module-inspector/Editor/AbstractPropertyDrawer.cs

using Module.Inspector.Editor.Utilities;
using UnityEditor;
using UnityEngine;

namespace Module.Inspector.Editor
{
    public abstract class AbstractPropertyDrawer : PropertyDrawer
    {
        public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
        {
            EditorPropertyUtility.Result result = EditorPropertyUtility.Query(fieldInfo);
            EAccessType accessType = GetAccessType(property, result);

            if (accessType == EAccessType.Hidden)
                return;

            bool prevEnabled = GUI.enabled;
            GUI.enabled = prevEnabled && accessType == EAccessType.Enabled;
            
            label.tooltip = result.tooltip;
            
            for (var i = 0; i < result.predrawerModifiers.Count; i++)
            {
                EditorPropertyUtility.ResultValue<PredrawerModifierPropertyAttribute, PredrawerModifierPropertyDrawer> value = result.predrawerModifiers[i];
                value.drawer.Modify(value.attribute, property, label);
            }

            var isValid = true;
            var validationError = string.Empty;

            for (var i = 0; i < result.validators.Count; i++)
            {
                EditorPropertyUtility.ResultValue<ValidatePropertyAttribute, ValidatePropertyDrawer> value = result.validators[i];

                if (value.drawer.Validate(value.attribute, property))
                    continue;

                validationError += value.drawer.GetValidationError(property);
                isValid = false;
            }
            
            Color prevColor = GUI.color;

            if (!isValid)
            {
                if (string.IsNullOrEmpty(label.tooltip))
                    label.tooltip = validationError;
                else
                    label.tooltip += "\n" + validationError;
                
                GUI.color = Color.red;
            }

            if (result.draw != null)
            {
                if (!result.draw.drawer.Draw(position, result.draw.attribute, property, label, result))
                {
                    GUI.color = Color.red;
                    var errorContent = new GUIContent(result.draw.drawer.GetErrorMessage(property));
                    EditorGUI.LabelField(position, label, errorContent);
                }
            }
            else
            {
                EditorGUI.PropertyField(position, property, label, true);
            }
            
            GUI.color = prevColor;
            GUI.enabled = prevEnabled;

            for (var i = 0; i < result.valueModifiers.Count; i++)
            {
                EditorPropertyUtility.ResultValue<ValueModifierPropertyAttribute, ValueModifierPropertyDrawer> value = result.valueModifiers[i];
                value.drawer.Modify(value.attribute, property);
            }
        }

        public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
        {
            EditorPropertyUtility.Result result = EditorPropertyUtility.Query(fieldInfo);
            EAccessType accessType = GetAccessType(property, result);
            return accessType != EAccessType.Hidden ? EditorGUI.GetPropertyHeight(property, label) : 0.0f;
        }

        private static EAccessType GetAccessType(SerializedProperty property, EditorPropertyUtility.Result result)
        {
            if (result.accessModifiers.Count == 0)
                return EAccessType.Enabled;

            EAccessType accessType = 0;
                
            for (var i = 0; i < result.accessModifiers.Count; i++)
            {
                EditorPropertyUtility.ResultValue<AccessModifierPropertyAttribute, AccessModifierPropertyDrawer> value = result.accessModifiers[i];
                accessType = value.drawer.GetAccessType(value.attribute, property, accessType);
            }

            return accessType;
        }
    }
}