gistfile1.m

//
//  QWListChange.h
//
//  Created by Denis Mikhaylov on 04/12/13.
//  Copyright (c) 2013 QIWI. All rights reserved.
//


// Header

typedef NS_ENUM(NSInteger, QWListChangeType)
{
	QWListChangeInsert = 1,
	QWListChangeDelete = 2,
	QWListChangeMove = 3,
	QWListChangeUpdate = 4
};

@protocol QWSectionedList;
@interface QWSectionedListChange : NSObject
+ (instancetype)batchWithChanges:(NSArray *)changes;
+ (instancetype)changeOfItem:(id)item atIndexPath:(NSIndexPath *)indexPath type:(QWListChangeType)type newIndexPath:(NSIndexPath *)newIndexPath;
+ (instancetype)changeOfSectionAtIndex:(NSUInteger)index type:(QWListChangeType)type;
- (void)applyToList:(id <QWSectionedList>)list;
@end

@protocol QWSectionedList <NSObject>
- (void)beginUpdates;
- (void)changeSectionAtIndex:(NSUInteger)sectionIndex changeType:(QWListChangeType)type;
- (void)changeItem:(id)item atIndexPath:(NSIndexPath *)indexPath changeType:(QWListChangeType)type newIndexPath:(NSIndexPath *)newIndexPath;
- (void)endUpdates;
@end	

// Implementation

@interface QWBlockBasedListChange : QWSectionedListChange
@property (nonatomic, copy, readonly) void (^block)(id <QWSectionedList>);
- (id)initWithBlock:(void (^)(id <QWSectionedList> list))block;
@end

@implementation QWSectionedListChange
+ (instancetype)batchWithChanges:(NSArray *)changes
{
	return [[QWBlockBasedListChange alloc] initWithBlock:^(id<QWSectionedList> list) {
		[list beginUpdates];
		[changes each:^(id x) {
			[x applyToList:list];
		}];
		[list endUpdates];
	}];
}

+ (instancetype)changeOfItem:(id)item atIndexPath:(NSIndexPath *)indexPath type:(QWListChangeType)type newIndexPath:(NSIndexPath *)newIndexPath
{
	return [[QWBlockBasedListChange alloc] initWithBlock:^(id<QWSectionedList> list) {
		[list changeItem:item atIndexPath:indexPath changeType:type newIndexPath:newIndexPath];
	}];
}

+ (instancetype)changeOfSectionAtIndex:(NSUInteger)index type:(QWListChangeType)type
{
	return [[QWBlockBasedListChange alloc] initWithBlock:^(id<QWSectionedList> list) {
		[list changeSectionAtIndex:index changeType:type];
	}];
}

- (void)applyToList:(id<QWSectionedList>)list
{
	
}
@end

@implementation QWBlockBasedListChange
- (id)initWithBlock:(void (^)(id<QWSectionedList>))block
{
    self = [super init];
    if (self) {
        _block = [block copy];
    }
    return self;
}

- (void)applyToList:(id<QWSectionedList>)list
{
	self.block(list);
}
@end