using System;
using System.Collections;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using Cysharp.Threading.Tasks;
using UnityEngine;

namespace BITKit.Sensors
{
	public class SensorQueue : MonoBehaviour
	{
		internal static readonly Dictionary<int,ISensor> Sensors=new();
		internal static readonly ConcurrentDictionary<int, float> LastDetectedTime = new();
		private static bool IsDirty;
		
		[SerializeField,ReadOnly] private int _position;
		
		private static int[] _keys;
		
		public static void Register(int id,ISensor sensor)
		{
			Sensors.Add(id,sensor);
			MarkDirty();
		}
		public static void UnRegister(int id)
		{
			Sensors.Remove(id);
			MarkDirty();
		}
		public static void MarkDirty()
		{
			IsDirty = true;
		}
		
		[SerializeField] private MonoBehaviour[] sensors;
		[SerializeReference,SubclassSelector] private ITicker ticker;

		private bool _isBusy;

		private void Start()
		{
			ticker.Add(OnTick);
			destroyCancellationToken.Register(Dispose);
		}
		private void Dispose()
		{
			ticker.Remove(OnTick);
		}
		private async void OnTick(float obj)
		{
			if (_isBusy) return;
			if (SensorGlobalSettings.Enabled is false) return;

			_isBusy = true;
			if(IsDirty)
			{
				_position = 0;
				_keys = Sensors.Where(IsEnabled).Select(x=>x.Key).ToArray();
				IsDirty = false;
				sensors = Sensors.Values.Where(IsEnabled).OfType<MonoBehaviour>().ToArray();
			}

			if (Sensors.Count is 0)
			{
				_isBusy = false;
				return;
			}

			var current = Sensors.ElementAt(_position++).Value;
			var currentUpdateTime = LastDetectedTime.GetOrAdd(current.Id,Time.time);
				await current.Execute(Time.time-currentUpdateTime);
				float UpdateValueFactory(int key, float old) => Time.time;
				LastDetectedTime.AddOrUpdate(current.Id,Time.time,UpdateValueFactory);
				
			if (destroyCancellationToken.IsCancellationRequested) {
				_isBusy = false;
				return;
			}
			
			_position %= Sensors.Count;
			_isBusy = false;
		}
		private bool IsEnabled(ISensor sensor)
		{
			return sensor.AutoUpdate;
		}
		private bool IsEnabled(KeyValuePair<int,ISensor> pair)
		{
			return pair.Value.AutoUpdate;
		}
	}

}