/**
 * 保存圖片到相冊
 */
- (IBAction)saveImage {
  PHAuthorizationStatus status = [PHPhotoLibrary authorizationStatus];
  if (status == PHAuthorizationStatusDenied) {
    NSLog(@"請到【設(shè)置-隱私-照片】打開訪問開關(guān)");
  } else if (status == PHAuthorizationStatusRestricted) {
    NSLog(@"無法訪問相冊");
  } else {
    // 保存相片的標識
    __block NSString *assetId = nil;
       
    [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
      // 保存相片到相機膠卷，并返回標識
      assetId = [PHAssetCreationRequest creationRequestForAssetFromImage:[UIImage imageNamed:@"logo"]].placeholderForCreatedAsset.localIdentifier;
    } completionHandler:^(BOOL success, NSError * _Nullable error) {
      if (!success) {
        NSLog(@"保存失敗：%@", error);
        return;
      }
         
      // 根據(jù)標識獲得相片對象
      PHAsset *asset = [PHAsset fetchAssetsWithLocalIdentifiers:@[assetId] options:nil].lastObject;
         
      // 拿到自定義的相冊對象
      PHAssetCollection *collection = [self collection];
      if (collection == nil) return;
         
      // 保存相片到自定義相冊中
      [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
        [[PHAssetCollectionChangeRequest changeRequestForAssetCollection:collection] addAssets:@[asset]];
      } completionHandler:^(BOOL success, NSError * _Nullable error) {
        if (success) {
          NSLog(@"保存成功");
        } else {
          NSLog(@"保存失?。?@", error);
        }
      }];
    }];
  }
}

/**
 * 查詢所有的圖片
 */
- (IBAction)searchAllImages {
     
  // 遍歷所有的自定義相冊
  PHFetchResult<PHAssetCollection *> *collectionResult0 = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];
  for (PHAssetCollection *collection in collectionResult0) {
    [self searchAllImagesInCollection:collection];
  }
     
  // 獲得相機膠卷的圖片
  PHFetchResult<PHAssetCollection *> *collectionResult1 = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];
  for (PHAssetCollection *collection in collectionResult1) {
    if (![collection.localizedTitle isEqualToString:@"Camera Roll"]) continue;
    [self searchAllImagesInCollection:collection];
    break;
  }
}
   
/**
 * 查詢某個相冊里面的所有圖片
 */
- (void)searchAllImagesInCollection:(PHAssetCollection *)collection
{
  // 采取同步獲取圖片（只獲得一次圖片）
  PHImageRequestOptions *imageOptions = [[PHImageRequestOptions alloc] init];
  imageOptions.synchronous = YES;
     
  NSLog(@"相冊名字：%@", collection.localizedTitle);
     
  // 遍歷這個相冊中的所有圖片
  PHFetchResult<PHAsset *> *assetResult = [PHAsset fetchAssetsInAssetCollection:collection options:nil];
  for (PHAsset *asset in assetResult) {
    // 過濾非圖片
    if (asset.mediaType != PHAssetMediaTypeImage) continue;
       
    // 圖片原尺寸
    CGSize targetSize = CGSizeMake(asset.pixelWidth, asset.pixelHeight);
    // 請求圖片
    [[PHImageManager defaultManager] requestImageForAsset:asset targetSize:targetSize contentMode:PHImageContentModeDefault options:imageOptions resultHandler:^(UIImage * _Nullable result, NSDictionary * _Nullable info) {
      NSLog(@"圖片：%@", result);
    }];
  }
}