using System;
using UnityEngine;
using UnityEngine.Profiling;
using UnityEngine.Rendering;

namespace FidelityFX.FrameGen
{
    internal abstract class FrameInterpolationPass: IDisposable
    {
        protected readonly FrameInterpolation.ContextDescription ContextDescription;
        protected readonly FrameInterpolationResources Resources;
        protected readonly ComputeBuffer Constants;
        
        protected ComputeShader ComputeShader;
        protected int KernelIndex;
        
        private CustomSampler _sampler;
        
        protected FrameInterpolationPass(FrameInterpolation.ContextDescription contextDescription, FrameInterpolationResources resources, ComputeBuffer constants)
        {
            ContextDescription = contextDescription;
            Resources = resources;
            Constants = constants;
        }

        public virtual void Dispose()
        {
        }
        
        public void ScheduleDispatch(CommandBuffer commandBuffer, OpticalFlow.DispatchDescription dispatchParams, int frameIndex, int dispatchX, int dispatchY, int dispatchZ = 1)
        {
            commandBuffer.BeginSample(_sampler);
            DoScheduleDispatch(commandBuffer, dispatchParams, frameIndex, dispatchX, dispatchY, dispatchZ);
            commandBuffer.EndSample(_sampler);
        }

        protected abstract void DoScheduleDispatch(CommandBuffer commandBuffer, OpticalFlow.DispatchDescription dispatchParams, int frameIndex, int dispatchX, int dispatchY, int dispatchZ);

        protected void InitComputeShader(string passName, ComputeShader shader)
        {
            if (shader == null)
            {
                throw new MissingReferenceException($"Shader for Frame Interpolation pass '{passName}' could not be loaded! Please ensure it is included in the project correctly.");
            }

            ComputeShader = shader;
            KernelIndex = ComputeShader.FindKernel("CS");
            _sampler = CustomSampler.Create(passName);
            
            // TODO: shader variants
        }
    }
}