/** 
  * Equation Selector for CtrlPanl.class re DifEqnAp.class
  * @author Robert J Morton
  * @version 27 November 1997 modified 07 August 2009, 18 April 2012 */

/*  This class contains a pair of radio buttons for
    choosing which of the two difference equations
    to iterate: x = x**2 + c or x = cx(1 - x) */

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 seleqn extends JPanel {

  private cval sc;            // reference to the c value text entry panel
  private timegr tg;          // reference to time-graph instance
  private bouncegr bg;        // reference to bounce-graph instance
  private formula f;          // instance reference to formula class
  private JLabel L;           // reference for the title label
  private ButtonGroup G;      // reference for the checkbox group
  private JRadioButton a, b;  // references for the two buttons
  private int ls = 0;         // language switch: 0=English 1=Portuguese
  private String s;           // for multi-language

  private boolean 
    Flags[] = {false,true},  // the two flag options
    EqnFlag = false;         /* false means x = cx(1 - x) is selected
                                true means x = x**2 + c is selected */

  seleqn(cval sc, timegr tg, bouncegr bg, formula f, Color pc, int ls) {
    this.sc = sc;  // set instance ref. of cval class to local variable
    this.tg = tg;  // set instance ref. of timegr class to local variable
    this.bg = bg;  // set instance ref. of bouncegr class to local variable
    this.f = f;    // set instance ref. of formula class to local variable
    this.ls = ls;  // language switch

    setBackground(pc);     // set panel colour
    setLayout(
      new GridLayout(3,0)  // lay out the 3 objects one beneath the next
    );
    s = "Equation";        // English/Portuguese
    if(ls != 0)
      s = "Equação";

    L = new JLabel(s,Label.LEFT);  // create equation selector panel label
    add(L);                        // add it to this panel
    G = new ButtonGroup();         // group container for radio buttons

    a = new JRadioButton("x = cx(1 - x)",true);
    G.add(a);  // add it to the button-group
    add(a);    // add it to this panel
    a.addItemListener(new eqnbut(0,this));  // create Item Listener for it

    b = new JRadioButton("x = x * x + c",false);
    G.add(b);  // add it to the button-group
    add(b);    // add it to this panel
    b.addItemListener(new eqnbut(1,this));  // create Item Listener for it
  }


  void selectEquation(int i) {
    EqnFlag = Flags[i];  // set new state of the equation selector
    f.setEF(EqnFlag);    // set equation-flag state in formula class
    tg.setEF(EqnFlag);   // set equation-flag state in time-graph class
    bg.setEF(EqnFlag);   // set equation-flag state in bounce-graph class
    sc.setEF(EqnFlag);   // set equation-flag state in C-value class
    sc.initCval();       // reset c to default value for selected equation
  }
}


// LISTENS FOR EVENTS FROM EQUATION SELECTION BUTTONS
class eqnbut implements ItemListener {
  int id;     // one of the above events
  seleqn se;  // the application that called: always the above class

  // constructor for a new checkbox event
  public eqnbut(int id, seleqn se) {
    this.id = id;  // set id number pertaining to this instance
    this.se = se;  // set reference to the instance of above class
  }                // from which it came.

  // event has occurred from checkbox 'id'
  public void itemStateChanged(ItemEvent e) {
    switch(id) {
      case 0: se.selectEquation(0); break;  // equation x = cx(1 - x) selected
      case 1: se.selectEquation(1);         // equation x = x**2 + c selected
    }
  }
}