/** 
  * Bandscope Receiver Applet 1.0.0 [BAND TYPE AND BAND SELECTOR]
  * @author Robert J Morton <robmorton@clara.net> YE572246C
  * @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

  private static final String bandNames[][] = {

    // Broadcast Bands
    {"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)"},

    // Amateur Bands
    {"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"},

    // Air Bands
    {"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)"},

    // Marine Bands
    {"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

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

  private JComboBox<String>
    BandTypes,  // Choice selector for the type of radio band required
    Bands;      // Choice selector for the required radio band


  bands(Container cp, centrefreq cf, freqspan sp) {  // CONSTRUCTOR
    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

    // Create the band-type selector label
    JLabel TypesLab = new JLabel("Select Band Type");
    cp.add(TypesLab);  // add it to the applet's content pane
    TypesLab.setBounds(X,y,W,h);  // then 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");            // Set up its permanent
    BandTypes.addItem("Broadcast");       // 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 band selector label
    cp.add(BandLab);             // add it to the applet's content pane
    BandLab.setBounds(X,y,W,h);  // and set its position and size

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

    Bands = new JComboBox<String>();  // Create the band selector menu,
    Bands.addItem("None");            // add at least one item [this is abso-
                                      // lutely vital to avoid a hang-up]
    cp.add(Bands);                    // add it to the applet's content pane
    Bands.setBounds(X,y,W,H);         // set its position and size

    // Create a new item listener to listen for when a new band is selected.
    Bands.addItemListener(new bdchl(bdchl.BANDS, this));
  }

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


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


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


  void selBandType() {  // DO WHEN NEW BANDSCOPE SPAN IS SELECTED

    // Set index number & corresponding array index of selected band type.
    sBT = BandTypes.getSelectedIndex();

    sbt = sBT - 1;           // Remove the band names of the
    Bands.removeAllItems();  // previously-selected band type.

    if(sBT > 0) {                       // If valid band selected (not None)
      int I = (bandNames[sbt]).length;  // get number of bands of this type

      for(int i = 0; i < I; i++)  // For each band of this type:

        // Load the appropriate bands into the band choice menu.
        Bands.addItem(bandNames[sbt][i]);

      } 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: set the selected
  band type variable to the required value and the band-type selector
  choice menu to the required band-type. */

  void setSelectedType(int x) { sBT = x; BandTypes.setSelectedIndex(x); }


  /* ALLOWS AN EXTERNAL CLASS TO SELECT A BAND OF THE CURRENT TYPE: set
  the selected band variable to the required value and the band selector
  choice menu to the required band. */

  void setSelectedBand(int x) { sB = x; Bands.setSelectedIndex(x); }


  // 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's been manually selected
      s = bandNames[sbt][sb];  // then get its name
    else s = "default";        // otherwise call it the default band.
    return s;
  }
}


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

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

  // constructor for a new Choice selection event
  public bdchl(int id, bands ap) {
     this.id = id;  // set the id number pertaining to this instance of 'cl'
     this.ap = ap;  // set the reference to the instance of the 'bs' applet
  }                 // from which it came. (there can only be one instance).

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

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

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