using Microsoft.Extensions.Logging.Abstractions;
using Opc.Ua;
using Shouldly;
using Xunit;

namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests;

/// <summary>
///     Phase C Task 2 — node-manager materialisation honours the historize intent. Boot a real
///     <see cref="OtOpcUaSdkServer"/> through <see cref="OpcUaApplicationHost"/> (the same harness
///     <see cref="SdkAddressSpaceSinkTests"/> uses), drive <see cref="OtOpcUaNodeManager.EnsureVariable"/>
///     with / without a historian tagname, and assert the created <see cref="BaseDataVariableState"/>'s
///     <c>Historizing</c> flag + <c>HistoryRead</c> access bit + the NodeId→tagname registration.
/// </summary>
public sealed class NodeManagerHistorizeTests : IDisposable
{
    private static CancellationToken Ct => TestContext.Current.CancellationToken;

    private readonly string _pkiRoot = Path.Combine(
        Path.GetTempPath(),
        $"otopcua-historize-{Guid.NewGuid():N}");

    /// <summary>A historized variable is created Historizing, gains the HistoryRead access bit in BOTH
    /// AccessLevel and UserAccessLevel, and its NodeId→tagname registration is queryable.</summary>
    [Fact]
    public async Task EnsureVariable_with_historian_tagname_sets_historizing_and_history_read_bit()
    {
        var (host, server) = await BootAsync();
        var nm = server.NodeManager!;

        nm.EnsureVariable("eq-1/temp", parentFolderNodeId: null, displayName: "Temp", dataType: "Float",
            writable: false, historianTagname: "WW.Tag");

        var variable = nm.TryGetVariable("eq-1/temp");
        variable.ShouldNotBeNull();
        variable!.Historizing.ShouldBeTrue();
        (variable.AccessLevel & AccessLevels.HistoryRead).ShouldNotBe((byte)0);
        (variable.UserAccessLevel & AccessLevels.HistoryRead).ShouldNotBe((byte)0);
        // Read-only historized node still grants CurrentRead.
        (variable.AccessLevel & AccessLevels.CurrentRead).ShouldNotBe((byte)0);

        // The NodeId→resolved-tagname registration is queryable for the (later) HistoryRead override.
        nm.TryGetHistorizedTagname("eq-1/temp", out var tagname).ShouldBeTrue();
        tagname.ShouldBe("WW.Tag");

        await host.DisposeAsync();
    }

    /// <summary>A non-historized variable (tagname null / omitted) stays Historizing=false, has no
    /// HistoryRead bit, and is NOT registered in the NodeId→tagname map.</summary>
    [Fact]
    public async Task EnsureVariable_without_historian_tagname_is_not_historized()
    {
        var (host, server) = await BootAsync();
        var nm = server.NodeManager!;

        // Explicit null and the defaulted-param form both mean "not historized".
        nm.EnsureVariable("eq-1/plain", parentFolderNodeId: null, displayName: "Plain", dataType: "Int32",
            writable: false, historianTagname: null);
        nm.EnsureVariable("eq-1/plain2", parentFolderNodeId: null, displayName: "Plain2", dataType: "Int32",
            writable: false);

        foreach (var nodeId in new[] { "eq-1/plain", "eq-1/plain2" })
        {
            var variable = nm.TryGetVariable(nodeId);
            variable.ShouldNotBeNull();
            variable!.Historizing.ShouldBeFalse();
            (variable.AccessLevel & AccessLevels.HistoryRead).ShouldBe((byte)0);
            (variable.UserAccessLevel & AccessLevels.HistoryRead).ShouldBe((byte)0);
            nm.TryGetHistorizedTagname(nodeId, out var tagname).ShouldBeFalse();
            tagname.ShouldBeNull();
        }

        await host.DisposeAsync();
    }

    /// <summary>A historized AND writable node keeps the CurrentRead|CurrentWrite composite AND gains the
    /// HistoryRead bit (the three bits are OR-ed, not replaced).</summary>
    [Fact]
    public async Task EnsureVariable_historized_and_writable_keeps_read_write_and_adds_history_read()
    {
        var (host, server) = await BootAsync();
        var nm = server.NodeManager!;

        nm.EnsureVariable("eq-1/setpoint", parentFolderNodeId: null, displayName: "Setpoint", dataType: "Float",
            writable: true, historianTagname: "WW.Setpoint");

        var variable = nm.TryGetVariable("eq-1/setpoint");
        variable.ShouldNotBeNull();
        variable!.Historizing.ShouldBeTrue();
        (variable.AccessLevel & AccessLevels.CurrentRead).ShouldNotBe((byte)0);
        (variable.AccessLevel & AccessLevels.CurrentWrite).ShouldNotBe((byte)0);
        (variable.AccessLevel & AccessLevels.HistoryRead).ShouldNotBe((byte)0);
        // The composite is exactly CurrentRead | CurrentWrite | HistoryRead.
        variable.AccessLevel.ShouldBe((byte)(AccessLevels.CurrentRead | AccessLevels.CurrentWrite | AccessLevels.HistoryRead));
        variable.UserAccessLevel.ShouldBe(variable.AccessLevel);

        nm.TryGetHistorizedTagname("eq-1/setpoint", out var tagname).ShouldBeTrue();
        tagname.ShouldBe("WW.Setpoint");

        await host.DisposeAsync();
    }

    /// <summary>RebuildAddressSpace drops the NodeId→tagname registrations alongside the variables.</summary>
    [Fact]
    public async Task RebuildAddressSpace_clears_historized_tagname_registrations()
    {
        var (host, server) = await BootAsync();
        var nm = server.NodeManager!;

        nm.EnsureVariable("eq-1/temp", parentFolderNodeId: null, displayName: "Temp", dataType: "Float",
            writable: false, historianTagname: "WW.Tag");
        nm.TryGetHistorizedTagname("eq-1/temp", out _).ShouldBeTrue();

        nm.RebuildAddressSpace();

        nm.TryGetHistorizedTagname("eq-1/temp", out var tagname).ShouldBeFalse();
        tagname.ShouldBeNull();

        await host.DisposeAsync();
    }

    private async Task<(OpcUaApplicationHost Host, OtOpcUaSdkServer Server)> BootAsync()
    {
        var host = new OpcUaApplicationHost(
            new OpcUaApplicationHostOptions
            {
                ApplicationName = "OtOpcUa.HistorizeTest",
                ApplicationUri = $"urn:OtOpcUa.HistorizeTest:{Guid.NewGuid():N}",
                OpcUaPort = AllocateFreePort(),
                PublicHostname = "localhost",
                PkiStoreRoot = _pkiRoot,
            },
            NullLogger<OpcUaApplicationHost>.Instance);

        var server = new OtOpcUaSdkServer();
        await host.StartAsync(server, Ct);
        return (host, server);
    }

    private static int AllocateFreePort()
    {
        using var listener = new System.Net.Sockets.TcpListener(System.Net.IPAddress.Loopback, 0);
        listener.Start();
        var port = ((System.Net.IPEndPoint)listener.LocalEndpoint).Port;
        listener.Stop();
        return port;
    }

    /// <summary>Cleans up the PKI root directory.</summary>
    public void Dispose()
    {
        if (Directory.Exists(_pkiRoot))
        {
            try { Directory.Delete(_pkiRoot, recursive: true); }
            catch { /* best-effort cleanup */ }
        }
    }
}