#
# Emesary interface to access nav data such as airport information, fixes etc.
#

var NavDataInterface = {

new : func (device)
{
  var obj = { parents : [ NavDataInterface ] };

  # Emesary
  obj._recipient = nil;
  obj._transmitter = emesary.GlobalTransmitter;
  obj._registered = 0;
  obj._device = device;

  return obj;
},

# Find the airports within 200nm and return them.
getNearestAirports : func()
{
  # To make this more efficient for areas with a high density of airports, we'll try
  # a small radius first and expand until we have reached 200nm or have 25 airports.
  var radius = 0;
  var apts = [];

  while ((radius <= 200) and (size(apts) < 25)) {
    radius = radius + 50;
    apts = findAirportsWithinRange(radius);
  }

  if (size(apts) > 25) {
    apts = subvec(apts, 0, 25);
  }

  return apts;
},

# Find a specific airport by ID
getAirportById : func(id)
{
  var apt = airportinfo(id);
  return apt;
},

RegisterWithEmesary : func()
{
  if (me._recipient == nil){
    me._recipient = emesary.Recipient.new("DataInterface");
    var pfd_obj = me._device;
    var controller = me;
    me._recipient.Receive = func(notification)
    {
      if (notification.Device_Id == pfd_obj.device_id
          and notification.NotificationType == notifications.PFDEventNotification.DefaultType) {
        if (notification.Event_Id == notifications.PFDEventNotification.NavData
            and notification.EventParameter != nil)
        {
          var id = notification.EventParameter.Id;

          if (id == "NearestAirports") {
            notification.EventParameter.Value = controller.getNearestAirports();
            return emesary.Transmitter.ReceiptStatus_Finished;
          }
          if (id == "AirportByID") {
            var apt = controller.getAirportById(notification.EventParameter.Value);
            notification.EventParameter.Value = apt;
            return emesary.Transmitter.ReceiptStatus_Finished;
          }
        }
      }
      return emesary.Transmitter.ReceiptStatus_NotProcessed;
    };
  }

  me._transmitter.Register(me._recipient);
  me._registered = 1;
},

DeRegisterWithEmesary : func()
{
  # remove registration from transmitter; but keep the recipient once it is created.
  if (me._registered == 1) me._transmitter.DeRegister(me._recipient);
  me._registered = 0;
},


start : func() {
  me.RegisterWithEmesary();
},
stop : func() {
  me.DeRegisterWithEmesary();
},



};