'''
Created on Oct 20, 2017
Simple State Machine

@author: Begining Game Development with Python using Pygame Book
'''

class State(object):

    def __init__(self, name):
        self.name = name

    def update(self, dt_s):
        pass

    def check_conditions(self):
        pass

    def entry_actions(self):
        pass

    def exit_actions(self):
        pass


class State_Machine(object):

    def __init__(self):

        self.states = {}
        self.active_state = None

    def add_state(self, state):
        self.states[state.name] = state

    def update(self, dt):

        if self.active_state is None:
            return

        self.active_state.update(dt)

        new_state_name = self.active_state.check_conditions()

        if new_state_name is not None:
            self.set_state(new_state_name)


    def set_state(self, new_state_name):

        if self.active_state is not None:
            self.active_state.exit_actions()

        self.active_state = self.states[new_state_name]
        self.active_state.entry_actions()