/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef ViewRegion_h
#define ViewRegion_h

#include "Units.h"
#include "nsRegion.h"
#include "nsTArray.h"

class nsCocoaWindow;

@class NSView;

namespace mozilla {

/**
 * Manages a set of NSViews to cover a LayoutDeviceIntRegion.
 */
class ViewRegion {
 public:
  ~ViewRegion();

  const mozilla::LayoutDeviceIntRegion& Region() const { return mRegion; }
  Span<NSView* const> Views() const { return mViews; }

  /**
   * Update the region.
   * @param aRegion  The new region.
   * @param aCoordinateConverter  The nsCocoaWindow to use for converting
   *   LayoutDeviceIntRect device pixel coordinates into Cocoa NSRect
   * coordinates.
   * @param aContainerView  The view that's going to be the superview of the
   *   NSViews which will be created for this region.
   * @param aViewCreationCallback  A block that instantiates new NSViews.
   * @return  Whether or not the region changed.
   */
  bool UpdateRegion(const mozilla::LayoutDeviceIntRegion& aRegion,
                    const nsCocoaWindow& aCoordinateConverter,
                    NSView* aContainerView, NSView* (^aViewCreationCallback)());

  /**
   * Return an NSView from the region, if there is any.
   */
  NSView* GetAnyView() { return mViews.Length() > 0 ? mViews[0] : nullptr; }

 private:
  mozilla::LayoutDeviceIntRegion mRegion;
  // This array holds retained references to all the views we created. We
  // don't rely on the lifetime of the superview to keep our views alive,
  // because we don't own the superview and don't know when it will be
  // released.
  nsTArray<NSView*> mViews;
};

}  // namespace mozilla

#endif  // ViewRegion_h