BUTR/Bannerlord.BLSE

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

namespace Bannerlord.LauncherEx.TPac;

internal static class TypedDataFactory
{
    private static readonly Dictionary<Guid, Type> guidToLoaderTypeMap = new();
    private static readonly Dictionary<Guid, ConstructorInfo> guidToLoaderConstructorMap = new();

    static TypedDataFactory()
    {
        RegisterType(typeof(TexturePixelData));
    }

    public static void RegisterType(Type typeClass)
    {
        var field = typeClass.GetField("TYPE_GUID", BindingFlags.Static | BindingFlags.Public) ?? throw new ArgumentException("Cannot find public static field \"TYPE_GUID\" from class " + typeClass.FullName);
        if (field.FieldType != typeof(Guid)) throw new ArgumentException("\"TYPE_GUID\" must be Guid");
        var guid = (Guid) field.GetValue(null);
        RegisterType(guid, typeClass);
    }

    public static void RegisterType(Guid typeGuid, Type typeClass)
    {
        if (!typeof(ExternalData).IsAssignableFrom(typeClass))
            throw new ArgumentException("Registered type must extend from ExternalData");

        var constructor = typeClass.GetConstructor(Type.EmptyTypes);
        if (constructor == null) throw new ArgumentException("Registered type must have a param-less constructor");

        var loaderType = typeof(ExternalLoader<>).MakeGenericType(typeClass);
        guidToLoaderTypeMap[typeGuid] = loaderType;
        guidToLoaderConstructorMap[typeGuid] = loaderType.GetConstructor(BindingFlags.Instance | BindingFlags.NonPublic, null, new[] { typeof(FileInfo) }, null);
    }

    public static bool CreateTypedLoader(Guid typeGuid, FileInfo file, out AbstractExternalLoader result)
    {
        AbstractExternalLoader? loader = null;
        var isFound = false;
        if (guidToLoaderTypeMap.ContainsKey(typeGuid))
        {
            var constructor = guidToLoaderConstructorMap[typeGuid];
            loader = (AbstractExternalLoader) constructor.Invoke(new object[] { file });
            isFound = true;
        }

        loader ??= new ExternalLoader<ExternalData>(file);

        loader.TypeGuid = typeGuid;
        result = loader;
        return isFound;
    }
}