"""Course containers.
"""
import grok
from zope.interface import implementedBy
from zope.component.interfaces import IFactory
from waeup.interfaces import ICourseContainer, ICourse

class CourseContainer(grok.Container):
    """See interfaces for description.
    """
    grok.implements(ICourseContainer)
    grok.require('waeup.manageUniversity')

    def addCourse(self, course):
        """Add a course.
        """
        if not ICourse.providedBy(course):
            raise TypeError('CourseContainers contain only ICourse instances')
        self[course.code] = course
        return

    def clear(self):
        """Remove all objects from course container.
        """
        keys = self.keys()
        for key in keys:
            del self[key]

class CourseContainerFactory(grok.GlobalUtility):
    """A factory for course containers.
    """
    grok.implements(IFactory)
    grok.name(u'waeup.CourseContainer')
    title = u"Create a new course container.",
    description = u"This factory instantiates new course containers."

    def __call__(self, *args, **kw):
        return CourseContainer(*args, **kw)

    def getInterfaces(self):
        return implementedBy(CourseContainer)