An editor field to quickly pick Ink knots from inside a given sub-folder in Assets

StoryKnot.cs

using System;


namespace _project.utilities
{
    /// <summary>
    /// Struct that is used for an editor GUI to simplify picking an ink knot from the Assets folder
    /// </summary>
    [Serializable]
    public struct StoryKnot
    {
        public string name;

        public StoryKnot( string n ) => name = n;

        public bool IsValid => !string.IsNullOrEmpty( name );
    }
}

StoryKnotDrawer.cs

using System.Collections.Generic;
using System.IO;
using _project.utilities;
using UnityEditor;
using UnityEngine;


namespace _project
{
    [CustomPropertyDrawer( typeof(StoryKnot) )]
    public class StoryKnotDrawer : PropertyDrawer
    {
        private static Dictionary<string, List<string>> _fileToKnotsLookup = new Dictionary<string, List<string>>();

        private string _selectedName = "";
        
        public override void OnGUI(
            Rect position,
            SerializedProperty property,
            GUIContent label )
        {
            label = EditorGUI.BeginProperty( position, label, property );
            Rect contentPosition = EditorGUI.PrefixLabel(position, label);
            
            EditorGUI.BeginChangeCheck();

            var nameProperty = property.FindPropertyRelative( "name" );
            var buttonLabel = string.IsNullOrEmpty( nameProperty.stringValue )
                ? "Pick knot name" 
                : nameProperty.stringValue;

            if ( EditorGUI.DropdownButton( contentPosition, new GUIContent( buttonLabel ),
                                           FocusType.Passive ) )
            {
                if ( _fileToKnotsLookup.Count == 0 )
                {
                    FetchKnots();
                }
                ConstructThenShowMenu();
            }

            if ( !string.IsNullOrEmpty( _selectedName ) )
            {
                nameProperty.stringValue = _selectedName;
                _selectedName = "";
            }

            EditorGUI.EndChangeCheck();
            EditorGUI.EndProperty();
        }

        public override float GetPropertyHeight( SerializedProperty property, GUIContent label )
        {
            return EditorGUIUtility.singleLineHeight;
        }


        #region Menu

        
        private void FetchKnots()
        {
            _fileToKnotsLookup.Clear();

            var folderPath = "Assets/_content/writing";
            var guids = AssetDatabase.FindAssets( "", new []{ folderPath } );

            foreach ( var guid in guids )
            {
                var path = AssetDatabase.GUIDToAssetPath( guid );

                if ( path.EndsWith( ".ink" ) )
                {
                    var splits = path.Split( '/' );
                    var knots = LoadInkThenParse( path );
                    var reduced = path.Remove( 0, folderPath.Length + 1 );
                    
                    //Debug.Log( $"path? {path}" );
                    //Debug.Log( $" reduced: {reduced}, split: {splits[splits.Length - 1]}" );
                    //Debug.Log( $"knots: [{string.Join( ",", knots )}]" );
                    
                    _fileToKnotsLookup.Add( reduced, knots );
                }
                // ignore .jsons
            }
        }

        private List<string> LoadInkThenParse( string path )
        {
            List<string> value = new List<string>();
            
            using ( var reader = File.OpenText( path ) )
            {
                var line = "";
                while ( !reader.EndOfStream )
                {
                    line = reader.ReadLine();

                    if ( line.StartsWith( "==" ) )
                    {
                        line = line.Replace( "==", "" );
                        line = line.Trim();
                        value.Add( line );
                    }
                }
            }

            return value;
        }

        private void ConstructThenShowMenu()
        {
            GenericMenu menu = new GenericMenu();

            foreach ( var pair in _fileToKnotsLookup )
            {
                string root = pair.Key;

                foreach ( var s in pair.Value )
                {
                    AddMenuItemForKnot( menu, $"{root}/{s}", s );
                }
            }
            
            menu.ShowAsContext();
        }
        void AddMenuItemForKnot(GenericMenu menu, string menuPath, string knot)
        {
            menu.AddItem(new GUIContent(menuPath), _selectedName.Equals(knot), OnStringSelected, knot);
        }    
        void OnStringSelected(object knot)
        {
            _selectedName = (string)knot;
        }

        #endregion
    }
}