using System;
using System.Collections.Generic;
using System.Linq;
using UnityEditor.VFX.Block;
using UnityEngine;

namespace UnityEditor.VFX.HDRP
{
    internal class VFXDistortionPlanarPrimitiveOutputProvider : VariantProvider
    {
        public override IEnumerable<Variant> GetVariants()
        {
            foreach (var primitive in Enum.GetValues(typeof(VFXPrimitiveType)).Cast<VFXPrimitiveType>())
            {
                yield return new Variant(
                    $"Output Particle HDRP Distortion {primitive}",
                    "Output",
                    typeof(VFXDistortionPlanarPrimitiveOutput),
                    new[] {new KeyValuePair<string, object>("primitiveType", primitive)}
                );
            }
        }
    }

    [VFXInfo(variantProvider = typeof(VFXDistortionPlanarPrimitiveOutputProvider))]
    class VFXDistortionPlanarPrimitiveOutput : VFXAbstractDistortionOutput
    {
        [VFXSetting(VFXSettingAttribute.VisibleFlags.InInspector), SerializeField]
        protected VFXPrimitiveType primitiveType = VFXPrimitiveType.Quad;

        //[VFXSetting] // tmp dont expose as settings atm
        public bool useGeometryShader = false;

        public override string name { get { return "Output Particle HDRP Distortion " + primitiveType.ToString(); } }
        public override string codeGeneratorTemplate { get { return RenderPipeTemplate("VFXParticleDistortionPlanarPrimitive"); } }
        public override VFXTaskType taskType
        {
            get
            {
                if (useGeometryShader)
                    return VFXTaskType.ParticlePointOutput;

                return VFXPlanarPrimitiveHelper.GetTaskType(primitiveType);
            }
        }
        public override bool supportsUV { get { return true; } }

        public override IEnumerable<string> additionalDefines
        {
            get
            {
                foreach (var def in base.additionalDefines)
                    yield return def;

                if (useGeometryShader)
                    yield return "USE_GEOMETRY_SHADER";

                yield return VFXPlanarPrimitiveHelper.GetShaderDefine(primitiveType);
            }
        }

        protected override IEnumerable<VFXPropertyWithValue> inputProperties
        {
            get
            {
                IEnumerable<VFXPropertyWithValue> properties = base.inputProperties;
                foreach (var property in properties)
                    yield return property;

                if (primitiveType == VFXPrimitiveType.Octagon)
                    foreach (var property in PropertiesFromType(typeof(VFXPlanarPrimitiveHelper.OctagonInputProperties)))
                        yield return property;
            }
        }

        protected override IEnumerable<VFXNamedExpression> CollectGPUExpressions(IEnumerable<VFXNamedExpression> slotExpressions)
        {
            foreach (var exp in base.CollectGPUExpressions(slotExpressions))
                yield return exp;

            if (primitiveType == VFXPrimitiveType.Octagon)
                yield return slotExpressions.First(o => o.name == "cropFactor");
        }
    }
}