MessageCommon.sedona

@palette=false
abstract internal class MessageCommon extends Component
{
  ////////////////////////////////////////////////////////////////
  // Properties
  ////////////////////////////////////////////////////////////////
  @summary=true
  @config @asStr property Buf(topicNameLen) topic = ""

  define int Ok = 0
  define int Err_InvalidParent = 1
  define int Err_InvalidTopic = 2
  define Str ErrorMessages = "Ok, InvalidParent, InvalidTopic"

  @range=ErrorMessages
  @readonly property byte error = 0

  ////////////////////////////////////////////////////////////////
  // Interface Methods
  ////////////////////////////////////////////////////////////////
  **
  ** reset current message's local state
  **
  public abstract void reset()

  **
  ** publish linked value to MQTT broker
  **
  public abstract void publish(Obj handle)

  **
  ** subscribe topic on MQTT broker refered by given handle
  **
  public abstract void subscribe(Obj handle)

  **
  ** unsubscribe topic on MQTT broker refered by given handle
  **
  public abstract void unsubscribe(Obj handle)

  public virtual void onTopicChanged() {}

  ////////////////////////////////////////////////////////////////
  // Methods
  ////////////////////////////////////////////////////////////////
  override virtual void start() 
  {
    validateInputs()
  }

  override virtual void changed(Slot slot)
  {
    super.changed(slot)
    if (slot.name == "topic")
    {
      validateInputs()
      if (error == Ok)
        onTopicChanged()
    }
  }

  protected void validateInputs()
  {
    Component parentComponent = Sys.app.lookup(parent)
    Str parentName = parentComponent?.type?.name
    if (!parentComponent.type.is(Publisher.type) &&
        !parentComponent.type.is(Subscriber.type) &&
        !parentComponent.type.is(TopicGroup.type))
    {
      error := Err_InvalidParent;
    }
    else if (topic.toStr().length() > 0)
    {
      if (parentComponent.type.is(TopicGroup.type))
        error := ((TopicGroup)parentComponent).error
      else
        error := Ok
    }
    else
      error := Err_InvalidTopic
  }

  static private bool appendStr(Str dst, Str src, int maxDstLen)
  {
    bool res = true;
    int startIndx = dst.length()
    int bytesCopy = src.length()
    bytesCopy = bytesCopy + 1
    if ((dst.length() + bytesCopy) > maxDstLen)
    {
      bytesCopy = maxDstLen - dst.length()
      res = false
    }

    for(int i = 0; i < bytesCopy; i++)
      dst.set(startIndx + i, src.get(i))

    return res
  }

  protected void collectTopics(Str buf, int maxBufLen)
  {
    Component parentComp = Sys.app.lookup(parent)
    if (parentComp!=null && parentComp.type.is(MessageCommon.type))
    {
      MessageCommon parentMsg = (MessageCommon)parentComp
      parentMsg.collectTopics(buf, maxBufLen)
    }

    //make sure topics are connected with '/'
    if (buf.length() > 0 && buf.get(buf.length()-1) != '/' && topic.get(0) != '/')
      appendStr(buf, "/", maxBufLen);

    appendStr(buf, topic.toStr(), maxBufLen);
  }

  protected Obj getHandle()
  {
    Component parentComp = Sys.app.lookup(parent)
    while(parentComp!=null) 
    {
      if (parentComp.type.is(Worker.type)) {
        Worker w = (Worker)parentComp
        return w.getHandle()
      }
      parentComp = Sys.app.lookup(parentComp.parent)
    }
    return null
  }

  override int parentEvent(int eType, Component parent)
  {
    if (eType == Component.ADDED &&
        (!parent.type.is(Publisher.type) &&
         !parent.type.is(Subscriber.type)&&
         !parent.type.is(TopicGroup.type)))
      error := Err_InvalidParent;
    return 0
  }

  ////////////////////////////////////////////////////////////////
  // Fields
  ////////////////////////////////////////////////////////////////
  define int topicNameLen = 64 
}