using System;
using System.Runtime.CompilerServices;



namespace fsm;



public class Context
{

}

public class State<T, CTX>
	where T : State<T, CTX>
	where CTX : Context
{
	virtual public void onEnter( CTX ctx, State<T, CTX> oldState )
	{
	}

	virtual public void onExit( CTX ctx, State<T, CTX> newState )
	{
	}
}

public class FSM<T, CTX, ST>
	where T : FSM<T, CTX, ST>
	where CTX : Context
	where ST : State<ST, CTX>
{
	public CTX Context { get; private set; }
	public ST State { get; private set; }

	public FSM( CTX context, ST state )
	{
		Context = context;
		State = state;

		State.onEnter( Context, state );
	}

	public void transition( ST newState, string reason = "",
													[CallerMemberName] string member = "",
													[CallerFilePath] string path = "",
													[CallerLineNumber] int line = 0 )
	{
		log.debug( $"{GetType().Name} switching to {newState.GetType().Name}from {State.GetType().Name}  bcs {reason} Code {log.relativePath( path )}:({line}): {member}" );

		State.onExit( Context, newState );
		newState.onEnter( Context, State );
		State = newState;
	}

}

/*

Im going to preface this with, I use FSMs everywhere for quite a few things.

*/