fgdata/gui/dialogs/weather_scenario.xml

<?xml version="1.0"?>

<PropertyList>
  <name>weather_scenario</name>
  <modal>false</modal>
  <layout>vbox</layout>
  <resizable>true</resizable>
  <default-padding>3</default-padding>

  <group>
    <layout>hbox</layout>
    <default-padding>1</default-padding>

    <empty><stretch>true</stretch></empty>

    <text>
      <label>Automatic Weather Generation</label>
    </text>

    <empty><stretch>true</stretch></empty>

    <button>
      <legend></legend>
      <key>Esc</key>
      <pref-width>16</pref-width>
      <pref-height>16</pref-height>
      <border>2</border>
      <binding>
        <command>dialog-close</command>
      </binding>
    </button>
  </group>

  <hrule/>
  <group>
    <layout>hbox</layout>
    <text>
      <label>METAR Source</label>
    </text>
    <empty><stretch>true</stretch></empty>
  </group>

  <combo>
    <name>source-selection</name>
    <halign>fill</halign>
    <stretch>true</stretch>
    <property>sim/gui/dialogs/weather-scenario/source-selection</property>
    <binding>
      <command>dialog-apply</command>
      <object-name>source-selection</object-name>
    </binding>
    <binding>
      <command>dialog-update</command>
      <object-name>metar</object-name>
    </binding>
  </combo>

  <textbox>
    <name>description</name>
    <halign>fill</halign>
    <stretch>true</stretch>
    <pref-width>180</pref-width>
    <pref-height>100</pref-height>
    <slider>20</slider>
    <editable>false</editable>
    <wrap>true</wrap>
    <live>true</live>
    <property>sim/gui/dialogs/weather-scenario/description</property>
  </textbox>

  <group>
    <layout>hbox</layout>
    <text>
      <label>METAR Data</label>
    </text>
    <empty><stretch>true</stretch></empty>
  </group>

  <textbox>
    <name>metar</name>
    <halign>fill</halign>
    <stretch>true</stretch>
    <pref-width>180</pref-width>
    <pref-height>50</pref-height>
    <slider>20</slider>
    <editable>true</editable>
    <wrap>true</wrap>
    <live>false</live>
    <property>sim/gui/dialogs/weather-scenario/metar</property>
  </textbox>

  <hrule/>

  <group>
    <layout>hbox</layout>
    <empty><stretch>true</stretch></empty>
    <checkbox>
      <property>/environment/params/metar-updates-winds-aloft</property>
      <label>Update winds aloft</label>
      <name>aloft</name>
    </checkbox>
    <empty><stretch>true</stretch></empty>
  </group>

  <group>
    <layout>hbox</layout>

    <empty><stretch>true</stretch></empty>
    <button>
      <legend>OK</legend>
      <default>true</default>
      <equal>true</equal>
      <binding>
        <command>dialog-apply</command>
      </binding>
      <binding>
        <command>dialog-close</command>
      </binding>
    </button>

    <button>
      <legend>Apply</legend>
      <equal>true</equal>
      <binding>
        <command>nasal</command>
        <script>apply()</script>
      </binding>
      <binding>
        <command>dialog-apply</command>
      </binding>
    </button>

    <button>
      <legend>Instant-Apply</legend>
      <equal>true</equal>
      <binding>
        <command>nasal</command>
        <script>apply()</script>
      </binding>
      <binding>
        <command>dialog-apply</command>
      </binding>
      <binding>
        <command>reinit</command>
        <subsystem>environment</subsystem>
      </binding>
    </button>

    <button>
      <legend>Cancel</legend>
      <equal>true</equal>
      <key>Esc</key>
      <binding>
        <command>dialog-close</command>
      </binding>
    </button>

    <empty><stretch>true</stretch></empty>
  </group>

  <nasal>
    <open><![CDATA[
      var dlg_root = cmdarg();

      var normalize_string = func(src) {
        if( src == nil ) src = "";
        var dst = "";
        for( var i = 0; i < size(src); i+=1 ) {
          if( src[i] == `\n` or src[i] == `\r` )
            src[i] = ` `;

          if( i != 0 and src[i] == ` ` and src[i-1] == ` ` )
            continue;

          dst = dst ~ " ";
          dst[size(dst)-1] = src[i];
        }
        return dst;
      }

      var findScenarioByName = func(name) {
        var wsn = props.globals.getNode( "/environment/weather-scenarios" );
        if( wsn != nil ) {
          var scenarios = wsn.getChildren("scenario");
          foreach (var scenario; scenarios ) {
            if( scenario.getNode("name").getValue() == name )
              return scenario;
          }
        }
        return nil;
      }

      var findElementByName = func(rootN, name) {
        foreach( var child; rootN.getChildren() ) {
          var n = child.getNode( "name" );
          if( n != nil and n.getValue() == name )
            return child;
          var f = findElementByName(child,name);
          if( f != nil ) return f;
        }
        return nil;
      };

      var propertyChangeListener = setlistener( "sim/gui/dialogs/weather-scenario/source-selection", func(n) {
        description = "";
        metar = "nil";
        var scenario = findScenarioByName( n.getValue() );
        if( scenario != nil ) {
          description = normalize_string(scenario.getNode("description", 1 ).getValue());
          metar = normalize_string(scenario.getNode("metar", 1 ).getValue());
        }
        setprop("sim/gui/dialogs/weather-scenario/description", description );
        setprop("sim/gui/dialogs/weather-scenario/metar", metar );
      });

      #initialize the METAR source selection
      if( getprop( "environment/params/metar-updates-environment" ) == 0 ) {
        setprop("sim/gui/dialogs/weather-scenario/source-selection", "Disabled" );
      } else if( getprop( "environment/params/real-world-weather-fetch" ) ) {
        setprop("sim/gui/dialogs/weather-scenario/source-selection", "Live data" );
      } else {
        setprop("sim/gui/dialogs/weather-scenario/source-selection", "Manual input" );
      }
      setprop( "sim/gui/dialogs/weather-scenario/metar", normalize_string(getprop("environment/metar/data")) );


      # fill the METAR source combo box
      var combo = findElementByName( dlg_root, "source-selection" );
      var wsn = props.globals.getNode( "/environment/weather-scenarios" );
      if( wsn != nil ) {
        var scenarios = wsn.getChildren("scenario");
        forindex (var i; scenarios )
          combo.getChild("value", i, 1).setValue(scenarios[i].getNode("name").getValue());
      }


      var apply = func {
        var scenarioName = getprop("sim/gui/dialogs/weather-scenario/source-selection");
        var metar = nil;
        if( scenarioName == "Disabled" ) {
          setprop( "/environment/params/metar-updates-environment", 0 );
          setprop( "/environment/params/real-world-weather-fetch", 0 );
        } else if( scenarioName == "Live data" ) {
          setprop( "/environment/params/metar-updates-environment", 1 );
          setprop( "/environment/params/real-world-weather-fetch", 1 );
        } else if( scenarioName == "Manual input" ) {
          setprop( "/environment/params/metar-updates-environment", 1 );
          setprop( "/environment/params/real-world-weather-fetch", 0 );
          metar = getprop( "sim/gui/dialogs/weather-scenario/metar" );
        } else {
          metar = getprop( "sim/gui/dialogs/weather-scenario/metar" );
        }
        if( metar != nil )
          setprop( "environment/metar/data", normalize_string(metar) );
      }

    ]]></open>

    <close><![CDATA[
      removelistener( propertyChangeListener );
    ]]></close>

  </nasal>
</PropertyList>