using Shouldly;
using Xunit;

namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Tests;

/// <summary>
///     Gitea #676 — the driver connects to the endpoint URL the server ADVERTISES in GetEndpoints. A server behind NAT,
///     a port map or a proxy advertises an address the client cannot reach (or one that bypasses the proxy), so the
///     driver must rewrite host AND port to the configured URL when the scheme matches — what the SDK's own
///     <c>CoreClientUtils.SelectEndpoint</c> does.
/// </summary>
public sealed class OpcUaClientEndpointRewriteTests
{
    [Fact]
    public void Host_and_port_of_the_advertised_url_are_replaced_by_the_configured_ones()
    {
        OpcUaClientDriver.RewriteEndpointUrl("opc.tcp://internal-host:4840/OtOpcUa", "opc.tcp://10.1.2.3:54840/OtOpcUa")
            .ShouldBe("opc.tcp://10.1.2.3:54840/OtOpcUa");
    }

    [Fact]
    public void The_advertised_path_is_kept()
    {
        // The path is the server's to choose (several endpoints may share a host:port); only the address is ours.
        OpcUaClientDriver.RewriteEndpointUrl("opc.tcp://plc-a:4840/Server/Ua", "opc.tcp://gateway:6000/")
            .ShouldBe("opc.tcp://gateway:6000/Server/Ua");
    }

    [Fact]
    public void Only_the_port_differs_still_rewrites()
    {
        // The in-process stall proxy shape: same host, the configured port is the proxy's.
        OpcUaClientDriver.RewriteEndpointUrl("opc.tcp://127.0.0.1:4840/OtOpcUa", "opc.tcp://127.0.0.1:61000/OtOpcUa")
            .ShouldBe("opc.tcp://127.0.0.1:61000/OtOpcUa");
    }

    [Fact]
    public void A_configured_url_without_a_port_keeps_the_advertised_port()
    {
        // Review of 3b88056f: Uri.Port is -1 for a port-less opc.tcp URL; copying it would drop the advertised port and
        // the SDK would fall back to 4840.
        OpcUaClientDriver.RewriteEndpointUrl("opc.tcp://internal-host:62541/Server", "opc.tcp://gateway/Server")
            .ShouldBe("opc.tcp://gateway:62541/Server");
    }

    [Fact]
    public void An_IPv6_configured_host_is_bracketed()
    {
        OpcUaClientDriver.RewriteEndpointUrl("opc.tcp://internal-host:4840/OtOpcUa", "opc.tcp://[fd00::1]:54840/OtOpcUa")
            .ShouldBe("opc.tcp://[fd00::1]:54840/OtOpcUa");
    }

    [Fact]
    public void A_different_scheme_is_left_alone()
    {
        // An https endpoint advertised next to an opc.tcp one is a different transport, not a NAT artefact.
        OpcUaClientDriver.RewriteEndpointUrl("https://srv:443/ua", "opc.tcp://srv:4840/ua")
            .ShouldBe("https://srv:443/ua");
    }

    [Theory]
    [InlineData(null)]
    [InlineData("")]
    [InlineData("not a url")]
    public void An_unusable_advertised_url_falls_back_to_the_configured_one(string? advertised)
    {
        OpcUaClientDriver.RewriteEndpointUrl(advertised, "opc.tcp://srv:4840/ua").ShouldBe("opc.tcp://srv:4840/ua");
    }
}