using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using Akka.Actor;
using Akka.Configuration;
using ZB.MOM.WW.ScadaBridge.ClusterInfrastructure;
using ZB.MOM.WW.ScadaBridge.Host.Actors;

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

/// <summary>
/// The opt-in Akka.Remote TLS block that <see cref="AkkaHostedService.BuildHocon"/> emits from
/// <c>ScadaBridge:Cluster:RemotingTls</c> (ScadaBridge#64). Off must add nothing to the document;
/// on must render keys Akka actually reads — proven by booting a real transport on it.
/// </summary>
public class HoconRemotingTlsTests
{
    private const string TlsPrefix = "akka.remote.dot-netty.tcp.";

    private static NodeOptions Node(int port = 8081) => new() { Role = "Central", NodeHostname = "localhost", RemotingPort = port };

    private static ClusterOptions Cluster(ClusterRemotingTlsOptions tls, bool emptySeeds = false) => new()
    {
        SeedNodes = new List<string> { "akka.ssl.tcp://scadabridge@localhost:8081", "akka.ssl.tcp://scadabridge@peer:8081" },
        SplitBrainResolverStrategy = "auto-down",
        // The bootstrap guard renders an EMPTY seed list, which lets the boot test below start an
        // unjoined node that does not try to dial a peer that is not there.
        BootstrapGuard = new ClusterBootstrapGuardOptions { Enabled = emptySeeds },
        RemotingTls = tls,
    };

    private static string Build(ClusterRemotingTlsOptions tls, NodeOptions? node = null, bool emptySeeds = false) =>
        AkkaHostedService.BuildHocon(node ?? Node(), Cluster(tls, emptySeeds), new[] { "Central" },
            TimeSpan.FromSeconds(5), TimeSpan.FromSeconds(15));

    /// <summary>Verifies the default (off) document carries no SSL key at all.</summary>
    [Fact]
    public void Default_emits_no_ssl_keys()
    {
        var hocon = Build(new ClusterRemotingTlsOptions());

        // (The fixture's seeds say akka.ssl.tcp, so assert on the keys, not the bare word.)
        Assert.DoesNotContain("enable-ssl", hocon, StringComparison.Ordinal);
        Assert.DoesNotContain("ssl {", hocon, StringComparison.Ordinal);
        var config = ConfigurationFactory.ParseString(hocon);
        Assert.False(config.HasPath(TlsPrefix + "enable-ssl"));
        Assert.False(config.HasPath(TlsPrefix + "ssl.certificate.path"));
    }

    /// <summary>
    /// Verifies a DISABLED block with every field populated renders exactly the default document —
    /// the fields are inert until <c>Enabled</c>, byte for byte.
    /// </summary>
    [Fact]
    public void Disabled_block_with_fields_is_byte_identical_to_default()
    {
        var populated = new ClusterRemotingTlsOptions
        {
            Enabled = false,
            CertificatePath = "/certs/x.pfx",
            CertificatePassword = "pw",
            CertificateThumbprint = "ABC",
            StoreName = "Root",
            StoreLocation = "current-user",
            RequireMutualAuthentication = false,
            ValidateCertificateHostname = true,
        };

        Assert.Equal(Build(new ClusterRemotingTlsOptions()), Build(populated));
    }

    /// <summary>Verifies a file certificate renders the path/password keys Akka reads.</summary>
    [Fact]
    public void Enabled_with_path_renders_file_certificate_keys()
    {
        var config = ConfigurationFactory.ParseString(Build(new ClusterRemotingTlsOptions
        {
            Enabled = true,
            CertificatePath = "/certs/node1.pfx",
            CertificatePassword = "p\"w\\d",
        }));

        Assert.True(config.GetBoolean(TlsPrefix + "enable-ssl"));
        Assert.False(config.GetBoolean(TlsPrefix + "ssl.certificate.use-thumbprint-over-file"));
        Assert.Equal("/certs/node1.pfx", config.GetString(TlsPrefix + "ssl.certificate.path"));
        // Quote and backslash survive the round trip: the password cannot break out of its literal.
        Assert.Equal("p\"w\\d", config.GetString(TlsPrefix + "ssl.certificate.password"));
        Assert.False(config.GetBoolean(TlsPrefix + "ssl.suppress-validation"));
        Assert.True(config.GetBoolean(TlsPrefix + "ssl.require-mutual-authentication"));
        Assert.False(config.GetBoolean(TlsPrefix + "ssl.validate-certificate-hostname"));
        // The block sits inside dot-netty.tcp without disturbing its siblings.
        Assert.Equal("localhost", config.GetString(TlsPrefix + "hostname"));
        Assert.Equal(8081, config.GetInt(TlsPrefix + "port"));
        Assert.Equal(1, config.GetInt("akka.cluster.min-nr-of-members"));
    }

    /// <summary>Verifies a store certificate renders the thumbprint keys and the policy switches.</summary>
    [Fact]
    public void Enabled_with_thumbprint_renders_store_keys()
    {
        var config = ConfigurationFactory.ParseString(Build(new ClusterRemotingTlsOptions
        {
            Enabled = true,
            CertificateThumbprint = "45df32e258c92a7abf6c112e54912ab15bbb9eb0",
            RequireMutualAuthentication = false,
            ValidateCertificateHostname = true,
        }));

        Assert.True(config.GetBoolean(TlsPrefix + "ssl.certificate.use-thumbprint-over-file"));
        Assert.Equal("45df32e258c92a7abf6c112e54912ab15bbb9eb0", config.GetString(TlsPrefix + "ssl.certificate.thumbprint"));
        Assert.Equal("My", config.GetString(TlsPrefix + "ssl.certificate.store-name"));
        Assert.Equal("local-machine", config.GetString(TlsPrefix + "ssl.certificate.store-location"));
        Assert.False(config.HasPath(TlsPrefix + "ssl.certificate.path"));
        Assert.False(config.GetBoolean(TlsPrefix + "ssl.require-mutual-authentication"));
        Assert.True(config.GetBoolean(TlsPrefix + "ssl.validate-certificate-hostname"));
    }

    /// <summary>
    /// Boots a real ActorSystem on the emitted TLS document with a generated certificate and checks
    /// Akka.Remote came up as a TLS transport: its address scheme is <c>akka.ssl.tcp</c>. This is the
    /// fact the seed-scheme rule in <c>ClusterOptionsValidator</c> relies on, and it fails if the
    /// rendered keys are ones Akka does not read (the transport would come up plain <c>akka.tcp</c>).
    /// </summary>
    [Fact]
    public async Task Enabled_document_boots_a_tls_transport_with_akka_ssl_tcp_addresses()
    {
        var dir = Directory.CreateTempSubdirectory("sb-akka-tls-");
        try
        {
            const string password = "test-only-pfx-password";
            var pfxPath = Path.Combine(dir.FullName, "node.pfx");
            using (var rsa = RSA.Create(2048))
            {
                var request = new CertificateRequest("CN=localhost", rsa, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
                var san = new SubjectAlternativeNameBuilder();
                san.AddDnsName("localhost");
                request.CertificateExtensions.Add(san.Build());
                using var cert = request.CreateSelfSigned(DateTimeOffset.UtcNow.AddMinutes(-5), DateTimeOffset.UtcNow.AddDays(1));
                await File.WriteAllBytesAsync(pfxPath, cert.Export(X509ContentType.Pfx, password));
            }

            var hocon = Build(
                new ClusterRemotingTlsOptions { Enabled = true, CertificatePath = pfxPath, CertificatePassword = password },
                Node(port: 0),
                emptySeeds: true);

            var system = ActorSystem.Create("scadabridge", ConfigurationFactory.ParseString(hocon));
            try
            {
                var address = ((ExtendedActorSystem)system).Provider.DefaultAddress;
                Assert.Equal("akka.ssl.tcp", address.Protocol);
                Assert.True(address.Port > 0);
            }
            finally
            {
                await system.Terminate();
            }
        }
        finally
        {
            dir.Delete(recursive: true);
        }
    }
}