// Copyright (c) Umbraco.
// See LICENSE for more details.

using System;
using System.Text;
using NUnit.Framework;
using Umbraco.Cms.Core;

namespace Umbraco.Cms.Tests.UnitTests.Umbraco.Core
{
    public class HexEncoderTests
    {
        [Test]
        public void ToHexStringCreatesCorrectValue()
        {
            var buffer = new byte[255];
            var random = new Random();
            random.NextBytes(buffer);

            var sb = new StringBuilder(buffer.Length * 2);
            for (var i = 0; i < buffer.Length; i++)
            {
                sb.Append(buffer[i].ToString("X2"));
            }

            var expected = sb.ToString();

            var actual = HexEncoder.Encode(buffer);
            Assert.AreEqual(expected, actual);
        }

        [Test]
        public void ToHexStringWithSeparatorCreatesCorrectValue()
        {
            var buffer = new byte[255];
            var random = new Random();
            random.NextBytes(buffer);

            var expected = ToHexString(buffer, '/', 2, 4);
            var actual = HexEncoder.Encode(buffer, '/', 2, 4);

            Assert.AreEqual(expected, actual);
        }

        private static readonly char[] s_bytesToHexStringLookup = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };

        // Reference implementation taken from original extension method.
        private static string ToHexString(byte[] bytes, char separator, int blockSize, int blockCount)
        {
            int p = 0, bytesLength = bytes.Length, count = 0, size = 0;
            var chars = new char[(bytesLength * 2) + blockCount];
            for (var i = 0; i < bytesLength; i++)
            {
                var b = bytes[i];
                chars[p++] = s_bytesToHexStringLookup[b / 0x10];
                chars[p++] = s_bytesToHexStringLookup[b % 0x10];
                if (count == blockCount)
                {
                    continue;
                }

                if (++size < blockSize)
                {
                    continue;
                }

                chars[p++] = separator;
                size = 0;
                count++;
            }

            return new string(chars, 0, chars.Length);
        }
    }
}
