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#ifndef nsInterfaceState_h__
#define nsInterfaceState_h__


#include "nsISelectionListener.h"
#include "nsIDocumentStateListener.h"
#include "nsITransactionListener.h"
#include "nsIWebShell.h"
#include "nsITimer.h"
#include "nsITimerCallback.h"

class nsIHTMLEditor;
class nsIDOMDocument;

// class responsible for communicating changes in local state back to the UI.
// This is currently somewhat tied to a given XUL UI implementation

class nsInterfaceState : public nsISelectionListener,
                         public nsIDocumentStateListener,
                         public nsITransactionListener,
                         public nsITimerCallback
{
public:

                nsInterfaceState();
  virtual       ~nsInterfaceState();
  
  NS_DECL_ISUPPORTS
  
  NS_IMETHOD    Init(nsIHTMLEditor* aEditor, nsIDOMDocument *aChromeDoc);

  // nsISelectionListener interface
  NS_IMETHOD    NotifySelectionChanged(nsIDOMDocument *aDoc, nsISelection *aSel, short aReason);

  NS_DECL_NSIDOCUMENTSTATELISTENER
  
  // nsITimerCallback interfaces
  NS_IMETHOD_(void) Notify(nsITimer *timer);

  /** nsITransactionListener interfaces
    */
  
  NS_IMETHOD WillDo(nsITransactionManager *aManager, nsITransaction *aTransaction, PRBool *aInterrupt);
  NS_IMETHOD DidDo(nsITransactionManager *aManager, nsITransaction *aTransaction, nsresult aDoResult);
  NS_IMETHOD WillUndo(nsITransactionManager *aManager, nsITransaction *aTransaction, PRBool *aInterrupt);
  NS_IMETHOD DidUndo(nsITransactionManager *aManager, nsITransaction *aTransaction, nsresult aUndoResult);
  NS_IMETHOD WillRedo(nsITransactionManager *aManager, nsITransaction *aTransaction, PRBool *aInterrupt);
  NS_IMETHOD DidRedo(nsITransactionManager *aManager, nsITransaction *aTransaction, nsresult aRedoResult);
  NS_IMETHOD WillBeginBatch(nsITransactionManager *aManager, PRBool *aInterrupt);
  NS_IMETHOD DidBeginBatch(nsITransactionManager *aManager, nsresult aResult);
  NS_IMETHOD WillEndBatch(nsITransactionManager *aManager, PRBool *aInterrupt);
  NS_IMETHOD DidEndBatch(nsITransactionManager *aManager, nsresult aResult);
  NS_IMETHOD WillMerge(nsITransactionManager *aManager, nsITransaction *aTopTransaction,
                       nsITransaction *aTransactionToMerge, PRBool *aInterrupt);
  NS_IMETHOD DidMerge(nsITransactionManager *aManager, nsITransaction *aTopTransaction,
                      nsITransaction *aTransactionToMerge,
                      PRBool aDidMerge, nsresult aMergeResult);

protected:

  enum {
    eStateUninitialized   = -1,
    eStateOff             = PR_FALSE,
    eStateOn              = PR_TRUE
  };
  
  PRBool        SelectionIsCollapsed();
  nsresult      UpdateDirtyState(PRBool aNowDirty);  
  nsresult      CallUpdateCommands(const nsAString& aCommand);
  nsresult      UpdateUndoCommands(nsITransactionManager *aManager);
  nsresult      PrimeUpdateTimer();
  void          TimerCallback();

  // this class should not hold references to the editor or editorShell. Doing
  // so would result in cirular reference chains.
  
  nsIHTMLEditor*   mEditor;		 // the HTML editor
  nsIDOMDocument*  mChromeDoc;  // XUL document for the chrome area

  nsIDOMWindowInternal*       mDOMWindow;   // nsIDOMWindowInternal used for calling UpdateCommands
  
  nsCOMPtr<nsITimer>  mUpdateTimer;
    
  PRInt8        mDirtyState;  
  PRInt8        mSelectionCollapsed;  
  PRPackedBool  mFirstDoOfFirstUndo;
  PRInt32       mBatchDepth;
    
};

extern "C" nsresult NS_NewInterfaceState(nsIHTMLEditor* aEditor, nsIDOMDocument* aChromeDoc, nsISelectionListener** aInstancePtrResult);

#endif // nsInterfaceState_h__
