Infratest/Assets/Code/StateMachine/AbstractStateMachine.cs

using System.Collections.Generic;
using UnityEngine;

namespace Code.StateMachine
{
    public abstract class AbstractStateMachine<TStateEnum, TStateMachineContext>
        where TStateMachineContext : new()
    {
        public TStateEnum CurrentState { get; protected set; }
        public BaseState<TStateEnum, TStateMachineContext> CurrentBaseState { get; protected set; }
        private BaseState<TStateEnum, TStateMachineContext> _previousBaseState;

        protected Dictionary<TStateEnum, BaseState<TStateEnum, TStateMachineContext>> States = new();
        public TStateEnum AllowedStates { get; set; }

        public TStateMachineContext StateMachineContext { get; protected set; } = new();
        
        // protected virtual void Update()
        // {
        //     CurrentBaseState.Tick();
        // }
        //
        // protected void LateUpdate()
        // {
        //     CurrentBaseState.LateTick();
        // }
 
        // Костыли 2 шт. для флагового енама в шаблонах 
        protected abstract bool CheckTransitionAllowed(TStateEnum nextState);
        protected abstract void ResetAllowedTransitions();

        // TODO Если в EnterState вызывается ExitState, то будет гарантированная поломка
        public virtual AbstractStateMachine<TStateEnum, TStateMachineContext> SwitchState(TStateEnum nextState)
        {
            if (!CheckTransitionAllowed(nextState))
            {
                return null;
            }

            ResetAllowedTransitions();
            
            _previousBaseState = CurrentBaseState;
            
            CurrentBaseState = States[nextState];

            if (_previousBaseState != null)
            {
                _previousBaseState.OnExited += CurrentBaseState.EnterState;
                _previousBaseState.OnExited += FinishBaseStateTransition;
                _previousBaseState.ExitState();
            }
            else
            {
                CurrentBaseState.EnterState();
            }
            
            CurrentState = nextState;
            
            return this;
        }

        protected virtual void FinishBaseStateTransition()
        {
            _previousBaseState.OnExited -= CurrentBaseState.EnterState;
            _previousBaseState.OnExited -= FinishBaseStateTransition;

            _previousBaseState = null;
        }
    }
}