using System;
using System.Reflection;
using Harmony;
using HutongGames.PlayMaker;
using MSCLoader;
using UnityEngine;

namespace MSCO
{
    /// <summary>
    /// Schutz vor Abstürzen durch nachgespielte Aktionen: Wird beim Beitreten eine Montage-Aktion in einer
    /// etwas anderen Welt nachgespielt, kann die "SetParent"-Aktion eines Teils ein Objekt unter sein eigenes
    /// Kind hängen. Das ergibt einen Kreis in der Hierarchie und Unity stürzt nativ ab (Stack Overflow in
    /// Transform::GetClassIDStatic). Solche Aufrufe werden hier abgefangen und übersprungen.
    /// </summary>
    public static class SafetyPatches
    {
        static bool applied;
        static FieldInfo gameObjectField, parentField;
        static int blocked;

        public static void Apply()
        {
            if (applied) return;
            applied = true;
            try
            {
                Type action = null;
                foreach (Assembly asm in AppDomain.CurrentDomain.GetAssemblies())
                {
                    action = asm.GetType("HutongGames.PlayMaker.Actions.SetParent");
                    if (action != null) break;
                }
                MethodInfo onEnter = action != null ? action.GetMethod("OnEnter", BindingFlags.Instance | BindingFlags.Public) : null;
                if (onEnter == null) { ModConsole.Warning("[MSCO] SetParent action not found - hierarchy guard disabled"); return; }

                gameObjectField = action.GetField("gameObject");
                parentField = action.GetField("parent");
                HarmonyInstance.Create("mbm.msco.safety").Patch(onEnter,
                    new HarmonyMethod(typeof(SafetyPatches).GetMethod("SetParentPrefix", BindingFlags.Static | BindingFlags.NonPublic)), null);
            }
            catch (Exception e)
            {
                ModConsole.Warning("[MSCO] Could not install hierarchy guard: " + e.Message);
            }
        }

        static bool SetParentPrefix(FsmStateAction __instance)
        {
            try
            {
                var owner = gameObjectField != null ? gameObjectField.GetValue(__instance) as FsmOwnerDefault : null;
                var parent = parentField != null ? parentField.GetValue(__instance) as FsmGameObject : null;
                if (owner == null || parent == null || parent.Value == null) return true;
                GameObject go = __instance.Fsm.GetOwnerDefaultTarget(owner);
                if (go == null) return true;

                Transform child = go.transform, newParent = parent.Value.transform;
                if (newParent != child && !newParent.IsChildOf(child)) return true;

                blocked++;
                if (blocked <= 20)
                    ModConsole.Warning("[MSCO] Blocked SetParent that would crash the game: " + go.name + " -> " + parent.Value.name +
                                       " (" + __instance.Fsm.Name + ")");
                __instance.Finish();
                return false;
            }
            catch
            {
                return true;
            }
        }
    }
}