BUTR/Bannerlord.BLSE

using Bannerlord.BUTR.Shared.Extensions;
using Bannerlord.LauncherEx.Extensions;

using HarmonyLib;
using HarmonyLib.BUTR.Extensions;

using System;
using System.Collections.Generic;
using System.IO;

using TaleWorlds.TwoDimension.Standalone;

namespace Bannerlord.LauncherEx.ResourceManagers;

internal static class GraphicsContextManager
{
    public static WeakReference<GraphicsContext?> Instance { get; private set; } = default!;

    private static readonly Dictionary<string, OpenGLTexture> Textures = new();
    private static readonly Dictionary<string, Func<OpenGLTexture>> DeferredInitialization = new();

    public static OpenGLTexture Create(string name, Stream stream)
    {
        var texture = new OpenGLTexture();
        if (texture.LoadFromStream(name, stream))
            return texture;

        var path = Path.GetTempFileName();
        using (var fs = File.OpenWrite(path))
            stream.CopyTo(fs);
        var openGLTexture = OpenGLTexture.FromFile(path);
        File.Delete(path);

        return openGLTexture;
    }
    private static OpenGLTexture CreateAssetTexture(string name, TPac.Texture assetTexture)
    {
        var texture = new OpenGLTexture();
        texture.LoadFromAssetTexture(name, assetTexture);
        return texture;
    }
    public static void Register(string name, Func<OpenGLTexture> func) => DeferredInitialization.Add(name, func);
    public static void CreateAndRegister(string name, Stream stream) => Register(name, () => Create(name, stream));
    public static void CreateAssetTextureAndRegister(string name, TPac.Texture texture) => Register(name, () => CreateAssetTexture(name, texture));

    public static void Clear()
    {
        Textures.Clear();
        DeferredInitialization.Clear();
        Instance.SetTarget(null);
    }

    internal static bool Enable(Harmony harmony)
    {
        var res1 = harmony.TryPatch(
            AccessTools2.DeclaredMethod(typeof(GraphicsContext), "GetTexture"),
            prefix: AccessTools2.DeclaredMethod(typeof(GraphicsContextManager), nameof(GetTexturePrefix)));
        if (!res1) return false;

        var res2 = harmony.TryPatch(
            AccessTools2.DeclaredMethod(typeof(GraphicsContext), "CreateContext"),
            postfix: AccessTools2.DeclaredMethod(typeof(GraphicsContextManager), nameof(CreateContextPostfix)));
        if (!res2) return false;

        return true;
    }

    private static bool GetTexturePrefix(string textureName, ref OpenGLTexture? __result)
    {
        if (!Textures.TryGetValue(textureName, out __result))
            return true;
        return false;
    }

    private static void CreateContextPostfix(GraphicsContext __instance)
    {
        Instance = new(__instance);

        foreach (var (name, func) in DeferredInitialization)
        {
            Textures[name] = func();
        }
    }

    private static IEnumerable<CodeInstruction> BlankTranspiler(IEnumerable<CodeInstruction> instructions) => instructions;
}