using System;
using System.Runtime.CompilerServices;

using RobocraftX.Character;
using RobocraftX.Character.Movement;
using RobocraftX.Common.Players;
using RobocraftX.Common.Input;
using RobocraftX.CR.MachineEditing.BoxSelect;
using RobocraftX.Physics;
using RobocraftX.Blocks.Ghost;
using RobocraftX.Common;
using RobocraftX.Multiplayer;
using RobocraftX.SimulationModeState;
using Svelto.ECS;
using Techblox.Camera;
using Unity.Mathematics;
using Svelto.ECS.DataStructures;
using Techblox.BuildingDrone;
using Techblox.Character;

using TechbloxModdingAPI.Engines;
using TechbloxModdingAPI.Input;
using TechbloxModdingAPI.Utility;

namespace TechbloxModdingAPI.Players
{
	internal class PlayerEngine : IFunEngine
	{
		public string Name { get; } = "TechbloxModdingAPIPlayerGameEngine";

		public EntitiesDB entitiesDB { set; private get; }

		public bool isRemovable => false;

		public IEntityFunctions Functions { get; set; }

		private bool isReady = false;

		public void Dispose()
		{
			isReady = false;
		}

		public void Ready()
		{
			isReady = true;
		}

        public uint GetLocalPlayer()
		{
			if (!isReady) return uint.MaxValue;
			var (localPlayers, count) = entitiesDB.QueryEntities<PlayerIDStruct>(PlayersExclusiveGroups.LocalPlayers);
			if (count > 0)
			{
				return localPlayers[0].ID.entityID;
			}
			return uint.MaxValue;
		}

        public uint GetRemotePlayer()
		{
			if (!isReady) return uint.MaxValue;
			var (localPlayers, count) = entitiesDB.QueryEntities<PlayerIDStruct>(PlayersExclusiveGroups.RemotePlayers);
            if (count > 0)
            {
                return localPlayers[0].ID.entityID;
            }
			return uint.MaxValue;
		}

        public long GetAllPlayerCount()
		{
			if (entitiesDB == null) return 0;
			long count = 0;
			foreach (ExclusiveGroupStruct eg in PlayersExclusiveGroups.AllPlayers)
			{
				count += entitiesDB.Count<PlayerIDStruct>(eg);
			}
			return count;
		}

        public long GetLocalPlayerCount()
		{
			if (entitiesDB == null) return 0;
			return entitiesDB.Count<PlayerIDStruct>(PlayersExclusiveGroups.LocalPlayers);
		}

		public long GetRemotePlayerCount()
        {
			if (entitiesDB == null) return 0;
            return entitiesDB.Count<PlayerIDStruct>(PlayersExclusiveGroups.RemotePlayers);
        }

        public bool ExistsById(uint playerId)
		{
			if (entitiesDB == null) return false;
			return entitiesDB.Exists<PlayerIDStruct>(playerId, PlayersExclusiveGroups.LocalPlayers)
			       || entitiesDB.Exists<PlayerIDStruct>(playerId, PlayersExclusiveGroups.RemotePlayers);
		}

		public bool SetLocation(uint playerId, float3 location, bool exitSeat = true)
		{
			if (entitiesDB == null) return false;
			var rbesOpt = GetCharacterStruct<RigidBodyEntityStruct>(playerId, out var group);
			if (!rbesOpt)
				return false;
			if (group == CharacterExclusiveGroups.InPilotSeatGroup && exitSeat)
			{
				ExitSeat(playerId);
			}
			rbesOpt.Get().position = location;
			return true;
		}

		public bool IsDead(uint playerId)
		{
			if (entitiesDB == null) return true;
			return entitiesDB.Exists<RigidBodyEntityStruct>(playerId, CharacterExclusiveGroups.DeadGroup);
		}

        // reusable methods

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public OptionalRef<T> GetCharacterStruct<T>(uint playerId) where T : unmanaged, IEntityComponent =>
	        GetCharacterStruct<T>(playerId, out _);

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
		public OptionalRef<T> GetCharacterStruct<T>(uint playerId, out ExclusiveGroupStruct group) where T : unmanaged, IEntityComponent
		{
			group = default;
			if (GameState.IsBuildMode())
				return entitiesDB.QueryEntityOptional<T>(new EGID(playerId, LocalBuildingDrone.BuildGroup));

			var characterGroups = CharacterExclusiveGroups.AllCharacters;
			for (int i = 0; i < characterGroups.count; i++)
			{
				EGID egid = new EGID(playerId, characterGroups[i]);
				var opt = entitiesDB.QueryEntityOptional<T>(egid);
				if (opt.Exists)
				{
					group = characterGroups[i];
					return opt;
				}
			}

			return new OptionalRef<T>();
		}

		[MethodImpl(MethodImplOptions.AggressiveInlining)]
        public OptionalRef<T> GetPlayerStruct<T>(uint playerId, PlayerType type) where T : unmanaged, IEntityComponent
        {
            var playerGroup =  type == PlayerType.Local ? PlayersExclusiveGroups.LocalPlayers : PlayersExclusiveGroups.RemotePlayers;
            EGID egid = new EGID(playerId, playerGroup);
            return entitiesDB.QueryEntityOptional<T>(egid);
        }

        public OptionalRef<T> GetCameraStruct<T>(uint playerId) where T : unmanaged, IEntityComponent
        {
	        return entitiesDB.QueryEntityOptional<T>(new EGID(playerId, CameraExclusiveGroups.PhysicCameraGroup));
        }

        public EGID GetThingLookedAt(uint playerId, float maxDistance = -1f)
        {
	        var opt = GetCameraStruct<PhysicCameraRayCastEntityStruct>(playerId);
	        if (!opt) return default;
	        PhysicCameraRayCastEntityStruct rayCast = opt;
	        EGID physicCameraEgid = new EGID(playerId, CameraExclusiveGroups.PhysicCameraGroup);
	        float distance = maxDistance < 0
		        ? GhostBlockUtils.GetBuildInteractionDistance(entitiesDB, rayCast, physicCameraEgid,
			        GhostBlockUtils.GhostCastMethod.GhostCastProportionalToBlockSize)
		        : maxDistance;
	        if (rayCast.hit && rayCast.distance <= distance)
		        return rayCast.hitEgid; //May be EGID.Empty (default)

	        return default;
        }

        public unsafe Block[] GetSelectedBlocks(uint playerid)
        {
	        if (!entitiesDB.Exists<BoxSelectStateEntityStruct>(playerid,
		        BoxSelectExclusiveGroups.BoxSelectVolumeExclusiveGroup))
		        return Array.Empty<Block>();
	        var state = entitiesDB.QueryEntity<BoxSelectStateEntityStruct>(playerid,
		        BoxSelectExclusiveGroups.BoxSelectVolumeExclusiveGroup);
	        var blocks = entitiesDB.QueryEntity<SelectedBlocksStruct>(playerid,
		        BoxSelectExclusiveGroups.BoxSelectVolumeExclusiveGroup);
	        if (!state.active) return Array.Empty<Block>();
	        var pointer = (EGID*) blocks.selectedBlocks.ToPointer();
	        var ret = new Block[blocks.count];
	        for (int j = 0; j < blocks.count; j++)
	        {
		        var egid = pointer[j];
		        ret[j] = Block.New(egid);
	        }

	        return ret;
        }

        public void EnterSeat(uint playerId, EGID seatId)
        {
	        if (!TimeRunningModeUtil.IsTimeRunningMode(entitiesDB))
		        return;
	        /*PilotSeatGroupUtils.SwapTagTo<OCCUPIED_TAG>(Functions, seatId);
	        var opt = GetCharacterStruct<CharacterPilotSeatEntityStruct>(playerId, out var group);
	        if (!opt) return; - TODO: This is server code and mods run in client code atm. We can only send inputs even in singleplayer as it is.
	        ref CharacterPilotSeatEntityStruct charSeat = ref opt.Get();
	        var charId = new EGID(playerId, group);
	        charSeat.pilotSeatEntity = entitiesDB.GetEntityReference(seatId);
	        charSeat.entryPositionOffset =
		        entitiesDB.QueryEntity<PositionEntityStruct>(charId).position -
		        entitiesDB.QueryEntity<PositionEntityStruct>(seatId).position;
	        ref var seat = ref entitiesDB.QueryEntity<PilotSeatEntityStruct>(seatId);
	        seat.occupyingCharacter = entitiesDB.GetEntityReference(charId);
	        charSeat.followCam = entitiesDB.QueryEntity<SeatFollowCamComponent>(seatId).followCam;
	        Functions.SwapEntityGroup<CharacterEntityDescriptor>(charId, CharacterExclusiveGroups.InPilotSeatGroup);*/
        }

        public void ExitSeat(uint playerId)
        {
	        if (!TimeRunningModeUtil.IsTimeRunningMode(entitiesDB))
		        return;
	        /*EGID egid = new EGID(playerId, CharacterExclusiveGroups.InPilotSeatGroup);
	        var opt = entitiesDB.QueryEntityOptional<CharacterPilotSeatEntityStruct>(egid);
	        if (!opt) return;
	        opt.Get().instantExit = true;
	        entitiesDB.PublishEntityChange<CharacterPilotSeatEntityStruct>(egid);*/
        }

        public bool SpawnMachine(uint playerId)
        {
	        if (!TimeRunningModeUtil.IsTimeRunningMode(entitiesDB))
		        return false;
	        EGID egid = new EGID(playerId, CharacterExclusiveGroups.MachineSpawningGroup);
	        if (!entitiesDB.Exists<CharacterTagEntityStruct>(egid))
		        return false;
	        if (entitiesDB.QueryEntity<CharacterMachineSpawningValidityComponent>(egid).isMachinePlacementInvalid)
	        {
		        Logging.MetaDebugLog("Machine placement invalid");
		        return false;
	        }
	        //Functions.SwapEntityGroup<CharacterEntityDescriptor>(egid, CharacterExclusiveGroups.OnFootGroup);
	        FakeInput.ActionInput(playerId, primary: true);
	        return true;
        }

        public bool DespawnMachine(uint playerId)
        {
	        if (!TimeRunningModeUtil.IsTimeRunningMode(entitiesDB))
		        return false;
	        GetCharacterStruct<CharacterTagEntityStruct>(playerId, out var group);
	        if (group.isInvalid)
		        return false;
		    EGID egid = new EGID(playerId, group);
	        if (!entitiesDB.Exists<CharacterTagEntityStruct>(egid))
		        return false;
	        Functions.SwapEntityGroup<CharacterEntityDescriptor>(egid, CharacterExclusiveGroups.MachineSpawningGroup);
	        return true;
        }

        public uint GetPing()
        {
	        return entitiesDB
		        .QueryUniqueEntity<NetworkStatsEntityStruct>(MultiplayerExclusiveGroups.MultiplayerStateGroup)
		        .networkStats.PingMs;
        }

        public Block GetGhostBlock(uint playerId)
        {
	        var egid = new EGID(playerId, GHOST_BLOCKS_ENABLED.Group);
	        return entitiesDB.Exists<DBEntityStruct>(egid) ? Block.New(egid) : null;
        }
	}
}