using System.Reflection;
using System.Text.Json;
using Recordingtest.EngineBridge;
using Xunit;

namespace Recordingtest.EngineBridge.Tests;

public sealed class EngineBridgeTests
{
    private static readonly Lazy<string?> SutRootLazy = new(FindSutRoot);
    private static string? SutRoot => SutRootLazy.Value;
    private static bool SutAvailable => SutRoot != null;

    private static readonly string[] TargetAssemblies =
    {
        "HmEG.dll",
        "HmGeometry.dll",
        "HmGeometry.V2.dll",
        "HmTriangle.dll",
        "EditorCore.dll",
        "Editor02.HmEGAppManager.dll",
        "Editor03.PluginInterface.dll",
    };

    private static string? FindSutRoot()
    {
        var dir = new DirectoryInfo(AppContext.BaseDirectory);
        for (int i = 0; i < 10 && dir != null; i++)
        {
            var candidate = Path.Combine(dir.FullName, "EG-BIM Modeler");
            if (Directory.Exists(candidate) && File.Exists(Path.Combine(candidate, "HmEG.dll")))
                return candidate;
            dir = dir.Parent;
        }
        return null;
    }

    [Fact]
    public void MetadataLoader_LoadsHmegAssembly_WithoutExecution()
    {
        if (!SutAvailable) { Assert.True(true, "SUT not available — skipped"); return; }

        // MetadataLoadContext is pure metadata: it never runs type initializers
        // or any user code from the loaded assembly. The fact that we can load
        // HmEG.dll (which would otherwise need SharpDX/WPF at runtime) and
        // enumerate DefinedTypes without a TypeInitializationException is the
        // observable evidence of that guarantee.
        using var loader = new MetadataLoader(SutRoot!);
        var types = loader.LoadTypes(new[] { "HmEG.dll" }).ToList();
        Assert.True(types.Count > 0);
    }

    [Fact]
    public void CandidateFinder_FindsSelectionRelatedTypes()
    {
        if (!SutAvailable) { Assert.True(true, "SUT not available — skipped"); return; }

        using var loader = new MetadataLoader(SutRoot!);
        var types = loader.LoadTypes(TargetAssemblies).ToList();
        var candidates = CandidateFinder.Find(types);
        Assert.Contains(candidates, c => c.Category == "select");
    }

    [Fact]
    public void CatalogSerializer_OutputsSorted_Idempotent()
    {
        if (!SutAvailable) { Assert.True(true, "SUT not available — skipped"); return; }

        using var loader = new MetadataLoader(SutRoot!);
        var types = loader.LoadTypes(new[] { "HmEG.dll" }).ToList();
        var candidates = CandidateFinder.Find(types);

        var tmp1 = Path.Combine(Path.GetTempPath(), "eb-cand-1-" + Guid.NewGuid().ToString("N") + ".json");
        var tmp2 = Path.Combine(Path.GetTempPath(), "eb-cand-2-" + Guid.NewGuid().ToString("N") + ".json");
        try
        {
            CatalogWriter.WriteCandidates(tmp1, candidates);
            CatalogWriter.WriteCandidates(tmp2, candidates);
            Assert.Equal(File.ReadAllBytes(tmp1), File.ReadAllBytes(tmp2));
        }
        finally
        {
            File.Delete(tmp1);
            File.Delete(tmp2);
        }
    }

    [Fact]
    public void HmEgSnapshot_DefaultInstance_ThrowsNotImplemented()
    {
        var s = new HmEgSnapshot();
        Assert.Throws<NotImplementedException>(() => _ = s.SelectedObjectIds);
        Assert.Throws<NotImplementedException>(() => _ = s.Camera);
        Assert.Throws<NotImplementedException>(() => _ = s.Scene);
        Assert.Throws<NotImplementedException>(() => _ = s.IsRenderComplete);
    }

    [Fact]
    public void CandidateCategories_AllFourPresent()
    {
        if (!SutAvailable) { Assert.True(true, "SUT not available — skipped"); return; }

        using var loader = new MetadataLoader(SutRoot!);
        var types = loader.LoadTypes(TargetAssemblies).ToList();
        var candidates = CandidateFinder.Find(types);

        foreach (var cat in new[] { "select", "camera", "scene", "render" })
        {
            Assert.True(candidates.Any(c => c.Category == cat), $"category '{cat}' missing");
        }
    }

    [Fact]
    public void HmEgSnapshot_Constants_MatchCatalog()
    {
        if (!SutAvailable) { Assert.True(true, "SUT not available — skipped"); return; }

        using var loader = new MetadataLoader(SutRoot!);
        var types = loader.LoadTypes(TargetAssemblies).ToList();
        var candidates = CandidateFinder.Find(types);

        // HmEgAssemblyHint ("HmEG") should be a prefix of at least one loaded assembly.
        var asmNames = types.Select(t => t.Assembly.GetName().Name ?? "").Distinct().ToList();
        Assert.Contains(asmNames, a => a.StartsWith(HmEgSnapshot.HmEgAssemblyHint, StringComparison.Ordinal));

        // EditorManagerTypeHint ("HmEGAppManager") should appear in at least one candidate TypeName OR type entry.
        var appearsInCandidates = candidates.Any(c =>
            c.TypeName.Contains(HmEgSnapshot.EditorManagerTypeHint, StringComparison.Ordinal));
        var appearsInTypes = types.Any(t =>
            (t.FullName ?? t.Name).Contains(HmEgSnapshot.EditorManagerTypeHint, StringComparison.Ordinal) ||
            (t.Assembly.GetName().Name ?? "").Contains(HmEgSnapshot.EditorManagerTypeHint, StringComparison.Ordinal));
        Assert.True(appearsInCandidates || appearsInTypes,
            $"EditorManagerTypeHint '{HmEgSnapshot.EditorManagerTypeHint}' not found in catalog");
    }
}