using UnityEditor;
using UnityEngine;
using Ashwild.Building;
using FishNet.Object;

namespace Ashwild.EditorTools
{
    /// <summary>
    /// One-shot migration for the move to server-spawned builds: every committed structure is now a real
    /// NetworkObject, so each buildable's BuiltPrefab needs a NetworkObject and a BuiltStructure on its
    /// root. Prefabs authored before that change have neither (or only BuiltStructure, which is now a
    /// NetworkBehaviour and cannot function alone), and a missing NetworkObject makes the prefab silently
    /// unspawnable — the exact failure that used to leave a placed chest deactivated.
    ///
    /// Safe to re-run: it only touches prefabs that are actually missing a component, and reports what it
    /// changed. Kept as an explicit menu action rather than an automatic postprocessor because it rewrites
    /// authored assets, which should never happen behind the designer's back.
    /// </summary>
    public static class BuiltPrefabMigrator
    {
        #region Menu

        /// <summary>
        /// Scans every BuildableData, ensures its BuiltPrefab carries NetworkObject + BuiltStructure, and
        /// asks FishNet to rescan its spawnable prefab collection afterwards.
        /// </summary>
        [MenuItem("Tools/Ashwild/Migrate Built Prefabs To Network Objects")]
        public static void Migrate()
        {
            string[] guids = AssetDatabase.FindAssets("t:BuildableData");
            int migrated = 0;
            int alreadyFine = 0;
            int missingPrefab = 0;

            foreach (string guid in guids)
            {
                BuildableData buildable = AssetDatabase.LoadAssetAtPath<BuildableData>(AssetDatabase.GUIDToAssetPath(guid));
                if (buildable == null) continue;

                if (buildable.BuiltPrefab == null)
                {
                    Debug.LogWarning($"[BuiltPrefabMigrator] '{buildable.name}' has no BuiltPrefab — skipped.", buildable);
                    missingPrefab++;
                    continue;
                }

                if (EnsureNetworked(buildable.BuiltPrefab)) migrated++;
                else alreadyFine++;
            }

            AssetDatabase.SaveAssets();
            AssetDatabase.Refresh();
            RefreshNetworkPrefabRegistry();

            Debug.Log($"[BuiltPrefabMigrator] Done — {migrated} prefab(s) migrated, {alreadyFine} already correct, {missingPrefab} buildable(s) without a BuiltPrefab.");
        }

        #endregion

        #region Internal Helpers

        /// <summary>
        /// Adds whatever the prefab root is missing and saves it. The NetworkObject goes on first so that
        /// BuiltStructure's RequireComponent is already satisfied when it is added. Returns true when the
        /// prefab was actually changed.
        /// </summary>
        private static bool EnsureNetworked(GameObject prefab)
        {
            string path = AssetDatabase.GetAssetPath(prefab);
            if (string.IsNullOrEmpty(path)) return false;

            GameObject root = PrefabUtility.LoadPrefabContents(path);
            bool changed = false;

            if (root.GetComponent<NetworkObject>() == null)
            {
                root.AddComponent<NetworkObject>();
                changed = true;
            }
            if (root.GetComponent<BuiltStructure>() == null)
            {
                root.AddComponent<BuiltStructure>();
                changed = true;
            }

            if (changed)
            {
                PrefabUtility.SaveAsPrefabAsset(root, path);
                Debug.Log($"[BuiltPrefabMigrator] Migrated '{path}'.", AssetDatabase.LoadAssetAtPath<GameObject>(path));
            }

            PrefabUtility.UnloadPrefabContents(root);
            return changed;
        }

        /// <summary>
        /// Forces FishNet to rescan DefaultPrefabObjects so the migrated prefabs are spawnable. Invoked
        /// through the menu item because the generator API is internal to the FishNet assembly.
        /// </summary>
        private static void RefreshNetworkPrefabRegistry()
        {
            const string menu = "Tools/Fish-Networking/Utility/Refresh Default Prefabs";
            if (!EditorApplication.ExecuteMenuItem(menu))
                Debug.LogWarning($"[BuiltPrefabMigrator] Could not run '{menu}' — run it by hand so the built prefabs are registered as spawnable.");
        }

        #endregion
    }
}