using UnityEngine;
using UnityEditor;

namespace Agens.Editor
{

    public static class MoveComponentContext
    {
        internal enum Destination
        {
            Top,
            Bottom
        }

        private const string ComponentArrayName = "m_Component";
        private const int FirstComponentIndex = 1;


        [MenuItem("CONTEXT/Component/Move to Top")]
        public static void Top(MenuCommand command)
        {
            Move(command.context, Destination.Top);
        }


        [MenuItem("CONTEXT/Component/Move to Bottom")]
        public static void Bottom(MenuCommand command)
        {
            Move(command.context, Destination.Bottom);
        }


        private static void Move(Object target, Destination destination)
        {
            var component = target as Component;
            if (component == null)
            {
                Debug.LogWarning("Cant move " + target + " to " + destination, target);
                return;
            }
            var serializedObject = new SerializedObject(component.gameObject);
            var componentArray = serializedObject.FindProperty(ComponentArrayName);

            var lastComponentIndex = componentArray.arraySize - 1;
            var targetIndex = destination == Destination.Top ? FirstComponentIndex : lastComponentIndex;

            for (int index = FirstComponentIndex; index <= lastComponentIndex; ++index)
            {
                var iterator = componentArray.GetArrayElementAtIndex(index);
                iterator.Next(true);
                iterator.Next(true);

                if (iterator.objectReferenceValue == target)
                {
                    componentArray.MoveArrayElement(index, targetIndex);
                    serializedObject.ApplyModifiedProperties();

                    break;
                }
            }
        }
    }
}