AsyncPhotoCaching.swift

/// An interface for caching images by identifier and size.
protocol AsyncPhotoCaching {

  /// Store the specified image by size and identifier.
  /// - Parameters:
  ///   - image: The image to be cached.
  ///   - id: The unique identifier of the image.
  func store(_ image: UIImage, forID id: any Hashable)


  /// Returns the image associated with a given id and size.
  /// - Parameters:
  ///   - id: The unique identifier of the image.
  ///   - size: The size of the image stored in the cache.
  /// - Returns: The image associated with id and size, or nil if no image is associated with id and size.
  func image(for id: any Hashable, size: CGSize) -> UIImage?


  /// Returns the caching key by combining a given image id and a size.
  /// - Parameters:
  ///   - id: The unique identifier of the image.
  ///   - size: The size of the image stored in the cache.
  /// - Returns: The caching key by combining a given id and size.
  func cacheKey(for id: any Hashable, size: CGSize) -> String
}

extension AsyncPhotoCaching {
  func cacheKey(for id: any Hashable, size: CGSize) -> String {
    "\(id.hashValue):w\(Int(size.width))h\(Int(size.height))"
  }
}