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

namespace Smuggler
{
    public struct PBRLight
    {
        public Vector3 direction;
        public Vector3 colour;

        public PBRLight(Vector3 direction, Vector3 colour)
        {
            this.direction = direction;
            this.colour = colour;
        }
    }

    public class PBREffect : Effect
    {
        readonly EffectParameter modelParam;
        readonly EffectParameter viewParam;
        readonly EffectParameter projectionParam;
        readonly EffectParameter lightDirParam;
        readonly EffectParameter lightColourParam;
        readonly EffectParameter normalScaleParam;
        readonly EffectParameter emissiveFactorParam;
        readonly EffectParameter occlusionStrengthParam;
        readonly EffectParameter metallicRoughnessValuesParam;
        readonly EffectParameter baseColorFactorParam;
        readonly EffectParameter cameraLookParam;

        readonly EffectParameter baseColourTextureParam;
        readonly EffectParameter normalTextureParam;
        readonly EffectParameter emissionTextureParam;
        readonly EffectParameter occlusionTextureParam;
        readonly EffectParameter metallicRoughnessTextureParam;
        readonly EffectParameter envDiffuseTextureParam;
        readonly EffectParameter brdfLutTextureParam;
        readonly EffectParameter envSpecularTextureParam;

        Matrix world = Matrix.Identity;
        Matrix view = Matrix.Identity;
        Matrix projection = Matrix.Identity;
        PBRLight light = new PBRLight();
        float normalScale = 1;
        Vector3 emissiveFactor;
        float occlusionStrength;
        Vector2 metallicRoughnessValue;
        Vector4 baseColorFactor;

        public Matrix World
        {
            get { return world; }
            set 
            { 
                world = value;
                modelParam.SetValue(world); 
            }
        }

        public Matrix View
        {
            get { return view; }
            set 
            { 
                view = value;
                viewParam.SetValue(view);
                cameraLookParam.SetValue(-new Vector3(
                    view.M13,
                    view.M23,
                    view.M33
                ));
            }
        }

        public Matrix Projection
        {
            get { return projection; }
            set 
            { 
                projection = value;
                projectionParam.SetValue(value);
            }
        }

        public PBRLight Light
        {
            get { return light; }
            set 
            { 
                light = value;
                lightDirParam.SetValue(light.direction); 
                lightColourParam.SetValue(light.colour);
            }
        }

        public float NormalScale
        {
            get { return normalScale; }
            set 
            {
                normalScale = value;
                normalScaleParam.SetValue(normalScale); 
            }
        }

        public Vector3 EmissiveFactor
        {
            get { return emissiveFactor; }
            set 
            { 
                emissiveFactor = value;
                emissiveFactorParam.SetValue(emissiveFactor); 
            }
        }

        public float OcclusionStrength
        {
            get { return occlusionStrength; }
            set 
            {
                occlusionStrength = value;
                occlusionStrengthParam.SetValue(occlusionStrength); 
            }
        }

        public Vector2 MetallicRoughnessValue
        {
            get { return metallicRoughnessValue; }
            set
            {
                metallicRoughnessValue = value;
                metallicRoughnessValuesParam.SetValue(metallicRoughnessValue);
            }
        }

        public Vector4 BaseColorFactor
        {
            get { return baseColorFactor; }
            set
            {
                baseColorFactor = value;
                baseColorFactorParam.SetValue(baseColorFactor);
            }
        }

        public Texture2D BaseColourTexture
        {
            get { return baseColourTextureParam.GetValueTexture2D(); }
            set { baseColourTextureParam.SetValue(value); }
        }

        public Texture2D NormalTexture
        {
            get { return normalTextureParam.GetValueTexture2D(); }
            set { normalTextureParam.SetValue(value); }
        }

        public Texture2D EmissionTexture
        {
            get { return emissionTextureParam.GetValueTexture2D(); }
            set { emissionTextureParam.SetValue(value); }
        }

        public Texture2D OcclusionTexture
        {
            get { return occlusionTextureParam.GetValueTexture2D(); }
            set { occlusionTextureParam.SetValue(value); }
        }

        public Texture2D MetallicRoughnessTexture
        {
            get { return metallicRoughnessTextureParam.GetValueTexture2D(); }
            set { metallicRoughnessTextureParam.SetValue(value); }
        }

        public TextureCube EnvDiffuseTexture
        {
            get { return envDiffuseTextureParam.GetValueTextureCube(); }
            set { envDiffuseTextureParam.SetValue(value); }
        }

        public Texture2D BRDFLutTexture
        {
            get { return brdfLutTextureParam.GetValueTexture2D(); }
            set { brdfLutTextureParam.SetValue(value); }
        }

        public TextureCube EnvSpecularTexture
        {
            get { return envSpecularTextureParam.GetValueTextureCube(); }
            set { envSpecularTextureParam.SetValue(value); }
        }

        public PBREffect(GraphicsDevice graphicsDevice) : base(graphicsDevice, Resources.PBREffect)
        {
            modelParam = Parameters["model"];
            viewParam  = Parameters["view"];
            projectionParam = Parameters["projection"];

            lightDirParam = Parameters["lightDir"];
            lightColourParam = Parameters["lightColour"];

            normalScaleParam = Parameters["normalScale"];
            emissiveFactorParam = Parameters["emissiveFactor"];
            occlusionStrengthParam = Parameters["occlusionStrength"];
            metallicRoughnessValuesParam = Parameters["metallicRoughnessValues"];
            baseColorFactorParam = Parameters["baseColorFactor"];
            cameraLookParam = Parameters["camera"];

            baseColourTextureParam = Parameters["baseColourTexture"];
            normalTextureParam = Parameters["normalTexture"];
            emissionTextureParam = Parameters["emissionTexture"];
            occlusionTextureParam = Parameters["occlusionTexture"];
            metallicRoughnessTextureParam = Parameters["metallicRoughnessTexture"];
            envDiffuseTextureParam = Parameters["envDiffuseTexture"];
            brdfLutTextureParam = Parameters["brdfLutTexture"];
            envSpecularTextureParam = Parameters["envSpecularTexture"];
        }

        protected PBREffect(PBREffect cloneSource) : base(cloneSource)
        {
            modelParam = Parameters["model"];
            viewParam  = Parameters["view"];
            projectionParam = Parameters["param"];

            lightDirParam = Parameters["lightDir"];
            lightColourParam = Parameters["lightColour"];

            normalScaleParam = Parameters["normalScale"];
            emissiveFactorParam = Parameters["emissiveFactor"];
            occlusionStrengthParam = Parameters["occlusionStrength"];
            metallicRoughnessValuesParam = Parameters["metallicRoughnessValues"];
            baseColorFactorParam = Parameters["baseColorFactor"];
            cameraLookParam = Parameters["camera"];

            baseColourTextureParam = Parameters["baseColourTexture"];
            normalTextureParam = Parameters["normalTexture"];
            emissionTextureParam = Parameters["emissionTexture"];
            occlusionTextureParam = Parameters["occlusionTexture"];
            metallicRoughnessTextureParam = Parameters["metallicRoughnessTexture"];
            envDiffuseTextureParam = Parameters["envDiffuseTexture"];
            brdfLutTextureParam = Parameters["brdfLutTexture"];
            envSpecularTextureParam = Parameters["envSpecularTexture"];

            World = cloneSource.World;
            View = cloneSource.View;
            Projection = cloneSource.Projection;

            Light = cloneSource.Light;

            NormalScale = cloneSource.normalScale;
            EmissiveFactor = cloneSource.EmissiveFactor;
            OcclusionStrength = cloneSource.OcclusionStrength;
            MetallicRoughnessValue = cloneSource.MetallicRoughnessValue;
            BaseColorFactor = cloneSource.BaseColorFactor;

            BaseColourTexture = cloneSource.BaseColourTexture;
            NormalTexture = cloneSource.NormalTexture;
            EmissionTexture = cloneSource.EmissionTexture;
            OcclusionTexture = cloneSource.OcclusionTexture;
            MetallicRoughnessTexture = cloneSource.MetallicRoughnessTexture;
            EnvDiffuseTexture = cloneSource.EnvDiffuseTexture;
            BRDFLutTexture = cloneSource.BRDFLutTexture;
            EnvSpecularTexture = cloneSource.EnvSpecularTexture;
        }

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

        // FIXME: do param applications here for performance
        protected override void OnApply()
        {
            base.OnApply();
        }
    }
}