module-project-validator/Editor/Settings/ProjectValidatorSettings.cs

using System.Collections.Generic;
using UnityEditor;
using UnityEngine;
using UnityEngine.UIElements;
using UnityEditor.UIElements;
using UnityEditorInternal;

namespace Module.ProjectValidator.Editor
{
    internal sealed class ProjectValidatorSettings : ScriptableObject
    {
        public List<string> assemblies = new();
        
        private const string AssetPath = "ProjectSettings/ProjectValidatorSettings.asset";
        private const string StyleSheetName = "StyleSheetProjectValidatorSettings";

        internal static ProjectValidatorSettings GetOrCreate()
        {
            var objects = InternalEditorUtility.LoadSerializedFileAndForget(AssetPath);
            
            if (objects.Length != 0)
                return (ProjectValidatorSettings)objects[0];

            var settings = CreateInstance<ProjectValidatorSettings>();
            InternalEditorUtility.SaveToSerializedFileAndForget(new Object[] { settings }, AssetPath, true);
            return settings;
        }
        
        [SettingsProvider]
        public static SettingsProvider CreateProvider()
        {
            return new SettingsProvider("Project/Project Validator", SettingsScope.Project)
            {
                label = "Project Validator",
                activateHandler = (_, root) =>
                {
                    var settings = GetOrCreate();
                    var serializedObject = new SerializedObject(settings);
                    var container = new VisualElement { style = { flexDirection = FlexDirection.Column } };
                    var propertyField = new PropertyField(serializedObject.FindProperty("assemblies"), "Assemblies");
                    propertyField.RegisterCallback<ChangeEvent<string>>(_ => InternalEditorUtility.SaveToSerializedFileAndForget(new[] { serializedObject.targetObject }, AssetPath, true));
                    container.Add(propertyField);
                    root.Add(container);
                    root.Bind(serializedObject);
                    root.styleSheets.Add(EditorAssetUtility.LoadFirstAsset<StyleSheet>(StyleSheetName));
                },
                keywords = new HashSet<string>(new[] { "Project", "Validator", "Assemblies" })
            };
        }
    }
}