/// A file extension used by an ``Asset``.
///
/// Each case's raw value is the extension itself (e.g. `"css"`), which an asset appends to its file name when resolving paths.
public enum AssetExtension: String, Sendable {
    /// A Cascading Style Sheets file.
    case css
    /// A JavaScript file.
    case js
    /// A Portable Network Graphics image.
    case png
    /// A Windows icon image.
    case ico
    /// A Scalable Vector Graphics image.
    case svg
    /// A plain text file.
    case txt
    /// A web application manifest file.
    case webmanifest
    /// An Extensible Markup Language file.
    case xml
}

// MARK: - Extensions

public extension AssetExtension {

    // MARK: Computed

    /// The file's content type.
    var contentType: String {
        switch self {
        case .css: "text/css"
        case .js: "text/javascript"
        case .png: "image/png"
        case .ico: "image/vnd.microsoft.icon"
        case .svg: "image/svg+xml"
        case .txt: "text/plain"
        case .webmanifest: "application/manifest+json"
        case .xml: "application/xml"
        }
    }

    /// The sub-directory within the static root that holds files with this extension, if any.
    var subdirectory: String? {
        switch self {
        case .css: "css"
        case .js: "js"
        default: nil
        }
    }

}