// robert bradshaw 11/98


import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.util.Vector;
import java.io.*;


public class TuringRuleEditorApplet extends Applet implements ActionListener, ItemListener  {
  
  TuringMachineApplet theMachineApplet;
  List ruleList;
  TextField curState, curChar, newState, newChar;
  Choice moveDir;
  Button setBtn, newBtn, remBtn, saveBtn, loadBtn;
  Button setState, setTape;
  TextField stateFld, tapeFld, tapeIndexFld;
  TuringMachine theMachine;
  
  
  public TuringRuleEditorApplet() { this(null); }
  public TuringRuleEditorApplet(TuringMachineApplet tm) {
    theMachineApplet=tm;
    init();
  }
  
  public void init() {
    
    KeyListener intL = new IntFieldListener();
    KeyListener charL= new SingleCharListener();
    FocusListener selAL = new SelectAllListener();
      
    curState=new TextField(1);
    curState.addKeyListener(intL);
    curState.addKeyListener(charL);
    curState.addFocusListener(selAL);
      
    curChar=new TextField(1);
    curChar.addKeyListener(charL);
    curChar.addFocusListener(selAL);
      
    newState=new TextField(1);
    newState.addKeyListener(intL);
    newState.addKeyListener(charL);
    newState.addFocusListener(selAL);
      
    newChar=new TextField();
    newChar.addKeyListener(charL);
    newChar.addFocusListener(selAL);
      
    moveDir=new Choice();
    moveDir.add("Right");
    moveDir.add("Left");
    
    setBtn=new Button("Set Rules");
    setBtn.addActionListener(this);
    
    newBtn=new Button("New Rule");
    newBtn.addActionListener(this);
    
    remBtn=new Button("Remove Rule");
    remBtn.addActionListener(this);
    
    saveBtn=new Button("Save Rule");
    saveBtn.addActionListener(this);
    
    loadBtn=new Button("Load Set...");
    loadBtn.addActionListener(this);
    
    setState=new Button("Set state");
    setState.addActionListener(this);
    
    setTape=new Button("Set tape");
    setTape.addActionListener(this);
      
    stateFld=new TextField(1);
    stateFld.addKeyListener(intL);
    stateFld.addKeyListener(charL);
    stateFld.addFocusListener(selAL);
    
    tapeFld=new TextField(30);
      
    tapeIndexFld=new TextField(2);
    tapeIndexFld.addKeyListener(intL);
    tapeIndexFld.addKeyListener(charL);
    tapeIndexFld.addFocusListener(selAL);    
    
    ruleList=new List();
    ruleList.addItemListener(this);
    TuringRule[] rules=getMachineApplet().getMachineRules();
    for(int i=0; i<rules.length; i++) {
      ruleList.add(rules[i].toString());
    }
    
    setLayout(new BorderLayout());
    add(ruleList,"West");
    ruleList.setFont(new Font("Courier",0,12));
    Panel p=new Panel(new BorderLayout());
    Panel p2=new Panel(new FlowLayout(FlowLayout.LEFT));
    
    Panel p2_1=new Panel(new FlowLayout(FlowLayout.LEFT));
    p2_1.add(new Label("If state is"));
    p2_1.add(curState);
    p2_1.add(new Label(" and the tape reads"));
    p2_1.add(curChar);
    
    Panel p2_2=new Panel(new FlowLayout(FlowLayout.LEFT));
    p2_2.add(new Label("Set the state to"));
    p2_2.add(newState);
    p2_2.add(new Label(" write"));
    p2_2.add(newChar);
    p2_2.add(new Label(" and move"));
    p2_2.add(moveDir);
    
    Panel p2_3=new Panel(new FlowLayout(FlowLayout.LEFT));
    p2_3.add(setState);
    p2_3.add(new Label(" to"));
    p2_3.add(stateFld);
    
    Panel p2_4=new Panel(new FlowLayout(FlowLayout.LEFT));
    p2_4.add(setTape);
    p2_4.add(new Label(" to"));
    p2_4.add(tapeFld);
    p2_4.add(new Label(", index:"));
    p2_4.add(tapeIndexFld);
    
    p2.add(p2_1);
    p2.add(p2_2);
    p2.add(p2_3);
    p2.add(p2_4);
    Panel p3=new Panel(new FlowLayout(FlowLayout.RIGHT));
    if (theMachineApplet!=null) p3.add(loadBtn);
    p3.add(remBtn);
    p3.add(newBtn);
    p3.add(saveBtn);
    p3.add(setBtn);
    p.add(p2);
    p.add(p3,"South");
    add(p);
  }
  
  public void actionPerformed(ActionEvent e) {
    if (e.getSource()==newBtn) {
      ruleList.add("0 0 0");
      ruleList.select(ruleList.getItemCount()-1);
      clear();
    }
    else if (e.getSource()==remBtn) {
      ruleList.remove(ruleList.getSelectedIndex());
    }
    else if (e.getSource()==saveBtn) {
      int si=ruleList.getSelectedIndex();
      if (si==-1) {
        ruleList.add(getRule().toString());
        ruleList.select(ruleList.getItemCount()-1);
      }
      else {
        ruleList.replaceItem(getRule().toString(),si);
        ruleList.select(si);
      }
    }
    else if (e.getSource()==loadBtn) {
      FileDialog fileDialog=new FileDialog((Frame)this.getParent());
      fileDialog.show();
      importRuleList(new File(fileDialog.getDirectory(), fileDialog.getFile()));
    }
    else if (e.getSource()==setBtn) {
      getMachineApplet().setMachineRules(getRuleList());
    }
    else if (e.getSource()==setState) {
      if (stateFld.getText().equals("")) stateFld.setText("0");
      getMachineApplet().setMachineState(Integer.parseInt(stateFld.getText()));
    }
    else if (e.getSource()==setTape) {
      if (tapeIndexFld.getText().equals("")) tapeIndexFld.setText("0");
      getMachineApplet().setMachineTape(new TuringTape(tapeFld.getText(), Integer.parseInt(tapeIndexFld.getText())));
    }
  }
  
  public void itemStateChanged(ItemEvent e) {
    if (e.getStateChange()==ItemEvent.SELECTED) {
      setRule(new TuringRule(ruleList.getSelectedItem()));
    }
    else {
      ruleList.replaceItem(getRule().toString(),ruleList.getSelectedIndex());
    }
  }
  
  void importRuleList(File f) {
    try {
      FileInputStream fin=new FileInputStream(f);
      String rulesS="";
      byte[] b=new byte[5];
      int i=fin.read(b);
      while (i!=-1) {
        rulesS=rulesS+new String(b);
        i=fin.read(b);
      }
      TuringRule[] rules=TuringRule.parseRules(rulesS);
      ruleList.removeAll();
      for(i=0; i<rules.length; i++) {
        ruleList.add(rules[i].toString());
      }
    }
    catch (IOException e) { e.printStackTrace(System.out); }
  }
  
  TuringRule[] getRuleList() {
    TuringRule[] rules=new TuringRule[ruleList.getItemCount()];
    for(int i=0; i<rules.length; i++) {
      rules[i]=new TuringRule(ruleList.getItem(i));
    }
    return rules;
  }
  
  TuringRule getRule() {
    if (curState.getText().equals("")) curState.setText("0");
    if (curChar .getText().equals("")) curState.setText(" ");
    if (newState.getText().equals("")) curState.setText("0");
    if (newChar .getText().equals("")) curState.setText(" ");
    String dir="R";
    if (moveDir.getSelectedIndex()==1) dir="L";
    return new TuringRule(curState.getText()+
                          curChar .getText()+
                          newState.getText()+
                          newChar .getText()+
                          dir);
  }
  
  void setRule(TuringRule rule) {
    if (rule==null) clear();
    else {
      curState.setText(""+rule.getCurState());
      curChar .setText(""+rule.getCurTapeChar());
      newState.setText(""+rule.getNewState());
      newChar .setText(""+rule.getNewTapeChar());
      if (rule.getMoveDir() == 'L' || rule.getMoveDir() == 'l') moveDir.select(1);
      else moveDir.select(0);
    }
  }
    
  void clear() {
    curState.setText("");
    curChar.setText("");
    newState.setText("");
    newChar.setText("");
    moveDir.select(0);
  }
  
  private TuringMachineApplet getMachineApplet() {
    if (theMachineApplet!=null) return theMachineApplet;
    else {
      return (TuringMachineApplet)getAppletContext().getApplet(getParameter("mainAppletName"));
    }
  }
  
}