#ifndef __DW_OOFAWAREWIDGET_HH__
#define __DW_OOFAWAREWIDGET_HH__

#include "core.hh"
#include "outofflowmgr.hh"

namespace dw {

namespace oof {

/**
 * \brief Base class for widgets which can act as container and
 *     generator for widgets out of flow.
 *
 * (Perhaps it should be diffenciated between the two roles, container
 * and generator, but this would make multiple inheritance necessary.)
 *
 * A sub class should at least take care to call these methods at the
 * respective points:
 *
 * - dw::oof::OOFAwareWidget::correctRequisitionByOOF (from
 *   dw::core::Widget::getExtremesImpl)
 * - dw::oof::OOFAwareWidget::correctExtremesByOOF (from
 *   dw::core::Widget::sizeRequestImpl)
 * - dw::oof::OOFAwareWidget::sizeAllocateStart
 * - dw::oof::OOFAwareWidget::sizeAllocateEnd (latter two from
 *   dw::core::Widget::sizeAllocateImpl)
 * - dw::oof::OOFAwareWidget::containerSizeChangedForChildrenOOF
 *   (from dw::core::Widget::containerSizeChangedForChildren)
 * - dw::oof::OOFAwareWidget::drawOOF (from dw::core::Widget::draw)
 * - dw::oof::OOFAwareWidget::getWidgetOOFAtPoint (from
 *   dw::core::Widget::getWidgetAtPoint)
 *
 * See dw::Textblock on how this is done best.
 *
 * Furthermore, implementations of dw::core::Widget::getAvailWidthOfChild
 * and dw::core::Widget::getAvailHeightOfChild have to distinguish
 * between widgets in flow and out of flow; see implementations of
 * dw::oof::OOFAwareWidget. (Open issue: What about
 * dw::core::Widget::correctRequisitionOfChild and
 * dw::core::Widget::correctExtremesOfChild? Currently, all widgets
 * are used the default implementation.)
 *
 * For both generators
 * and containers of floats (which is only implemented by
 * dw::Textblock) it gets a bit more complicated.
 */
class OOFAwareWidget: public core::Widget
{
protected:
   enum { OOFM_FLOATS, OOFM_ABSOLUTE, OOFM_FIXED, NUM_OOFM };
   enum { PARENT_REF_OOFM_BITS = 2,
          PARENT_REF_OOFM_MASK = (1 << PARENT_REF_OOFM_BITS) - 1 };

   class OOFAwareWidgetIterator: public core::Iterator
   {
   private:
      enum { NUM_SECTIONS = NUM_OOFM + 1 };
      int sectionIndex; // 0 means in flow, otherwise OOFM index + 1
      int index;

      int numParts (int sectionIndex, int numContentsInFlow = -1);
      void getPart (int sectionIndex, int index, core::Content *content);

   protected:
      virtual int numContentsInFlow () = 0;
      virtual void getContentInFlow (int index, core::Content *content) = 0;

      void setValues (int sectionIndex, int index);
      inline void cloneValues (OOFAwareWidgetIterator *other)
      { other->setValues (sectionIndex, index); }         

      inline bool inFlow () { return sectionIndex == 0; }
      inline bool getInFlowIndex () { assert (inFlow ()); return index; }
      void highlightOOF (int start, int end, core::HighlightLayer layer);
      void unhighlightOOF (int direction, core::HighlightLayer layer);
      void getAllocationOOF (int start, int end, core::Allocation *allocation);

   public:
      OOFAwareWidgetIterator (OOFAwareWidget *widget, core::Content::Type mask,
                              bool atEnd, int numContentsInFlow);

      int compareTo(lout::object::Comparable *other);

      bool next ();
      bool prev ();
      void print ();
   };

   inline bool isParentRefOOF (int parentRef)
   { return parentRef != -1 && (parentRef & PARENT_REF_OOFM_MASK); }

   inline int makeParentRefInFlow (int inFlowSubRef)
   { return (inFlowSubRef << PARENT_REF_OOFM_BITS); }
   inline int getParentRefInFlowSubRef (int parentRef)
   { assert (!isParentRefOOF (parentRef));
      return parentRef >> PARENT_REF_OOFM_BITS; }

   inline int makeParentRefOOF (int oofmIndex, int oofmSubRef)
   { return (oofmSubRef << PARENT_REF_OOFM_BITS) | (oofmIndex + 1); }
   inline int getParentRefOOFSubRef (int parentRef)
   { assert (isParentRefOOF (parentRef));
      return parentRef >> PARENT_REF_OOFM_BITS; }
   inline int getParentRefOOFIndex (int parentRef)
   { assert (isParentRefOOF (parentRef));
      return (parentRef & PARENT_REF_OOFM_MASK) - 1; }
   inline oof::OutOfFlowMgr *getParentRefOutOfFlowMgr (int parentRef)
   { return outOfFlowMgr[getParentRefOOFIndex (parentRef)]; }

   inline bool isWidgetOOF (Widget *widget)
   { return isParentRefOOF (widget->parentRef); }

   inline int getWidgetInFlowSubRef (Widget *widget)
   { return getParentRefInFlowSubRef (widget->parentRef); }

   inline int getWidgetOOFSubRef (Widget *widget)
   { return getParentRefOOFSubRef (widget->parentRef); }
   inline int getWidgetOOFIndex (Widget *widget)
   { return getParentRefOOFIndex (widget->parentRef); }
   inline oof::OutOfFlowMgr *getWidgetOutOfFlowMgr (Widget *widget)
   { return getParentRefOutOfFlowMgr (widget->parentRef); }

   OOFAwareWidget *oofContainer[NUM_OOFM];
   OutOfFlowMgr *outOfFlowMgr[NUM_OOFM];

   inline OutOfFlowMgr *searchOutOfFlowMgr (int oofmIndex)
   { return oofContainer[oofmIndex] ?
         oofContainer[oofmIndex]->outOfFlowMgr[oofmIndex] : NULL; }

   static inline bool testWidgetFloat (Widget *widget)
   { return widget->getStyle()->vloat != core::style::FLOAT_NONE; }
   static inline bool testWidgetAbsolutelyPositioned (Widget *widget)
   { return widget->getStyle()->position == core::style::POSITION_ABSOLUTE; }
   static inline bool testWidgetFixedlyPositioned (Widget *widget)
   { return widget->getStyle()->position == core::style::POSITION_FIXED; }
   static inline bool testWidgetOutOfFlow (Widget *widget)
   { return testWidgetFloat (widget) || testWidgetAbsolutelyPositioned (widget)
         || testWidgetFixedlyPositioned (widget); }

   static inline bool testWidgetRelativelyPositioned (Widget *widget)
   { return widget->getStyle()->position == core::style::POSITION_RELATIVE; }

   void initOutOfFlowMgrs ();
   void correctRequisitionByOOF (core::Requisition *requisition);
   void correctExtremesByOOF (core::Extremes *extremes);
   void sizeAllocateStart (core::Allocation *allocation);
   void sizeAllocateEnd ();
   void containerSizeChangedForChildrenOOF ();
   void drawOOF (core::View *view, core::Rectangle *area);
   core::Widget *getWidgetOOFAtPoint (int x, int y, int level);

   static bool isOOFContainer (Widget *widget, int oofmIndex);

   void notifySetAsTopLevel();
   void notifySetParent();

   int getAvailWidthOfChild (Widget *child, bool forceValue);
   int getAvailHeightOfChild (Widget *child, bool forceValue);

public:
   static int CLASS_ID;

   OOFAwareWidget ();
   ~OOFAwareWidget ();

   virtual void borderChanged (int y, core::Widget *vloat);
   virtual void oofSizeChanged (bool extremesChanged);
   virtual int getLineBreakWidth (); // Should perhaps be renamed.
   virtual bool isPossibleContainer (int oofmIndex);
   virtual bool isPossibleContainerParent (int oofmIndex);
};

} // namespace oof

} // namespace dw

#endif // __DW_OOFAWAREWIDGET_HH__