using System;
using System.Collections.Generic;
using UnityEngine;

namespace UnityEditor.VFX.Block
{
    class GPUEventOnDie : VFXBlock
    {
        public override void Sanitize(int version)
        {
            base.Sanitize(version);
            var newBlock = ScriptableObject.CreateInstance<TriggerEvent>();
            newBlock.SetSettingValue("mode", TriggerEvent.Mode.OnDie);
            VFXSlot.CopyLinksAndValue(newBlock.GetInputSlot(0), GetInputSlot(0));
            VFXSlot.CopyLinksAndValue(newBlock.GetOutputSlot(0), GetOutputSlot(0));
            ReplaceModel(newBlock, this);
        }

        public override string name { get { return "Trigger Event On Die"; } }
        public override VFXContextType compatibleContexts { get { return VFXContextType.Update; } }
        public override VFXDataType compatibleData { get { return VFXDataType.Particle; } }

        public override IEnumerable<VFXAttributeInfo> attributes
        {
            get
            {
                yield return new VFXAttributeInfo(VFXAttribute.Lifetime, VFXAttributeMode.Read);
                yield return new VFXAttributeInfo(VFXAttribute.Age, VFXAttributeMode.Read);
                yield return new VFXAttributeInfo(VFXAttribute.Alive, VFXAttributeMode.Read);
                yield return new VFXAttributeInfo(VFXAttribute.EventCount, VFXAttributeMode.Write);
            }
        }
        public override IEnumerable<VFXNamedExpression> parameters
        {
            get
            {
                foreach (var param in base.parameters)
                    yield return param;
                yield return new VFXNamedExpression(VFXBuiltInExpression.DeltaTime, "deltaTime");
            }
        }

        public class InputProperties
        {
            [Tooltip("Sets the number of particles spawned via a GPU event when this block is triggered.")]
            public uint count = 1u;
        }

        public class OutputProperties
        {
            [Tooltip("Outputs a GPU event which can connect to another system via a GPUEvent context. Attributes from the current system can be inherited in the new system.")]
            public GPUEvent evt = new GPUEvent();
        }

        public override string source
        {
            get
            {
                return "eventCount = (age + deltaTime > lifetime || !alive) ? count : 0;";
            }
        }
    }
}