// Crest Water System
// Copyright © 2024 Wave Harmonic. All rights reserved.

using UnityEngine;
using WaveHarmonic.Crest.Internal;

namespace WaveHarmonic.Crest.ShallowWater
{
    /// <summary>
    /// Debug helper - designed to be used in conjunction with the SWSProbe shader to visualise simulation state.
    /// </summary>
    [@ExecuteDuringEditMode]
    [@HelpURL("Packages/ShallowWater/Manual.html")]
    [AddComponentMenu(Constants.k_MenuPrefixDebug + "Shallow Water Visualizer")]
    sealed class ShallowWaterVisualizer : ManagedBehaviour<WaterRenderer>
    {
        [SerializeField, HideInInspector]
#pragma warning disable 414
        int _Version = 0;
#pragma warning restore 414

        [SerializeField]
        ShallowWaterSimulation _ShallowWaterSimulation;

        [SerializeField]
        bool _RenderFinalHeight = true;

        Material _Material;

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

        private protected override void Initialize()
        {
            base.Initialize();
            _Material = new Material(WaterResources.Instance.Shaders._ShallowWaterSimulationVisualizer);
        }

        private protected override void OnDisable()
        {
            base.OnDisable();
            Helpers.Destroy(_Material);
        }

        // Data is ready in LateUpdate.
        private protected override System.Action<WaterRenderer> OnLateUpdateMethod => OnLateUpdate;
        void OnLateUpdate(WaterRenderer water)
        {
            var sws = _ShallowWaterSimulation;
            if (sws == null)
            {
                var rect = new Rect(transform.position.XZ() - transform.lossyScale.XZ() * 0.5f, transform.lossyScale.XZ());
                sws = ShallowWaterSimulation.Get(rect);
                if (sws == null) return;
            }

            sws.SetUniforms(_Material);
            _Material.SetBoolean(ShaderIDs.s_RenderFinalHeight, _RenderFinalHeight);
            Graphics.RenderMesh(new RenderParams(_Material), Helpers.SphereMesh, 0, transform.localToWorldMatrix);
        }
    }
}