/** 
  * Geoid Selector Class for Rob's Moving Map Navigator
  * @author Robert J Morton
  * @version 16 April 2010
*/
/*  This class contains a drop-down menu object for choosing which of the
    geodic ellipsoids is to be used for the Vincenty distance and bearing
    computations. */

import javax.swing.*;     // Java Swing GUI utilities
import java.awt.*;        // Java Abstract Windowing Toolkit
import java.awt.event.*;  // for the new-fangled event handling

public class selgeoid {  // to allow manual selection of the geoid
  private static final double 
    A[] = {         //  SEMI-MAJOR AXES OF AVAILABLE GEOIDS
      6378137.000,  //  0 GRS80 / WGS84 (NAD83) *
      6378206.400,  //  1 Clark 1866 (NAD27)
      6377563.396,  //  2 Airy 1858
      6377340.189,  //  3 Airy Modified
      6378160.000,  //  4 Australian National
      6377397.155,  //  5 Bessel 1841
      6378249.145,  //  6 Clark 1880
      6377276.345,  //  7 Everest 1830
      6377304.063,  //  8 Everest Modified
      6378166.000,  //  9 Fisher 1960
      6378150.000,  // 10 Fisher 1968
      6378270.000,  // 11 Hough 1956
      6378388.000,  // 12 International (Hayford)
      6378245.000,  // 13 Krassovsky 1938
      6378145.000,  // 14 NWL-9D  (WGS 66)
      6378160.000,  // 15 South American 1969
      6378136.000,  // 16 Soviet Geod. System 1985
      6378135.000,  // 17 WGS 72
    },                          
    F[] = {                                //  FLATTENING FACTORS OF GEOIDS
      0.00335281068118366789616980869833,  //  0 GRS80 / WGS84 (NAD83) *
      0.00339007530392991937343144432063,  //  1 Clark 1866 (NAD27)
      0.00334085064149707745426055919427,  //  2 Airy 1858
      0.00334085064149707745426055919427,  //  3 Airy Modified
      0.00335289186923721709974853310981,  //  4 Australian National
      0.00334277318217480587901060845382,  //  5 Bessel 1841
      0.00340756137869933382175046428024,  //  6 Clark 1880
      0.00332444929666288455151682985834,  //  7 Everest 1830
      0.00332444929666288455151682985834,  //  8 Everest Modified
      0.00335232986925913509889373114314,  //  9 Fisher 1960
      0.00335232986925913509889373114314,  // 10 Fisher 1968
      0.00336700336700336700336700336700,  // 11 Hough 1956
      0.00336700336700336700336700336700,  // 12 International (Hayford)
      0.00335232986925913509889373114314,  // 13 Krassovsky 1938
      0.00335289186923721709974853310981,  // 14 NWL-9D  (WGS 66)
      0.00335289186923721709974853310981,  // 15 South American 1969
      0.00335281317789691440603238146967,  // 16 Soviet Geod. System 1985
      0.00335277945416750486153020854288,  // 17 WGS 72
    };

  private static final String N[] = {  // NAMES OF THE OF AVAILABLE GEOIDS
    "GRS80 / WGS84 (NAD83)",         // 00
    "Clark 1866 (NAD27)",            // 01
    "Airy 1858",                     // 02
    "Airy Modified",                 // 03
    "Australian National",           // 04
    "Bessel 1841",                   // 05
    "Clark 1880",                    // 06
    "Everest 1830",                  // 07
    "Everest Modified",              // 08
    "Fisher 1960",                   // 09
    "Fisher 1968",                   // 10
    "Hough 1956",                    // 11
    "International (Hayford)",       // 12
    "Krassovsky 1938",               // 13
    "NWL-9D  (WGS 66)",              // 14
    "South American 1969",           // 15
    "Soviet Geod. System 1985",      // 16
    "WGS 72"                         // 17
  };

  private static selgeoid gsel;  // reference to geoid selector object
  private int 
    n,  // number of currently selected geoid

    /* Position on the applet panel of the top left corner of geoid
    selector plus the width and height of geoid selector. */

    Gx = 425, Gy = 480, Gw = 180, Gh =  35;

  private double a, f;  // major axis and flattening factor for the above

  private JComboBox<String> gcm;  // reference for geoid choice menu

  private movmap mm;  // object reference to the main applet
  private dandb db;   // object reference to the vincenty class

  // construct instance of geoid selector menu
  selgeoid(movmap mm, Container cp) {
    this.mm = mm;  // local variable for reference to main applet
    gsel = this;   // set reference to geoid selector object
    n = 0;         // set default ellipsiod GRS80 / WGS84 (NAD83)
    a = A[n];      // semi-major axis of default geoid (metres)
    f = F[n];      // flattening factor of default geoid

    db = new dandb(a,f);  // create a new instance of distance and bearing

    /* create an instance of goeoid selector, add it to the applet's
    content pane then set its size and position on the pane. */

    gcm = new JComboBox<String>();
    cp.add(gcm);
    gcm.setBounds(Gx,Gy,Gw,Gh);

    // Add each of the listed geoid names to the goid choice menu.
    for(int i = 0; i < N.length; i++)
      gcm.addItem(N[i]);

    gcm.setSelectedIndex(n);  // show the default geoid as selected

    // create and register an event listener for this choice menu
    gcm.addItemListener(new glistener(glistener.E,this));
  }

  void select() {  // A NEW GEOID HAS JUST BEEN SELECTED
    // get the menu item number of the currently selected geoid
    n = gcm.getSelectedIndex();
    a = A[n];          // semi-major axis of default geoid (metres)
    f = F[n];          // flattening factor of default geoid
    db.setaf(a, f);    // set new values of semi-major axis and flattening
    gcm.getItemAt(n);  // show name of currently selected geoid
  }

  dandb getDandB() { return db; }
}



// LISTENS FOR EVENTS FROM THE GEOID CHOICE MENU
class glistener implements ItemListener {
  static final int E = 0;  // an event from the 'geoids' Choice Menu
  int id;                  // one of the above events
  selgeoid gsel;           // calling application: always the above applet

  // constructor for a new Choice selection listener
  public glistener(int id, selgeoid gsel) {
    this.id = id;      // set the id number for this instance of 'selgeoid'
    this.gsel = gsel;  // set the reference to this instance of 'selgeoid'
  }                    // from which it came. (only one instance).

  // a Choice selection event from checkbox 'id'
  public void itemStateChanged(ItemEvent e) {
    // Execute the appropriate method in the above applet.
    switch(id) { case E: gsel.select(); break; }
  }
}