using System;
using System.Reflection;

using DataLoader;
using HarmonyLib;
using RobocraftX.Blocks;
using RobocraftX.Blocks.Scaling;
using RobocraftX.Character;
using RobocraftX.Common;
using RobocraftX.CR.MachineEditing;
using Svelto.ECS;
using Svelto.ECS.EntityStructs;
using Unity.Mathematics;
using UnityEngine;

using GamecraftModdingAPI.Utility;
using GamecraftModdingAPI.Engines;
using GamecraftModdingAPI.Players;
using RobocraftX.Rendering.GPUI;

namespace GamecraftModdingAPI.Blocks
{
    /// <summary>
    /// Engine which executes block placement actions
    /// </summary>
    public class PlacementEngine : IApiEngine
    {
        public bool IsInGame;

        public void Dispose()
        {
            IsInGame = false;
        }

        public void Ready()
        {
            IsInGame = true;
        }

        public EntitiesDB entitiesDB { get; set; }
        private static BlockEntityFactory _blockEntityFactory; //Injected from PlaceSingleBlockEngine

        public EGID PlaceBlock(BlockIDs block, BlockColor color, BlockMaterial materialId, float3 position, int uscale,
            float3 scale, Player player, float3 rotation, out EntityInitializer initializer)
        { //It appears that only the non-uniform scale has any visible effect, but if that's not given here it will be set to the uniform one
            if (color.Darkness > 9)
                throw new Exception("That is too dark. Make sure to use 0-9 as darkness. (0 is default.)");
            initializer = BuildBlock((ushort) block, color.Index, (byte) materialId, position, uscale, scale, rotation,
                (player ?? new Player(PlayerType.Local)).Id);
            return initializer.EGID;
        }

        private EntityInitializer BuildBlock(ushort block, byte color, byte materialId, float3 position, int uscale, float3 scale, float3 rot, uint playerId)
        {
            if (_blockEntityFactory == null)
                throw new BlockException("The factory is null.");
            if (uscale < 1)
                throw new BlockException("Scale needs to be at least 1");
            if (scale.x < 4e-5) scale.x = uscale;
            if (scale.y < 4e-5) scale.y = uscale;
            if (scale.z < 4e-5) scale.z = uscale;
            uint resourceId = (uint) PrefabsID.GenerateResourceID(0, block);
            if (!PrefabsID.PrefabIDByResourceIDMap.ContainsKey(resourceId))
                throw new BlockException("Block with ID " + block + " not found!");
            //RobocraftX.CR.MachineEditing.PlaceSingleBlockEngine
            ScalingEntityStruct scaling = new ScalingEntityStruct {scale = scale};
            Quaternion rotQ = Quaternion.Euler(rot);
            RotationEntityStruct rotation = new RotationEntityStruct {rotation = rotQ};
            GridRotationStruct gridRotation = new GridRotationStruct
                {position = position, rotation = rotQ};
            DBEntityStruct dbEntity = new DBEntityStruct {DBID = block};
            BlockPlacementScaleEntityStruct placementScale = new BlockPlacementScaleEntityStruct
            {
                blockPlacementHeight = uscale, blockPlacementWidth = uscale, desiredScaleFactor = uscale
            };

            EntityInitializer structInitializer = _blockEntityFactory.Build(CommonExclusiveGroups.nextBlockEntityID, block); //The ghost block index is only used for triggers
            if (color != byte.MaxValue)
                structInitializer.Init(new ColourParameterEntityStruct
                {
                    indexInPalette = color,
                    hasNetworkChange = true
                });
            if (materialId != byte.MaxValue)
                structInitializer.Init(new CubeMaterialStruct
                {
                    materialId = materialId
                });
            uint prefabId = PrefabsID.GetOrCreatePrefabID(block, 0, 0, false); //TODO
            structInitializer.Init(new GFXPrefabEntityStructGPUI(prefabId));
            structInitializer.Init(new PhysicsPrefabEntityStruct(prefabId));
            structInitializer.Init(dbEntity);
            structInitializer.Init(new PositionEntityStruct {position = position});
            structInitializer.Init(rotation);
            structInitializer.Init(scaling);
            structInitializer.Init(gridRotation);
            structInitializer.Init(new UniformBlockScaleEntityStruct
            {
                scaleFactor = placementScale.desiredScaleFactor
            });
            structInitializer.Init(new BlockPlacementInfoStruct()
            {
                loadedFromDisk = false,
                placedBy = playerId,
                triggerAutoWiring = false //TODO
            });

            /*structInitializer.Init(new CollisionFilterOverride
            {
                belongsTo = 32U,
                collidesWith = 239532U
            });*/

            EGID playerEGID = new EGID(playerId, CharacterExclusiveGroups.OnFootGroup);
            ref PickedBlockExtraDataStruct pickedBlock = ref entitiesDB.QueryEntity<PickedBlockExtraDataStruct>(playerEGID);
            pickedBlock.placedBlockEntityID = structInitializer.EGID;
            pickedBlock.placedBlockWasAPickedBlock = false;
            return structInitializer;
        }

        public string Name { get; } = "GamecraftModdingAPIPlacementGameEngine";

        public bool isRemovable => false;

        [HarmonyPatch]
        public class FactoryObtainerPatch
        {
            static void Postfix(BlockEntityFactory blockEntityFactory)
            {
                _blockEntityFactory = blockEntityFactory;
                Logging.MetaDebugLog("Block entity factory injected.");
            }

            static MethodBase TargetMethod(Harmony instance)
            {
                return AccessTools.TypeByName("RobocraftX.CR.MachineEditing.PlaceSingleBlockEngine").GetConstructors()[0];
            }
        }
    }
}