using System.Security.Claims;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using ZB.MOM.WW.Auth.Abstractions.Ldap;
using ZB.MOM.WW.Auth.Ldap;
using ZB.MOM.WW.MxGateway.Server.Configuration;
using ZB.MOM.WW.MxGateway.Server.Dashboard;
using LibraryLdapOptions = ZB.MOM.WW.Auth.Abstractions.Ldap.LdapOptions;

namespace ZB.MOM.WW.MxGateway.IntegrationTests;

[Collection(LiveResourcesCollection.Name)]
[Trait("Category", "LiveLdap")]
public sealed class DashboardLdapLiveTests
{
    /// <summary>
    /// The shared dev/test directory issues every human tester the same well-known password, so
    /// the fixtures name it once rather than repeating a literal that drifts per test. This is a
    /// published dev credential (see <c>glauth.md</c> and <c>scadaproj/infra/glauth/config.toml</c>),
    /// not a secret — unlike the service-account bind password, which is never in source and must
    /// arrive via <c>MxGateway__Ldap__ServiceAccountPassword</c>.
    /// </summary>
    private const string SharedDirectoryPassword = "password";

    /// <summary>
    /// Verifies that <c>admin</c> — a shared-directory user whose <c>othergroups</c> include
    /// GwAdmin (gid 5610) — authenticates successfully and is granted the Admin dashboard role.
    /// </summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [LiveLdapFact]
    public async Task AuthenticateAsync_AdminInGwAdminGroup_Succeeds()
    {
        DashboardAuthenticator authenticator = CreateAuthenticator();

        DashboardAuthenticationResult result = await authenticator.AuthenticateAsync(
            "admin",
            SharedDirectoryPassword,
            CancellationToken.None);

        Assert.True(result.Succeeded);
        Assert.NotNull(result.Principal);
        Assert.Equal("admin", result.Principal.FindFirst(ClaimTypes.NameIdentifier)?.Value);
        Assert.Contains(result.Principal.Claims, claim =>
            claim.Type == DashboardAuthenticationDefaults.LdapGroupClaimType
            && claim.Value.Contains("GwAdmin", StringComparison.OrdinalIgnoreCase));

        Assert.Contains(result.Principal.Claims, claim =>
            claim.Type == ClaimTypes.Role
            && claim.Value == DashboardRoles.Admin);
    }

    /// <summary>
    /// Verifies that <c>gw-viewer</c> — a shared-directory user whose only group is GwReader
    /// (gid 5611), which this suite's GroupToRole map deliberately leaves unmapped — is denied
    /// even though its bind succeeds, and that the denial is indistinguishable from the
    /// unknown-user denial.
    /// </summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [LiveLdapFact]
    public async Task AuthenticateAsync_ViewerMissingGwAdminGroup_FailsIndistinguishably()
    {
        DashboardAuthenticator authenticator = CreateAuthenticator();

        DashboardAuthenticationResult result = await authenticator.AuthenticateAsync(
            "gw-viewer",
            SharedDirectoryPassword,
            CancellationToken.None);

        Assert.False(result.Succeeded);
        Assert.Null(result.Principal);

        // This test used to assert the failure message did not echo the credential literal.
        // That check cannot survive the move to the shared directory: the real password is the
        // word "password", which legitimately occurs in the generic denial text ("The username
        // or password is invalid, ..."), so the assertion would fail for the wrong reason. The
        // no-leak property is still covered — with a distinctive literal — by
        // AuthenticateAsync_AdminWithWrongPassword_FailsWithoutLeakingPassword below. What is
        // asserted here instead is the property this fixture is actually uniquely able to prove:
        // an authorization failure (valid credentials, no mapped role) must be reported with the
        // same message as an authentication failure, so the response cannot be used to enumerate
        // valid accounts.
        DashboardAuthenticationResult unknownUserResult = await authenticator.AuthenticateAsync(
            "no-such-user-9f3c1",
            "irrelevant-password",
            CancellationToken.None);

        Assert.False(string.IsNullOrWhiteSpace(result.FailureMessage));
        Assert.Equal(unknownUserResult.FailureMessage, result.FailureMessage);
    }

    /// <summary>Verifies that authentication with wrong password fails without leaking the password.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [LiveLdapFact]
    public async Task AuthenticateAsync_AdminWithWrongPassword_FailsWithoutLeakingPassword()
    {
        // Exercises the user-bind-failure branch: the user exists and the service
        // account search succeeds, but the candidate bind is rejected.
        const string wrongPassword = "definitely-not-the-admin-password";
        DashboardAuthenticator authenticator = CreateAuthenticator();

        DashboardAuthenticationResult result = await authenticator.AuthenticateAsync(
            "admin",
            wrongPassword,
            CancellationToken.None);

        Assert.False(result.Succeeded);
        Assert.Null(result.Principal);
        Assert.DoesNotContain(wrongPassword, result.FailureMessage, StringComparison.Ordinal);
    }

    /// <summary>Verifies that authentication with unknown username fails.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [LiveLdapFact]
    public async Task AuthenticateAsync_UnknownUsername_Fails()
    {
        // Exercises the user-not-found branch: the service-account search returns no
        // entry, so no candidate bind is attempted.
        DashboardAuthenticator authenticator = CreateAuthenticator();

        DashboardAuthenticationResult result = await authenticator.AuthenticateAsync(
            "no-such-user-9f3c1",
            "irrelevant-password",
            CancellationToken.None);

        Assert.False(result.Succeeded);
        Assert.Null(result.Principal);
    }

    /// <summary>Verifies that authentication fails gracefully when the server is unreachable.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [LiveLdapFact]
    public async Task AuthenticateAsync_ServerUnreachable_FailsWithoutThrowing()
    {
        // Exercises the connect-failure path: overriding only the port keeps whatever host
        // the run targets (localhost by default, the shared GLAuth under the
        // MxGateway__Ldap__Server override) while pointing at a port nothing listens on, so
        // the connection error the shared LdapAuthService must absorb into a Fail result —
        // rather than propagate as an exception to the dashboard — is reproduced either way.
        DashboardAuthenticator authenticator = CreateAuthenticator(LibraryOptions() with
        {
            // 1 is a reserved port number that no LDAP server listens on.
            Port = 1,
        });

        DashboardAuthenticationResult result = await authenticator.AuthenticateAsync(
            "admin",
            SharedDirectoryPassword,
            CancellationToken.None);

        Assert.False(result.Succeeded);
        Assert.Null(result.Principal);
    }

    private static DashboardAuthenticator CreateAuthenticator() => CreateAuthenticator(LibraryOptions());

    private static DashboardAuthenticator CreateAuthenticator(LibraryLdapOptions ldapOptions)
    {
        GatewayOptions gatewayOptions = new()
        {
            Dashboard = new DashboardOptions
            {
                GroupToRole = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase)
                {
                    ["GwAdmin"] = DashboardRoles.Admin,
                },
            },
        };

        return new DashboardAuthenticator(
            new LdapAuthService(ldapOptions),
            new DashboardGroupRoleMapper(Options.Create(gatewayOptions)),
            NullLogger<DashboardAuthenticator>.Instance);
    }

    /// <summary>
    /// Builds the shared library <see cref="LibraryLdapOptions"/> by binding the real
    /// <c>MxGateway:Ldap</c> configuration section the same way production does in
    /// <c>AddZbLdapAuth(configuration, "MxGateway:Ldap")</c>, rather than hand-copying the
    /// gateway shadow <c>LdapOptions</c> defaults field by field.
    /// Binding the section directly onto the shared type means the live tests exercise the
    /// exact option-binding path production uses, pick up every shared field (including
    /// <see cref="LibraryLdapOptions.ConnectionTimeoutMs"/>, which governs the
    /// unreachable-server test's timing) at whatever value the operator configured, and
    /// cannot silently drop a field added to the shared type. The gateway's
    /// <c>appsettings.json</c> seeds the dev directory connection (port 3893, plaintext,
    /// AllowInsecure) but ships <c>Server=localhost</c>, so a run against the shared GLAuth
    /// needs the <c>MxGateway__Ldap__Server=10.100.0.35</c> environment override that the
    /// <c>AddEnvironmentVariables()</c> layer below applies.
    /// </summary>
    private static LibraryLdapOptions LibraryOptions()
    {
        string repositoryRoot = IntegrationTestEnvironment.ResolveRepositoryRoot(AppContext.BaseDirectory);
        string appSettingsPath = Path.Combine(
            repositoryRoot,
            "src",
            "ZB.MOM.WW.MxGateway.Server",
            "appsettings.json");

        IConfiguration configuration = new ConfigurationBuilder()
            .AddJsonFile(appSettingsPath, optional: false)
            .AddEnvironmentVariables()
            .Build();

        // Same section production binds in AddZbLdapAuth(configuration, "MxGateway:Ldap").
        // Get<T> returns null only when the section is absent; appsettings.json always
        // carries it, so fall back to shared defaults defensively rather than throw.
        LibraryLdapOptions options = configuration.GetSection("MxGateway:Ldap").Get<LibraryLdapOptions>()
            ?? new LibraryLdapOptions();

        // appsettings.json now ships the bind password as the unexpanded
        // "${secret:ldap/mxgateway/bind}" token (resolved at gateway startup by the
        // pre-host secrets expander, which this bare ConfigurationBuilder does not run).
        // AddEnvironmentVariables() above lets MxGateway__Ldap__ServiceAccountPassword
        // override the token with the real password. Fail loud rather than silently
        // binding with the literal token string, which would make every live test in
        // this file fail with a confusing LDAP bind error instead of an actionable one.
        if (string.IsNullOrEmpty(options.ServiceAccountPassword)
            || options.ServiceAccountPassword.StartsWith("${secret:", StringComparison.Ordinal))
        {
            throw new InvalidOperationException(
                "Live LDAP tests require the real bind password via the "
                + "MxGateway__Ldap__ServiceAccountPassword environment variable "
                + "(appsettings now ships a ${secret:} token that this suite does not expand). "
                + "Set it before running.");
        }

        return options;
    }
}