namespace TuringMachine.Core
{
    public enum MoveDirection
    {
        Left,
        Right,
        Stay
    }

    public record TransitionKey(string State, char ReadSymbol);
    public record TransitionResult(string NewState, char WriteSymbol, MoveDirection MoveDirection, string Comment = "");

    public class TransitionTable
    {
        private readonly Dictionary<TransitionKey, TransitionResult> _transitions = new();

        public void Add(string state, char readSymbol, string newState, char writeSymbol, MoveDirection moveDirection, string comment = "")
        {
            _transitions[new TransitionKey(state, readSymbol)] = new TransitionResult(newState, writeSymbol, moveDirection, comment);
        }

        public bool TryGetTransition(string state, char readSymbol, out TransitionResult? result)
        {
            return _transitions.TryGetValue(new TransitionKey(state, readSymbol), out result);
        }
        
        public IEnumerable<KeyValuePair<TransitionKey, TransitionResult>> Items => _transitions;

        public void Clear() => _transitions.Clear();
    }
}