@interface TYPagerViewLayout<__covariant ItemType> : NSObject

@property (nonatomic, weak, nullable) id<TYPagerViewLayoutDataSource> dataSource;
@property (nonatomic, weak, nullable) id<TYPagerViewLayoutDelegate> delegate;

// strong,will control the delegate,don't set delegate on other place.
@property (nonatomic, strong, readonly) UIScrollView *scrollView;
// if viewcontroller's automaticallyAdjustsScrollViewInsets YES ,will cause frame problems, you can set YES, default YES
@property (nonatomic, assign) BOOL adjustScrollViewInset;

@property (nonatomic, assign, readonly) NSInteger countOfPagerItems;
@property (nonatomic, assign, readonly) NSInteger curIndex;// default -1

@property (nonatomic, strong, readonly) NSCache<NSNumber *,ItemType> *memoryCache;; // will cache pagerView,you can set countLimit
@property (nonatomic, assign) BOOL autoMemoryCache; // default YES

@property (nonatomic, assign) NSInteger prefetchItemCount;// preload left and right item's count , default 0

@property (nonatomic, assign, readonly) NSRange prefetchRange;
@property (nonatomic, assign, readonly) NSRange visibleRange;

@property (nonatomic, strong, nullable, readonly) NSArray<NSNumber *> * visibleIndexs;
@property (nonatomic, strong, nullable, readonly) NSArray<ItemType> * visibleItems;

// default YES, if NO,will not call delegate transitionFromIndex:toIndex:progress:,but will call transitionFromIndex:toIndex:
@property (nonatomic, assign) BOOL progressAnimateEnabel;

// default NO, when scroll visible range change will add item.If YES add item only when scroll animate end, suggest set prefetchItemCount 1 or more
@property (nonatomic, assign) BOOL addVisibleItemOnlyWhenScrollAnimatedEnd;

// default 0.5,when scroll progress percent will change index, only progressAnimateEnabel is NO or don't implement delegate transitionFromIndex: toIndex: progress:
@property (nonatomic, assign) CGFloat changeIndexWhenScrollProgress;

@interface TYPagerView : UIView

@property (nonatomic, weak, nullable) id<TYPagerViewDataSource> dataSource;
@property (nonatomic, weak, nullable) id<TYPagerViewDelegate> delegate;
// pagerView's layout,don't set layout's dataSource to other
@property (nonatomic, strong, readonly) TYPagerViewLayout<UIView *> *layout;
@property (nonatomic, strong, readonly) UIScrollView *scrollView;

@property (nonatomic, assign, readonly) NSInteger countOfPagerViews;
@property (nonatomic, assign, readonly) NSInteger curIndex;// default -1

@property (nonatomic, assign, nullable, readonly) NSArray<UIView *> *visibleViews;

@property (nonatomic, assign) UIEdgeInsets contentInset;

//if not visible, prefecth, cache view at index, return nil
- (UIView *_Nullable)viewForIndex:(NSInteger)index;

// register && dequeue's usage like tableView
- (void)registerClass:(Class)Class forViewWithReuseIdentifier:(NSString *)identifier;
- (void)registerNib:(UINib *)nib forViewWithReuseIdentifier:(NSString *)identifier;
- (UIView *)dequeueReusableViewWithReuseIdentifier:(NSString *)identifier forIndex:(NSInteger)index;

// scroll to index
- (void)scrollToViewAtIndex:(NSInteger)index animate:(BOOL)animate;

// update data and layout,but don't reset propertys(curIndex,visibleDatas,prefechDatas)
- (void)updateData;

// reload data and reset propertys
- (void)reloadData;

@protocol TYTabPagerControllerDelegate <TYPagerControllerDelegate>

// configre collectionview cell
- (void)pagerController:(TYTabPagerController *)pagerController configreCell:(UICollectionViewCell *)cell forItemTitle:(NSString *)title atIndexPath:(NSIndexPath *)indexPath;

// transition frome cell to cell with animated
- (void)pagerController:(TYTabPagerController *)pagerController transitionFromeCell:(UICollectionViewCell *)fromCell toCell:(UICollectionViewCell *)toCell animated:(BOOL)animated;

// transition frome cell to cell with progress
- (void)pagerController:(TYTabPagerController *)pagerController transitionFromeCell:(UICollectionViewCell *)fromCell toCell:(UICollectionViewCell *)toCell progress:(CGFloat)progress;

@end

@interface TYPagerController : UIViewController

@property (nonatomic, weak, nullable) id<TYPagerControllerDataSource> dataSource;
@property (nonatomic, weak, nullable) id<TYPagerControllerDelegate>   delegate;
// pagerController's layout,don't set layout's dataSource to other
@property (nonatomic, strong, readonly) TYPagerViewLayout<UIViewController *> *layout;
@property (nonatomic, weak, readonly) UIScrollView *scrollView;

@property (nonatomic, assign, readonly) NSInteger countOfControllers;
@property (nonatomic, assign, readonly) NSInteger curIndex;// default -1

@property (nonatomic, strong, nullable, readonly) NSArray<UIViewController *> *visibleControllers;

@property (nonatomic, assign) UIEdgeInsets contentInset;

//if not visible, prefecth, cache view at index, return nil
- (UIViewController *_Nullable)controllerForIndex:(NSInteger)index;

// register && dequeue's usage like tableView
- (void)registerClass:(Class)Class forControllerWithReuseIdentifier:(NSString *)identifier;
- (void)registerNib:(UINib *)nib forControllerWithReuseIdentifier:(NSString *)identifier;
- (UIViewController *)dequeueReusableControllerWithReuseIdentifier:(NSString *)identifier forIndex:(NSInteger)index;

// scroll to index
- (void)scrollToControllerAtIndex:(NSInteger)index animate:(BOOL)animate;

//  update data and layout,but don't reset propertys(curIndex,visibleDatas,prefechDatas)
- (void)updateData;

// reload data and reset propertys
- (void)reloadData;

- (void)addTabPagerView {
    TYTabPagerView *pagerView = [[TYTabPagerView alloc]init];
    pagerView.tabBar.layout.barStyle = TYPagerBarStyleCoverView;
    pagerView.tabBar.progressView.backgroundColor = [UIColor lightGrayColor];
    pagerView.dataSource = self;
    pagerView.delegate = self;
    [self.view addSubview:pagerView];
    _pagerView = pagerView;
}

#pragma mark - TYTabPagerViewDataSource

- (NSInteger)numberOfViewsInTabPagerView {
    return _datas.count;
}

- (UIView *)tabPagerView:(TYTabPagerView *)tabPagerView viewForIndex:(NSInteger)index prefetching:(BOOL)prefetching {
    UIView *view = [[UIView alloc]initWithFrame:[tabPagerView.layout frameForItemAtIndex:index]];
    view.backgroundColor = [UIColor colorWithRed:arc4random()%255/255.0 green:arc4random()%255/255.0 blue:arc4random()%255/255.0 alpha:arc4random()%255/255.0];
    //NSLog(@"viewForIndex:%ld prefetching:%d",index,prefetching);
    return view;
}

- (NSString *)tabPagerView:(TYTabPagerView *)tabPagerView titleForIndex:(NSInteger)index {
    NSString *title = _datas[index];
    return title;
}

@interface TabPagerControllerDemoController : TYTabPagerController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.title = @"TabPagerControllerDemoController";
    self.tabBar.layout.barStyle = TYPagerBarStyleProgressView;
    self.dataSource = self;
    self.delegate = self;
    
    [self loadData];
}

- (void)loadData {
    _datas = [datas copy];
    // must call reloadData
    [self reloadData];
}

#pragma mark - TYTabPagerControllerDataSource

- (NSInteger)numberOfControllersInTabPagerController {
    return _datas.count;
}

- (UIViewController *)tabPagerController:(TYTabPagerController *)tabPagerController controllerForIndex:(NSInteger)index prefetching:(BOOL)prefetching {
    if (index%3 == 0) {
        CustomViewController *VC = [[CustomViewController alloc]init];
        VC.text = [@(index) stringValue];
        return VC;
    }else if (index%3 == 1) {
        ListViewController *VC = [[ListViewController alloc]init];
        VC.text = [@(index) stringValue];
        return VC;
    }else {
        CollectionViewController *VC = [[CollectionViewController alloc]init];
        VC.text = [@(index) stringValue];
        return VC;
    }
}

- (NSString *)tabPagerController:(TYTabPagerController *)tabPagerController titleForIndex:(NSInteger)index {
    NSString *title = _datas[index];
    return title;
}