using System.Net;
using System.Net.Http.Headers;
using System.Text;
using Omika.Core.Observability.Outbox;

namespace Omika.Tests.Observability.Outbox;

/// <summary>Tests du client HTTP d'upload : classification des statuts, timeout, anti-boucle.</summary>
public class DiagnosticUploadClientTests
{
    private static DiagnosticBatchDto NewBatch() =>
        new()
        {
            Events =
            [
                new DiagnosticEventDto { EventId = Guid.NewGuid(), EventCode = "OMK-MOB-APP-001" }
            ]
        };

    private static DiagnosticUploadClient CreateClient(
        StubHandler handler,
        DiagnosticUploadOptions? options = null,
        string? token = "token-1") =>
        new(
            new HttpClient(handler),
            "http://localhost:5000",
            () => token,
            options ?? new DiagnosticUploadOptions { Timeout = TimeSpan.FromSeconds(5) });

    [Fact]
    public async Task NoToken_ReturnsUnauthorized_WithoutHttp()
    {
        var handler = new StubHandler { StatusCode = HttpStatusCode.OK };
        DiagnosticUploadClient client = CreateClient(handler, token: null);

        DiagnosticUploadResult result = await client.UploadAsync(NewBatch());

        Assert.Equal(DiagnosticUploadOutcome.Unauthorized, result.Outcome);
        Assert.Equal(0, handler.Calls);
    }

    [Fact]
    public async Task Success_MapsToSuccess_WithAcceptedCount()
    {
        var handler = new StubHandler
        {
            StatusCode = HttpStatusCode.OK,
            ResponseBody = """{"batchId":"00000000-0000-0000-0000-000000000001","acceptedCount":3}"""
        };
        DiagnosticUploadClient client = CreateClient(handler);

        DiagnosticUploadResult result = await client.UploadAsync(NewBatch());

        Assert.Equal(DiagnosticUploadOutcome.Success, result.Outcome);
        Assert.Equal(3, result.AcceptedCount);
    }

    [Theory]
    [InlineData(HttpStatusCode.Unauthorized, DiagnosticUploadOutcome.Unauthorized)]
    [InlineData(HttpStatusCode.Forbidden, DiagnosticUploadOutcome.Unauthorized)]
    [InlineData(HttpStatusCode.BadRequest, DiagnosticUploadOutcome.Rejected)]
    [InlineData(HttpStatusCode.RequestEntityTooLarge, DiagnosticUploadOutcome.TooLarge)]
    [InlineData(HttpStatusCode.InternalServerError, DiagnosticUploadOutcome.Transient)]
    [InlineData(HttpStatusCode.ServiceUnavailable, DiagnosticUploadOutcome.Transient)]
    [InlineData(HttpStatusCode.GatewayTimeout, DiagnosticUploadOutcome.Transient)]
    public async Task StatusCodes_MapToExpectedOutcome(HttpStatusCode status, DiagnosticUploadOutcome expected)
    {
        var handler = new StubHandler { StatusCode = status };
        DiagnosticUploadClient client = CreateClient(handler);

        DiagnosticUploadResult result = await client.UploadAsync(NewBatch());

        Assert.Equal(expected, result.Outcome);
        Assert.Equal((int)status, result.StatusCode);
    }

    [Fact]
    public async Task RateLimited_HonorsRetryAfter()
    {
        var handler = new StubHandler
        {
            StatusCode = HttpStatusCode.TooManyRequests,
            RetryAfterSeconds = 42
        };
        DiagnosticUploadClient client = CreateClient(handler);

        DiagnosticUploadResult result = await client.UploadAsync(NewBatch());

        Assert.Equal(DiagnosticUploadOutcome.RateLimited, result.Outcome);
        Assert.Equal(TimeSpan.FromSeconds(42), result.RetryAfter);
    }

    [Fact]
    public async Task Timeout_MapsToTransient()
    {
        var handler = new StubHandler { DelayMs = 2000, StatusCode = HttpStatusCode.OK };
        DiagnosticUploadClient client = CreateClient(handler, new DiagnosticUploadOptions { Timeout = TimeSpan.FromMilliseconds(10) });

        DiagnosticUploadResult result = await client.UploadAsync(NewBatch());

        Assert.Equal(DiagnosticUploadOutcome.Transient, result.Outcome);
    }

    [Fact]
    public async Task Upload_SendsBearerToken()
    {
        var handler = new StubHandler { StatusCode = HttpStatusCode.OK };
        DiagnosticUploadClient client = CreateClient(handler, token: "secret-token");

        await client.UploadAsync(NewBatch());

        Assert.Equal("Bearer secret-token", handler.LastAuthorization);
    }

    private sealed class StubHandler : HttpMessageHandler
    {
        public HttpStatusCode StatusCode { get; set; } = HttpStatusCode.OK;

        public int DelayMs { get; set; }

        public string ResponseBody { get; set; } = "{}";

        public int? RetryAfterSeconds { get; set; }

        public int Calls { get; private set; }

        public string? LastAuthorization { get; private set; }

        protected override async Task<HttpResponseMessage> SendAsync(
            HttpRequestMessage request,
            CancellationToken cancellationToken)
        {
            Calls++;
            LastAuthorization = request.Headers.Authorization?.ToString();
            if (DelayMs > 0)
            {
                await Task.Delay(DelayMs, cancellationToken);
            }

            var response = new HttpResponseMessage(StatusCode);
            if (RetryAfterSeconds is { } seconds)
            {
                response.Headers.RetryAfter = new RetryConditionHeaderValue(TimeSpan.FromSeconds(seconds));
            }

            response.Content = new StringContent(ResponseBody, Encoding.UTF8, "application/json");
            return response;
        }
    }
}