/// A type that provides data extraction and manipulation functions from relative path representations.
enum PathProvider {
    
    // MARK: Functions
    
    /// Extracts the root *DocC* archive relative path from a given URL relative path.
    ///
    /// Given that the provided URL relative path is expected to have the prefix `/archives/archive-name`, then a root *DocC* archive generated out of the
    /// archive name obtained from the URL relative path is returned. Otherwise, an empty string is returned.
    ///
    /// - Parameter path: A URL relative path from where to extract data.
    /// - Returns: A URL relative path to a root *DocC* archive or an empty string .
    static func archivePath(from path: String) -> String {
        let pathComponents = path.split(separator: .forwardSlash)
        
        return pathComponents.count > 1
            ? .init(format: .Format.Path.archive, String(pathComponents[1]))
            : .empty
    }
    
    /// Extracts the name of the *DocC* archive from a given URL relative path.
    ///
    /// Given that the provided URL relative path is expected to have the prefix `/archives/archive-name`, then a lowercased archive name from the URL
    /// relative path is returned. Otherwise, an empty string is returned.
    ///
    /// - Parameter path: A URL relative path from where to extract data.
    /// - Returns: A lowercased name of the archive or an empty string.
    static func archiveName(from path: String) -> String {
        let pathComponents = path.split(separator: .forwardSlash)
        
        return pathComponents.count > 1
            ? .init(pathComponents[1]).lowercased()
            : .empty
    }
    
    /// Extracts the name of the *DocC* archive from a given URL relative path.
    ///
    /// Given that the provided URL relative path is expected to have the format `/archives/archive-name/path/to/resource`, then the path to a
    /// resource extracted from the URL relative path is returned. Otherwise, a forward slash string is returned.
    ///
    /// - Parameter path: A URL relative path from where to extract data.
    /// - Returns: A URL relative path to a resource or a forward slash.
    static func resourcePath(from path: String) -> String {
        let matches = path.matches(of: /\//)
        
        return matches.count > 2
            ? .init(path[matches[2].startIndex...])
            : .forwardSlash
    }
    
}

// MARK: - Character+Constants

private extension Character {
    static let forwardSlash: Character = "/"
}