using System.Net;
using Microsoft.AspNetCore.Mvc.Testing;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Admin.Security;
using ZB.MOM.WW.OtOpcUa.Admin.Services;

namespace ZB.MOM.WW.OtOpcUa.Admin.Tests;

/// <summary>
///     Regression coverage for Admin-003 / Admin-005.
///
///     Admin-005 — the login is a static-rendered form posting to the <c>/auth/login</c>
///     minimal-API endpoint, which performs the LDAP bind, cookie <c>SignInAsync</c> and
///     redirect while it still owns the HTTP response (no interactive Blazor circuit).
///
///     Admin-003 — the three SignalR hubs reject anonymous connections.
///
///     These are HTTP-pipeline tests with a stubbed <see cref="ILdapAuthService"/>, so they
///     run without LDAP or the central SQL Server.
/// </summary>
public sealed class AuthEndpointsTests : IClassFixture<AuthEndpointsTests.StubbedAuthAppFactory>
{
    private readonly StubbedAuthAppFactory _factory;

    public AuthEndpointsTests(StubbedAuthAppFactory factory) => _factory = factory;

    /// <summary>
    ///     Admin app host with the LDAP service stubbed (a fixed-credential pass/fail) and the
    ///     background poller removed so the host starts clean without DB or directory access.
    /// </summary>
    public sealed class StubbedAuthAppFactory : WebApplicationFactory<Program>
    {
        protected override IHost CreateHost(IHostBuilder builder)
        {
            builder.ConfigureServices(services =>
            {
                var poller = services.SingleOrDefault(d =>
                    d.ImplementationType?.Name == "FleetStatusPoller");
                if (poller is not null) services.Remove(poller);

                var ldap = services.SingleOrDefault(d => d.ServiceType == typeof(ILdapAuthService));
                if (ldap is not null) services.Remove(ldap);
                services.AddScoped<ILdapAuthService, StubLdapAuthService>();

                var resolver = services.SingleOrDefault(d => d.ServiceType == typeof(IAdminRoleGrantResolver));
                if (resolver is not null) services.Remove(resolver);
                services.AddScoped<IAdminRoleGrantResolver, StubRoleGrantResolver>();
            });
            return base.CreateHost(builder);
        }

        public HttpClient CreateNonRedirectingClient() =>
            CreateClient(new WebApplicationFactoryClientOptions { AllowAutoRedirect = false });
    }

    /// <summary>Stub LDAP: <c>good</c>/<c>pw</c> binds; anything else fails.</summary>
    private sealed class StubLdapAuthService : ILdapAuthService
    {
        public Task<LdapAuthResult> AuthenticateAsync(string username, string password, CancellationToken ct = default) =>
            Task.FromResult(username == "good" && password == "pw"
                ? new LdapAuthResult(true, "Good Operator", "good", ["FleetAdmins"], ["FleetAdmin"], null)
                : new LdapAuthResult(false, null, username, [], [], "Invalid username or password"));
    }

    /// <summary>Stub resolver: any non-empty group set yields a FleetAdmin grant.</summary>
    private sealed class StubRoleGrantResolver : IAdminRoleGrantResolver
    {
        public Task<AdminRoleGrants> ResolveAsync(IReadOnlyList<string> ldapGroups, CancellationToken cancellationToken) =>
            Task.FromResult(ldapGroups.Count == 0
                ? AdminRoleGrants.Empty
                : new AdminRoleGrants([AdminRoles.FleetAdmin], []));
    }

    private static FormUrlEncodedContent Form(params (string Key, string Value)[] fields) =>
        new(fields.Select(f => new KeyValuePair<string, string>(f.Key, f.Value)));

    // ── Admin-005: /auth/login endpoint ─────────────────────────────────────────

    [Fact]
    public async Task Valid_login_issues_the_auth_cookie_and_redirects_home()
    {
        using var client = _factory.CreateNonRedirectingClient();

        var response = await client.PostAsync("/auth/login",
            Form(("username", "good"), ("password", "pw")));

        // The endpoint owns the response, so the Set-Cookie header is actually emitted.
        response.StatusCode.ShouldBeOneOf(HttpStatusCode.Redirect, HttpStatusCode.Found);
        response.Headers.Location!.OriginalString.ShouldBe("/");
        response.Headers.TryGetValues("Set-Cookie", out var cookies).ShouldBeTrue(
            "a successful /auth/login must emit the auth cookie");
        string.Join(';', cookies!).ShouldContain("OtOpcUa.Admin");
    }

    [Fact]
    public async Task Invalid_login_redirects_back_to_login_with_an_error()
    {
        using var client = _factory.CreateNonRedirectingClient();

        var response = await client.PostAsync("/auth/login",
            Form(("username", "bad"), ("password", "wrong")));

        response.StatusCode.ShouldBeOneOf(HttpStatusCode.Redirect, HttpStatusCode.Found);
        response.Headers.Location!.OriginalString.ShouldContain("/login");
        response.Headers.Location!.OriginalString.ShouldContain("error");
        response.Headers.TryGetValues("Set-Cookie", out var cookies);
        (cookies is null || !string.Join(';', cookies).Contains("OtOpcUa.Admin")).ShouldBeTrue(
            "a failed bind must not issue the auth cookie");
    }

    [Fact]
    public async Task Login_with_missing_credentials_redirects_back_to_login()
    {
        using var client = _factory.CreateNonRedirectingClient();

        var response = await client.PostAsync("/auth/login", Form(("username", ""), ("password", "")));

        response.StatusCode.ShouldBeOneOf(HttpStatusCode.Redirect, HttpStatusCode.Found);
        response.Headers.Location!.OriginalString.ShouldContain("/login");
    }

    [Fact]
    public async Task Login_redirect_target_is_open_redirect_safe()
    {
        using var client = _factory.CreateNonRedirectingClient();

        // A returnUrl pointing off-site must be ignored — the post lands at the site root.
        var response = await client.PostAsync("/auth/login",
            Form(("username", "good"), ("password", "pw"), ("returnUrl", "https://evil.example.com/")));

        response.StatusCode.ShouldBeOneOf(HttpStatusCode.Redirect, HttpStatusCode.Found);
        response.Headers.Location!.OriginalString.ShouldBe("/");
    }

    [Fact]
    public async Task Login_honours_a_local_return_url()
    {
        using var client = _factory.CreateNonRedirectingClient();

        var response = await client.PostAsync("/auth/login",
            Form(("username", "good"), ("password", "pw"), ("returnUrl", "/fleet")));

        response.StatusCode.ShouldBeOneOf(HttpStatusCode.Redirect, HttpStatusCode.Found);
        response.Headers.Location!.OriginalString.ShouldBe("/fleet");
    }

    [Fact]
    public async Task Logout_with_valid_session_but_no_antiforgery_token_is_rejected()
    {
        // Admin-006: the logout endpoint no longer calls .DisableAntiforgery(), so the
        // UseAntiforgery() middleware must reject a POST that carries no token with 400.
        // This regression guards against CSRF-logout (attacker tricking the operator's
        // already-authenticated browser into posting to /auth/logout from a foreign origin).
        //
        // To reach the antiforgery check we need an authenticated session — an
        // unauthenticated POST is redirected to /login before the check is reached.
        // We obtain the auth cookie via a valid /auth/login round-trip first.
        using var client = _factory.CreateNonRedirectingClient();

        // Step 1: log in to get the session cookie.
        var loginResponse = await client.PostAsync("/auth/login",
            Form(("username", "good"), ("password", "pw")));
        loginResponse.StatusCode.ShouldBeOneOf(HttpStatusCode.Redirect, HttpStatusCode.Found);

        // The cookie jar on the client now holds the auth cookie; subsequent requests are
        // authenticated. Step 2: POST to /auth/logout without an antiforgery token.
        var logoutResponse = await client.PostAsync("/auth/logout",
            new FormUrlEncodedContent(Array.Empty<KeyValuePair<string, string>>()));

        // The antiforgery middleware must reject the missing token with 400.
        logoutResponse.StatusCode.ShouldBe(HttpStatusCode.BadRequest,
            "/auth/logout from an authenticated session without an antiforgery token must be rejected (Admin-006)");
    }

    // ── Admin-003: SignalR hubs reject anonymous connections ────────────────────

    [Theory]
    [InlineData("/hubs/fleet")]
    [InlineData("/hubs/alerts")]
    [InlineData("/hubs/script-log")]
    public async Task Anonymous_hub_negotiate_is_rejected(string hubPath)
    {
        using var client = _factory.CreateNonRedirectingClient();

        // The SignalR negotiate handshake is a POST to <hub>/negotiate. An [Authorize]'d hub
        // must refuse it for an unauthenticated caller (302 to login or 401).
        var response = await client.PostAsync($"{hubPath}/negotiate",
            new FormUrlEncodedContent(Array.Empty<KeyValuePair<string, string>>()));

        response.StatusCode.ShouldNotBe(HttpStatusCode.OK,
            $"anonymous negotiate of {hubPath} must not succeed — the hub is [Authorize]-gated");
        response.StatusCode.ShouldBeOneOf(
            HttpStatusCode.Unauthorized, HttpStatusCode.Forbidden,
            HttpStatusCode.Redirect, HttpStatusCode.Found);
    }
}