import Foundation

enum Base64URLCoding {
    static func encode(_ data: Data) -> String {
        data.base64EncodedString()
            .replacingOccurrences(of: "+", with: "-")
            .replacingOccurrences(of: "/", with: "_")
            .replacingOccurrences(of: "=", with: "")
    }

    static func decode(_ string: String) -> Data? {
        var base64 = string
        let padding = (4 - (base64.count % 4)) % 4
        if padding > 0 {
            base64 += String(repeating: "=", count: padding)
        }
        base64 = base64
            .replacingOccurrences(of: "-", with: "+")
            .replacingOccurrences(of: "_", with: "/")
        return Data(base64Encoded: base64)
    }
}