using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;

public class VolumetricFogLightsFeature : ScriptableRendererFeature
{
    class LightsPass : ScriptableRenderPass
    {
        static readonly int _CountID = Shader.PropertyToID("_FogLightCount");
        static readonly int _PosID   = Shader.PropertyToID("_FogLightPos");
        static readonly int _ColorID = Shader.PropertyToID("_FogLightColor");
        static readonly int _RangeID = Shader.PropertyToID("_FogLightRange");

        const int MAX = 16;
        Vector4[] pos   = new Vector4[MAX];
        Vector4[] color = new Vector4[MAX];
        float[]   range = new float[MAX];

        public override void Execute(ScriptableRenderContext ctx, ref RenderingData data)
        {
            int count = 0;
            foreach (var vl in data.lightData.visibleLights)
            {
                if (count >= MAX) break;
                if (vl.lightType == LightType.Point || vl.lightType == LightType.Spot)
                {
                    pos[count]   = vl.light.transform.position;
                    color[count] = vl.finalColor;
                    range[count] = vl.range;
                    count++;
                }
            }

            var cmd = CommandBufferPool.Get("FogLights");
            cmd.SetGlobalInt(_CountID, count);
            cmd.SetGlobalVectorArray(_PosID, pos);
            cmd.SetGlobalVectorArray(_ColorID, color);
            cmd.SetGlobalFloatArray(_RangeID, range);
            ctx.ExecuteCommandBuffer(cmd);
            CommandBufferPool.Release(cmd);

            Debug.Log($"[FogLights] Passed {count} lights to shader");
        }
    }

    LightsPass pass;

    public override void Create()
    {
        pass = new LightsPass { renderPassEvent = RenderPassEvent.BeforeRendering };
    }

    public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData data)
    {
        renderer.EnqueuePass(pass);
    }
}