    Panel p = new Panel();
    p.setLayout( new BorderLayout());
    this.add(p, "North");
    Label l = new Label("Text to search for:");
    searchPattern = new TextField();
    searchPattern.requestFocus();
    p.add(l, "West");
    p.add(searchPattern);
    this.add(results = new TextArea("", 24,80, TextArea.SCROLLBARS_BOTH));
    results.setEditable(false);
    p = new Panel();
    p.setLayout( new BorderLayout());
    Panel q = new Panel();
    this.add(p, "South");
    Button doSearch = new Button("Start Search");
    doSearch.addActionListener( new Button_Search( this));
    Button clear = new Button("Clear");
    clear.addActionListener( new Button_Clear( this));
    Checkbox sh = new Checkbox("Show all (reasonable) headers", false);
    sh.addItemListener( new Checkbox_Flag( this));
    p.add(q, "North");
    q.add(sh);
    q.add(doSearch);
    q.add(clear);
    amWorking = new Label("Status: idle");
    whichArchive = new Label("");
    p.add(amWorking, "West");
    p.add(whichArchive);
  }
    
  /**
   * The separator between messages.
   */
  public static final String sep	= "";
  /**
   * The separator between the full headers and the useful ones!
   */
  public static final String skipbefore = "*** EOOH ***";

  public URL base;
  public static String encoding = "ISO-8859-1";
  public Searcher searcher;

  public synchronized Searcher getSearcher() {
    return searcher;
  }
  public synchronized void setSearcher(Searcher searcher) {
    this.searcher = searcher;
  }

  public BufferedReader openDataStream(String filename)
       throws MalformedURLException, IOException
  {
    // Get the net stream
    URL url = new URL(base, filename);
    InputStream netStream = url.openStream();

    // Get the reader (possibly with gunzipping...)
    Reader r;
    if (filename.endsWith(".gz")) {
      InputStream is = new GZIPInputStream(netStream);
      r = new InputStreamReader(is, encoding);
    } else {
      r = new InputStreamReader(netStream, encoding);
    }

    // Get the buffered input stream, and return...
    return new BufferedReader(r);
  }

  public static final String visualsep = "--------------------------------------------------------------------------------\n";

  public class Searcher extends Thread {
    Search ui;
    String manifestFile;
    String searchString;
    private Calendar calendar;
    private DateFormat formatter;

    public Searcher(Search ui, String searchString, String manifestFile) {
      super();
      this.ui = ui;
      this.searchString = searchString;
      this.manifestFile = manifestFile;
      this.start();
      calendar = Calendar.getInstance();
      formatter = DateFormat.getDateInstance(DateFormat.MEDIUM);
    }
    public Searcher(Search ui, String searchString) {
      this(ui, searchString, "manifest.txt");
    }

    void puts(String s) {
      ui.results.append(s);
    }
    void progress(String s) {
      ui.whichArchive.setText(s);
    }
    private Date parseDateFromString(String s, int start, int end) {
      int y,m,d;

      d = Integer.parseInt(s.substring(start,   start+1));
      m = Integer.parseInt(s.substring(start+3, start+4));
      y = Integer.parseInt(s.substring(start+6, end-1));
      if (y<50) {
	y += 2000;
      } else if (y<100) {
	y += 1900;
      }
      synchronized(calendar) {
	calendar.set(y,m,d);
	return calendar.getTime();
      }
    }
    private String printDateToString(Date date) {
      return formatter.format(date);
    }
    void progress(String head, String filename, String tail) {
      if (filename.startsWith("archive.")) {
	int datestart1 = 8;
	int dateend1 = filename.indexOf(",",datestart1);
	int datestart2 = dateend1+1;
	int dateend2 = filename.indexOf(".",datestart2);
	if (dateend2<0) {
	  dateend2 = filename.length();
	}

	Date date1 = parseDateFromString(filename, datestart1, dateend1);
	Date date2 = parseDateFromString(filename, datestart2, dateend2);
	progress("(examining archive period from " +
		 printDateToString(date1) + " to " +
		 printDateToString(date2) + ")");
      } else {
	progress(head + filename + tail);
      }
    }

    Enumeration getFilenames(String manifestFile) throws IOException {
      BufferedReader manifest = ui.openDataStream(manifestFile);
      Stack filenameStack = new Stack();

      try {
	while (true) {
	  String s = manifest.readLine();
	  if (s == null) {
	    break;
	  }
	  s = s.trim();
	  if (s.length() <= 0 || s.startsWith("<")) {
	    break;
	  }
	  filenameStack.push(s);
	}
      } catch (EOFException e) {}

      manifest.close();
      return filenameStack.elements();
    }

    boolean finishedflag, matchedflag;
    String getMessage(BufferedReader is, String pat) throws IOException {
      StringBuffer message = new StringBuffer();
      matchedflag = false;
      boolean skipping = true;
      boolean showHeaders = ui.showHeaders;

      try {
	while (true) {
	  String s = is.readLine();
	  if (s == null) {
	    finishedflag = true;
	    break;
	  }
	  if (s.equals(sep)) {
	    break;
	  } else if (skipping) {
	    if (s.equals(skipbefore)) {
	      skipping = false;
	    }
	    continue;
	  }
	  if (!showHeaders) {
	    if (s.length() == 0) {
	      showHeaders = true;
	    } else if (!s.startsWith("Date:") &&
		       !s.startsWith("From:") &&
		       !s.startsWith("Subject:")) {
	      continue;
	    }
	  }
	  if (!matchedflag && s.indexOf(pat) >= 0) {
	    matchedflag = true;
	  }
	  message.append(s).append("\n");
	}
      } catch (EOFException e) {
	finishedflag = true;
      }
      return message.toString();
    }

    Cursor savedCursor;
    public synchronized void makeBusy() {
      if (savedCursor == null) {
	setSearcher(this);
	savedCursor = ui.results.getCursor();
	ui.results.setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
	ui.amWorking.setText("Status: busy");
      }
    }
    public synchronized void makeIdle() {
      if (savedCursor != null) {
	ui.results.setCursor(savedCursor);
	ui.amWorking.setText("Status: idle");
	progress("");
	setSearcher(null);
	savedCursor = null;
      }
    }

    public void run() {
      makeBusy();
      puts("Looking for \"" + searchString + "\"\n");

      try {
	progress("(reading manifest)");

	Enumeration filenames = getFilenames(manifestFile);

	if (searchString.length()==0 || !filenames.hasMoreElements()) {
	  puts("empty search!");
	} else {

	  while (filenames.hasMoreElements()) {
	    String filename = (String)filenames.nextElement();

	    progress("(looking in ", filename, ")");

	    BufferedReader stream = ui.openDataStream(filename);
	    finishedflag = false;
	    while (!finishedflag) {
	      String msg = getMessage(stream, searchString);
	      if (matchedflag) {
		puts(visualsep + msg);
	      }
	    }
	  }
	  puts(visualsep + "Search completed.");
	}

      } catch (MalformedURLException mue) {
	puts("MalformedURLException thrown! Detail follows:\n" + mue.toString()
	     + "\n");
      } catch (UnknownHostException uhe) {
	puts("Could not find host \"" + base.getHost() + "\"\n");
      } catch (IOException ioe) {
	puts("IOException thrown! Details follows:\n" + ioe.toString()
	     + "\n");
      }

      makeIdle();
    }
  }

  public synchronized void killSearcher() {
    try {
      getSearcher().stop();
      getSearcher().makeIdle();
    } catch (Exception e) {}
  }
  public synchronized void search(String searchString) {
    killSearcher();
    new Searcher(this, searchString);
  }
}