// Crest Ocean System

// Copyright 2020 Wave Harmonic Ltd

using UnityEngine;

namespace Crest.Examples
{
    [AddComponentMenu(Crest.Internal.Constants.MENU_PREFIX_EXAMPLE + "Ripple Generator")]
    public class RippleGenerator : MonoBehaviour
    {
        /// <summary>
        /// The version of this asset. Can be used to migrate across versions. This value should
        /// only be changed when the editor upgrades the version.
        /// </summary>
        [SerializeField, HideInInspector]
#pragma warning disable 414
        int _version = 0;
#pragma warning restore 414

        public bool _animate = true;
        public float _warmUp = 3f;
        public float _onTime = 0.2f;
        public float _period = 4f;

        Renderer _rend;
        MaterialPropertyBlock _mpb;

        RegisterDynWavesInput _rdwi;

        public static class ShaderIDs
        {
            public static readonly int s_SimCount = Shader.PropertyToID("_SimCount");
        }

        void Start()
        {
            TryGetComponent(out _rdwi);

            if (OceanRenderer.Instance == null || !OceanRenderer.Instance.CreateDynamicWaveSim || _rdwi == null)
            {
                enabled = false;
                return;
            }

            _rend = GetComponent<Renderer>();
            _mpb = new MaterialPropertyBlock();
        }

        void Update()
        {
            if (OceanRenderer.Instance == null)
            {
                return;
            }

            if (_animate)
            {
                float t = OceanRenderer.Instance.CurrentTime;
                if (t < _warmUp)
                    return;
                t -= _warmUp;
                t = Mathf.Repeat(t, _period);
                _rdwi.enabled = t < _onTime;
            }

            // which lod is this object in (roughly)?
            Rect thisRect = new Rect(new Vector2(transform.position.x, transform.position.z), Vector3.zero);
            int minLod = LodDataMgrAnimWaves.SuggestDataLOD(thisRect);
            if (minLod == -1)
            {
                // outside all lods, nothing to update!
                return;
            }

            // how many active wave sims currently apply to this object - ideally this would eliminate sims that are too
            // low res, by providing a max grid size param
            LodDataMgrDynWaves.CountWaveSims(minLod, out var simsPresent, out var simsActive);
            if (simsPresent == 0)
            {
                enabled = false;
                return;
            }

            var dt = 1 / OceanRenderer.Instance._lodDataDynWaves.Settings._simulationFrequency;

            _rend.GetPropertyBlock(_mpb);

            _mpb.SetFloat(ShaderIDs.s_SimCount, simsActive);
            _mpb.SetFloat(LodDataMgrPersistent.sp_SimDeltaTime, dt);

            _rend.SetPropertyBlock(_mpb);
        }
    }
}