unit Messagner.View;

interface

uses
   System.SysUtils, System.Classes, System.Types,
   System.Messaging, System.SyncObjs, System.Generics.Collections,
   Vcl.Controls, Vcl.Forms, Vcl.StdCtrls;

type
   TIdleMessage = class(System.Messaging.TMessage)
   end;

   TDateTimeMessage = class(System.Messaging.TMessage<TDateTime>)
   end;

   TForm1 = class(TForm)
     mmoLog : TMemo;
     procedure FormCreate(Sender : TObject);
     procedure FormDestroy(Sender : TObject);
   private
     FIdleID,
     FDateTimeID : Integer;
     FQueue : TQueue<TDateTime>;

     procedure OnNewDateTimeMessage(const Sender : TObject; const M : TMessage);
     procedure GetIdleMessage(const Sender : TObject; const M : TMessage);
     procedure DoSendMessage(const ADateTime : TDateTime);
     procedure LogToMemo(const Text : string);
   public
     procedure DoIdle(Sender : TObject; var Done : Boolean);
   end;

var
   Form1 : TForm1;

implementation

{$R *.dfm}


procedure TForm1.LogToMemo(const Text : string);
begin
   mmoLog.Lines.Add(Text);
end;

procedure TForm1.OnNewDateTimeMessage(const Sender : TObject; const M : TMessage);
var
   LMessage : TDateTimeMessage;
begin
   LMessage := M as TDateTimeMessage;
   LogToMemo(sLineBreak + '- - - > ' + FormatDateTime('hh:mm:ss:zzz', LMessage.Value) + sLineBreak);
end;

procedure TForm1.DoIdle(Sender : TObject; var Done : Boolean);
begin
   TMessageManager.DefaultManager.SendMessage(Self, TIdleMessage.Create, False);
end;

procedure TForm1.FormCreate(Sender : TObject);
begin
   Vcl.Forms.Application.OnIdle := DoIdle;
   FQueue := TQueue<TDateTime>.Create;
   FIdleID := TMessageManager.DefaultManager.SubscribeToMessage(TIdleMessage, GetIdleMessage);
   FDateTimeID := TMessageManager.DefaultManager.SubscribeToMessage(TDateTimeMessage, OnNewDateTimeMessage);
end;

procedure TForm1.FormDestroy(Sender : TObject);
begin
  TMessageManager.DefaultManager.Unsubscribe(TIdleMessage,FIdleID,true);
  TMessageManager.DefaultManager.Unsubscribe(TDateTimeMessage,FDateTimeID,true);
end;

procedure TForm1.DoSendMessage(const ADateTime : TDateTime);
var
   LMessage : TDateTimeMessage;
begin
   LMessage := TDateTimeMessage.Create(ADateTime);
   TMessageManager.DefaultManager.SendMessage(Self, LMessage, True);
end;

procedure TForm1.GetIdleMessage(const Sender : TObject; const M : TMessage);
var
   LDateTime : TDateTime;
begin
   LDateTime := System.SysUtils.Now;

   if FQueue.Count <> 0 then
   begin
     if FQueue.Peek <> LDateTime then
     begin
       FQueue.Enqueue(LDateTime);
     end;
   end
   else
   begin
     FQueue.Enqueue(LDateTime);
   end;
end;

end.