import lib.screenful as screenful

class Update:
    def __init__(self):
        self.message_queue = []
        self.model = None
        self.view = None

    def update_model(self):
        # check if we need to reset the model
        reset = False
        for msg in self.message_queue:
            if msg.reset():
                reset = True
                break
        
        if reset:
            self.model.pre_reset()
            
        # check if we need to signal the data change
        for msg in self.message_queue:
            if msg.data_change():
                screenful.changed()
                break
            
        # do update
        for msg in self.message_queue:
            msg.update_model(self.model)
            
        if reset:
            self.model.post_reset()

        self.message_queue = []
        self.view.view(self.model)

    def schedule(self, msg):
        self.message_queue.append(msg)
        # for now, directly clearing message queue
        self.update_model()
    
    def set_model(self, model):
        self.model = model

    def set_view(self, view):
        self.view = view


update = Update()