using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Threading;
using UnityEngine;

namespace UltimateWater.Internal
{
	public sealed class WaterAsynchronousTasks : MonoBehaviour
	{
		private static WaterAsynchronousTasks _Instance;

		private bool _Run;

		private readonly List<WaterTileSpectrum> _FFTSpectra = new List<WaterTileSpectrum>();

		private int _FFTSpectrumIndex;

		private float _FFTTimeStep = 0.2f;

		private readonly List<WaterSample> _Computations = new List<WaterSample>();

		private int _ComputationIndex;

		private Exception _ThreadException;

		public static WaterAsynchronousTasks Instance
		{
			get
			{
				if (_Instance == null)
				{
					_Instance = UnityEngine.Object.FindObjectOfType<WaterAsynchronousTasks>();
					if (_Instance == null)
					{
						_Instance = new GameObject("Ultimate Water Spectrum Sampler")
						{
							hideFlags = HideFlags.HideInHierarchy
						}.AddComponent<WaterAsynchronousTasks>();
					}
				}
				return _Instance;
			}
		}

		public static bool HasInstance => _Instance != null;

		public void AddWaterSampleComputations(WaterSample computation)
		{
			lock (_Computations)
			{
				_Computations.Add(computation);
			}
		}

		public void RemoveWaterSampleComputations(WaterSample computation)
		{
			lock (_Computations)
			{
				int num = _Computations.IndexOf(computation);
				if (num != -1)
				{
					if (num < _ComputationIndex)
					{
						_ComputationIndex--;
					}
					_Computations.RemoveAt(num);
				}
			}
		}

		public void AddFFTComputations(WaterTileSpectrum scale)
		{
			lock (_FFTSpectra)
			{
				_FFTSpectra.Add(scale);
			}
		}

		public void RemoveFFTComputations(WaterTileSpectrum scale)
		{
			lock (_FFTSpectra)
			{
				int num = _FFTSpectra.IndexOf(scale);
				if (num != -1)
				{
					if (num < _FFTSpectrumIndex)
					{
						_FFTSpectrumIndex--;
					}
					_FFTSpectra.RemoveAt(num);
				}
			}
		}

		private void Awake()
		{
			_Run = true;
			if (_Instance == null)
			{
				_Instance = this;
			}
			else if (_Instance != this)
			{
				base.gameObject.Destroy();
				return;
			}
			if (Application.isPlaying)
			{
				UnityEngine.Object.DontDestroyOnLoad(base.gameObject);
				for (int i = 0; i < WaterProjectSettings.Instance.PhysicsThreads; i++)
				{
					Thread thread = new Thread(RunSamplingTask);
					thread.Priority = WaterProjectSettings.Instance.PhysicsThreadsPriority;
					thread.Start();
				}
				Thread thread2 = new Thread(RunFFTTask);
				thread2.Priority = WaterProjectSettings.Instance.PhysicsThreadsPriority;
				thread2.Start();
			}
		}

		private void OnDisable()
		{
			_Run = false;
			if (_ThreadException != null)
			{
				UnityEngine.Debug.LogException(_ThreadException);
			}
		}

		private void RunSamplingTask()
		{
			try
			{
				while (_Run)
				{
					WaterSample waterSample = null;
					lock (_Computations)
					{
						if (_Computations.Count != 0)
						{
							if (_ComputationIndex >= _Computations.Count)
							{
								_ComputationIndex = 0;
							}
							waterSample = _Computations[_ComputationIndex++];
						}
					}
					if (waterSample == null)
					{
						Thread.Sleep(2);
						continue;
					}
					lock (waterSample)
					{
						waterSample.ComputationStep();
					}
				}
			}
			catch (Exception threadException)
			{
				_ThreadException = threadException;
			}
		}

		private void RunFFTTask()
		{
			try
			{
				CpuFFT cpuFFT = new CpuFFT();
				Stopwatch stopwatch = new Stopwatch();
				bool flag = false;
				while (_Run)
				{
					WaterTileSpectrum waterTileSpectrum = null;
					lock (_FFTSpectra)
					{
						if (_FFTSpectra.Count != 0)
						{
							if (_FFTSpectrumIndex >= _FFTSpectra.Count)
							{
								_FFTSpectrumIndex = 0;
							}
							if (_FFTSpectrumIndex == 0)
							{
								if ((float)stopwatch.ElapsedMilliseconds > _FFTTimeStep * 900f)
								{
									if (flag)
									{
										_FFTTimeStep += 0.05f;
									}
									else
									{
										flag = true;
									}
								}
								else
								{
									flag = false;
									if (_FFTTimeStep > 0.2f)
									{
										_FFTTimeStep -= 0.001f;
									}
								}
								stopwatch.Reset();
								stopwatch.Start();
							}
							waterTileSpectrum = _FFTSpectra[_FFTSpectrumIndex++];
						}
					}
					if (waterTileSpectrum == null)
					{
						stopwatch.Reset();
						Thread.Sleep(6);
						continue;
					}
					bool flag2 = false;
					SpectrumResolver spectrumResolver = waterTileSpectrum.WindWaves.SpectrumResolver;
					if (spectrumResolver == null)
					{
						continue;
					}
					int recentResultIndex = waterTileSpectrum.RecentResultIndex;
					int num = (recentResultIndex + 2) % waterTileSpectrum.ResultsTiming.Length;
					int num2 = (recentResultIndex + 1) % waterTileSpectrum.ResultsTiming.Length;
					float num3 = waterTileSpectrum.ResultsTiming[recentResultIndex];
					float num4 = waterTileSpectrum.ResultsTiming[num];
					float num5 = waterTileSpectrum.ResultsTiming[num2];
					float lastFrameTime = spectrumResolver.LastFrameTime;
					if (num4 <= lastFrameTime || num5 > lastFrameTime)
					{
						float loopDuration = waterTileSpectrum.WindWaves.LoopDuration;
						float num6 = ((loopDuration != 0f) ? (Mathf.Round((num3 % loopDuration + 0.2f) / 0.2f) * 0.2f) : ((!(num5 > lastFrameTime)) ? (Mathf.Max(num3, lastFrameTime) + _FFTTimeStep) : (lastFrameTime + _FFTTimeStep)));
						if (num6 != num5)
						{
							cpuFFT.Compute(waterTileSpectrum, num6, num2);
							waterTileSpectrum.ResultsTiming[num2] = num6;
							flag2 = true;
						}
						waterTileSpectrum.RecentResultIndex = num2;
					}
					if (!flag2)
					{
						stopwatch.Reset();
						Thread.Sleep(3);
					}
				}
			}
			catch (Exception threadException)
			{
				_ThreadException = threadException;
			}
		}
	}
}