using System.Security.Cryptography;
using System.Text;
using Azaion.Services;
using FluentAssertions;
using Newtonsoft.Json;
using Xunit;

namespace Azaion.Test;

public class SecurityTest
{
    [Fact]
    public async Task EncryptDecryptTest()
    {
        var testString = "Hello World Test dfvjkhsdbfvkljh sabdljsdafv asdv";
        var email = "user@azaion.com";
        var password = "testpw";
        var hardwareId = "test_hardware_id";

        var key = Security.MakeEncryptionKey(email, password, hardwareId);

        var encryptedStream = new MemoryStream();
        await StringToStream(testString).EncryptTo(encryptedStream, key);
        encryptedStream.Seek(0, SeekOrigin.Begin);

        await using var decryptedStream   = new MemoryStream();
        await encryptedStream.DecryptTo(decryptedStream, key);
        encryptedStream.Close();

        var str = StreamToString(decryptedStream);
        str.Should().Be(testString);
    }

    [Fact]
    public async Task EncryptDecryptLargeFileTest()
    {
        var username = "user@azaion.com";
        var password = "testpw";
        var hardwareId = "test_hardware_id";

        var key = Security.MakeEncryptionKey(username, password, hardwareId);

        var largeFilePath = "large.txt";
        var largeFileDecryptedPath = "large_decrypted.txt";

        var stream = await CreateLargeFile(largeFilePath);
        stream.Seek(0, SeekOrigin.Begin);

        var encryptedStream = new MemoryStream();

        await stream.EncryptTo(encryptedStream, key);
        encryptedStream.Seek(0, SeekOrigin.Begin);

        File.Delete(largeFileDecryptedPath);
        await using var decryptedStream = new FileStream(largeFileDecryptedPath, FileMode.OpenOrCreate, FileAccess.Write);
        await encryptedStream.DecryptTo(decryptedStream, key);

        encryptedStream.Close();
        stream.Close();
        decryptedStream.Close();

        await CompareFiles(largeFilePath, largeFileDecryptedPath);
        File.Delete(largeFilePath);
        File.Delete(largeFileDecryptedPath);
    }

    private async Task CompareFiles(string largeFilePath, string largeFileDecryptedPath)
    {
        await using var stream1 = new FileStream(largeFilePath, FileMode.Open, FileAccess.Read);
        await using var stream2 = new FileStream(largeFileDecryptedPath, FileMode.Open, FileAccess.Read);

        var sha256Bytes1 = Encoding.UTF8.GetString(await SHA256.HashDataAsync(stream1));
        var sha256Bytes2 = Encoding.UTF8.GetString(await SHA256.HashDataAsync(stream2));
        sha256Bytes1.Should().Be(sha256Bytes2);
    }

    private async Task<Stream> CreateLargeFile(string largeTxtPath)
    {
        var max = 4000000;
        File.Delete(largeTxtPath);
        var stream = new FileStream(largeTxtPath, FileMode.OpenOrCreate, FileAccess.ReadWrite);
        var numbersList = Enumerable.Range(1, max).Chunk(100000);
        foreach (var numbers in numbersList)
        {
            var dict = numbers.ToDictionary(x => x, _ => DateTime.UtcNow);
            var bytes = Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(dict, Formatting.Indented));
            await stream.WriteAsync(bytes);
            Console.WriteLine($"Writing numbers from {(numbers.FirstOrDefault()*100 / (double)max):F1} %");
        }
        await stream.FlushAsync();
        return stream;
    }

    private static string StreamToString(Stream stream)
    {
        stream.Position = 0;
        using var reader = new StreamReader(stream, Encoding.UTF8);
        return reader.ReadToEnd();
    }

    private static Stream StringToStream(string src)
    {
        var byteArray = Encoding.UTF8.GetBytes(src);
        return new MemoryStream(byteArray);
    }

}