AssetRipper_AssetRipper/Source/AssetRipper.Processing/Scenes/SceneHelpers.cs

using AssetRipper.Assets;
using AssetRipper.Assets.Collections;
using AssetRipper.SourceGenerated.Classes.ClassID_1;
using AssetRipper.SourceGenerated.Classes.ClassID_1001;
using AssetRipper.SourceGenerated.Classes.ClassID_114;
using AssetRipper.SourceGenerated.Classes.ClassID_141;
using AssetRipper.SourceGenerated.Classes.ClassID_2;
using AssetRipper.SourceGenerated.Classes.ClassID_3;
using AssetRipper.SourceGenerated.Extensions;
using System.Text.RegularExpressions;

namespace AssetRipper.Processing.Scenes
{
	public static class SceneHelpers
	{
		private const string AssetsName = "Assets/";
		private const string LevelName = "level";
		private const string MainSceneName = "maindata";

		private static readonly Regex s_sceneNameFormat = new Regex($"^{LevelName}(0|[1-9][0-9]*)$");

		public static int FileNameToSceneIndex(string name, UnityVersion version)
		{
			if (HasMainData(version))
			{
				if (name == MainSceneName)
				{
					return 0;
				}

				return int.Parse(name.AsSpan(LevelName.Length)) + 1;
			}
			else
			{
				return int.Parse(name.AsSpan(LevelName.Length));
			}
		}

		/// <summary>
		/// Less than 5.3.0
		/// </summary>
		public static bool HasMainData(UnityVersion version) => version.LessThan(5, 3);

		/// <summary>
		/// GameObjects, Classes inheriting from LevelGameManager, MonoBehaviours with GameObjects, Components, and PrefabInstances
		/// </summary>
		public static bool IsSceneCompatible(IUnityObjectBase asset)
		{
			return asset switch
			{
				IGameObject => true,
				ILevelGameManager => true,
				IMonoBehaviour monoBeh => monoBeh.IsComponentOnGameObject(),
				IComponent => true,
				IPrefabInstance => true,
				_ => false,
			};
		}

		public static string SceneIndexToFileName(int index, UnityVersion version)
		{
			if (HasMainData(version))
			{
				if (index == 0)
				{
					return MainSceneName;
				}
				return $"{LevelName}{index - 1}";
			}
			return $"{LevelName}{index}";
		}

		public static bool TryGetScenePath(AssetCollection collection, [NotNullWhen(true)] IBuildSettings? buildSettings, [NotNullWhen(true)] out string? result)
		{
			if (buildSettings is not null && IsSceneName(collection.Name))
			{
				int index = FileNameToSceneIndex(collection.Name, collection.Version);
				if (index >= buildSettings.Scenes.Count)
				{
					//This can happen in the following situation:
					//1. A game is built with N scenes and published to a distribution platform.
					//2. One of the scenes is removed from the project, for whatever reason.
					//3. The game is built again, with the new scene list.
					//4. When updating the game, the developer forgets to delete the Nth scene file.
					//5. Now, there are N-1 scenes in the BuildSettings, but N scene files for AssetRipper to find.
					result = null;
					return false;
				}
				string scenePath = buildSettings.Scenes[index].String;
				if (scenePath.StartsWith(AssetsName, StringComparison.Ordinal))
				{
					string extension = Path.GetExtension(scenePath);
					result = scenePath[..^extension.Length];
					return true;
				}
				else if (Path.IsPathRooted(scenePath))
				{
					// pull/uTiny 617
					// NOTE: absolute project path may contain Assets/ in its name so in this case we get incorrect scene path, but there is no way to bypass this issue
					int assetIndex = scenePath.IndexOf(AssetsName);
					string extension = Path.GetExtension(scenePath);
					result = scenePath.Substring(assetIndex, scenePath.Length - assetIndex - extension.Length);
					return true;
				}
				else if (scenePath.Length == 0)
				{
					// If a game is built without included scenes, Unity creates one with empty name.
					result = null;
					return false;
				}
				else
				{
					result = Path.Join("Assets", "Scenes", scenePath);
					return true;
				}
			}
			result = null;
			return false;
		}

		public static bool IsSceneDuplicate(int sceneIndex, IBuildSettings? buildSettings)
		{
			if (buildSettings == null)
			{
				return false;
			}

			string sceneName = buildSettings.Scenes[sceneIndex].String;
			for (int i = 0; i < buildSettings.Scenes.Count; i++)
			{
				if (buildSettings.Scenes[i] == sceneName)
				{
					if (i != sceneIndex)
					{
						return true;
					}
				}
			}
			return false;
		}

		public static bool IsSceneName(string name) => name == MainSceneName || s_sceneNameFormat.IsMatch(name);
	}
}