using Microsoft.AspNetCore.Components;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.AdminUI.Components.Shared;

namespace ZB.MOM.WW.OtOpcUa.AdminUI.Tests.Raw;

/// <summary>
///     R04 H2: the modals' DynamicComponent parameter dictionaries are reused across renders while their
///     values are unchanged, and rebuilt — carrying the current value — the moment one changes. The second
///     half is the regression a naive build-once cache would introduce (stale JSON stranding every edit).
/// </summary>
[Trait("Category", "Unit")]
public sealed class ParameterDictionaryCacheTests
{
    [Fact]
    public void Unchanged_values_return_the_same_dictionary()
    {
        var cache = new ParameterDictionaryCache();
        var builds = 0;
        var json = "{}";
        Dictionary<string, object> Build() { builds++; return new() { ["Json"] = json }; }

        var first = cache.Get([json], Build);
        cache.Get([json], Build).ShouldBeSameAs(first);
        builds.ShouldBe(1);
    }

    [Fact]
    public void A_changed_value_rebuilds_with_the_current_value()
    {
        var cache = new ParameterDictionaryCache();
        var json = "{}";
        Dictionary<string, object> Build() => new() { ["Json"] = json };

        cache.Get([json], Build)["Json"].ShouldBe("{}");
        json = "{\"a\":1}";
        cache.Get([json], Build)["Json"].ShouldBe("{\"a\":1}");
    }

    [Fact]
    public void Null_values_compare_and_reset_forces_a_rebuild()
    {
        var cache = new ParameterDictionaryCache();
        var builds = 0;
        Dictionary<string, object> Build() { builds++; return new(); }

        cache.Get(["x", null], Build);
        cache.Get(["x", null], Build);
        builds.ShouldBe(1);

        cache.Reset();
        cache.Get(["x", null], Build);
        builds.ShouldBe(2);
    }

    [Fact]
    public void Modals_build_their_parameters_through_the_cache_with_reused_callbacks()
    {
        foreach (var (path, cacheField) in new[]
                 {
                     (new[] { "Components", "Shared", "Drivers", "DriverConfigModal.razor" }, "_formParameterCache.Get("),
                     (new[] { "Components", "Shared", "Drivers", "DeviceModal.razor" }, "_deviceFormParameterCache.Get("),
                     (new[] { "Components", "Shared", "Raw", "RawTagModal.razor" }, "_editorParameterCache.Get("),
                 })
        {
            var src = AdminUiSource.Read(path);
            src.ShouldContain(cacheField, customMessage: path[^1]);
            // Every EventCallback is created behind a ??= so it is made once per component.
            var all = System.Text.RegularExpressions.Regex.Matches(src, @"EventCallback\.Factory\.Create").Count;
            var once = System.Text.RegularExpressions.Regex.Matches(src, @"\?\?=\s*EventCallback\.Factory\.Create").Count;
            all.ShouldBeGreaterThan(0, path[^1]);
            once.ShouldBe(all, path[^1]);
        }
    }

    [Fact]
    public void RawTagModal_reuses_its_callback_across_renders()
    {
        var modal = new ZB.MOM.WW.OtOpcUa.AdminUI.Components.Shared.Raw.RawTagModal();
        var first = modal.BuildEditorParameters();
        var second = modal.BuildEditorParameters();

        second.ShouldBeSameAs(first);
        ((EventCallback<string>)first["ConfigJsonChanged"]).HasDelegate.ShouldBeTrue();
    }
}