using System.Security.Cryptography;

namespace Renci.SshNet.IntegrationTests
{
    public abstract class TestBase : IntegrationTestBase
    {
        protected static MemoryStream CreateMemoryStream(int size)
        {
            var memoryStream = new MemoryStream();
            FillStream(memoryStream, size);
            return memoryStream;
        }

        protected static void FillStream(Stream stream, int size)
        {
            var randomContent = new byte[50];
            var random = new Random();

            var numberOfBytesToWrite = size;

            while (numberOfBytesToWrite > 0)
            {
                random.NextBytes(randomContent);

                var numberOfCharsToWrite = Math.Min(numberOfBytesToWrite, randomContent.Length);
                stream.Write(randomContent, 0, numberOfCharsToWrite);
                numberOfBytesToWrite -= numberOfCharsToWrite;
            }
        }

        protected static string CreateHash(Stream stream)
        {
            using MD5 md5 = MD5.Create();
            var hash = md5.ComputeHash(stream);
            return Encoding.ASCII.GetString(hash);
        }

        protected static string CreateHash(byte[] buffer)
        {
            using (var ms = new MemoryStream(buffer))
            {
                return CreateHash(ms);
            }
        }

        protected static string CreateFileHash(string path)
        {
            using (var fs = File.OpenRead(path))
            {
                return CreateHash(fs);
            }
        }

        protected static string CreateTempFile(int size)
        {
            var file = Path.GetTempFileName();
            CreateFile(file, size);
            return file;
        }

        protected static void CreateFile(string fileName, int size)
        {
            using (var fs = File.OpenWrite(fileName))
            {
                FillStream(fs, size);
            }
        }

        internal static Stream GetData(string name)
        {
            string resourceName = $"Renci.SshNet.IntegrationTests.{name}";

            return typeof(TestBase).Assembly.GetManifestResourceStream(resourceName)
                ?? throw new ArgumentException($"Resource '{resourceName}' not found in assembly '{typeof(TestBase).Assembly.FullName}'.", nameof(name));
        }
    }
}