/** 
  * Stop/Start/Reset Buttons for CtrlPanl.class re DifEqnAp.class
  * @author Robert J Morton UK-YE572246C
  * @version 27 November 1997 modified 07 August 2009, 18 April 2012 */

/*  This Panel class contains 4 buttons: Stop, Start, Reset, Spot
    to control the operation of the applet */

import java.awt.*;        // for graphics operations (GUI)
import java.awt.event.*;  // for the new-fangled 1.1 event handling
import javax.swing.*;     // library for constructing Swing GUI


public class setbutt extends JPanel {
  private difeqnap ap;   // instance reference of the main applet class
  private timegr tg;     // instance reference of the timegr class
  private bouncegr bg;   // instance reference of the bouncegr class
  private formula f;     // instance reference of the formula class
  private JButton a, b;  // references for the 2 buttons

  private boolean 
    RunFlag = false;  // applet starts off with the equation not iterating


  setbutt(difeqnap ap, timegr tg, bouncegr bg, formula f) {
    this.ap = ap;  // instance ref. of main applet class
    this.tg = tg;  // instance ref. of timegr class
    this.bg = bg;  // instance ref. of bouncegr class
    this.f = f;    // instance ref. of formula class

    setLayout(null);  // to allow the button panel to be laid out manually

    /* Create the 'start' button, annotate it with the word
    "Start", add it to this panel, set its position and size
     add a listener to listen for when it is pressed. */

    a = new JButton(); a.setText("Start");
    add(a); a.setBounds(5, 1, 110, 33);
    a.addActionListener(new stopbut(0, this));

    /* Create the 'cleat' button, annotate it with the word
    "Clear", add it to this panel, set its position and size
    add a listener to listen for when it is pressed. */

    b = new JButton(); b.setText("Clear");
    add(b); b.setBounds(120,1,110, 33);
    b.addActionListener(new stopbut(1, this));
  }


  /* Stop the iteration process by clearing the 'run' flag to
  stop iteration and updating the Run Flag state in main applet. */

  void Stop() { Relabel(RunFlag = false); ap.setRF(false); }


  void reset() {      // USED BY RESET BUTTON, EQN CHANGE, C CHANGE
    RunFlag = false;  // stop the program from iterating
    Relabel(false);   // relabel the button to 'Start'
    ap.setRF(false);  // stop the iteration loop in the main applet
    tg.reset();       // reinitialise the time graph
    bg.reset();       // reinitialise the bounce graph
    ap.showStatus("Graphs cleared, iteration process stopped and reset.");
  }


  private void Relabel(boolean Flag) {
    if(Flag) {             // if the run flag is set
      a.setText("Stop");   // re-label the button 'Stop'
      ap.showStatus("Applet is iterating the equation...");
    } else {               // otherwise...
      a.setText("Start");  // re-label the button 'Start'
      ap.showStatus("Iteration process halted.");
    }
  }


  /* THIS METHOD IS ONLY CALLED BY THE LISTENER
  CLASS BELOW IF A CONTROL BUTTON HAS BEEN PRESSED */

  void whichButton(int i) { 
    if(i == 0) {                    // If 'Start/Stop' button has been pressed
      Relabel(RunFlag = !RunFlag);  // start iterating the selected equation
      if(RunFlag) f.reset();        // if starting, initialise formula class
      ap.setRF(RunFlag);            // update Run Flag state in main applet
    } else
      reset();  // Else, CLEAR button has been pressed, so clear
  }             // graphs and reset 'x' to its start value.
}



// LISTENS FOR EVENTS FROM START/STOP AND CLEAR BUTTONS
class stopbut implements ActionListener {
  int id;      // one of the above events
  setbutt sb;  // the application that called: always the above class

  /* Constructor for a new checkbox event: by setting the 'id' number
  pertaining to this instance and the reference to the instance of
  the class from which it came. (there will only be one instance). */

  public stopbut(int id, setbutt sb) { this.id = id; this.sb = sb; }

  // an event has occurred from checkbox 'id'
  public void actionPerformed(ActionEvent e) {
    switch(id) {
      case 0: sb.whichButton(0); break;  // stop/start button
      case 1: sb.whichButton(1); break;  // clear button
    }
  }
}