// Copyright (c) 2023 bradson
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/.

using Mono.Cecil;
using Mono.Cecil.Cil;
using PerformanceFish.Prepatching;
using RimWorld.Planet;

namespace PerformanceFish.Planet;

public sealed class WorldObjectsOptimization : ClassWithFishPrepatches
{
	public sealed class WorldObjectsHolderTickPatch : FishPrepatch
	{
		public override bool DefaultState => true;

		private static List<WorldObject>? _cachedWorldObjectsReference;
		private static List<WorldObject>? _cachedSnapshotReference;
		private static int _cachedSnapshotVersion = -2;

		public override string? Description { get; }
			= "Reuses the world-object tick snapshot until the source list changes. Every object still receives DoTick.";

		public override MethodBase TargetMethodBase { get; }
			= AccessTools.Method(typeof(WorldObjectsHolder), nameof(WorldObjectsHolder.WorldObjectsHolderTick));

		public override void Transpiler(ILProcessor ilProcessor, ModuleDefinition module)
			=> ilProcessor.ReplaceBodyWith(WorldObjectsHolderTick);

		public static void WorldObjectsHolderTick(WorldObjectsHolder instance)
		{
			if (CacheDirty(instance))
				UpdateCache(instance);

			var worldObjects = WorldObjectsHolder.tmpWorldObjects;
			for (var i = 0; i < worldObjects.Count; i++)
#if V1_6
				worldObjects[i].DoTick();
#else
				worldObjects[i].Tick();
#endif
		}

		public static void UpdateCache(WorldObjectsHolder instance)
		{
			var instanceWorldObjects = instance.worldObjects;
			var snapshot = WorldObjectsHolder.tmpWorldObjects;
			snapshot.Clear();
			snapshot.AddRange(instanceWorldObjects);

			CachedWorldObjectsVersion = instanceWorldObjects._version;
			_cachedWorldObjectsReference = instanceWorldObjects;
			_cachedSnapshotReference = snapshot;
			_cachedSnapshotVersion = snapshot._version;
		}

		public static int
			CachedWorldObjectsVersion = -2,
			CachedMapsVersion = -2;

		// Retained for mods that called the old whitelist API. The snapshot no longer skips any ticks.
		public static void AddCompToWhiteList(Type compType) => SetDirty();
		public static void AddWorldObjectToWhiteList(Type worldObjectType) => SetDirty();

		public static bool CacheDirty(WorldObjectsHolder instance)
		{
			var source = instance.worldObjects;
			var snapshot = WorldObjectsHolder.tmpWorldObjects;
			return !ReferenceEquals(_cachedWorldObjectsReference, source)
				|| CachedWorldObjectsVersion != source._version
				|| !ReferenceEquals(_cachedSnapshotReference, snapshot)
				|| _cachedSnapshotVersion != snapshot._version
				|| snapshot.Count != source.Count;
		}

		public static void SetDirty() => CachedWorldObjectsVersion = CachedMapsVersion = -2;

		static WorldObjectsHolderTickPatch()
		{
			Cache.Utility.Cleared += SetDirty;
		}
	}

	public sealed class ExpandingIconCaching : FishPrepatch
	{
		public override string? Description { get; }
			= "Caches icons that get displayed for world objects like settlements on the planet view and adds various "
			+ "safety checks to better catch and log errors in case of missing icons";

		public override MethodBase TargetMethodBase { get; }
			= AccessTools.DeclaredPropertyGetter(typeof(WorldObject), nameof(WorldObject.ExpandingIcon));

		public override void Transpiler(ILProcessor ilProcessor, ModuleDefinition module)
			=> ilProcessor.ReplaceBodyWith(ReplacementBody);

		public static Texture2D ReplacementBody(WorldObject __instance)
			=> __instance.ExpandingIconCache() ?? InitializeExpandingIcon(__instance);

		[MethodImpl(MethodImplOptions.NoInlining)]
		public static Texture2D InitializeExpandingIcon(WorldObject? worldObject)
		{
			if (worldObject is null)
				return BaseContent.BadTex;
			
			var def = worldObject.def;
			ref var cache = ref worldObject.ExpandingIconCache();
			
			try
			{
				cache = def?.ExpandingIconTexture;

				if (cache != null)
					return cache;

				var material = worldObject.Material;
				if (material != null)
					cache = material.mainTexture as Texture2D;

				if (cache == null)
				{
					cache = BaseContent.BadTex;
					Log.Error($"No expanding icon found for '{worldObject.ToStringSafe()}' of def '{
						def?.ToStringSafe()}' from mod '{def?.modContentPack?.Name}'. Assigning default.");
				}
				
				return cache;
			}
			catch (Exception ex)
			{
				Log.Error($"Exception while initializing icon for '{worldObject.ToStringSafe()}' of def '{
					def?.ToStringSafe()}' from mod '{def?.modContentPack?.Name}':\n{ex}");
				
				return cache = BaseContent.BadTex;
			}
		}
	}
	
	public sealed class ExpandingIconColorCaching : FishPrepatch
	{
		public override string? Description { get; }
			= "Caches colors of icons that get displayed for world objects like settlements on the planet view and "
			+ "adds various safety checks to better catch and log errors in case of missing data";

		public override MethodBase TargetMethodBase { get; }
			= AccessTools.DeclaredPropertyGetter(typeof(WorldObject), nameof(WorldObject.ExpandingIconColor));

		public override void Transpiler(ILProcessor ilProcessor, ModuleDefinition module)
			=> ilProcessor.ReplaceBodyWith(ReplacementBody);

		public static Color ReplacementBody(WorldObject __instance)
			=> __instance.ExpandingIconColorCache() ?? InitializeExpandingIconColor(__instance);

		[MethodImpl(MethodImplOptions.NoInlining)]
		public static Color InitializeExpandingIconColor(WorldObject? worldObject)
		{
			if (worldObject is null)
				return Color.white;
			
			var def = worldObject.def;
			ref var cache = ref worldObject.ExpandingIconColorCache();
			
			try
			{
				cache = def?.expandingIconColor;

				if (cache != null)
					return cache.GetValueOrDefault();

				var material = worldObject.Material;
				if (material != null)
					cache = material.color;

				if (cache == null)
				{
					cache = Color.white;
					Log.Error($"No expanding icon color found for '{worldObject.ToStringSafe()}' of def '{
						def?.ToStringSafe()}' from mod '{def?.modContentPack?.Name}'. Assigning default.");
				}
				
				return cache.GetValueOrDefault();
			}
			catch (Exception ex)
			{
				Log.Error($"Exception while initializing icon color for '{worldObject.ToStringSafe()}' of def '{
					def?.ToStringSafe()}' from mod '{def?.modContentPack?.Name}':\n{ex}");
				
				return (cache = Color.white).GetValueOrDefault();
			}
		}
	}
}