import Foundation

/**
 Localized configuration data for link previews of site elements.

 This struct is embedded in localized metadata and intended to be filled in the JSON source.
 */
struct LinkPreviewMetadata {

    /**
     The title to use for the link preview.

     If `nil` is specified, then the localized element `title` is used.
     */
    let title: String?

    /**
     The file name of the link preview image.
     - Note: The image must be located in the element folder.
     - Note: If `nil` is specified, then the (localized) thumbnail is used.
     */
    let image: String?

    /**
     The description text for the link preview.
     - Note: If `nil` is specified, then first the (localized) element `subtitle` is used.
     If this is `nil` too, then the localized `description` of the element is used.
     */
    let description: String?
}

extension LinkPreviewMetadata: Codable { }

extension LinkPreviewMetadata {

    static var initial: LinkPreviewMetadata {
        .init(title: nil,
              image: nil,
              description: "The page description for link previews")
    }
}