/******************************************************************************
 * Copyright (C) Ultraleap, Inc. 2011-2021.                                   *
 *                                                                            *
 * Use subject to the terms of the Apache License 2.0 available at            *
 * http://www.apache.org/licenses/LICENSE-2.0, or another agreement           *
 * between Ultraleap and you, your company or other organization.             *
 ******************************************************************************/

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

namespace Leap.Unity
{

    [CustomPropertyDrawer(typeof(SingleLayer))]
    public class SingleLayerEditor : PropertyDrawer
    {
        private GUIContent[] _layerNames;
        private List<int> _layerValues;

        public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
        {
            ensureLayersInitialized();

            SerializedProperty layerProperty = property.FindPropertyRelative("layerIndex");
            if (layerProperty == null)
            {
                Debug.LogWarning("Could not find the layer index property, was it renamed or removed?");
                return;
            }

            int index = _layerValues.IndexOf(layerProperty.intValue);
            if (index < 0)
            {
                if (Application.isPlaying)
                {
                    //If application is playing we dont want to change the layers on the fly
                    //Instead, just display them as an int value
                    layerProperty.intValue = EditorGUI.IntField(position, property.displayName, layerProperty.intValue);
                    return;
                }
                else
                {
                    //If the application is not running, reset the layer to the default layer
                    layerProperty.intValue = 0;
                    index = 0;
                }
            }

            var tooltipAttribute = fieldInfo.GetCustomAttributes(typeof(TooltipAttribute), true).
                                             Cast<TooltipAttribute>().
                                             FirstOrDefault();

            if (tooltipAttribute != null)
            {
                label.tooltip = tooltipAttribute.tooltip;
            }

            bool originalMixedValue = EditorGUI.showMixedValue;
            if (layerProperty.hasMultipleDifferentValues)
            {
                EditorGUI.showMixedValue = true;
            }

            EditorGUI.BeginChangeCheck();
            index = EditorGUI.Popup(position, label, index, _layerNames);
            if (EditorGUI.EndChangeCheck())
            {
                layerProperty.intValue = _layerValues[index];
            }

            EditorGUI.showMixedValue = originalMixedValue;
        }

        private void ensureLayersInitialized()
        {
            if (_layerNames == null)
            {
                Dictionary<int, GUIContent> valueToLayer = new Dictionary<int, GUIContent>();
                for (int i = 0; i < 32; i++)
                {
                    string layerName = LayerMask.LayerToName(i);
                    if (!string.IsNullOrEmpty(layerName))
                    {
                        valueToLayer[i] = new GUIContent(layerName);
                    }
                }

                _layerValues = valueToLayer.Keys.ToList();
                _layerNames = valueToLayer.Values.ToArray();
            }
        }
    }
}