import Foundation

struct Site {

    static let linkPreviewDesiredImageWidth = 1600

    let elements: [SiteElement]

    let metadata: Metadata

    let inputFolder: URL

    init?(folder: URL) throws {
        self.inputFolder = folder
        
        guard let metadata = try Metadata(in: folder) else {
            return nil
        }
        guard !metadata.languages.isEmpty else {
            throw GenerationError.invalidLanguageSpecification("No languages specified in site.json")
        }
        self.metadata = metadata
        self.elements = try FileSystem.folders(in: folder)
            .filter { !metadata.ignoredSubFolders.contains($0.lastPathComponent) }
            .compactMap { sectionUrl in
                return try Section(
                    folder: sectionUrl, path: sectionUrl.lastPathComponent)
            }
        print("Loaded site with \(elements.count) sections and \(metadata.languages.count) languages")

        // Create example metadata
        //_ = try? Page.Metadata(in: folder)
        //_ = try? Section.Metadata(in: folder)
    }
}

extension Site: LocalizedMetadataContainer {

}

extension Site: SiteElement {
    
    var sortIndex: Int? { 0 }

    var sortDate: Date? { nil }

    var path: String { "" }

    func cornerText(for language: String) -> String? { nil }

    func backLinkText(for language: String) throws -> String? {
        localized(for: language).backLinkText
    }
}