using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Driver.AbCip;

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

/// <summary>
///     A controller's <c>@tags</c> listing names each program (<c>Program:UN01_Press</c>, a system
///     symbol) but none of its tags — those are listed only by <c>Program:&lt;name&gt;.@tags</c>.
///     Seen live on a production press: the PackML state (<c>Program:UN01_Press.Out_eState</c>) and
///     every alarm bit the Ignition project reads are program-scoped, and the browse showed none.
/// </summary>
[Trait("Category", "Unit")]
public sealed class AbCipProgramScopeEnumerationTests
{
    // Captured entries (CompactLogix 5069-L320ERS2 rev 34.11): WW_InCycle + the Program:UN01_Press entry
    // from @tags, and Out_eState from Program:UN01_Press.@tags.
    private const string ControllerListing =
        "AF010000C10001000000000000000000000000000A0057575F496E4379636C65" +
        "7900000068100000000000000000000000000000120050726F6772616D3A554E30315F5072657373";

    private const string Un01Listing = "1A000000C40004000000000000000000000000000A004F75745F655374617465";

    private static readonly AbCipTagCreateParams Params = new(
        Gateway: "10.0.0.5", Port: 44818, CipPath: "1,0", LibplctagPlcAttribute: "controllogix",
        TagName: "@tags", Timeout: TimeSpan.FromSeconds(2));

    /// <summary>The enumerator reads each program's own listing and yields its tags program-scoped.</summary>
    [Fact]
    public async Task Program_scoped_tags_are_enumerated_from_each_program_listing()
    {
        var reads = new List<string>();
        using var enumerator = new SymbolListingEnumerator((_, name, _) =>
        {
            reads.Add(name);
            return Task.FromResult(name switch
            {
                "@tags" => Convert.FromHexString(ControllerListing),
                "Program:UN01_Press.@tags" => Convert.FromHexString(Un01Listing),
                _ => throw new InvalidOperationException(name),
            });
        });

        var tags = new List<AbCipDiscoveredTag>();
        await foreach (var t in enumerator.EnumerateAsync(Params, TestContext.Current.CancellationToken))
            tags.Add(t);

        reads.ShouldBe(["@tags", "Program:UN01_Press.@tags"]);
        var outState = tags.Single(t => t.Name == "Out_eState");
        outState.ProgramScope.ShouldBe("UN01_Press");
        outState.DataType.ShouldBe(AbCipDataType.DInt);
        tags.ShouldContain(t => t.Name == "WW_InCycle" && t.ProgramScope == null);
    }

    /// <summary>One unreadable program listing does not cost the controller tags or other programs.</summary>
    [Fact]
    public async Task A_failing_program_listing_is_skipped()
    {
        using var enumerator = new SymbolListingEnumerator((_, name, _) => name == "@tags"
            ? Task.FromResult(Convert.FromHexString(ControllerListing))
            : Task.FromException<byte[]>(new InvalidOperationException("ErrorNotFound")));

        var tags = new List<AbCipDiscoveredTag>();
        await foreach (var t in enumerator.EnumerateAsync(Params, TestContext.Current.CancellationToken))
            tags.Add(t);

        tags.ShouldContain(t => t.Name == "WW_InCycle");
    }
}