using ZB.MOM.WW.ScadaBridge.Commons.Types.DataConnections;
using ZB.MOM.WW.ScadaBridge.Commons.Types.Flattening;
using ZB.MOM.WW.ScadaBridge.Commons.Validators;

namespace ZB.MOM.WW.ScadaBridge.Commons.Tests.Validators;

public class OpcUaEndpointConfigValidatorTests
{
    private static OpcUaEndpointConfig Valid() => new()
    {
        EndpointUrl = "opc.tcp://plant-a:4840",
        // Defaults satisfy the spec: Lifetime(30) >= 3 * KeepAlive(10).
    };

    /// <summary>Verifies that the default settings with a valid endpoint URL validate successfully.</summary>
    [Fact]
    public void Validate_DefaultsWithValidUrl_IsValid()
    {
        var result = OpcUaEndpointConfigValidator.Validate(Valid());
        Assert.True(result.IsValid);
        Assert.Empty(result.Errors);
    }

    /// <summary>Verifies that a missing endpoint URL fails validation.</summary>
    [Fact]
    public void Validate_MissingEndpointUrl_Fails()
    {
        var c = Valid();
        c.EndpointUrl = "";
        var r = OpcUaEndpointConfigValidator.Validate(c);
        Assert.False(r.IsValid);
        Assert.Contains(r.Errors, e =>
            e.EntityName == "EndpointUrl"
            && e.Category == ValidationCategory.ConnectionConfig
            && e.Message.Contains("required", StringComparison.OrdinalIgnoreCase));
    }

    /// <summary>Verifies that a malformed or non-OPC UA endpoint URL fails validation.</summary>
    /// <param name="url">The invalid endpoint URL to validate.</param>
    [Theory]
    [InlineData("http://x")]
    [InlineData("opc.tcp://")]
    [InlineData("not a url")]
    public void Validate_BadEndpointUrl_Fails(string url)
    {
        var c = Valid();
        c.EndpointUrl = url;
        var r = OpcUaEndpointConfigValidator.Validate(c);
        Assert.False(r.IsValid);
        Assert.Contains(r.Errors, e => e.EntityName == "EndpointUrl");
    }

    /// <summary>Verifies that a lifetime count below three times the keep-alive count fails validation.</summary>
    [Fact]
    public void Validate_LifetimeLessThanThreeTimesKeepAlive_Fails()
    {
        var c = Valid();
        c.KeepAliveCount = 10;
        c.LifetimeCount = 29; // 3*10 = 30; 29 < 30 → invalid
        var r = OpcUaEndpointConfigValidator.Validate(c);
        Assert.False(r.IsValid);
        Assert.Contains(r.Errors, e => e.EntityName == "LifetimeCount");
    }

    /// <summary>Verifies that a non-positive timing value fails validation.</summary>
    /// <param name="field">The name of the timing field set to a non-positive value.</param>
    [Theory]
    [InlineData(nameof(OpcUaEndpointConfig.SessionTimeoutMs))]
    [InlineData(nameof(OpcUaEndpointConfig.OperationTimeoutMs))]
    [InlineData(nameof(OpcUaEndpointConfig.PublishingIntervalMs))]
    [InlineData(nameof(OpcUaEndpointConfig.SamplingIntervalMs))]
    public void Validate_NonPositiveTiming_Fails(string field)
    {
        var c = Valid();
        typeof(OpcUaEndpointConfig).GetProperty(field)!.SetValue(c, 0);
        var r = OpcUaEndpointConfigValidator.Validate(c);
        Assert.False(r.IsValid);
        Assert.Contains(r.Errors, e => e.EntityName == field);
    }

    /// <summary>Verifies that a queue size of zero fails validation.</summary>
    [Fact]
    public void Validate_QueueSizeZero_Fails()
    {
        var c = Valid();
        c.QueueSize = 0;
        var r = OpcUaEndpointConfigValidator.Validate(c);
        Assert.Contains(r.Errors, e => e.EntityName == "QueueSize");
    }

    /// <summary>Verifies that enabling the heartbeat without a tag path fails validation.</summary>
    [Fact]
    public void Validate_HeartbeatEnabledNoTagPath_Fails()
    {
        var c = Valid();
        c.Heartbeat = new OpcUaHeartbeatConfig { TagPath = "", MaxSilenceSeconds = 30 };
        var r = OpcUaEndpointConfigValidator.Validate(c);
        Assert.Contains(r.Errors, e => e.EntityName == "Heartbeat.TagPath");
    }

    /// <summary>Verifies that a non-positive heartbeat silence threshold fails validation.</summary>
    [Fact]
    public void Validate_HeartbeatNonPositiveSilence_Fails()
    {
        var c = Valid();
        c.Heartbeat = new OpcUaHeartbeatConfig { TagPath = "Hb", MaxSilenceSeconds = 0 };
        var r = OpcUaEndpointConfigValidator.Validate(c);
        Assert.Contains(r.Errors, e => e.EntityName == "Heartbeat.MaxSilenceSeconds");
    }

    /// <summary>Verifies that the field prefix is applied to every validation error.</summary>
    [Fact]
    public void Validate_FieldPrefix_AppliedToEveryError()
    {
        var c = Valid();
        c.EndpointUrl = "";
        c.QueueSize = 0;
        var r = OpcUaEndpointConfigValidator.Validate(c, fieldPrefix: "Primary.");
        Assert.All(r.Errors, e => Assert.StartsWith("Primary.", e.EntityName!));
        Assert.Contains(r.Errors, e => e.EntityName == "Primary.EndpointUrl");
        Assert.Contains(r.Errors, e => e.EntityName == "Primary.QueueSize");
    }

    // ── Layer B extensions: auth, deadband, subscription display name ──

    /// <summary>Verifies that an empty subscription display name fails validation.</summary>
    [Fact]
    public void Validate_EmptySubscriptionDisplayName_Fails()
    {
        var c = Valid();
        c.SubscriptionDisplayName = "";
        var r = OpcUaEndpointConfigValidator.Validate(c);
        Assert.Contains(r.Errors, e => e.EntityName == "SubscriptionDisplayName");
    }

    /// <summary>Verifies that an anonymous user identity requires no additional fields.</summary>
    [Fact]
    public void Validate_UserIdentityAnonymous_NoExtraFieldsRequired()
    {
        var c = Valid();
        c.UserIdentity = new OpcUaUserIdentityConfig { TokenType = OpcUaUserTokenType.Anonymous };
        var r = OpcUaEndpointConfigValidator.Validate(c);
        Assert.True(r.IsValid);
    }

    /// <summary>Verifies that a username/password identity without a username fails validation.</summary>
    [Fact]
    public void Validate_UsernamePasswordWithoutUsername_Fails()
    {
        var c = Valid();
        c.UserIdentity = new OpcUaUserIdentityConfig
        {
            TokenType = OpcUaUserTokenType.UsernamePassword,
            Username = "",
            Password = "secret"
        };
        var r = OpcUaEndpointConfigValidator.Validate(c);
        Assert.Contains(r.Errors, e => e.EntityName == "UserIdentity.Username");
    }

    /// <summary>Verifies that an X.509 identity without a certificate path fails validation.</summary>
    [Fact]
    public void Validate_X509WithoutCertificatePath_Fails()
    {
        var c = Valid();
        c.UserIdentity = new OpcUaUserIdentityConfig
        {
            TokenType = OpcUaUserTokenType.X509Certificate,
            CertificatePath = ""
        };
        var r = OpcUaEndpointConfigValidator.Validate(c);
        Assert.Contains(r.Errors, e => e.EntityName == "UserIdentity.CertificatePath");
    }

    /// <summary>Verifies that a username/password identity with a username passes validation.</summary>
    [Fact]
    public void Validate_UsernamePasswordWithUsername_Passes()
    {
        var c = Valid();
        c.UserIdentity = new OpcUaUserIdentityConfig
        {
            TokenType = OpcUaUserTokenType.UsernamePassword,
            Username = "alice",
            Password = ""
        };
        var r = OpcUaEndpointConfigValidator.Validate(c);
        Assert.True(r.IsValid);
    }

    /// <summary>Verifies that a deadband with a non-positive value fails validation.</summary>
    [Fact]
    public void Validate_DeadbandWithNonPositiveValue_Fails()
    {
        var c = Valid();
        c.Deadband = new OpcUaDeadbandConfig { Type = OpcUaDeadbandType.Absolute, Value = 0 };
        var r = OpcUaEndpointConfigValidator.Validate(c);
        Assert.Contains(r.Errors, e => e.EntityName == "Deadband.Value");
    }

    /// <summary>Verifies that a deadband with a positive value passes validation.</summary>
    [Fact]
    public void Validate_DeadbandWithPositiveValue_Passes()
    {
        var c = Valid();
        c.Deadband = new OpcUaDeadbandConfig { Type = OpcUaDeadbandType.Percent, Value = 1.5 };
        var r = OpcUaEndpointConfigValidator.Validate(c);
        Assert.True(r.IsValid);
    }

    /// <summary>Verifies that user identity errors carry the field prefix.</summary>
    [Fact]
    public void Validate_UserIdentityErrorsPrefixed_WithFieldPrefix()
    {
        var c = Valid();
        c.UserIdentity = new OpcUaUserIdentityConfig
        {
            TokenType = OpcUaUserTokenType.UsernamePassword,
            Username = ""
        };
        var r = OpcUaEndpointConfigValidator.Validate(c, fieldPrefix: "Primary.");
        Assert.Contains(r.Errors, e => e.EntityName == "Primary.UserIdentity.Username");
    }
}