from lecs.ecs import ECS, Entity, Component, System

# Create a simple component
class MooComponent(Component):
    """Data container for cow sounds."""
    def __init__(self):
        super().__init__()
        self.message = 'moo.'

# Create another simple component, from the MooComponent
class BullComponent(MooComponent):
    """A bull makes a louder MOO."""
    def __init__(self):
        super().__init__()
        self.message = 'MOO!'

# Now create a system to handle the components
class CattleSystem(System):
    def __init__(self, ecs, component_class):
        super().__init__(ecs, component_class)

    def execute(self):
        for component in self.get_component_list():
            print(component.message)


# Instantiate a base ECS container
ecs = ECS()


# Add a new empty entity
cow = ecs.add_entity()
# Add a MooComponent to the entity
cow.add_component(MooComponent())


# Let's add one more entity
bull = ecs.add_entity()
# This one is a bull, so we add the BullComponent
bull.add_component(BullComponent())

# We add the CattleSystem. We also add the class name of the component it looks for.
s = CattleSystem(ecs, ['MooComponent','BullComponent'])

# We call the System.execute() method.
s.execute()