/* Copyright (c) 2014-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

#import "ASRangeHandlerRender.h"

#import "ASDisplayNode.h"
#import "ASDisplayNode+Subclasses.h"
#import "ASDisplayNodeInternal.h"

@implementation ASRangeHandlerRender

+ (UIWindow *)workingWindow
{
  ASDisplayNodeAssertMainThread();
  
  // we add nodes' views to this invisible window to start async rendering
  static UIWindow *workingWindow = nil;
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
    workingWindow = [[UIWindow alloc] initWithFrame:CGRectZero];
    workingWindow.windowLevel = UIWindowLevelNormal - 1000;
    workingWindow.userInteractionEnabled = NO;
    workingWindow.clipsToBounds = YES;
    workingWindow.hidden = YES;
  });
  return workingWindow;
}

- (void)node:(ASDisplayNode *)node enteredRangeOfType:(ASLayoutRangeType)rangeType
{
  ASDisplayNodeAssertMainThread();
  ASDisplayNodeAssert(rangeType == ASLayoutRangeTypeRender, @"Render delegate should not handle other ranges");

  [node recursivelySetDisplaySuspended:NO];

  // add the node to an off-screen window to force display and preserve its contents
  [[self.class workingWindow] addSubnode:node];
}

- (void)node:(ASDisplayNode *)node exitedRangeOfType:(ASLayoutRangeType)rangeType
{
  ASDisplayNodeAssertMainThread();
  ASDisplayNodeAssert(rangeType == ASLayoutRangeTypeRender, @"Render delegate should not handle other ranges");

  [node recursivelySetDisplaySuspended:YES];
  [node.view removeFromSuperview];

  [node recursivelyClearRendering];
}

@end