namespace EnotaryoPH.Web.Common.Extensions
{
    public static class StringExtensions
    {
        private const char EqualsChar = '=';
        private const char Plus = '+';
        private const char Slash = '/';

        public static string DefaultIfEmpty(this string s, string defaultValue) => !string.IsNullOrWhiteSpace(s) ? s : (defaultValue ?? string.Empty);

        public static bool IsInList(this string s, params string[] list) => list.Contains(s, StringComparer.OrdinalIgnoreCase);

        public static string NullIfWhiteSpace(this string s) => string.IsNullOrWhiteSpace(s) ? null : s;

        public static Guid ToGuidFromBase64(this string s)
        {
            if (s.Length != 22)
            {
                return Guid.Empty;
            }

            var id = s.AsSpan();
            Span<char> base64Chars = stackalloc char[24];
            for (var i = 0; i < 22; i++)
            {
                base64Chars[i] = id[i] switch
                {
                    '-' => Slash,
                    '_' => Plus,
                    _ => id[i]
                };
            }
            base64Chars[22] = EqualsChar;
            base64Chars[23] = EqualsChar;

            Span<byte> idBytes = stackalloc byte[16];
            Convert.TryFromBase64Chars(base64Chars, idBytes, out _);
            return new Guid(idBytes);
        }
    }
}