using System.Net;
using System.Text.Json;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc.Testing;
using Microsoft.AspNetCore.TestHost;
using Microsoft.Extensions.DependencyInjection;

namespace ZB.MOM.WW.ScadaBridge.Host.Tests;

/// <summary>
/// Proves the site pipeline actually MAPS the health endpoints — the half
/// <see cref="SiteHealthCheckTests"/> cannot cover, since that fixture builds the site container
/// from <see cref="SiteServiceRegistration"/> and never runs <c>Program</c>'s endpoint wiring.
/// Without this, deleting <c>app.MapZbHealth()</c> from the site branch would leave every
/// registration test green while site nodes served 404 to the overview dashboard.
/// <para>
/// Boots the real <c>Program</c> in the Site role. <c>Program</c> builds its own
/// <c>ConfigurationBuilder</c> before the web host exists, so its role and settings come from
/// PROCESS-WIDE environment variables (<c>SCADABRIDGE_CONFIG</c> selects appsettings.Site.json)
/// rather than from <c>WithWebHostBuilder</c> — which is why this fixture joins
/// <see cref="HostBootCollection"/> and restores every var it sets.
/// </para>
/// </summary>
[Collection(HostBootCollection.Name)]
public class SiteHealthEndpointTests : IDisposable
{
    private readonly List<IDisposable> _disposables = new();
    private readonly Dictionary<string, string?> _previousEnv = new(StringComparer.Ordinal);
    private readonly string _tempDbPath;

    public SiteHealthEndpointTests()
    {
        _tempDbPath = Path.Combine(Path.GetTempPath(), $"scadabridge_health_ep_{Guid.NewGuid()}.db");

        // Whole-key env overrides, the sanctioned path: supplying GrpcPsk concretely makes the
        // pre-host secrets expander skip appsettings.Site.json's ${secret:SB-GRPC-PSK-site-1}
        // token, so this test needs no seeded secrets store.
        //
        // The remoting port is moved off the site default (8082) so this fixture cannot collide
        // with a locally running node, but it must be a REAL port and seed-nodes[0] must be this
        // node itself — StartupValidator enforces both before the host is built, and it runs
        // whether or not the Akka hosted service is later removed. Nothing binds it: the hosted
        // service is removed below.
        SetEnv("SCADABRIDGE_CONFIG", "Site");
        SetEnv("ScadaBridge__Node__Role", "Site");
        SetEnv("ScadaBridge__Node__SiteId", "TestSite");
        SetEnv("ScadaBridge__Node__NodeHostname", "localhost");
        SetEnv("ScadaBridge__Node__RemotingPort", "18082");
        SetEnv("ScadaBridge__Cluster__SeedNodes__0", "akka.tcp://scadabridge@localhost:18082");
        SetEnv("ScadaBridge__Cluster__SeedNodes__1", "akka.tcp://scadabridge@localhost:18085");
        SetEnv("ScadaBridge__Communication__GrpcPsk", "test-psk-0123456789");
        SetEnv("LocalDb__Path", _tempDbPath);
    }

    private void SetEnv(string key, string? value)
    {
        _previousEnv[key] = Environment.GetEnvironmentVariable(key);
        Environment.SetEnvironmentVariable(key, value);
    }

    public void Dispose()
    {
        foreach (var d in _disposables)
        {
            try { d.Dispose(); } catch { /* best effort */ }
        }

        foreach (var (key, value) in _previousEnv)
        {
            Environment.SetEnvironmentVariable(key, value);
        }

        try { File.Delete(_tempDbPath); } catch { /* best effort */ }

        GC.SuppressFinalize(this);
    }

    private HttpClient CreateSiteClient()
    {
        var factory = new WebApplicationFactory<Program>()
            .WithWebHostBuilder(builder =>
            {
                // WebApplicationFactory defaults the environment to Development, which turns on
                // ValidateOnBuild/ValidateScopes. The site graph carries scoped registrations whose
                // dependencies are central-only (ReconcileService → IDeploymentManagerRepository,
                // AuditLogKpiSampleSource → IAuditLogRepository) and are never resolved on a site
                // node, so eager validation fails on a composition that runs fine in production.
                // That is a pre-existing property of the site container, not of the health wiring
                // under test — run this fixture the way a site node actually runs.
                builder.UseEnvironment("Production");

                // ConfigureTestServices runs after the app's own registrations, so this drops the
                // hosted service that would form a real cluster while leaving the AkkaHostedService
                // singleton resolvable (the site pipeline resolves it for shutdown ordering).
                builder.ConfigureTestServices(AkkaHostedServiceRemover.RemoveAkkaHostedServiceOnly);
            });
        _disposables.Add(factory);

        var client = factory.CreateClient();
        _disposables.Add(client);
        return client;
    }

    [Fact]
    public async Task Site_MapsHealthReady_WithTheCanonicalJsonBody()
    {
        var response = await CreateSiteClient().GetAsync("/health/ready");

        // Never 404. 200 vs 503 depends on cluster state this fixture does not form, so both are
        // accepted — what is asserted is that the tier is mapped and answers in canonical shape.
        Assert.NotEqual(HttpStatusCode.NotFound, response.StatusCode);
        Assert.True(
            response.StatusCode is HttpStatusCode.OK or HttpStatusCode.ServiceUnavailable,
            $"Expected 200 or 503, got {(int)response.StatusCode}");

        using var doc = JsonDocument.Parse(await response.Content.ReadAsStringAsync());
        var entries = doc.RootElement.GetProperty("entries");

        Assert.True(entries.TryGetProperty("akka-cluster", out _), "ready tier must carry akka-cluster");
        Assert.True(entries.TryGetProperty("localdb", out _), "ready tier must carry localdb");
        // Readiness must NOT depend on being the primary, or a healthy standby would read unready.
        Assert.False(entries.TryGetProperty("active-node", out _), "active-node belongs to the Active tier");
    }

    [Fact]
    public async Task Site_MapsHealthActive_CarryingOnlyTheActiveNodeCheck()
    {
        var response = await CreateSiteClient().GetAsync("/health/active");

        Assert.NotEqual(HttpStatusCode.NotFound, response.StatusCode);

        using var doc = JsonDocument.Parse(await response.Content.ReadAsStringAsync());
        var entries = doc.RootElement.GetProperty("entries");

        Assert.Equal(
            new[] { "active-node" },
            entries.EnumerateObject().Select(p => p.Name).ToArray());
    }

    [Fact]
    public async Task Site_HealthEndpointsAreAnonymous()
    {
        // The dashboard authenticates nowhere. The site pipeline runs no authentication middleware
        // today, so this is a regression pin: adding one later must not silently close these.
        var client = CreateSiteClient();

        foreach (var path in new[] { "/health/ready", "/health/active", "/healthz" })
        {
            var response = await client.GetAsync(path);

            Assert.NotEqual(HttpStatusCode.Unauthorized, response.StatusCode);
            Assert.NotEqual(HttpStatusCode.Forbidden, response.StatusCode);
            Assert.NotEqual(HttpStatusCode.NotFound, response.StatusCode);
        }
    }
}