/** 
  * Bandscope Receiver Applet 1.0.0 [BAND TYPE AND BAND SELECTOR]
  * @author Robert J Morton <robmorton@clara.net>
  * @version 13 March 2002, 20 March 2012
  * @copyright Robert J Morton (all rights reserved) */


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

class bands {
  private static final int
    X = 395,  // x-coordinate of these components on applet panel
    Y = 69,   // y-coordinate of band type label on applet panel
    W = 140,  // width of combobox 
    H = 30,   // height of combobox
    h = 15;   // label area height

  // Band names for broadcast, amateur, air and marine bands respectively:
  private static final String bandNames[][] = {
    {"None","Long Wave","Medium Wave","120 metre","90 metre","75 metre",
     "60 metre","49 metre","39 metre","31 metre","25 metre","22 metre",
     "19 metre","16 metre","13 metre","11 metre","FM (Low half)",
     "FM (High half)"},
    {"None","Top Band","80 metre","40 metre","30 metre","20 metre",
     "17 metre","15 metre", "12 metre", "10 metre", "6 metre", "4 metre",
     "2 metre","70 cm","23 cm"},
    {"None","LF Navigation","3 Meg","3½ Meg","4½ Meg","5½ Meg","6½ Meg",
     "9 Meg","10 Meg","11 Meg","13 Meg","15 Meg","18 Meg","22 Meg","23 Meg",
     "VHF Civil (Lower Half)","VHF Civil (Upper Half)"},
    {"None","2-3 Meg","6½ Meg","8½ Meg","12-13 Meg","18.8 Meg","19.7 Meg",
     "22-23 Meg", "25 Meg", "Marine VHF"}
  };

  private int 
    sBT = 0,  // index number of selected band type
    sbt = 0,  // array index number of selected band type
    sB = 0,   // index number of selected band
    sb = 0;   // array index number of selected band

  private centrefreq cf;   // reference to the centre-frequency class
  private freqspan sp;     // reference to the frequency-span class
  private listeningon lo;  // reference to the "listening on" panel class
  private loader ld;       // reference to the loader class instance

  // selector for type of radio band required
  private JComboBox<String> BandTypes;

  // selector for the required radio band
  private JComboBox<String> Bands;


  bands(bs cp, centrefreq cf, freqspan sp) {
    this.cf = cf;  // set ref to centre-frequency class to local variable
    this.sp = sp;  // set ref to centre-frequency class to local variable

    int y = Y;  // y-coordinate of the band-type selector's label
    JLabel TypesLab = 
      new JLabel("Select Band Type");  // create band-type selector label
    cp.add(TypesLab);                  // add it to applet's content pane 
    TypesLab.setBounds(X,y,W,h);       // set its position and size

    y += 18;  // move down to the band-type selector position

    BandTypes = new JComboBox<String>();  // create the band-type selector
    BandTypes.addItem("None"); 
    BandTypes.addItem("Broadcast");  // set up its permanent menu entries 
    BandTypes.addItem("Amateur");
    BandTypes.addItem("Aircraft"); 
    BandTypes.addItem("Marine"); 
    cp.add(BandTypes);               // add it to the applet's content pane 
    BandTypes.setBounds(X,y,W,H);    // set its position and size

    /* Create a new item listener to listen 
    for when a new band-type is selected. */

    BandTypes.addItemListener(new bdchl(bdchl.BANDTYPES, this));

    y += 39;  // move down to the band selector label position

    JLabel BandLab = 
      new JLabel("Select Band");  // create the band selector label
    cp.add(BandLab);              // add it to the applet's content pane 
    BandLab.setBounds(X,y,W,h);   // set its position and size

    y += 18;  // move down to band selector position

    Bands = new JComboBox<String>();  // create the band selector
    Bands.addItem("None");            // absolutely vital to avoid hang-up
    cp.add(Bands);                    // add it to the applet's content pane 
    Bands.setBounds(X, y, W, H);      // set its position and size
    Bands.addItemListener(            // create a new item listener to listen
      new bdchl(bdchl.BANDS, this)    // for when a new band is selected
    );
  }


  // set the reference to the "listening on" panel class
  void setLo(listeningon lo) {
    this.lo = lo;  // because "listening on" is not created until 
  }                // after the "bands" object has been created


  void setLd(loader ld) {  // set reference to the loader class instance
    this.ld = ld;          // because the loader is not created until 
  }                        // after the "bands" object has been created


  void selBand() {  // ACTION TO BE TAKEN WHEN NEW BAND SELECTED
    sB = Bands.getSelectedIndex();  // index number of selected band
    sb = sB - 1;             // corresponding array index
    if(sB > 0 && sBT > 0) {  // if band is selected
      sp.setSpan(sbt, sb);   // set frequency span for selected band
      cf.setCF(sbt, sb);     // set centre frequency for selected band
      ld.load(sBT, sB);      // trigger loading of appropriate data file
    }
  }


  void selBandType() {  // WHEN NEW BANDSCOPE SPAN IS SELECTED
    sBT = BandTypes.getSelectedIndex();  // index number of selected band type
    sbt = sBT - 1;                       // corresponding array index

    Bands.removeAllItems();  /* remove the band names of the
                                previously-selected band type. */

    /* If a valid band is selected (ie not "None"), get the
    number of bands in this band-type (eg broadcast, amateur). */

    if(sBT > 0) {            
      int I = (bandNames[sbt]).length;

      for(int i = 0; i < I; i++)           // For each band of this type,
        Bands.addItem(bandNames[sbt][i]);  // load its name into the band
    }                                      // choice menu;

    else                      // else if "None" is selected,
      Bands.addItem("None");  // set up a null band
    lo.setReceiving(false);   // stop receiving. 
  }


  // ALLOWS AN EXTERNAL CLASS TO SELECT A BAND-TYPE
  void setSelectedType(int x) {
    sBT = x;  // set the selected band type variable to the required value

    BandTypes.setSelectedIndex(x);  // Set the band-type selector choice
  }                                 // menu to the required band-type.


  // ALLOWS AN EXTERNAL CLASS TO SELECT A BAND OF THE CURRENT TYPE
  void setSelectedBand(int x) {
    sB = x;  // set the selected band variable to the required value

    Bands.setSelectedIndex(x);  // Set the band selector choice 
  }                             // menu to the required band.


  // ALLOWS "SCOPE" CLASS TO GET THE CURRENTLY SELECTED BAND TYPE
  int getSelectedType() {return sBT;}

  // ALLOWS "SCOPE CLASS TO GET THE CURRENTLY SELECTED BAND
  int getSelectedBand() {return sB;}


  String getBandName() {  // USED BY "LOADER"
    String s;
    if(sBT > 0 && sB > 0)  // if a specific band has been manually selected
      s =  bandNames[sbt][sb];  // get its name
    else                        // otherwise
      s = "default";            // call it the default band
    return s;
  }
}


// LISTENS FOR EVENTS FROM THE CHOICE MENU SELECTORS
class bdchl implements ItemListener {

  // an event from the 'band type selector' choice menu
  static final int BANDTYPES = 0;

  static final int 
    BANDS = 1;  // an event from the 'band selector' choice menu
  int id;       // one of the above events
  bands ap;     // the application that called: always the above  class

  // constructor for a new Choice selection event
  public bdchl(int id, bands ap) {

    /* Set the id number pertaining to this instance of 'cl' then
    set the reference to the instance of the 'bs' applet from 
    which it came. (there will only be one instance anyway). */

    this.id = id;
    this.ap = ap;
  }

  // a Choice selection event has occurred
  public void itemStateChanged(ItemEvent e) {

    /* Execute the appropriate method in the above class 
    that deals with the selection event concerned. */

    switch(id) {
      case BANDTYPES: ap.selBandType(); break;
      case BANDS: ap.selBand();
    }
  }
}