using Grpc.Core;

namespace MxGateway.Client.Tests;

/// <summary>Tests for the shared gRPC-to-native exception mapping used by the transports.</summary>
public sealed class RpcExceptionMapperTests
{
    /// <summary>Verifies that an unauthenticated status maps to the authentication exception.</summary>
    [Fact]
    public void Map_UnauthenticatedStatus_ProducesAuthenticationException()
    {
        RpcException rpc = new(new Status(StatusCode.Unauthenticated, "no key"));

        Exception mapped = RpcExceptionMapper.Map(rpc, CancellationToken.None);

        MxGatewayAuthenticationException authentication =
            Assert.IsType<MxGatewayAuthenticationException>(mapped);
        Assert.Equal(StatusCode.Unauthenticated, authentication.StatusCode);
    }

    /// <summary>Verifies that a permission-denied status maps to the authorization exception.</summary>
    [Fact]
    public void Map_PermissionDeniedStatus_ProducesAuthorizationException()
    {
        RpcException rpc = new(new Status(StatusCode.PermissionDenied, "missing scope"));

        Exception mapped = RpcExceptionMapper.Map(rpc, CancellationToken.None);

        MxGatewayAuthorizationException authorization =
            Assert.IsType<MxGatewayAuthorizationException>(mapped);
        Assert.Equal(StatusCode.PermissionDenied, authorization.StatusCode);
    }

    /// <summary>Verifies that a cancelled status maps to OperationCanceledException.</summary>
    [Fact]
    public void Map_CancelledStatus_ProducesOperationCanceledException()
    {
        RpcException rpc = new(new Status(StatusCode.Cancelled, "cancelled"));

        Exception mapped = RpcExceptionMapper.Map(rpc, CancellationToken.None);

        Assert.IsType<OperationCanceledException>(mapped);
    }

    /// <summary>
    /// Verifies that non-auth statuses surface the originating gRPC status code on the
    /// mapped exception so callers can distinguish transient from permanent failures
    /// without reflecting into InnerException.
    /// </summary>
    [Theory]
    [InlineData(StatusCode.NotFound)]
    [InlineData(StatusCode.InvalidArgument)]
    [InlineData(StatusCode.ResourceExhausted)]
    [InlineData(StatusCode.FailedPrecondition)]
    [InlineData(StatusCode.Unavailable)]
    [InlineData(StatusCode.Internal)]
    public void Map_NonAuthStatus_CarriesStatusCodeOnMxGatewayException(StatusCode statusCode)
    {
        RpcException rpc = new(new Status(statusCode, "boom"));

        Exception mapped = RpcExceptionMapper.Map(rpc, CancellationToken.None);

        MxGatewayException gatewayException = Assert.IsType<MxGatewayException>(mapped);
        Assert.Equal(statusCode, gatewayException.StatusCode);
        Assert.Same(rpc, gatewayException.InnerException);
    }

    /// <summary>Verifies that an MxGatewayException built without a gRPC status reports a null StatusCode.</summary>
    [Fact]
    public void StatusCode_IsNull_WhenNoGrpcStatusProvided()
    {
        MxGatewayException gatewayException = new("plain failure");

        Assert.Null(gatewayException.StatusCode);
    }
}