ios/chrome/browser/ui/collection_view/collection_view_controller.h

// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef IOS_CHROME_BROWSER_UI_COLLECTION_VIEW_COLLECTION_VIEW_CONTROLLER_H_
#define IOS_CHROME_BROWSER_UI_COLLECTION_VIEW_COLLECTION_VIEW_CONTROLLER_H_

#import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
#import "ios/chrome/browser/ui/material_components/app_bar_presenting.h"
#import "ios/third_party/material_components_ios/src/components/Collections/src/MaterialCollections.h"

@class CollectionViewItem;

typedef NS_ENUM(NSInteger, CollectionViewControllerStyle) {
  // A simple collection view controller.
  CollectionViewControllerStyleDefault,
  // A collection view controller with an app bar.
  CollectionViewControllerStyleAppBar,
};

// Chrome-specific Material Design collection view controller. With
// CollectionViewControllerStyleAppBar, it features an app bar in the card
// style.
@interface CollectionViewController
    : MDCCollectionViewController<AppBarPresenting>

// The model of this controller.
@property(strong, nonatomic, readonly)
    CollectionViewModel<CollectionViewItem*>* collectionViewModel;

// Initializer with the desired style.
- (instancetype)initWithStyle:(CollectionViewControllerStyle)style
    NS_DESIGNATED_INITIALIZER;
- (instancetype)initWithCollectionViewLayout:(UICollectionViewLayout*)layout
    NS_UNAVAILABLE;
- (instancetype)initWithNibName:(NSString*)nibNameOrNil
                         bundle:(NSBundle*)nibBundleOrNil NS_UNAVAILABLE;
- (instancetype)initWithCoder:(NSCoder*)aDecoder NS_UNAVAILABLE;
- (instancetype)init NS_UNAVAILABLE;

// Initializes the collection view model. Must be called by subclasses if they
// override this method in order to get a clean collectionViewModel.
- (void)loadModel NS_REQUIRES_SUPER;

// Reconfigures the cells corresponding to the given |items| by calling
// |configureCell:| on each cell.
- (void)reconfigureCellsForItems:(NSArray*)items
         inSectionWithIdentifier:(NSInteger)sectionIdentifier;

// Reconfigures the cells corresponding to the given |indexPaths| by calling
// |configureCell:| on each cell.
- (void)reconfigureCellsAtIndexPaths:(NSArray*)indexPaths;

#pragma mark MDCCollectionViewEditingDelegate

// Updates the model with changes to the collection view items. Must be called
// by subclasses if they override this method in order to maintain this
// functionality.
- (void)collectionView:(UICollectionView*)collectionView
    willDeleteItemsAtIndexPaths:(NSArray*)indexPaths NS_REQUIRES_SUPER;

// Updates the model with changes to the collection view item. Must be called
// by subclasses if they override this method in order to maintain this
// functionality.
- (void)collectionView:(UICollectionView*)collectionView
    willMoveItemAtIndexPath:(NSIndexPath*)indexPath
                toIndexPath:(NSIndexPath*)newIndexPath NS_REQUIRES_SUPER;

#pragma mark UIScrollViewDelegate

// Updates the MDCFlexibleHeader with changes to the collection view scroll
// state. Must be called by subclasses if they override this method in order to
// maintain this functionality.
- (void)scrollViewDidScroll:(UIScrollView*)scrollView NS_REQUIRES_SUPER;

// Updates the MDCFlexibleHeader with changes to the collection view scroll
// state. Must be called by subclasses if they override this method in order to
// maintain this functionality.
- (void)scrollViewDidEndDragging:(UIScrollView*)scrollView
                  willDecelerate:(BOOL)decelerate NS_REQUIRES_SUPER;

// Updates the MDCFlexibleHeader with changes to the collection view scroll
// state. Must be called by subclasses if they override this method in order to
// maintain this functionality.
- (void)scrollViewDidEndDecelerating:(UIScrollView*)scrollView
    NS_REQUIRES_SUPER;

// Updates the MDCFlexibleHeader with changes to the collection view scroll
// state. Must be called by subclasses if they override this method in order to
// maintain this functionality.
- (void)scrollViewWillEndDragging:(UIScrollView*)scrollView
                     withVelocity:(CGPoint)velocity
              targetContentOffset:(inout CGPoint*)targetContentOffset
    NS_REQUIRES_SUPER;

@end

#endif  // IOS_CHROME_BROWSER_UI_COLLECTION_VIEW_COLLECTION_VIEW_CONTROLLER_H_