using System;
using Unity.Burst;
using Unity.Collections;
using Unity.Jobs;
using Unity.Mathematics;

namespace sc.splines.spawner.runtime
{
    [Serializable]
    [Modifier("Custom Modifier", "A custom modifier example", new []
    {
        //Optionally, specify distribution modes this modifier is incompatible with. A warning will be shown in the UI if it is in use.
        DistributionSettings.DistributionMode.Grid
    })]
    public class CustomModifier : Modifier
    {
        //Public parameters
        public float sineFrequency = 0.1f;
        public float sineAmplitude = 10f;
        
        [BurstCompile]
        private struct Job : IJobParallelFor
        {
            private readonly float sineFrequency;
            private readonly float sineAmplitude;
            
            [NativeDisableParallelForRestriction]
            private NativeList spawnPoints;

            public Job(CustomModifier settings, ref NativeList spawnPoints)
            {
                this.spawnPoints = spawnPoints;

                //Copy the parameters from the managed modifier, into the unmanaged job
                this.sineFrequency = settings.sineFrequency;
                this.sineAmplitude = settings.sineAmplitude;
            }

            public void Execute(int i)
            {
                SpawnPoint spawnPoint = spawnPoints[i];
                
                //Skip any spawn points that were previously invalidated
                if(spawnPoint.isValid == false) return;
                
                //Current position of spawn point
                float3 position = spawnPoint.position;
                
                //For the sake of this example, the spawn points are moved up in a 2D sine wave
                float3 offset = new float3(0, (math.sin(position.x * sineFrequency) + math.sin(position.z * sineFrequency)) * sineAmplitude, 0f);
                
                spawnPoint.position += offset;
                
                //Reassign the modified spawn point back
                spawnPoints[i] = spawnPoint;
            }
        }
        
        //This is called by the Spline Spawner component upon processing.
        //You may use the 'spawner' object to fetch an attached component to get some sort of custom data or access the Spline Container being used. Etc...
        //For the vast majority of modifiers, this function will remain identical
        public override JobHandle CreateJob(SplineSpawner spawner, ref NativeList spawnPoints)
        {
            Job job = new Job(this, ref spawnPoints);
            
            JobHandle jobHandle = job.Schedule(spawnPoints.Length, DEFAULT_BATCHSIZE);

            return jobHandle;
        }
    }
}

using sc.splines.spawner.runtime;
using UnityEditor;
using UnityEngine;

namespace sc.splines.spawner.editor
{
    [CustomPropertyDrawer(typeof(CustomModifier))]
    public class CustomModifierPropertyDrawer : PropertyDrawer
    {
        public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
        {
            EditorGUI.BeginProperty(position, label, property);
            
            ModifierAttribute attributes = ModifierAttribute.GetFor(property);
            EditorGUILayout.LabelField(new GUIContent(attributes.displayName, attributes.description), EditorStyles.boldLabel);

            EditorGUILayout.PropertyField(property.FindPropertyRelative("sineFrequency"));
            EditorGUILayout.PropertyField(property.FindPropertyRelative("sineAmplitude"));

            EditorGUI.EndProperty();
        }
    }
}