using System;

namespace XCEngine
{
    public sealed class ScriptableRenderPipelinePlanningContext
    {
        private readonly ulong m_nativeHandle;

        internal ScriptableRenderPipelinePlanningContext(ulong nativeHandle)
        {
            m_nativeHandle = nativeHandle;
        }

        public void ClearFullscreenStage(
            CameraFrameStage stage)
        {
            ValidateFullscreenStage(stage);
            InternalCalls.Rendering_ScriptableRenderPipelinePlanningContext_ClearFullscreenStage(
                m_nativeHandle,
                (int)stage);
        }

        public void RequestFullscreenStage(
            CameraFrameStage stage,
            CameraFrameColorSource source,
            bool usesGraphManagedOutputColor = false)
        {
            ValidateFullscreenStage(stage);
            if (source == CameraFrameColorSource.ExplicitSurface)
            {
                throw new ArgumentException(
                    "Managed planning currently requires a graph-managed color source for fullscreen stages.",
                    nameof(source));
            }

            if (stage == CameraFrameStage.FinalOutput && usesGraphManagedOutputColor)
            {
                throw new ArgumentException(
                    "FinalOutput fullscreen stages cannot publish a graph-managed output color.",
                    nameof(usesGraphManagedOutputColor));
            }

            if (!InternalCalls
                    .Rendering_ScriptableRenderPipelinePlanningContext_RequestFullscreenStage(
                        m_nativeHandle,
                        (int)stage,
                        (int)source,
                        usesGraphManagedOutputColor))
            {
                throw new InvalidOperationException(
                    $"Failed to request the managed fullscreen stage '{stage}'.");
            }
        }

        private static void ValidateFullscreenStage(
            CameraFrameStage stage)
        {
            if (stage != CameraFrameStage.PostProcess &&
                stage != CameraFrameStage.FinalOutput)
            {
                throw new ArgumentException(
                    "Managed planning currently supports only fullscreen sequence stages.",
                    nameof(stage));
            }
        }
    }
}