using System;
using System.Security.Cryptography;
using System.Text;
using JetBrains.Annotations;

namespace Fluctio.FluctioSim.Utils.Extensions
{
	public static class BytesExtensions
	{
		[Pure] public static byte[] Encode(this string str, Encoding encoding) => encoding.GetBytes(str);
		[Pure] public static string Decode(this byte[] bytes, Encoding encoding) => encoding.GetString(bytes);
		
		[Pure] public static string ToBase64(this byte[] bytes) => Convert.ToBase64String(bytes);
		
		[Pure] public static byte[] FromBase64(this string str) => Convert.FromBase64String(str);

		[Pure]
		public static string ToBase64UrlSafe(this byte[] bytes) =>
			bytes
				.ToBase64()
				.Replace("+", "-")
				.Replace("/", "_")
				.TrimEnd('=');

		[Pure]
		public static byte[] FromBase64UrlSafe(this string str)
		{
			var paddingToAdd = (str.Length % 4) switch
			{
				0 => 0,
				2 => 2,
				3 => 1,
				_ => throw new ArgumentException("Incorrect url-safe base64, wrong length", nameof(str))
			};
			var totalLength = str.Length + paddingToAdd;
			
			return str
				.PadRight(totalLength, '=')
				.Replace("-", "+")
				.Replace("_", "/")
				.FromBase64();
		}

		[Pure]
		public static byte[] Hash(this byte[] bytes, HashAlgorithmName algorithmName)
		{
			var algorithmNameString = algorithmName.Name;
			var algorithm = HashAlgorithm.Create(algorithmNameString);
			if (algorithm == null)
			{
				throw new ArgumentException("Invalid algorithm name", nameof(algorithmName));
			}
			return algorithm.ComputeHash(bytes);
		}
	}
}