/* 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 <Foundation/Foundation.h>

/**
 * Each mode has a complete set of tuning parameters for range types.
 * Depending on some conditions (including interface state and direction of the scroll view, state of rendering engine, etc),
 * a range controller can choose which mode it should use at a given time.
 */
typedef NS_ENUM(NSUInteger, ASLayoutRangeMode) {
  /**
   * Minimum mode is used when a range controller should limit the amount of work it performs.
   * Thus, fewer views/layers are created and less data is fetched, saving system resources.
   * Range controller can automatically switch to full mode when conditions change.
   */
  ASLayoutRangeModeMinimum = 0,
  /**
   * Normal/Full mode that a range controller uses to provide the best experience for end users.
   * This mode is usually used for an active scroll view.
   * A range controller under this requires more resources compare to minimum mode.
   */
  ASLayoutRangeModeFull,
  ASLayoutRangeModeCount
};

#define ASLayoutRangeModeInvalid ASLayoutRangeModeCount

typedef NS_ENUM(NSInteger, ASLayoutRangeType) {
  ASLayoutRangeTypeDisplay,
  ASLayoutRangeTypeFetchData,
  ASLayoutRangeTypeCount
};

#define ASLayoutRangeTypeRender ASLayoutRangeTypeDisplay
#define ASLayoutRangeTypePreload ASLayoutRangeTypeFetchData