import java.util.*;
import java.net.*;

public class FormattableURL implements Formattable {

  private URL delegate;
  
  public FormattableURL(URL url) {
    this.delegate = url;
  }
  
  public void formatTo(Formatter formatter, int flags, int width,
      int precision) {

    if (precision < -1) {
      throw new IllegalFormatPrecisionException(precision);
    }
    if (width < -1) {
      throw new IllegalFormatWidthException(width);
    }
    if (precision > width) {
      throw new IllegalFormatPrecisionException(precision);
    }
    
    // Check to see if we've been asked to use any flags we don't interpret
    int recognizedFlags 
     = FormattableFlags.UPPERCASE | FormattableFlags.LEFT_JUSTIFY;
    boolean unsupportedFlags = ((~recognizedFlags) & flags) != 0;
    if (unsupportedFlags) {
      // We should really pass the flags to this constructor.
      // However, Java doesn't offer any reasonable way to get these.
      throw new IllegalFormatFlagsException("#");
    }
    
    boolean upperCase = (flags & FormattableFlags.UPPERCASE) != 0;
    
    StringBuffer sb = new StringBuffer();
    
    String scheme = delegate.getProtocol();
    if (upperCase && scheme != null) {
      scheme = scheme.toUpperCase(Locale.ENGLISH);
    }

    String hostname = delegate.getHost();
    if (upperCase && hostname != null) {
      hostname = hostname.toUpperCase(Locale.ENGLISH);
    }
    
    String userInfo = delegate.getUserInfo();
    
    int port = delegate.getPort();
    String path = delegate.getPath();
    String query = delegate.getQuery();
    String fragment = delegate.getRef();
    
    if (scheme != null) {
      sb.append(scheme);
      sb.append("://");
    }
    
    if (userInfo != null) {
      sb.append(userInfo);
      sb.append("@");
    }
    
    if (hostname != null) {
      sb.append(hostname);
    }
    
    if (port != -1) {
      sb.append(':');
      sb.append(port);
    }
    
    if (path != null) {
      sb.append(path);
    }
    
    if (query != null) {
      sb.append('?');
      sb.append(query);
    }
    
    if (fragment != null) {
      sb.append('#');
      sb.append(fragment);
    }
    
    boolean leftJustify = (flags & FormattableFlags.LEFT_JUSTIFY) != 0;
    
    // Truncate on the right if necessary
    if (precision < sb.length()) {
      sb.setLength(precision);
    }
    else {// Pad with spaces if necessary
      while (sb.length() < width) {
        if (leftJustify) sb.append(' ');
        else sb.insert(0, ' ');
      }
    }
    
    formatter.format(sb.toString());
  }
}