module-inspector/Editor/ObjectEditor.cs

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

namespace Module.Inspector.Editor
{
    [CanEditMultipleObjects]
    [CustomEditor(typeof(Object), true, isFallback = true)]
    public sealed class ObjectEditor : UnityEditor.Editor
    {
        public override void OnInspectorGUI()
        {
            DrawDefaultInspector();
            DrawMethodInspector();
        }

        private void DrawMethodInspector()
        {
            if (!IsValidMethodTarget())
                return;
            
            EditorMethodUtility.ResultPrimary[] primaries = EditorMethodUtility.QueryPrimary(target);
            
            float totalHeight = CalculateMethodHeight(primaries);
            GUILayout.Space(totalHeight);
            
            var position = new Rect(0, 0, 1, 1);
            
            if (Event.current.type == EventType.Repaint)
            {
                position = GUILayoutUtility.GetLastRect();
                position.y -= totalHeight;

                #if UNITY_2020_1_OR_NEWER
                position.width = EditorGUIUtility.currentViewWidth - 22.0f;
                #endif
            }

            position.y = position.yMax + EditorGUIUtility.singleLineHeight;
            position.height = 0.0f;
            
            for (var i = 0; i < primaries.Length; i++)
            {
                EditorMethodUtility.ResultPrimary primary = primaries[i];

                float height = primary.drawer.GetHeight(target, primary.methodInfo);
                position.height = height;

                primary.drawer.OnGUI(position, target, primary.methodInfo);
                position.y += height;
            }
        }

        private float CalculateMethodHeight(EditorMethodUtility.ResultPrimary[] primaries)
        {
            float total = EditorGUIUtility.singleLineHeight;
            
            for (var i = 0; i < primaries.Length; i++)
            {
                EditorMethodUtility.ResultPrimary primary = primaries[i];
                total += primary.drawer.GetHeight(target, primary.methodInfo);
            }

            return total;
        }

        private bool IsValidMethodTarget()
        {
            return target != null && targets.Length == 1;
        }
    }
}