AssetRipper_AssetRipper/Source/AssetRipper.Import/Structure/GameInitializer.EngineResourceInjector.cs

using AssetRipper.Assets;
using AssetRipper.Assets.Bundles;
using AssetRipper.Assets.Collections;
using AssetRipper.Assets.Metadata;
using AssetRipper.IO.Files;
using AssetRipper.IO.Files.SerializedFiles;
using AssetRipper.IO.Files.Utils;
using AssetRipper.Mining.PredefinedAssets;
using AssetRipper.SourceGenerated;
using AssetRipper.Tpk;
using AssetRipper.Tpk.EngineAssets;
using Object = AssetRipper.Mining.PredefinedAssets.Object;

namespace AssetRipper.Import.Structure;

internal sealed partial record class GameInitializer
{
	private static class EngineResourceInjector
	{
		private sealed class InjectedEngineCollection : VirtualAssetCollection
		{
			public InjectedEngineCollection(string name, UnityVersion version, InjectedEngineBundle bundle) : base(bundle)
			{
				Name = name;
				Version = version;
				Platform = BuildTarget.NoTarget;
				Flags = TransferInstructionFlags.SerializeGameRelease | TransferInstructionFlags.IsBuiltinResourcesFile;
			}

			public void AddAssets(Dictionary<long, Object> assets)
			{
				foreach ((long pathID, Object @object) in assets)
				{
					IUnityObjectBase asset = AssetFactory.Create(new AssetInfo(this, pathID, @object.TypeID));
					if (asset is INamed named && @object is NamedObject namedObject)
					{
						named.Name = namedObject.Name;
					}
					AddAsset(asset);
				}
			}
		}

		private sealed class InjectedEngineBundle : VirtualBundle<InjectedEngineCollection>
		{
			public override string Name => "Generated Engine Collections";
		}

		public static void InjectEngineFilesIfNecessary(GameBundle gameBundle, UnityVersion targetVersion)
		{
			bool injectDefaultResources = gameBundle.ResolveCollection(FilenameUtils.DefaultResourceName1) is null;
			bool injectExtraResources = gameBundle.ResolveCollection(FilenameUtils.BuiltinExtraName2) is null;
			if (!injectDefaultResources && !injectExtraResources)
			{
				return;
			}

			if (targetVersion == default)
			{
				targetVersion = gameBundle.GetMaxUnityVersion();
			}

			InjectedEngineBundle bundle = new();
			gameBundle.AddBundle(bundle);

			EngineResourceData data = GetData(targetVersion);
			if (injectDefaultResources)
			{
				InjectedEngineCollection collection = new(FilenameUtils.DefaultResourceName1, targetVersion, bundle);
				collection.AddAssets(data.DefaultResources);
			}
			if (injectExtraResources)
			{
				InjectedEngineCollection collection = new(FilenameUtils.BuiltinExtraName2, targetVersion, bundle);
				collection.AddAssets(data.ExtraResources);
			}
		}

		private static EngineResourceData GetData(UnityVersion version)
		{
			TpkFile tpk = TpkFile.FromStream(EngineAssetsTpk.GetStream());
			TpkEngineAssetsBlob blob = (TpkEngineAssetsBlob)tpk.GetDataBlob();
			if (blob.Data.Count == 0)
			{
				return new EngineResourceData();
			}

			int index;
			if (version <= blob.Data[0].Key)
			{
				index = 0;
			}
			else
			{
				index = blob.Data.Count - 1;
				for (int i = 1; i < blob.Data.Count; i++)
				{
					if (version <= blob.Data[i].Key)
					{
						index = i - 1;
						break;
					}
				}
			}

			string json = blob.Data[index].Value;
			return EngineResourceData.FromJson(json);
		}
	}
}