using XCEngine;
using XCEngine.Rendering;

namespace XCEngine.Rendering.Universal
{
    public abstract class ScriptableRendererFeature
        : Object
    {
        private bool m_disposed;
        private bool m_runtimeCreated;
        private bool m_isActive = true;
        private int m_runtimeStateVersion = 1;
        private int m_runtimeStateHash;
        private bool m_runtimeStateHashResolved;
        private ScriptableRendererData m_owner;

        protected ScriptableRendererFeature()
        {
        }

        public bool isActive
        {
            get
            {
                return m_isActive;
            }
            set
            {
                if (m_isActive == value)
                {
                    return;
                }

                m_isActive = value;
                SetDirty();
            }
        }

        internal void BindOwnerInstance(
            ScriptableRendererData owner)
        {
            m_owner = owner;
        }

        internal int GetRuntimeStateVersionInstance()
        {
            SynchronizeRuntimeStateVersion();
            return m_runtimeStateVersion;
        }

        internal void CreateInstance()
        {
            if (m_runtimeCreated)
            {
                return;
            }

            m_disposed = false;
            Create();
            m_runtimeCreated = true;
        }

        internal void ReleaseRuntimeResourcesInstance()
        {
            if (m_disposed ||
                !m_runtimeCreated)
            {
                return;
            }

            ReleaseRuntimeResources();
            m_disposed = true;
            m_runtimeCreated = false;
        }

        public virtual void Create()
        {
        }

        public virtual void ConfigureCameraRenderRequest(
            CameraRenderRequestContext context)
        {
        }

        public virtual void ConfigureCameraFramePlan(
            ScriptableRenderPipelinePlanningContext context)
        {
        }

        public virtual void ConfigureRenderSceneSetup(
            RenderSceneSetupContext context)
        {
        }

        public virtual void ConfigureDirectionalShadowExecutionState(
            DirectionalShadowExecutionContext context)
        {
        }

        public virtual void AddRenderPasses(
            ScriptableRenderer renderer,
            RenderingData renderingData)
        {
        }

        protected bool HasDirectionalShadow(
            CameraRenderRequestContext context)
        {
            return context != null &&
                   InternalCalls
                       .Rendering_CameraRenderRequestContext_GetHasDirectionalShadow(
                           context.nativeHandle);
        }

        protected void ClearDirectionalShadow(
            CameraRenderRequestContext context)
        {
            if (context == null)
            {
                return;
            }

            InternalCalls
                .Rendering_CameraRenderRequestContext_ClearDirectionalShadow(
                    context.nativeHandle);
        }

        protected virtual void ReleaseRuntimeResources()
        {
        }

        protected virtual int ComputeRuntimeStateHash()
        {
            int hash = 17;
            hash =
                RuntimeStateHashUtility.Combine(
                    hash,
                    m_isActive);
            return hash;
        }

        protected void SetDirty()
        {
            ApplyDirty(
                ComputeRuntimeStateHash());
        }

        private void SynchronizeRuntimeStateVersion()
        {
            int runtimeStateHash =
                ComputeRuntimeStateHash();
            if (!m_runtimeStateHashResolved)
            {
                m_runtimeStateHash = runtimeStateHash;
                m_runtimeStateHashResolved = true;
                return;
            }

            if (runtimeStateHash == m_runtimeStateHash)
            {
                return;
            }

            ApplyDirty(runtimeStateHash);
        }

        private void ApplyDirty(
            int runtimeStateHash)
        {
            m_runtimeStateHash = runtimeStateHash;
            m_runtimeStateHashResolved = true;

            if (m_runtimeCreated &&
                !m_disposed)
            {
                ReleaseRuntimeResources();
            }

            m_disposed = false;
            m_runtimeCreated = false;

            unchecked
            {
                ++m_runtimeStateVersion;
            }

            if (m_runtimeStateVersion <= 0)
            {
                m_runtimeStateVersion = 1;
            }

            if (m_owner != null)
            {
                m_owner.InvalidateRendererFeaturesInstance();
            }
        }
    }

    internal static class RuntimeStateHashUtility
    {
        public static int Combine(
            int hash,
            bool value)
        {
            return Combine(
                hash,
                value ? 1 : 0);
        }

        public static int Combine(
            int hash,
            byte value)
        {
            return Combine(
                hash,
                (int)value);
        }

        public static int Combine(
            int hash,
            uint value)
        {
            unchecked
            {
                return (hash * 31) + (int)value;
            }
        }

        public static int Combine(
            int hash,
            int value)
        {
            unchecked
            {
                return (hash * 31) + value;
            }
        }

        public static int Combine(
            int hash,
            float value)
        {
            return Combine(
                hash,
                value.GetHashCode());
        }

        public static int Combine(
            int hash,
            string value)
        {
            return Combine(
                hash,
                value != null
                    ? value.GetHashCode()
                    : 0);
        }

        public static int Combine(
            int hash,
            Vector4 value)
        {
            hash = Combine(hash, value.X);
            hash = Combine(hash, value.Y);
            hash = Combine(hash, value.Z);
            hash = Combine(hash, value.W);
            return hash;
        }

        public static int Combine(
            int hash,
            RenderQueueRange value)
        {
            hash = Combine(hash, value.lowerBound);
            hash = Combine(hash, value.upperBound);
            return hash;
        }

        public static int Combine(
            int hash,
            FilteringSettings value)
        {
            hash = Combine(hash, value.renderQueueMin);
            hash = Combine(hash, value.renderQueueMax);
            hash = Combine(hash, value.renderLayerMask);
            hash = Combine(hash, value.requireShadowCasting);
            hash = Combine(hash, value.requireRenderObjectId);
            return hash;
        }

        public static int Combine(
            int hash,
            SortingSettings value)
        {
            return Combine(
                hash,
                (int)value.sortMode);
        }

        public static int Combine(
            int hash,
            RendererListDesc value)
        {
            hash = Combine(hash, (int)value.type);
            hash = Combine(hash, value.filtering);
            hash = Combine(hash, value.sorting);
            return hash;
        }

        public static int Combine(
            int hash,
            DepthState value)
        {
            hash = Combine(hash, value.writeEnabled);
            hash =
                Combine(hash, (int)value.compareFunction);
            return hash;
        }

        public static int Combine(
            int hash,
            StencilFaceState value)
        {
            hash =
                Combine(hash, (int)value.failOperation);
            hash =
                Combine(hash, (int)value.passOperation);
            hash =
                Combine(hash, (int)value.depthFailOperation);
            hash =
                Combine(hash, (int)value.compareFunction);
            return hash;
        }

        public static int Combine(
            int hash,
            StencilState value)
        {
            hash = Combine(hash, value.enabled);
            hash = Combine(hash, value.readMask);
            hash = Combine(hash, value.writeMask);
            hash = Combine(hash, value.frontFace);
            hash = Combine(hash, value.backFace);
            return hash;
        }

        public static int Combine(
            int hash,
            RenderStateBlock value)
        {
            hash = Combine(hash, (int)value.mask);
            hash = Combine(hash, value.depthState);
            hash = Combine(hash, value.stencilState);
            hash = Combine(hash, value.stencilReference);
            return hash;
        }

        public static int Combine(
            int hash,
            DrawingSettings value)
        {
            hash = Combine(hash, value.overrideMaterialPath);
            hash = Combine(hash, value.shaderPassName);
            hash = Combine(hash, value.renderStateBlock);
            return hash;
        }
    }
}