import Foundation

final class Page: ObservableObject {
    
    /**
     The unique id of the entry
     */
    @Published
    var id: String

    @Published
    var isDraft: Bool

    @Published
    var metadata: [LocalizedPage]

    /**
     All files which may occur in content but is stored externally.

     Missing files which would otherwise produce a warning are ignored when included here.
     - Note: This property defaults to an empty set.
     */
    @Published
    var externalFiles: Set<String> = []

    /**
     Specifies additional files which should be copied to the destination when generating the content.
     - Note: This property defaults to an empty set.
     */
    @Published
    var requiredFiles: Set<String> = []

    /**
     Additional images required by the element.

     These images are specified as: `source_name destination_name width (height)`.
     */
    @Published
    var images: Set<String> = []

    init(id: String, isDraft: Bool, metadata: [LocalizedPage], externalFiles: Set<String> = [], requiredFiles: Set<String> = [], images: Set<String> = []) {
        self.id = id
        self.isDraft = isDraft
        self.metadata = metadata
        self.externalFiles = externalFiles
        self.requiredFiles = requiredFiles
        self.images = images
    }

    func metadata(for language: ContentLanguage) -> LocalizedPage? {
        metadata.first { $0.language == language }
    }

}

struct LocalizedPage {

    let language: ContentLanguage

    /**
     The string to use when creating the url for the page.

     Defaults to ``id`` if unset.
     */
    var urlString: String?

    /**
     The headline to use when showing the entry on it's own page
     */
    var headline: String
}

extension Page: Identifiable {
    
}

extension Page: Equatable {

    static func == (lhs: Page, rhs: Page) -> Bool {
        lhs.id == rhs.id
    }
}

extension Page: Hashable {

    func hash(into hasher: inout Hasher) {
        hasher.combine(id)
    }
}