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{                                                                   }
{       ExpressWeb Framework by Developer Express                   }
{       Designer Module                                             }
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unit cxWebDsgnDelphiManager;

interface

{$I cxVer.inc}

uses
  Classes, SysUtils,
  {$IFDEF VCL}
  Controls, Forms;
  {$ELSE}
  QControls, QForms;
  {$ENDIF}

type
  TcxWebDelphiEditorManagerListener = class
  private
    FOnEditorFormActivated: TNotifyEvent;
  protected
    procedure EditorFormActivated;
  public
    constructor Create;
    destructor Destroy; override;
    property OnEditorFormActivated: TNotifyEvent read FOnEditorFormActivated
        write FOnEditorFormActivated;
  end;

  TcxWebDelphiEditorManager = class
  private
    FListeners: TList;
    FOldonActiveFormChanged: TNotifyEvent;

    procedure DoActiveFormChanged(Sender: TObject);

    procedure ActiveCustomFormChanged(ACustomForm: TCustomForm);
    procedure EditorFormActivated;
  protected
    constructor CreateInstance(ADummy: Boolean = True);
    class function AccessInstance(Request: Integer): TcxWebDelphiEditorManager;

    procedure RegisterListener(AListener: TcxWebDelphiEditorManagerListener);
    procedure UnregisterListener(AListener: TcxWebDelphiEditorManagerListener);
  public
    constructor Create;
    destructor Destroy; override;
    class function Instance: TcxWebDelphiEditorManager;
    class procedure ReleaseInstance;
  end;

function WebDelphiEditorManager: TcxWebDelphiEditorManager;

implementation

function WebDelphiEditorManager: TcxWebDelphiEditorManager;
begin
  Result := TcxWebDelphiEditorManager.Instance;
end;

{ TcxWebDelphiEditorManager }
constructor TcxWebDelphiEditorManager.Create;
begin
  raise Exception.CreateFmt('Access class %s through Instance only', [ClassName]);
end;

destructor TcxWebDelphiEditorManager.Destroy;
begin
  if Assigned(FOldonActiveFormChanged) then
  begin
    if not Application.Terminated and
      not (csDestroying in Screen.ComponentState) then
      Screen.OnActiveFormChange := FOldonActiveFormChanged
    else Screen.OnActiveFormChange := nil;
  end else
    if Screen <> nil then
      Screen.OnActiveFormChange := nil;
  FListeners.Free;
  inherited Destroy;
end;

var
  FInstance: TcxWebDelphiEditorManager = nil;

class function TcxWebDelphiEditorManager.AccessInstance(
  Request: Integer): TcxWebDelphiEditorManager;
begin
  case Request of
    0 : ;
    1 : if not Assigned(FInstance) then FInstance := CreateInstance;
    2 : FInstance := nil;
  else
    raise Exception.CreateFmt('Illegal request %d in AccessInstance',
      [Request]);
  end;
  Result := FInstance;
end;

constructor TcxWebDelphiEditorManager.CreateInstance(ADummy: Boolean = True);
begin
  FListeners := TList.Create;
  if Application.Terminated or (csDestroying in Screen.ComponentState) then exit;
  FOldonActiveFormChanged := Screen.OnActiveFormChange;
  Screen.OnActiveFormChange := DoActiveFormChanged;
end;

class function TcxWebDelphiEditorManager.Instance: TcxWebDelphiEditorManager;
begin
  Result := AccessInstance(1);
end;

class procedure TcxWebDelphiEditorManager.ReleaseInstance;
begin
  AccessInstance(0).Free;
end;

procedure TcxWebDelphiEditorManager.RegisterListener(AListener: TcxWebDelphiEditorManagerListener);
begin
  if FListeners.IndexOf(AListener) < 0 then
    FListeners.Add(AListener);
end;

procedure TcxWebDelphiEditorManager.UnregisterListener(AListener: TcxWebDelphiEditorManagerListener);
begin
  FListeners.Remove(AListener);
end;

procedure TcxWebDelphiEditorManager.DoActiveFormChanged(Sender: TObject);
begin
  if Assigned(FOldonActiveFormChanged) then
    FOldonActiveFormChanged(Sender);
  if not Application.Terminated and
    not (csDestroying in Screen.ComponentState) and
    (Screen.ActiveCustomForm <> nil) then
    ActiveCustomFormChanged(Screen.ActiveCustomForm);
end;

procedure TcxWebDelphiEditorManager.ActiveCustomFormChanged(ACustomForm: TCustomForm);
begin
  if (CompareText(ACustomForm.ClassName, 'TEditWindow') = 0) then
    EditorFormActivated;
end;

procedure TcxWebDelphiEditorManager.EditorFormActivated;
var
  I: Integer;
begin
  for I := 0 to FListeners.Count - 1 do
    TcxWebDelphiEditorManagerListener(FListeners[I]).EditorFormActivated;
end;

{ TcxWebDelphiEditorManagerListener }

constructor TcxWebDelphiEditorManagerListener.Create;
begin
  WebDelphiEditorManager.RegisterListener(self);
end;

destructor TcxWebDelphiEditorManagerListener.Destroy;
begin
  WebDelphiEditorManager.UnregisterListener(self);
  inherited Destroy;
end;

procedure TcxWebDelphiEditorManagerListener.EditorFormActivated;
begin
  if Assigned(FOnEditorFormActivated) then
    FOnEditorFormActivated(self);
end;

initialization

finalization
  TcxWebDelphiEditorManager.ReleaseInstance;
  
end.