using Examples.Billing.Microservice.Endpoints;
using Examples.Inventory.Microservice.Endpoints;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc.Testing;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection.Extensions;
using Microsoft.Extensions.Hosting;
using StellaOps.Microservice;
using StellaOps.Router.Common.Abstractions;
using StellaOps.Router.Common.Enums;
using StellaOps.Router.Transport.InMemory;
using Xunit;

namespace Examples.Integration.Tests;

/// <summary>
/// Test fixture that sets up the gateway and microservices for integration testing.
/// Uses in-memory transport for fast, isolated tests.
/// </summary>
public sealed class GatewayFixture : IAsyncLifetime
{
    private readonly InMemoryConnectionRegistry _registry = new();
    private WebApplicationFactory<Examples.Gateway.Program>? _gatewayFactory;
    private IHost? _billingHost;
    private IHost? _inventoryHost;

    public HttpClient GatewayClient { get; private set; } = null!;

    public async Task InitializeAsync()
    {
        // Start the gateway
        _gatewayFactory = new WebApplicationFactory<Examples.Gateway.Program>()
            .WithWebHostBuilder(builder =>
            {
                builder.UseEnvironment("Testing");
                builder.ConfigureServices(services =>
                {
                    services.RemoveAll<InMemoryConnectionRegistry>();
                    services.AddSingleton(_registry);
                });
            });

        GatewayClient = _gatewayFactory.CreateClient();

        // Start billing microservice
        var billingBuilder = Host.CreateApplicationBuilder();
        billingBuilder.Services.AddStellaMicroservice(options =>
        {
            options.ServiceName = "billing";
            options.Version = "1.0.0";
            options.Region = "test";
            options.InstanceId = "billing-test";
            options.Routers =
            [
                new RouterEndpointConfig
                {
                    Host = "localhost",
                    Port = 5100,
                    TransportType = TransportType.InMemory
                }
            ];
        });
        billingBuilder.Services.AddScoped<CreateInvoiceEndpoint>();
        billingBuilder.Services.AddScoped<GetInvoiceEndpoint>();
        billingBuilder.Services.AddScoped<UploadAttachmentEndpoint>();
        billingBuilder.Services.AddSingleton(_registry);
        billingBuilder.Services.AddInMemoryTransportClient();

        _billingHost = billingBuilder.Build();
        await _billingHost.StartAsync();

        // Start inventory microservice
        var inventoryBuilder = Host.CreateApplicationBuilder();
        inventoryBuilder.Services.AddStellaMicroservice(options =>
        {
            options.ServiceName = "inventory";
            options.Version = "1.0.0";
            options.Region = "test";
            options.InstanceId = "inventory-test";
            options.Routers =
            [
                new RouterEndpointConfig
                {
                    Host = "localhost",
                    Port = 5100,
                    TransportType = TransportType.InMemory
                }
            ];
        });
        inventoryBuilder.Services.AddScoped<ListItemsEndpoint>();
        inventoryBuilder.Services.AddScoped<GetItemEndpoint>();
        inventoryBuilder.Services.AddSingleton(_registry);
        inventoryBuilder.Services.AddInMemoryTransportClient();

        _inventoryHost = inventoryBuilder.Build();
        await _inventoryHost.StartAsync();

        await WaitForGatewayReadyAsync(TimeSpan.FromSeconds(5));
    }

    public async Task DisposeAsync()
    {
        GatewayClient.Dispose();

        if (_billingHost is not null)
        {
            await _billingHost.StopAsync();
            _billingHost.Dispose();
        }

        if (_inventoryHost is not null)
        {
            await _inventoryHost.StopAsync();
            _inventoryHost.Dispose();
        }

        _gatewayFactory?.Dispose();
    }

    private async Task WaitForGatewayReadyAsync(TimeSpan timeout)
    {
        if (_gatewayFactory is null)
        {
            throw new InvalidOperationException("Gateway factory not initialized.");
        }

        var routingState = _gatewayFactory.Services.GetRequiredService<IGlobalRoutingState>();
        var deadline = DateTimeOffset.UtcNow.Add(timeout);

        while (DateTimeOffset.UtcNow < deadline)
        {
            var connections = routingState.GetAllConnections();
            if (connections.Count >= 2 &&
                routingState.ResolveEndpoint("GET", "/items") is not null &&
                routingState.ResolveEndpoint("POST", "/invoices") is not null)
            {
                return;
            }

            await Task.Delay(50);
        }

        var currentConnections = routingState.GetAllConnections();
        throw new TimeoutException(
            $"Gateway routing state not ready after {timeout}. Connections={currentConnections.Count}.");
    }
}