using System.Net;
using System.Net.Http.Json;
using System.Security.Cryptography;
using System.Text;
using System.Text.Json;
using Azaion.E2E.Helpers;
using FluentAssertions;
using Xunit;

namespace Azaion.E2E.Tests;

[Collection("E2E")]
public sealed class ResourceTests
{
    private static readonly JsonSerializerOptions ResponseJsonOptions = new()
    {
        PropertyNameCaseInsensitive = true
    };

    private const string TestUserPassword = "TestPass1234";
    private const string SampleHardware =
        "CPU: TestCPU. GPU: TestGPU. Memory: 16384. DriveSerial: TESTDRIVE001.";

    private sealed record ErrorResponse(int ErrorCode, string Message);

    private readonly TestFixture _fixture;

    public ResourceTests(TestFixture fixture) => _fixture = fixture;

    [Fact]
    public async Task File_upload_succeeds()
    {
        // Arrange
        var folder = $"restest-{Guid.NewGuid():N}";
        var fileBytes = Encoding.UTF8.GetBytes(new string('a', 100));

        try
        {
            using var admin = _fixture.CreateAuthenticatedClient(_fixture.AdminToken);

            // Act
            using var response = await admin.UploadFileAsync($"/resources/{folder}", fileBytes, "upload.txt");

            // Assert
            response.StatusCode.Should().Be(HttpStatusCode.OK);
        }
        finally
        {
            using var adminCleanup = _fixture.CreateAuthenticatedClient(_fixture.AdminToken);
            using var clear = await adminCleanup.PostAsync($"/resources/clear/{folder}", new { });
            clear.EnsureSuccessStatusCode();
        }
    }

    [Fact]
    public async Task Encrypted_download_returns_octet_stream_and_non_empty_body()
    {
        // Arrange
        var folder = $"restest-{Guid.NewGuid():N}";
        const string fileName = "secure.bin";
        var fileBytes = Encoding.UTF8.GetBytes("download-test-payload");
        string? email = null;

        try
        {
            using (var admin = _fixture.CreateAuthenticatedClient(_fixture.AdminToken))
            {
                using var upload = await admin.UploadFileAsync($"/resources/{folder}", fileBytes, fileName);
                upload.EnsureSuccessStatusCode();
            }

            var candidateEmail = $"restest-{Guid.NewGuid():N}@azaion.com";
            using (var admin = _fixture.CreateAuthenticatedClient(_fixture.AdminToken))
            {
                using var createResp = await admin.PostAsync("/users",
                    new { Email = candidateEmail, Password = TestUserPassword, Role = 10 });
                createResp.EnsureSuccessStatusCode();
            }

            email = candidateEmail;

            using var loginClient = _fixture.CreateApiClient();
            var userToken = await loginClient.LoginAsync(email, TestUserPassword);
            using var userClient = _fixture.CreateAuthenticatedClient(userToken);
            using (var bind = await userClient.PostAsync("/resources/check", new { Hardware = SampleHardware }))
            {
                bind.EnsureSuccessStatusCode();
            }

            // Act
            using var response = await userClient.PostAsync($"/resources/get/{folder}",
                new { Password = TestUserPassword, Hardware = SampleHardware, FileName = fileName });

            // Assert
            response.StatusCode.Should().Be(HttpStatusCode.OK);
            response.Content.Headers.ContentType?.MediaType.Should().Be("application/octet-stream");
            var body = await response.Content.ReadAsByteArrayAsync();
            body.Should().NotBeEmpty();
        }
        finally
        {
            if (email is not null)
            {
                using var adminCleanup = _fixture.CreateAuthenticatedClient(_fixture.AdminToken);
                using var del = await adminCleanup.DeleteAsync($"/users/{Uri.EscapeDataString(email)}");
                del.EnsureSuccessStatusCode();
            }

            using var adminClear = _fixture.CreateAuthenticatedClient(_fixture.AdminToken);
            using var clear = await adminClear.PostAsync($"/resources/clear/{folder}", new { });
            clear.EnsureSuccessStatusCode();
        }
    }

    [Fact]
    public async Task Encryption_round_trip_decrypt_matches_original_bytes()
    {
        // Arrange
        var folder = $"restest-{Guid.NewGuid():N}";
        const string fileName = "roundtrip.bin";
        var original = Enumerable.Range(0, 128).Select(i => (byte)i).ToArray();
        const string password = "RoundTrip123";
        const string hardware = "RT-HW-CPU-001-GPU-002";
        string? email = null;

        try
        {
            using (var admin = _fixture.CreateAuthenticatedClient(_fixture.AdminToken))
            {
                using var upload = await admin.UploadFileAsync($"/resources/{folder}", original, fileName);
                upload.EnsureSuccessStatusCode();
            }

            var candidateEmail = $"roundtrip-{Guid.NewGuid():N}@azaion.com";
            using (var admin = _fixture.CreateAuthenticatedClient(_fixture.AdminToken))
            {
                using var createResp = await admin.PostAsync("/users",
                    new { Email = candidateEmail, Password = password, Role = 10 });
                createResp.EnsureSuccessStatusCode();
            }

            email = candidateEmail;

            using var loginClient = _fixture.CreateApiClient();
            var userToken = await loginClient.LoginAsync(email, password);
            using var userClient = _fixture.CreateAuthenticatedClient(userToken);
            using (var bind = await userClient.PostAsync("/resources/check", new { Hardware = hardware }))
            {
                bind.EnsureSuccessStatusCode();
            }

            // Act
            using var download = await userClient.PostAsync($"/resources/get/{folder}",
                new { Password = password, Hardware = hardware, FileName = fileName });
            download.EnsureSuccessStatusCode();
            var encrypted = await download.Content.ReadAsByteArrayAsync();
            var decrypted = DecryptResourcePayload(encrypted, email!, password, hardware);

            // Assert
            decrypted.Should().Equal(original);
        }
        finally
        {
            if (email is not null)
            {
                using var adminCleanup = _fixture.CreateAuthenticatedClient(_fixture.AdminToken);
                using var del = await adminCleanup.DeleteAsync($"/users/{Uri.EscapeDataString(email)}");
                del.EnsureSuccessStatusCode();
            }

            using var adminClear = _fixture.CreateAuthenticatedClient(_fixture.AdminToken);
            using var clear = await adminClear.PostAsync($"/resources/clear/{folder}", new { });
            clear.EnsureSuccessStatusCode();
        }
    }

    [Fact]
    public async Task Upload_without_file_is_rejected_with_400_or_409_and_60_on_conflict()
    {
        // Arrange
        var folder = $"restest-{Guid.NewGuid():N}";
        using var content = new MultipartFormDataContent();

        // Act
        using var response = await _fixture.HttpClient.PostAsync($"/resources/{folder}", content);

        // Assert
        response.StatusCode.Should().BeOneOf(HttpStatusCode.BadRequest, HttpStatusCode.Conflict);
        if (response.StatusCode == HttpStatusCode.Conflict)
        {
            var err = await response.Content.ReadFromJsonAsync<ErrorResponse>(ResponseJsonOptions);
            err.Should().NotBeNull();
            err!.ErrorCode.Should().Be(60);
        }
    }

    private static byte[] DecryptResourcePayload(byte[] encrypted, string email, string password, string hardware)
    {
        var hwHash = Convert.ToBase64String(SHA384.HashData(
            Encoding.UTF8.GetBytes($"Azaion_{hardware}_%$$$)0_")));
        var apiKey = Convert.ToBase64String(SHA384.HashData(
            Encoding.UTF8.GetBytes($"{email}-{password}-{hwHash}-#%@AzaionKey@%#---")));
        var aesKey = SHA256.HashData(Encoding.UTF8.GetBytes(apiKey));

        if (encrypted.Length <= 16)
            throw new InvalidOperationException("Encrypted payload too short.");

        using var aes = Aes.Create();
        aes.Key = aesKey;
        aes.IV = encrypted.AsSpan(0, 16).ToArray();
        aes.Mode = CipherMode.CBC;
        aes.Padding = PaddingMode.PKCS7;
        using var decryptor = aes.CreateDecryptor();
        return decryptor.TransformFinalBlock(encrypted, 16, encrypted.Length - 16);
    }
}