using System;
using System.Collections.Generic;
using UnityEngine;

namespace UltimateWater.Internal
{
	[Serializable]
	public class WaterCameraSubmersion
	{
		[Range(0f, 2f)]
		[SerializeField]
		private float _Radius = 1f;

		[SerializeField]
		private int _Subdivisions;

		private WaterCamera _Camera;

		private List<WaterSample> _Samples;

		private readonly List<Vector3> _Points = new List<Vector3>();

		public SubmersionState State
		{
			get
			{
				Water containingWater = _Camera._ContainingWater;
				if (containingWater == null)
				{
					return SubmersionState.None;
				}
				if (!containingWater.Volume.Boundless)
				{
					return SubmersionState.Partial;
				}
				return Evaluate();
			}
		}

		public void OnEnable(WaterCamera camera)
		{
			_Camera = camera;
		}

		public void OnDisable()
		{
		}

		public void OnDrawGizmos()
		{
			Camera cameraComponent = _Camera.CameraComponent;
			float num = CalculateNearPlaneHeight(cameraComponent);
			CreatePlanePoints(cameraComponent, _Subdivisions, _Points);
			Gizmos.color = new Color(0f, 1f, 1f, 0.2f);
			for (int i = 0; i < _Points.Count; i++)
			{
				Gizmos.DrawSphere(_Points[i], num * _Radius);
			}
		}

		public void Create()
		{
			if (_Samples != null)
			{
				Destroy();
			}
			Water containingWater = _Camera._ContainingWater;
			if (containingWater != null)
			{
				Camera cameraComponent = _Camera.CameraComponent;
				_Samples = new List<WaterSample>();
				CreatePlanePoints(cameraComponent, _Subdivisions, _Points);
				for (int i = 0; i < _Points.Count; i++)
				{
					WaterSample waterSample = new WaterSample(containingWater, WaterSample.DisplacementMode.Height, 0.4f);
					waterSample.Start(_Points[i]);
					_Samples.Add(waterSample);
				}
			}
		}

		public void Destroy()
		{
			if (_Samples != null)
			{
				foreach (WaterSample sample in _Samples)
				{
					sample.Stop();
				}
				_Samples.Clear();
				_Samples = null;
			}
			_Points.Clear();
		}

		public void OnValidate()
		{
			if (_Subdivisions < 0)
			{
				_Subdivisions = 0;
			}
			if (_Radius < 0f)
			{
				_Radius = 0f;
			}
		}

		private SubmersionState Evaluate()
		{
			int num = 0;
			float num2 = CalculateNearPlaneHeight(_Camera.CameraComponent);
			float num3 = num2 * _Radius;
			CreatePlanePoints(_Camera.CameraComponent, _Subdivisions, _Points);
			for (int i = 0; i < _Samples.Count; i++)
			{
				Vector3 origin = _Points[i];
				Vector3 andReset = _Samples[i].GetAndReset(origin);
				if (origin.y + num3 <= andReset.y)
				{
					num++;
				}
				if (origin.y + num3 >= andReset.y && origin.y - num3 <= andReset.y)
				{
					return SubmersionState.Partial;
				}
			}
			if (num == _Samples.Count)
			{
				return SubmersionState.Full;
			}
			if (num == 0)
			{
				return SubmersionState.None;
			}
			return SubmersionState.Partial;
		}

		private static void CreatePlanePoints(Camera camera, int subdivisions, List<Vector3> result)
		{
			result.Clear();
			float num = CalculateNearPlaneHeight(camera);
			float num2 = num * camera.aspect;
			Vector3 nearPlaneCenter = GetNearPlaneCenter(camera);
			if (subdivisions == 0)
			{
				result.Add(nearPlaneCenter);
				return;
			}
			subdivisions--;
			Vector3 vector = 0.5f * num * camera.transform.up;
			Vector3 vector2 = 0.5f * num2 * camera.transform.right;
			Vector3 vector3 = nearPlaneCenter - vector - vector2;
			Vector3 vector4 = nearPlaneCenter + vector - vector2;
			Vector3 vector5 = nearPlaneCenter + vector + vector2;
			Vector3 vector6 = nearPlaneCenter - vector + vector2;
			result.Add(vector3);
			result.Add(vector4);
			result.Add(vector5);
			result.Add(vector6);
			for (int i = 0; i < subdivisions; i++)
			{
				float t = ((float)i + 1f) / ((float)subdivisions + 1f);
				result.Add(Vector3.Lerp(vector3, vector4, t));
				result.Add(Vector3.Lerp(vector4, vector5, t));
				result.Add(Vector3.Lerp(vector5, vector6, t));
				result.Add(Vector3.Lerp(vector6, vector3, t));
			}
		}

		private static Vector3 GetNearPlaneCenter(Camera camera)
		{
			return camera.transform.position + camera.transform.forward * camera.nearClipPlane;
		}

		private static float CalculateNearPlaneHeight(Camera camera)
		{
			return 2f * camera.nearClipPlane * Mathf.Tan(0.5f * camera.fieldOfView * ((float)Math.PI / 180f));
		}
	}
}