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

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

/// <summary>
///     Gitea #548 — the sibling-name disambiguator that makes a CNC reporting two axes both
///     called <c>AA</c> publishable as <c>AA_1</c> / <c>AA_2</c>.
/// </summary>
[Trait("Category", "Unit")]
public sealed class FixedTreeNamesTests
{
    [Fact]
    public void Unique_names_pass_through_unchanged()
    {
        FixedTreeNames.Disambiguate(["X", "Y", "Z"]).ShouldBe(["X", "Y", "Z"]);
    }

    [Fact]
    public void Every_member_of_a_collision_set_is_suffixed_in_slot_order()
    {
        // The whole set, not just the second occurrence: bare "AA" must cease to exist when
        // ambiguous, or it would silently mean "one of the two".
        FixedTreeNames.Disambiguate(["AA", "Y", "AA"]).ShouldBe(["AA_1", "Y", "AA_2"]);
    }

    [Fact]
    public void An_unrelated_name_between_duplicates_does_not_shift_their_ordinals()
    {
        // The ordinal counts occurrences of the SAME name, not positions in the list — adding an
        // unrelated axis never renames an existing duplicate pair.
        FixedTreeNames.Disambiguate(["B", "AA", "Y", "AA"]).ShouldBe(["B", "AA_1", "Y", "AA_2"]);
    }

    [Fact]
    public void Duplicate_grouping_is_case_insensitive()
    {
        // The snapshot cache and the read path both compare OrdinalIgnoreCase, so "Aa" and "AA"
        // would collide there — they must be treated as one collision set here too.
        FixedTreeNames.Disambiguate(["Aa", "AA"]).ShouldBe(["Aa_1", "AA_2"]);
    }

    [Fact]
    public void A_generated_segment_never_collides_with_a_genuine_name()
    {
        // Pathological but must not silently alias: a real sibling already named "S_1" claims
        // that segment, so the duplicate set escalates past it.
        FixedTreeNames.Disambiguate(["S_1", "S", "S"]).ShouldBe(["S_1", "S_2", "S_3"]);
    }

    [Fact]
    public void Three_way_collisions_number_sequentially()
    {
        FixedTreeNames.Disambiguate(["AA", "AA", "AA"]).ShouldBe(["AA_1", "AA_2", "AA_3"]);
    }

    [Fact]
    public void The_output_is_always_unique()
    {
        var segments = FixedTreeNames.Disambiguate(["A", "A_1", "A", "A_2", "A"]);
        segments.Distinct(StringComparer.OrdinalIgnoreCase).Count().ShouldBe(segments.Count);
    }

    [Fact]
    public void An_empty_list_yields_an_empty_list()
    {
        FixedTreeNames.Disambiguate([]).ShouldBeEmpty();
    }
}