using System;
using System.Collections.Generic;
using System.Linq;
using HarmonyLib;

using Gamecraft.ColourPalette;
using Gamecraft.Wires;
using RobocraftX.Blocks;
using RobocraftX.Common;
using RobocraftX.Physics;
using RobocraftX.Rendering;
using RobocraftX.Rendering.GPUI;
using Svelto.DataStructures;
using Svelto.ECS;
using Svelto.ECS.EntityStructs;
using Svelto.ECS.Experimental;
using Svelto.ECS.Hybrid;
using Techblox.BuildingDrone;
using Techblox.ObjectIDBlockServer;
using Unity.Mathematics;

using TechbloxModdingAPI.Engines;
using TechbloxModdingAPI.Utility;

namespace TechbloxModdingAPI.Blocks.Engines
{
	/// <summary>
	/// Engine for executing general block actions
	/// </summary>
	public partial class BlockEngine : IApiEngine
	{
		public string Name { get; } = "TechbloxModdingAPIBlockGameEngine";

		public EntitiesDB entitiesDB { set; private get; }

		public bool isRemovable => false;

		public void Dispose()
		{
		}

		public void Ready()
		{
		}

		public Block[] GetConnectedBlocks(EGID blockID)
		{
			if (!BlockExists(blockID)) return Array.Empty<Block>();
			Stack<EGID> cubeStack = new Stack<EGID>();
			FasterList<EGID> cubes = new FasterList<EGID>(10);
			var coll = entitiesDB.QueryEntities<GridConnectionsEntityStruct>();
			foreach (var ((ecoll, count), _) in coll)
			{
				for(int i = 0; i < count; i++)
				{
					ecoll[i].isProcessed = false;
				}
			}
			
			//TODO: GetConnectedCubesUtility
			ConnectedCubesUtility.TreeTraversal.GetConnectedCubes(entitiesDB, blockID, cubeStack, cubes,
				(in GridConnectionsEntityStruct _) => false);

			var ret = new Block[cubes.count];
			for (int i = 0; i < cubes.count; i++)
				ret[i] = Block.New(cubes[i]);
			return ret;
		}

		public float4 ConvertBlockColor(byte index) => index == byte.MaxValue
			? new float4(-1f, -1f, -1f, -1f)
			: entitiesDB.QueryEntity<PaletteEntryEntityStruct>(index,
				CommonExclusiveGroups.COLOUR_PALETTE_GROUP).Colour;

		public OptionalRef<T> GetBlockInfoOptional<T>(Block block) where T : unmanaged, IEntityComponent
		{
			return entitiesDB.QueryEntityOptional<T>(block);
		}

		public ref T GetBlockInfo<T>(Block block) where T : unmanaged, IEntityComponent
		{
			#if DEBUG
			if (!typeof(BlockTagEntityStruct).IsAssignableFrom(typeof(T)) && block.Exists && block.InitData.Valid)
				throw new ArgumentException("The block exists but the init data has not been removed!");
			#endif
			return ref entitiesDB.QueryEntityOrDefault<T>(block);
		}

		internal ref T GetBlockInfo<T>(EcsObjectBase obj) where T : unmanaged, IEntityComponent
		{
			return ref entitiesDB.QueryEntityOrDefault<T>(obj);
		}

		public ref T GetBlockInfoViewComponent<T>(Block block) where T : struct, IEntityViewComponent
		{
			return ref entitiesDB.QueryEntityOrDefault<T>(block);
		}

		internal object GetBlockInfo(Block block, Type type, string name)
		{
			var opt = AccessTools.Method(typeof(NativeApiExtensions), "QueryEntityOptional",
					new[] { typeof(EntitiesDB), typeof(EcsObjectBase), typeof(ExclusiveGroupStruct) }, new[] { type })
				.Invoke(null, new object[] { entitiesDB, block, null });
			var str = AccessTools.Property(opt.GetType(), "Value").GetValue(opt);
			return AccessTools.Field(str.GetType(), name).GetValue(str);
		}

		internal void SetBlockInfo(Block block, Type type, string name, object value)
		{
			var opt = AccessTools.Method(typeof(BlockEngine), "GetBlockInfoOptional", generics: new[] { type })
				.Invoke(this, new object[] { block });
			var prop = AccessTools.Property(opt.GetType(), "Value");
			var str = prop.GetValue(opt);
			AccessTools.Field(str.GetType(), name).SetValue(str, value);
			prop.SetValue(opt, str);
		}

		public void UpdateDisplayedBlock(EGID id)
		{
			if (!BlockExists(id)) return;
			var pos = entitiesDB.QueryEntity<PositionEntityStruct>(id);
			var rot = entitiesDB.QueryEntity<RotationEntityStruct>(id);
			var scale = entitiesDB.QueryEntity<ScalingEntityStruct>(id);
			var skew = entitiesDB.QueryEntity<SkewComponent>(id);
			entitiesDB.QueryEntity<RenderingDataStruct>(id).matrix =
				math.mul(float4x4.TRS(pos.position, rot.rotation, scale.scale), skew.skewMatrix);
			entitiesDB.PublishEntityChangeDelayed<GFXPrefabEntityStructGPUI>(id); // Signal a prefab change so it updates the render buffers
		}

		internal void UpdatePrefab(Block block, byte material, bool flipped)
		{
			var prefabAssetIDOpt = entitiesDB.QueryEntityOptional<PrefabAssetIDComponent>(block);
			uint prefabAssetID = prefabAssetIDOpt
				? prefabAssetIDOpt.Get().prefabAssetID
				: uint.MaxValue;
			if (prefabAssetID == uint.MaxValue)
			{
				if (entitiesDB.QueryEntityOptional<BlockTagEntityStruct>(block)) //The block exists
					throw new BlockException("Prefab asset ID not found for block " + block); //Set by the game
				return;
			}

			uint prefabId =
				PrefabsID.GetOrAddPrefabID((ushort) prefabAssetID, material, 1, flipped);
			entitiesDB.QueryEntityOrDefault<GFXPrefabEntityStructGPUI>(block).prefabID = prefabId;
			if (block.Exists)
			{
				entitiesDB.PublishEntityChangeDelayed<CubeMaterialStruct>(block.Id);
				entitiesDB.PublishEntityChangeDelayed<GFXPrefabEntityStructGPUI>(block.Id);

				ref BuildingActionComponent local =
					ref entitiesDB.QueryEntity<BuildingActionComponent>(BuildingDroneUtility
						.GetLocalBuildingDrone(entitiesDB).ToEGID(entitiesDB));
				local.buildAction = BuildAction.ChangeMaterial;
				local.targetPosition = block.Position;
				this.entitiesDB.PublishEntityChangeDelayed<BuildingActionComponent>(local.ID);
			}
			//Phyiscs prefab: prefabAssetID, set on block creation from the CubeListData
		}

		public void UpdateBlockColor(EGID id)
		{
			entitiesDB.PublishEntityChange<ColourParameterEntityStruct>(id);
		}

		public bool BlockExists(EGID blockID)
		{
			return entitiesDB.Exists<BlockTagEntityStruct>(blockID);
		}

		public SimBody[] GetSimBodiesFromID(byte id)
		{
			var ret = new FasterList<SimBody>(4);
			var (oids, tags, count) = entitiesDB.QueryEntities<ObjectIdEntityStruct, BlockTagEntityStruct>(ObjectIDBlockExclusiveGroups.OBJECT_ID_BLOCK_GROUP);
			EGIDMapper<GridConnectionsEntityStruct>? connections = null;
			for (int i = 0; i < count; i++)
			{
				if (oids[i].objectId != id) continue;
				var tag = tags[i];
				if (!connections.HasValue) //Would need reflection to get the group from the build group otherwise
					connections = entitiesDB.QueryMappedEntities<GridConnectionsEntityStruct>(tag.ID.groupID);
				var rid = connections.Value.Entity(tag.ID.entityID).machineRigidBodyId;
				foreach (var rb in ret)
				{
					if (rb.Id.entityID == rid)
						goto DUPLICATE; //Multiple Object Identifiers on one rigid body
				}

				ret.Add(new SimBody(rid));
				DUPLICATE: ;
			}
			
			return ret.ToArray();
		}

		public SimBody[] GetConnectedSimBodies(uint id)
		{
			var (joints, count) = entitiesDB.QueryEntities<JointEntityStruct>(MachineSimulationGroups.JOINTS_GROUP);
			var list = new FasterList<SimBody>(4);
			for (int i = 0; i < count; i++)
			{
				ref var joint = ref joints[i];
				if (joint.isBroken) continue;
				if (joint.connectedEntityA == id) list.Add(new SimBody(joint.connectedEntityB));
				else if (joint.connectedEntityB == id) list.Add(new SimBody(joint.connectedEntityA));
			}

			return list.ToArray();
		}

		public SimBody[] GetClusterBodies(uint cid)
		{
			var groups = entitiesDB.QueryEntities<GridConnectionsEntityStruct>();
			var bodies = new HashSet<uint>();
			foreach (var ((coll, count), _) in groups)
			{
				for (var index = 0; index < count; index++)
				{
					var conn = coll[index];
					if (conn.clusterId == cid)
						bodies.Add(conn.machineRigidBodyId);
				}
			}

			return bodies.Select(id => new SimBody(id, cid)).ToArray();
		}

		public EGID? FindBlockEGID(uint id)
		{
			var groups = entitiesDB.FindGroups<BlockTagEntityStruct>();
			foreach (ExclusiveGroupStruct group in groups)
			{
				if (entitiesDB.Exists<BlockTagEntityStruct>(id, group))
					return new EGID(id, group);
			}

			return null;
		}

		public Cluster GetCluster(uint sbid)
		{
			var groups = entitiesDB.QueryEntities<GridConnectionsEntityStruct>();
			foreach (var ((coll, count), _) in groups)
			{
				for (var index = 0; index < count; index++)
				{
					var conn = coll[index];
					//Static blocks don't have a cluster ID but the cluster destruction manager should have one
					if (conn.machineRigidBodyId == sbid && conn.clusterId != uint.MaxValue)
						return new Cluster(conn.clusterId);
				}
			}

			return null;
		}

		public Block[] GetBodyBlocks(uint sbid)
		{
			var groups = entitiesDB.FindGroups<GridConnectionsEntityStruct>();
			groups = new QueryGroups(groups).Except(CommonExclusiveGroups.DISABLED_JOINTS_IN_SIM_GROUP).Evaluate().result;
			var set = new HashSet<Block>();
			foreach (var ((coll, tags, count), _) in entitiesDB.QueryEntities<GridConnectionsEntityStruct, BlockTagEntityStruct>(groups))
			{
				for (var index = 0; index < count; index++)
				{
					var conn = coll[index];
					if (conn.machineRigidBodyId == sbid)
						set.Add(Block.New(tags[index].ID));
				}
			}

			return set.ToArray();
		}

		public ObjectID[] GetObjectIDsFromID(byte id)
		{
			if (!entitiesDB.HasAny<ObjectIDTweakableComponent>(ObjectIDBlockExclusiveGroups.OBJECT_ID_BLOCK_GROUP))
				return Array.Empty<ObjectID>();

			var ret = new FasterList<ObjectID>(4);
			var (oids, tags, count) = entitiesDB.QueryEntities<ObjectIDTweakableComponent, BlockTagEntityStruct>(ObjectIDBlockExclusiveGroups.OBJECT_ID_BLOCK_GROUP);
			for (var index = 0; index < count; index++)
			{
				if (oids[index].objectIDToTrigger == id)
					ret.Add(new ObjectID(tags[index].ID));
			}

			return ret.ToArray();
		}
	}
}