#region Using statements

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

#endregion

namespace Unheimlich.VFX.StylisedWater
{
    public class WaterVolumeHelper : MonoBehaviour
    {
        #region Private static fields

        private static WaterVolumeHelper instance = null;

        #endregion

        #region Public fields

        public WaterVolumeBase WaterVolume = null;

        #endregion

        #region Public static properties

        public static WaterVolumeHelper Instance { get { return instance; } }

        #endregion

        #region Public methods

        public float? GetHeight(Vector3 _position)
        {
            // ensure a water volume
            if (!WaterVolume)
            {
                return 0f;
            }

            // ensure a material
            var renderer = WaterVolume.gameObject.GetComponent<MeshRenderer>();
            if (!renderer || !renderer.sharedMaterial)
            {
                return 0f;
            }

            // replicate the shader logic, using parameters pulled from the specific material, to return the height at the specified position
            var waterHeight = WaterVolume.GetHeight(_position);
            if (!waterHeight.HasValue)
            {
                return null;             
            }
            var _WaveFrequency = renderer.sharedMaterial.GetFloat("_WaveFrequency");
            var _WaveScale = renderer.sharedMaterial.GetFloat("_WaveScale");
            var _WaveSpeed = renderer.sharedMaterial.GetFloat("_WaveSpeed");
            var time = Time.time * _WaveSpeed;
            var shaderOffset = (Mathf.Sin(_position.x * _WaveFrequency + time) + Mathf.Cos(_position.z * _WaveFrequency + time)) * _WaveScale;
            return waterHeight.Value + shaderOffset;
        }

        #endregion

        #region MonoBehaviour events

        private void Awake()
        {
            instance = this;
        }

        #endregion
    }
}