using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;

namespace Kav
{
    public class DeferredPBR_PointLightEffect : Effect
    {
        EffectParameter gPositionParam;
        EffectParameter gAlbedoParam;
        EffectParameter gNormalParam;
        EffectParameter gMetallicRoughnessParam;
        EffectParameter shadowMapParam;

        EffectParameter eyePositionParam;

        EffectParameter pointLightColorParam;
        EffectParameter pointLightPositionParam;

        EffectParameter farPlaneParam;

        EffectParameter worldViewProjectionParam;

        public Texture2D GPosition { get; set; }
        public Texture2D GAlbedo { get; set; }
        public Texture2D GNormal { get; set; }
        public Texture2D GMetallicRoughness { get; set; }
        public TextureCube ShadowMap { get; set; }

        public Vector3 EyePosition { get; set; }

        public Vector3 PointLightPosition { get; set; }
        public Vector3 PointLightColor { get; set; }

        public float FarPlane { get; set; }

        Matrix world = Matrix.Identity;
        Matrix view = Matrix.Identity;
        Matrix projection = Matrix.Identity;

        EffectDirtyFlags dirtyFlags = EffectDirtyFlags.All;

        public Matrix World
        {
            get { return world; }
            set
            {
                world = value;
                dirtyFlags |= EffectDirtyFlags.WorldViewProj;
            }
        }

        public Matrix View
        {
            get { return view; }
            set
            {
                view = value;
                dirtyFlags |= EffectDirtyFlags.WorldViewProj;
            }
        }

        public Matrix Projection
        {
            get { return projection; }
            set
            {
                projection = value;
                dirtyFlags |= EffectDirtyFlags.WorldViewProj;
            }
        }

        public DeferredPBR_PointLightEffect(GraphicsDevice graphicsDevice) : base(graphicsDevice, Resources.DeferredPBR_PointLightEffect)
        {
            CacheEffectParameters();
        }

        public DeferredPBR_PointLightEffect(DeferredPBR_PointLightEffect cloneSource) : base(cloneSource)
        {
            CacheEffectParameters();
            
            GPosition = cloneSource.GPosition;
            GAlbedo = cloneSource.GAlbedo;
            GNormal = cloneSource.GNormal;
            GMetallicRoughness = cloneSource.GMetallicRoughness;
            ShadowMap = cloneSource.ShadowMap;

            EyePosition = cloneSource.EyePosition;

            PointLightPosition = cloneSource.PointLightPosition;
            PointLightColor = cloneSource.PointLightColor;

            FarPlane = cloneSource.FarPlane;
        }

        public override Effect Clone()
        {
            return new DeferredPBR_PointLightEffect(this);
        }

        protected override void OnApply()
        {
            gPositionParam.SetValue(GPosition);
            gAlbedoParam.SetValue(GAlbedo);
            gNormalParam.SetValue(GNormal);
            gMetallicRoughnessParam.SetValue(GMetallicRoughness);
            shadowMapParam.SetValue(ShadowMap);

            eyePositionParam.SetValue(EyePosition);

            pointLightPositionParam.SetValue(PointLightPosition);
            pointLightColorParam.SetValue(PointLightColor);

            farPlaneParam.SetValue(FarPlane);

            if ((dirtyFlags & EffectDirtyFlags.WorldViewProj) != 0)
            {
                worldViewProjectionParam.SetValue(world * view * projection);

                dirtyFlags &= ~EffectDirtyFlags.WorldViewProj;
            }
        }

        void CacheEffectParameters()
        {
            gPositionParam                 = Parameters["gPosition"];
            gAlbedoParam                   = Parameters["gAlbedo"];
            gNormalParam                   = Parameters["gNormal"];
            gMetallicRoughnessParam        = Parameters["gMetallicRoughness"];
            shadowMapParam                 = Parameters["shadowMap"];

            eyePositionParam               = Parameters["EyePosition"];

            pointLightPositionParam        = Parameters["PointLightPosition"];
            pointLightColorParam           = Parameters["PointLightColor"];

            farPlaneParam                  = Parameters["FarPlane"];

            worldViewProjectionParam       = Parameters["WorldViewProjection"];
        }
    }
}