// robert bradshaw 11/98


import java.util.StringTokenizer;

public class TuringRule {

  private int  curState;
  private int  newState;
  private char curTapeChar;
  private char newTapeChar;
  private char moveDir;
  
  public TuringRule(int cs, char ct, int ns, char nt, char md) {
    setRule(cs, ct, ns, nt, md);
  }
  
  public TuringRule(String s) {
    // assumes state <= 9
    try {
      setRule(Integer.parseInt(""+s.charAt(0)), 
           s.charAt(1),
           Integer.parseInt(""+s.charAt(2)),
           s.charAt(3),
           s.charAt(4));
    }
    catch (Exception e) { setRule(0,' ',0,' ','0'); }
  }
  
  private void setRule(int cs, char ct, int ns, char nt, char md) {
    curState    = cs;
    curTapeChar = ct;
    newState    = ns;
    newTapeChar = nt;
    moveDir     = md;
  }
  
  public static TuringRule[] parseRules(String s) {
    StringTokenizer st=new StringTokenizer(s, "\n,");
    TuringRule[] rules = new TuringRule[st.countTokens()];
    for(int i=0; i<rules.length; i++)
      rules[i]=new TuringRule(st.nextToken());
    return rules;
  }
  
  
  public boolean apply(TuringMachine m) {
    if (m.getState()!=curState || m.tape.read()!=curTapeChar) return false;
    else {
      m.setState(newState);
      m.tape.write(newTapeChar);
      m.tape.move(moveDir);
      return true;
    }
  }
  
  
  public int  getCurState()      { return curState; }
  public void setCurState(int i) { curState = i; }
  
  public int  getNewState()      { return newState; }
  public void setNewState(int i) { newState = i; }
  
  public char getCurTapeChar()       { return curTapeChar; }
  public void setCurTapeChar(char c) { curTapeChar = c; }
  
  public char getNewTapeChar()       { return newTapeChar; }
  public void getNewTapeChar(char c) { newTapeChar = c; }
  
  public char getMoveDir()           { return moveDir; }
  public void setMoveDir(char c)     { moveDir = c; }
  
  public String toString() {
    return ""+curState+curTapeChar+newState+newTapeChar+moveDir;
  }
  
}