using ScadaLink.Commons.Entities.Templates;

namespace ScadaLink.TemplateEngine.Tests;

/// <summary>
/// Coverage for <see cref="TemplateNaming.QualifiedName"/> — the computed
/// hierarchical name of a composition-derived template. Derived templates store
/// only their contained name (the composition slot's <c>InstanceName</c>); the
/// dotted path is resolved on read by walking the <c>OwnerCompositionId</c> chain.
/// </summary>
public class TemplateNamingTests
{
    private static (Dictionary<int, Template> byId, Dictionary<int, TemplateComposition> compById)
        BuildGraph(params Template[] templates)
    {
        var byId = templates.ToDictionary(t => t.Id);
        var compById = templates
            .SelectMany(t => t.Compositions)
            .ToDictionary(c => c.Id);
        return (byId, compById);
    }

    [Fact]
    public void QualifiedName_BaseTemplate_IsJustItsName()
    {
        var motorController = new Template("Motor Controller") { Id = 4 };
        var (byId, compById) = BuildGraph(motorController);

        Assert.Equal("Motor Controller", TemplateNaming.QualifiedName(motorController, byId, compById));
    }

    [Fact]
    public void QualifiedName_OneLevelDerived_PrefixesTheOwner()
    {
        // Motor Controller composes the Pump template into a slot named "Pump".
        var motorController = new Template("Motor Controller") { Id = 4 };
        motorController.Compositions.Add(
            new TemplateComposition("Pump") { Id = 1014, TemplateId = 4, ComposedTemplateId = 2018 });
        var derivedPump = new Template("Pump")
        {
            Id = 2018, IsDerived = true, OwnerCompositionId = 1014
        };
        var (byId, compById) = BuildGraph(motorController, derivedPump);

        Assert.Equal("Motor Controller.Pump", TemplateNaming.QualifiedName(derivedPump, byId, compById));
    }

    [Fact]
    public void QualifiedName_NestedDerived_WalksTheWholeChain()
    {
        // Motor Controller -> Pump slot -> TempSensor slot.
        var motorController = new Template("Motor Controller") { Id = 4 };
        motorController.Compositions.Add(
            new TemplateComposition("Pump") { Id = 1014, TemplateId = 4, ComposedTemplateId = 2018 });

        var derivedPump = new Template("Pump")
        {
            Id = 2018, IsDerived = true, OwnerCompositionId = 1014
        };
        derivedPump.Compositions.Add(
            new TemplateComposition("TempSensor") { Id = 1015, TemplateId = 2018, ComposedTemplateId = 2019 });

        var derivedTempSensor = new Template("TempSensor")
        {
            Id = 2019, IsDerived = true, OwnerCompositionId = 1015
        };
        var (byId, compById) = BuildGraph(motorController, derivedPump, derivedTempSensor);

        Assert.Equal(
            "Motor Controller.Pump.TempSensor",
            TemplateNaming.QualifiedName(derivedTempSensor, byId, compById));
    }

    [Fact]
    public void QualifiedName_DerivedWithMissingOwnerLink_FallsBackToStoredName()
    {
        // Defensive: a derived template whose owner composition is not in the
        // lookup must not throw — it falls back to the stored contained name.
        var orphan = new Template("TempSensor")
        {
            Id = 2019, IsDerived = true, OwnerCompositionId = 9999
        };
        var (byId, compById) = BuildGraph(orphan);

        Assert.Equal("TempSensor", TemplateNaming.QualifiedName(orphan, byId, compById));
    }
}