module-inspector/Editor/Utilities/EditorPropertyUtility.cs

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

namespace Module.Inspector.Editor.Utilities
{
    public static class EditorPropertyUtility
    {
        private static Dictionary<FieldInfo, Result> CACHED_RESULTS;
        private static Dictionary<Type, Type> CACHED_ATT_TO_DRAWER;
        
        private static void InitializeCache()
        {
            if (CACHED_ATT_TO_DRAWER != null)
                return;
            
            CACHED_ATT_TO_DRAWER = new Dictionary<Type, Type>();
                
            Type baseDrawerType = typeof(AbstractPropertyDrawer);
            var assembly = Assembly.GetAssembly(baseDrawerType);
            Type[] types = assembly.GetTypes();

            for (var i = 0; i < types.Length; i++)
            {
                Type type = types[i];
                    
                if (type.IsAbstract || !baseDrawerType.IsAssignableFrom(type))
                    continue;
                    
                IList<CustomAttributeData> attributes = type.GetCustomAttributesData();
                    
                for (var j = 0; j < attributes.Count; j++)
                {
                    CustomAttributeData attData = attributes[j];
                    IList<CustomAttributeTypedArgument> arguments = attData.ConstructorArguments;

                    for (var k = 0; k < arguments.Count; k++)
                    {
                        if (!(arguments[k].Value is Type argType))
                            continue;

                        if (CACHED_ATT_TO_DRAWER.ContainsKey(argType))
                            Debug.LogWarningFormat("Already contained {0}, but tried to add with {1} and already had {2}.", argType, type, CACHED_ATT_TO_DRAWER[argType]);
                        else
                            CACHED_ATT_TO_DRAWER.Add(argType, type);
                    }
                }
            }
        }

        public static Result Query(FieldInfo fieldInfo)
        {
            InitializeCache();
            
            if (CACHED_RESULTS == null)
                CACHED_RESULTS = new Dictionary<FieldInfo, Result>();

            if (CACHED_RESULTS.TryGetValue(fieldInfo, out Result result))
                return result;

            result = InternalFetchProperties(fieldInfo);
            CACHED_RESULTS.Add(fieldInfo, result);
            return result;
        }

        private static Result InternalFetchProperties(FieldInfo fieldInfo)
        {
            ResultValue<DrawerPropertyAttribute, DrawerPropertyDrawer> drawer = null;
            var typeDrawer = InternalCreateInstanceOf<DrawerPropertyDrawer>(fieldInfo);
            
            if (typeDrawer != null)
                drawer = new ResultValue<DrawerPropertyAttribute, DrawerPropertyDrawer>(null, typeDrawer);

            var predrawerModifiers = new List<ResultValue<PredrawerModifierPropertyAttribute, PredrawerModifierPropertyDrawer>>(2);
            var valueModifiers = new List<ResultValue<ValueModifierPropertyAttribute, ValueModifierPropertyDrawer>>(2);
            var accessModifiers = new List<ResultValue<AccessModifierPropertyAttribute, AccessModifierPropertyDrawer>>(2);
            object[] attributes = fieldInfo.GetCustomAttributes(false);
            string tooltip = null;
            var isObsolete = false;
            string obsoleteText = null;

            for (var i = 0; i < attributes.Length; i++)
            {
                object att = attributes[i];

                if (att is DrawerPropertyAttribute attDrawer)
                {
                    if (drawer != null)
                        continue;
                    
                    var prop = InternalCreateInstanceOf<DrawerPropertyDrawer>(attDrawer);
                    
                    if (prop != null)
                        drawer = new ResultValue<DrawerPropertyAttribute, DrawerPropertyDrawer>(attDrawer, prop);
                }
                else if (att is PredrawerModifierPropertyAttribute predawerModifier)
                {
                    var prop = InternalCreateInstanceOf<PredrawerModifierPropertyDrawer>(predawerModifier);
                    
                    if (prop != null)
                        predrawerModifiers.Add(new ResultValue<PredrawerModifierPropertyAttribute, PredrawerModifierPropertyDrawer>(predawerModifier, prop));
                }
                else if (att is ValueModifierPropertyAttribute valueModifier)
                {
                    var prop = InternalCreateInstanceOf<ValueModifierPropertyDrawer>(valueModifier);
                    
                    if (prop != null)
                        valueModifiers.Add(new ResultValue<ValueModifierPropertyAttribute, ValueModifierPropertyDrawer>(valueModifier, prop));
                }
                else if (att is AccessModifierPropertyAttribute accessModifier)
                {
                    var prop = InternalCreateInstanceOf<AccessModifierPropertyDrawer>(accessModifier);
                    
                    if (prop != null)
                        accessModifiers.Add(new ResultValue<AccessModifierPropertyAttribute, AccessModifierPropertyDrawer>(accessModifier, prop));
                }
                else if (att is TooltipAttribute attTooltip)
                {
                    tooltip = attTooltip.tooltip;
                }
                else if (att is ObsoleteAttribute attObsolete)
                {
                    isObsolete = true;
                    obsoleteText = attObsolete.Message;
                }
            }

            if (isObsolete)
            {
                if (string.IsNullOrEmpty(obsoleteText))
                {
                    if (tooltip != null)
                        tooltip += $"\n[Obsolete]";
                    else
                        tooltip = $"[Obsolete]";
                }
                else
                {
                    if (tooltip != null)
                        tooltip += $"\n[Obsolete: {obsoleteText}]";
                    else
                        tooltip = $"[Obsolete: {obsoleteText}]";
                }
            }

            return new Result(drawer, predrawerModifiers, valueModifiers, accessModifiers, tooltip, isObsolete);
        }

        private static T InternalCreateInstanceOf<T>(AbstractPropertyAttribute att) where T : AbstractPropertyDrawer
        {
            if (CACHED_ATT_TO_DRAWER.TryGetValue(att.GetType(), out Type drawerType))
                return Activator.CreateInstance(drawerType) as T;

            return null;
        }
        
        private static T InternalCreateInstanceOf<T>(FieldInfo fieldInfo) where T : AbstractPropertyDrawer
        {
            if (CACHED_ATT_TO_DRAWER.TryGetValue(fieldInfo.FieldType, out Type drawerType))
                return Activator.CreateInstance(drawerType) as T;

            return null;
        }
        
        /// <summary>
        /// Class: Result from property query
        /// </summary>
        public sealed class Result
        {
            public readonly ResultValue<DrawerPropertyAttribute, DrawerPropertyDrawer> draw;
            public readonly List<ResultValue<PredrawerModifierPropertyAttribute, PredrawerModifierPropertyDrawer>> predrawerModifiers;
            public readonly List<ResultValue<ValueModifierPropertyAttribute, ValueModifierPropertyDrawer>> valueModifiers;
            public readonly List<ResultValue<AccessModifierPropertyAttribute, AccessModifierPropertyDrawer>> accessModifiers;
            public readonly string tooltip;
            public readonly bool isObsolete;

            public Result(ResultValue<DrawerPropertyAttribute, DrawerPropertyDrawer> draw,
                          List<ResultValue<PredrawerModifierPropertyAttribute, PredrawerModifierPropertyDrawer>> predrawerModifiers,
                          List<ResultValue<ValueModifierPropertyAttribute, ValueModifierPropertyDrawer>> valueModifiers,
                          List<ResultValue<AccessModifierPropertyAttribute, AccessModifierPropertyDrawer>> accessModifiers,
                          string tooltip,
                          bool isObsolete)
            {
                this.draw = draw;
                this.predrawerModifiers = predrawerModifiers;
                this.valueModifiers = valueModifiers;
                this.accessModifiers = accessModifiers;
                this.tooltip = tooltip;
                this.isObsolete = isObsolete;
            }
            
            public T GetPredrawerModifier<T>() where T : PredrawerModifierPropertyAttribute
            {
                for (var i = 0; i < predrawerModifiers.Count; i++)
                {
                    if (predrawerModifiers[i].attribute is T att)
                        return att;
                }

                return null;
            }

            public T GetValueModifier<T>() where T : ValueModifierPropertyAttribute
            {
                for (var i = 0; i < valueModifiers.Count; i++)
                {
                    if (valueModifiers[i].attribute is T att)
                        return att;
                }

                return null;
            }
            
            public T GetAccessModifier<T>() where T : AccessModifierPropertyAttribute
            {
                for (var i = 0; i < accessModifiers.Count; i++)
                {
                    if (accessModifiers[i].attribute is T att)
                        return att;
                }

                return null;
            }
        }
        
        /// <summary>
        /// Class: Contains attribute and drawer values
        /// </summary>
        /// <typeparam name="T0"></typeparam>
        /// <typeparam name="T1"></typeparam>
        public sealed class ResultValue<T0, T1> where T0 : AbstractPropertyAttribute
                                                where T1 : AbstractPropertyDrawer
        {
            public readonly T0 attribute;
            public readonly T1 drawer;

            public ResultValue(T0 attribute, T1 drawer)
            {
                this.attribute = attribute;
                this.drawer = drawer;
            }
        }
    }
}