package pal;

public class LexAnal {
   String line = null;
   int index = 0;
   int marker = 0;
   String error = "";
   String name = "";
   String propval = "";
   static int EOF = -1;

   static final int R1 = 1, R2 = 2, R3 = 3, R4 = 4, R5 = 5, R6 = 6;

   LexAnal(String line) {
      line = line.replaceAll("\\(\\\\(?=\\d)", "\u0008");
      line = line.replaceAll("\\\\\\.", "\u0001");
      line = line.replaceAll("\\\\\\*", "\u0002");
      line = line.replaceAll("\\\\\\+", "\u0003");
      line = line.replaceAll("\\\\\\(", "\u0004");
      line = line.replaceAll("\\\\\\)", "\u0005");
      line = line.replaceAll("\\\\\\|", "\u0006");
      line = line.replaceAll("\\\\\\\\", "\u0007");
      this.line = line;
   }

   protected static boolean isdigit(char X) {
      return (X >= '0' && X <= '9');
   }

   protected static boolean isSpecialChar(char X) {
      return ((X == '.') || (X == '*') || (X == '+'));
   }

   protected static boolean isReducedASCII(char X) {
      return ((X >= 0x01 && X <= 0x0FF) && (X != '\u0008') && (X != '.') && (X != '*') && (X != '+') && (X != '(')
            && (X != ')') && (X != '|') && (X != '\\'));
   }

   // set marker and read next character
   private int getChar() {
      if (index >= line.length())
         return EOF;
      marker = index;
      return line.charAt(index++);
   }

   // set pointer one char back (to marked position)
   private void pushBackChar() {
      index = marker;
   }

   public void getToken() throws Exception {
      char[] tmp = new char[1];
      int myChar = 0;
      int state = R1;
      // String prop = "";
      name = "";
      propval = "";

      // read chars and create tokens
      try {
         do {
            // ///////////////////////////////////////////////////////////
            myChar = getChar();
            if (myChar == EOF && state != R1)
               return;
            else if (myChar == EOF) {
               name = "finished";
               return;
            }
            // throw new Exception("finished");

            switch (state) {

            case R1:
               if (myChar == '(') { // rule 2
                  name = "oBracket";
                  state = R1;
                  return;
               }
               if (myChar == ')') { // rule 2
                  name = "cBracket";
                  state = R1;
                  return;
               }
               if (myChar == 0x08) { // rule 4
                  name = "brefNum";
                  state = R2;
                  pushBackChar();
                  break;
               }
               if (isReducedASCII((char) myChar)) { // rule 5
                  name = "redASCII";
                  state = R3;
                  pushBackChar();
                  break;
               }
               if (isSpecialChar((char) myChar)) { // rule 6
                  name = "specChar";
                  tmp[0] = (char) myChar;
                  propval = "" + new String(tmp);
                  state = R1;
                  return;
               }
               if (myChar == '|') {
                  name = "or";
                  state = R1;
                  return;
               } else {
                  throw new Exception("bad char");
               }

            case R2:
               if (isdigit((char) myChar)) {
                  tmp[0] = (char) myChar;
                  propval = propval + new String(tmp);
                  break;
               } else if (myChar == ')') {
                  state = R1;
                  return;
               } else {
                  new Exception("lexerror");
               }
               break;

            case R3:
               if (isReducedASCII((char) myChar)) {
                  tmp[0] = (char) myChar;
                  propval = propval + new String(tmp);
                  break;
               } else {
                  pushBackChar();
                  state = R1;
                  return;
               }
            }
            // ///////////////////////////////////////////////////////////
         } while (true);

      } catch (Exception e) {
         if (e.getMessage().equals("finished"))
            throw new Exception("finished");
         tmp[0]=(char)myChar;
         error = "Found \"" + new String(tmp) + "\" expected something else";
         System.out.println(error);
         throw new Exception("lexerror");
      }
   }

   public static void main(String[] args) {
      // LexAnal la = new LexAnal("\\. \\. \\| j\\\\ \\+ \\(");
//      LexAnal la = new LexAnal("((xdss|y)+)=(\\2)");
      LexAnal la = new LexAnal("***");
//       LexAnal la = new LexAnal("(((\\(1\\))))");
      try {
         while (true) {
            la.getToken();
            System.out.println(String.format("%s %s", la.name, la.propval));
            if(la.name.equals("finished")){
               break;
            }
         }
      } catch (Exception e) {
         System.out.println(e.getMessage());
      }

   }
}