using System;
using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Rendering.HighDefinition;

[Serializable, VolumeComponentMenu("Post-processing/UTS Tonemapping")]
public sealed class UTSTonemapping : CustomPostProcessVolumeComponent, IPostProcessComponent
{
    [Tooltip("Controls the intensity of the effect.")]
    public BoolParameter state = new BoolParameter(false, BoolParameter.DisplayType.EnumPopup);

    private Material _material;

    public bool IsActive() => _material != null && state.value;

    // Do not forget to add this post process in the Custom Post Process Orders list (Project Settings > Graphics > HDRP Global Settings).
    public override CustomPostProcessInjectionPoint injectionPoint => CustomPostProcessInjectionPoint.AfterPostProcess;

    const string Shader_Name = "Hidden/Shader/UTSTonemapping";

    public override void Setup()
    {
        if (Shader.Find(Shader_Name) != null)
        {
            _material = CoreUtils.CreateEngineMaterial(Shader_Name);
        }
        else
        {
            Debug.LogError($"Unable to find shader '{Shader_Name}'. Post Process Volume UTSToonmapping is unable to load. To fix this, please edit the 'kShaderName' constant in UTSToonmapping.cs or change the name of your custom post process shader.");
        }
    }

    public override void Render(CommandBuffer cmd, HDCamera camera, RTHandle source, RTHandle destination)
    {
        if (_material == null || !state.value)
        {
            return;
        }

        _material.SetTexture("_MainTex", source);
        HDUtils.DrawFullScreen(cmd, _material, destination, shaderPassId: 0);
    }

    public override void Cleanup()
    {
        CoreUtils.Destroy(_material);
    }
}