#import <UIKit/UIScrollView.h>
#import <UIKit/UIKitDefines.h>
#import <Foundation/Foundation.h>

typedef NS_OPTIONS(NSUInteger, UICollectionViewScrollPosition) {
    UICollectionViewScrollPositionNone                 = 0,
    
   
   
    UICollectionViewScrollPositionTop                  = 1 << 0,
    UICollectionViewScrollPositionCenteredVertically   = 1 << 1,
    UICollectionViewScrollPositionBottom               = 1 << 2,
    
   
    UICollectionViewScrollPositionLeft                 = 1 << 3,
    UICollectionViewScrollPositionCenteredHorizontally = 1 << 4,
    UICollectionViewScrollPositionRight                = 1 << 5
};

@class UICollectionView;
@class UICollectionViewCell;
@class UICollectionViewLayout;
@class UICollectionViewTransitionLayout;
@class UICollectionViewLayoutAttributes;
@class UITouch;
@class UINib;
@class UICollectionReusableView;

typedef void(^UICollectionViewLayoutInteractiveTransitionCompletion)(BOOL completed, BOOL finish);

#pragma - mark - 数据源
@protocol UICollectionViewDataSource <NSObject>

@required
// 每一组的项目个数
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section;
// 每一行的cell
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath;

@optional
// 分组个数
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView;
// 附加视图
- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath;

@end

#pragma - mark - 代理
@protocol UICollectionViewDelegate <UIScrollViewDelegate>
@optional
// 是否高亮显示
- (BOOL)collectionView:(UICollectionView *)collectionView shouldHighlightItemAtIndexPath:(NSIndexPath *)indexPath;
// 已经高亮显示
- (void)collectionView:(UICollectionView *)collectionView didHighlightItemAtIndexPath:(NSIndexPath *)indexPath;
// 已经取消高亮显示
- (void)collectionView:(UICollectionView *)collectionView didUnhighlightItemAtIndexPath:(NSIndexPath *)indexPath;
// 是否选择indexPath
- (BOOL)collectionView:(UICollectionView *)collectionView shouldSelectItemAtIndexPath:(NSIndexPath *)indexPath;
// 是否取消选择
- (BOOL)collectionView:(UICollectionView *)collectionView shouldDeselectItemAtIndexPath:(NSIndexPath *)indexPath;
// 已经选择
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath;
// 已经取消选择
- (void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath;
// 已经结束显示cell
- (void)collectionView:(UICollectionView *)collectionView didEndDisplayingCell:(UICollectionViewCell *)cell forItemAtIndexPath:(NSIndexPath *)indexPath;
- (void)collectionView:(UICollectionView *)collectionView didEndDisplayingSupplementaryView:(UICollectionReusableView *)view forElementOfKind:(NSString *)elementKind atIndexPath:(NSIndexPath *)indexPath;
// 是否显示菜单
- (BOOL)collectionView:(UICollectionView *)collectionView shouldShowMenuForItemAtIndexPath:(NSIndexPath *)indexPath;
// 是否能执行方法
- (BOOL)collectionView:(UICollectionView *)collectionView canPerformAction:(SEL)action forItemAtIndexPath:(NSIndexPath *)indexPath withSender:(id)sender;
// 执行方法
- (void)collectionView:(UICollectionView *)collectionView performAction:(SEL)action forItemAtIndexPath:(NSIndexPath *)indexPath withSender:(id)sender;
// 切换布局的动画
- (UICollectionViewTransitionLayout *)collectionView:(UICollectionView *)collectionView transitionLayoutForOldLayout:(UICollectionViewLayout *)fromLayout newLayout:(UICollectionViewLayout *)toLayout;

@end

#pragma - mark -
NS_CLASS_AVAILABLE_IOS(6_0) @interface UICollectionView : UIScrollView

- (id)initWithFrame:(CGRect)frame collectionViewLayout:(UICollectionViewLayout *)layout;

@property (nonatomic, retain) UICollectionViewLayout *collectionViewLayout; // 布局方式
@property (nonatomic, assign) id <UICollectionViewDelegate> delegate;   // 代理
@property (nonatomic, assign) id <UICollectionViewDataSource> dataSource;   // 数据源
@property (nonatomic, retain) UIView *backgroundView;   // 背景视图
#pragma - mark 注册要使用的cell
- (void)registerClass:(Class)cellClass forCellWithReuseIdentifier:(NSString *)identifier;
- (void)registerNib:(UINib *)nib forCellWithReuseIdentifier:(NSString *)identifier;

- (void)registerClass:(Class)viewClass forSupplementaryViewOfKind:(NSString *)elementKind withReuseIdentifier:(NSString *)identifier;
- (void)registerNib:(UINib *)nib forSupplementaryViewOfKind:(NSString *)kind withReuseIdentifier:(NSString *)identifier;
// 通过标识从缓存池取cell
- (id)dequeueReusableCellWithReuseIdentifier:(NSString *)identifier forIndexPath:(NSIndexPath*)indexPath;
- (id)dequeueReusableSupplementaryViewOfKind:(NSString*)elementKind withReuseIdentifier:(NSString *)identifier forIndexPath:(NSIndexPath*)indexPath;

@property (nonatomic) BOOL allowsSelection; // 是否允许选择
@property (nonatomic) BOOL allowsMultipleSelection; // 是否允许多选

- (NSArray *)indexPathsForSelectedItems;    // 所有选择的indexPaths
// 选择某个indexPath
- (void)selectItemAtIndexPath:(NSIndexPath *)indexPath animated:(BOOL)animated scrollPosition:(UICollectionViewScrollPosition)scrollPosition;
// 取消选择某个indexPath
- (void)deselectItemAtIndexPath:(NSIndexPath *)indexPath animated:(BOOL)animated;
// 刷新数据
- (void)reloadData;
// 设置布局方式
- (void)setCollectionViewLayout:(UICollectionViewLayout *)layout animated:(BOOL)animated;
- (void)setCollectionViewLayout:(UICollectionViewLayout *)layout animated:(BOOL)animated completion:(void (^)(BOOL finished))completion NS_AVAILABLE_IOS(7_0);

#pragma - mark 转场动画相关
- (UICollectionViewTransitionLayout *)startInteractiveTransitionToCollectionViewLayout:(UICollectionViewLayout *)layout completion:(UICollectionViewLayoutInteractiveTransitionCompletion) completion NS_AVAILABLE_IOS(7_0);
- (void)finishInteractiveTransition NS_AVAILABLE_IOS(7_0);
- (void)cancelInteractiveTransition NS_AVAILABLE_IOS(7_0);

// 分组数
- (NSInteger)numberOfSections;
// 每一组的cell个数
- (NSInteger)numberOfItemsInSection:(NSInteger)section;
// indexPath处的布局属性
- (UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath;
- (UICollectionViewLayoutAttributes *)layoutAttributesForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath;
// 返回某一点处的indexPath
- (NSIndexPath *)indexPathForItemAtPoint:(CGPoint)point;
// 某个cell的indexPath
- (NSIndexPath *)indexPathForCell:(UICollectionViewCell *)cell;
// 返回indexPath处的cell
- (UICollectionViewCell *)cellForItemAtIndexPath:(NSIndexPath *)indexPath;
// 所有可见的cell
- (NSArray *)visibleCells;
// 所有可见的cell的indexPath
- (NSArray *)indexPathsForVisibleItems;

// 滚动到某一个indexPath
- (void)scrollToItemAtIndexPath:(NSIndexPath *)indexPath atScrollPosition:(UICollectionViewScrollPosition)scrollPosition animated:(BOOL)animated;
// 插入一些组
- (void)insertSections:(NSIndexSet *)sections;
// 删除一些组
- (void)deleteSections:(NSIndexSet *)sections;
// 刷新某些组
- (void)reloadSections:(NSIndexSet *)sections;
// 移动一组到另一组
- (void)moveSection:(NSInteger)section toSection:(NSInteger)newSection;

// 插入一些项目到indexPaths
- (void)insertItemsAtIndexPaths:(NSArray *)indexPaths;
// 删除indexPaths处的项目
- (void)deleteItemsAtIndexPaths:(NSArray *)indexPaths;
// 重新加载
- (void)reloadItemsAtIndexPaths:(NSArray *)indexPaths;
// 移动
- (void)moveItemAtIndexPath:(NSIndexPath *)indexPath toIndexPath:(NSIndexPath *)newIndexPath;

- (void)performBatchUpdates:(void (^)(void))updates completion:(void (^)(BOOL finished))completion;

@end

@interface NSIndexPath (UICollectionViewAdditions)

+ (NSIndexPath *)indexPathForItem:(NSInteger)item inSection:(NSInteger)section NS_AVAILABLE_IOS(6_0);

@property (nonatomic, readonly) NSInteger item NS_AVAILABLE_IOS(6_0);

@end