terra-llm/Assets/LLM/Editor/Commands/CreatePrefabCommand.cs

using UnityEngine;
using UnityEditor;
using JetBrains.Annotations;

namespace LLM.Editor.Commands
{
    [System.Serializable]
    public class CreatePrefabParams
    {
        public string sourceObjectQuery; // e.g., "Racer t:Model"
        public string defaultName; // e.g., "Racer.prefab"
    }

    [UsedImplicitly]
    public class CreatePrefabCommand : ICommand
    {
        // This key is used to pass the chosen path to subsequent commands.
        public const string CONTEXT_KEY_PREFAB_PATH = "lastCreatedPrefabPath";
        private readonly CreatePrefabParams _params;

        public CreatePrefabCommand(string jsonParams)
        {
            _params = JsonUtility.FromJson<CreatePrefabParams>(jsonParams);
        }

        public void Execute(Data.CommandContext context)
        {
            // Step 1: Ask the user for a save path.
            var path = EditorUtility.SaveFilePanel("Save New Prefab", "Assets/", _params.defaultName, "prefab");
            if (string.IsNullOrEmpty(path))
            {
                Debug.LogWarning("[CreatePrefabCommand] User cancelled save dialog. Aborting.");
                // We could clear the command queue here if we want cancellation to stop everything.
                return;
            }
            
            // We need a relative path for AssetDatabase
            var prefabPath = "Assets" + path[Application.dataPath.Length..];

            // Step 2: Find the source asset.
            var guids = AssetDatabase.FindAssets(_params.sourceObjectQuery);
            if (guids.Length == 0)
            {
                Debug.LogError($"[CreatePrefabCommand] No asset found for query: '{_params.sourceObjectQuery}'");
                return;
            }
            
            var assetPath = AssetDatabase.GUIDToAssetPath(guids[0]);
            var sourceAsset = AssetDatabase.LoadAssetAtPath<GameObject>(assetPath);

            // Step 3: Create the prefab.
            var instance = (GameObject)PrefabUtility.InstantiatePrefab(sourceAsset);
            PrefabUtility.SaveAsPrefabAsset(instance, prefabPath);
            Object.DestroyImmediate(instance);

            // Step 4: Store the chosen path in the context for the next commands.
            context.transientData[CONTEXT_KEY_PREFAB_PATH] = prefabPath;
            Debug.Log($"[CreatePrefabCommand] Created prefab at '{prefabPath}' from source '{assetPath}'.");
        }
    }
}