unit UNotifier;

interface

uses Classes, Dialogs, UMeta;

type

  TRefreshProc = procedure (ASign: string) of object;

  ArrayOfString = array of string;

  TSubscriber = record
    Signs: ArrayOfString;
    Obj: TObject;
    Refresh: TRefreshProc;
  end;

  TNotifier = class
  private
    Subs: array of TSubscriber;
  public
    procedure SendChanges(ASign: string);
    procedure Subscribe(AObj: TObject; ASign: ArrayOfString; ARefresh: TRefreshProc);
    procedure UnSubscribe(AObj: TObject);
  end;

  function GetSigns(ANum: integer; SelfInclude: boolean): ArrayOfString;

var
  Notif: TNotifier;

implementation

function GetSigns(ANum: integer; SelfInclude: boolean): ArrayOfString;
var
  i: Integer;
begin
  if SelfInclude then begin
    SetLength(result, Length(result) + 1);
    result[High(result)] := Meta.FTables[ANum].Name;
  end;
  with Meta.FTables[ANum] do
  for i := 0 to High(TableFields) do
    if TableFields[i].RefTable > -1 then begin
      SetLength(result, Length(result) + 1);
      result[High(result)] := Meta.FTables[TableFields[i].RefTable].Name;
    end;
end;

{ TNotifier }

procedure TNotifier.SendChanges(ASign: string);
var
  i, j: Integer;
begin
  for i := 0 to High(Subs) do
    for j := 0 to High(Subs[i].Signs) do
      if Subs[i].Signs[j] = ASign then
        Subs[i].Refresh(ASign);
end;

procedure TNotifier.Subscribe(AObj: TObject; ASign: ArrayOfString; ARefresh: TRefreshProc);
var NewSub: TSubscriber;
begin
  NewSub.Signs := ASign;
  NewSub.Obj := AObj;
  NewSub.Refresh := ARefresh;
  SetLength(Subs, Length(Subs)+1);
  Subs[High(Subs)] := NewSub;
end;

procedure TNotifier.UnSubscribe(AObj: TObject);
var
  i, Index: Integer;
begin
  Index := 0;
  for i := 0 to High(Subs) do
    if Subs[i].Obj = AObj then begin
      Index := i;
      break;
    end;
  for i := Index to High(Subs)-1 do
    Subs[i] := Subs[i+1];
  SetLength(Subs, Length(Subs)-1);
end;

initialization

Notif := TNotifier.Create;

end.