using System.IO;
using ModernKeePassLib.Cryptography;
using ModernKeePassLib.Utility;
using Xunit;

namespace ModernKeePassLib.Test.Cryptography
{
    public class HashingStreamExTests
    {
        const string data = "test";

        // The expected hash includes the \n added by WriteLine
        static readonly byte[] sha256HashOfData =
        {
            0xf2, 0xca, 0x1b, 0xb6, 0xc7, 0xe9, 0x07, 0xd0,
            0x6d, 0xaf, 0xe4, 0x68, 0x7e, 0x57, 0x9f, 0xce,
            0x76, 0xb3, 0x7e, 0x4e, 0x93, 0xb7, 0x60, 0x50,
            0x22, 0xda, 0x52, 0xe6, 0xcc, 0xc2, 0x6f, 0xd2
        };

        [Fact]
        public void TestRead()
        {
            // if we use larger size, StreamReader will read past newline and cause bad hash
            var bytes = new byte[data.Length + 1];
            using (var ms = new MemoryStream(bytes))
            {
                using (var sw = new StreamWriter(ms))
                {
                    // set NewLine to ensure we don't run into cross-platform issues on Windows
                    sw.NewLine = "\n";
                    sw.WriteLine(data);
                }
            }
            using (var ms = new MemoryStream(bytes))
            {
                using (var hs = new HashingStreamEx(ms, false, null))
                {
                    using (var sr = new StreamReader(hs))
                    {
                        var read = sr.ReadLine();
                        Assert.Equal(read, data);
                    }
                    // When the StreamReader is disposed, it calls Dispose on the
                    //HasingStreamEx, which computes the hash.
                    Assert.True(MemUtil.ArraysEqual(hs.Hash, sha256HashOfData));
                }
            }
        }

        [Fact]
        public void TestWrite()
        {
            var bytes = new byte[16];
            using (var ms = new MemoryStream(bytes))
            {
                using (var hs = new HashingStreamEx(ms, true, null))
                {
                    using (var sw = new StreamWriter(hs))
                    {
                        // set NewLine to ensure we don't run into cross-platform issues on Windows
                        sw.NewLine = "\n";
                        sw.WriteLine(data);
                    }
                    // When the StreamWriter is disposed, it calls Dispose on the
                    //HasingStreamEx, which computes the hash.
                    Assert.True(MemUtil.ArraysEqual(hs.Hash, sha256HashOfData));
                }
            }
            using (var ms = new MemoryStream(bytes))
            {
                using (var sr = new StreamReader(ms))
                {
                    var read = sr.ReadLine();
                    Assert.Equal(read, data);
                }
            }
        }
    }
}