using System.Text;
using Microsoft.Extensions.DependencyInjection;
using StellaOps.Router.Common.Enums;
using StellaOps.Router.Common.Models;
using StellaOps.Router.Transport.InMemory;
using Xunit;

namespace StellaOps.Router.Transport.InMemory.Tests;

public class RequestResponseFlowTests
{
    private readonly InMemoryConnectionRegistry _registry;
    private readonly InMemoryTransportServer _server;
    private readonly InMemoryTransportClient _client;

    public RequestResponseFlowTests()
    {
        var services = new ServiceCollection();
        services.AddLogging();
        services.AddInMemoryTransport();

        var provider = services.BuildServiceProvider();
        _registry = provider.GetRequiredService<InMemoryConnectionRegistry>();
        _server = provider.GetRequiredService<InMemoryTransportServer>();
        _client = provider.GetRequiredService<InMemoryTransportClient>();
    }

    [Fact]
    public async Task RequestResponse_RoundTrip()
    {
        // Arrange
        var instance = new InstanceDescriptor
        {
            InstanceId = "inst-1",
            ServiceName = "test-service",
            Version = "1.0.0",
            Region = "eu1"
        };

        var endpoints = new List<EndpointDescriptor>
        {
            new()
            {
                ServiceName = "test-service",
                Version = "1.0.0",
                Method = "GET",
                Path = "/api/echo"
            }
        };

        await _server.StartAsync(CancellationToken.None);
        await _client.ConnectAsync(instance, endpoints, CancellationToken.None);

        // Setup request handler that echoes the payload
        _client.OnRequestReceived += (frame, ct) =>
        {
            var response = new Frame
            {
                Type = FrameType.Response,
                CorrelationId = frame.CorrelationId,
                Payload = frame.Payload
            };
            return Task.FromResult(response);
        };

        // Start listening to the connection
        var connectionId = _registry.ConnectionIds.First();
        _server.StartListeningToConnection(connectionId);

        // Give server time to start listening
        await Task.Delay(50);

        // Get connection state
        var connections = _registry.GetAllConnections();
        var connection = connections[0];

        // Act - send request from server to microservice
        var requestPayload = Encoding.UTF8.GetBytes("Hello, World!");
        var requestFrame = new Frame
        {
            Type = FrameType.Request,
            CorrelationId = Guid.NewGuid().ToString("N"),
            Payload = requestPayload
        };

        await _server.SendToMicroserviceAsync(connectionId, requestFrame, CancellationToken.None);

        // Wait for response
        await Task.Delay(200);

        // Assert - we sent the request successfully
        // In a full implementation, we'd capture the response via events
        Assert.Equal(1, _registry.Count);
    }

    [Fact]
    public async Task SendRequestAsync_TimesOut()
    {
        // Arrange
        var instance = new InstanceDescriptor
        {
            InstanceId = "inst-1",
            ServiceName = "test-service",
            Version = "1.0.0",
            Region = "eu1"
        };

        await _server.StartAsync(CancellationToken.None);
        await _client.ConnectAsync(instance, [], CancellationToken.None);

        // No handler registered - request will never be answered
        var connectionId = _registry.ConnectionIds.First();
        _server.StartListeningToConnection(connectionId);

        var connections = _registry.GetAllConnections();
        var connection = connections[0];

        var requestFrame = new Frame
        {
            Type = FrameType.Request,
            CorrelationId = Guid.NewGuid().ToString("N"),
            Payload = ReadOnlyMemory<byte>.Empty
        };

        // Act & Assert
        await Assert.ThrowsAsync<TimeoutException>(() =>
            _client.SendRequestAsync(connection, requestFrame, TimeSpan.FromMilliseconds(100), CancellationToken.None));
    }
}