"""Course containers.
"""
import grok
from zope.interface import implementedBy
from zope.component.interfaces import IFactory, ComponentLookupError
from zope.catalog.interfaces import ICatalog
from zope.component import getUtility
from waeup.sirp.university.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')
        try:
            cat = getUtility(ICatalog, name='courses_catalog')
        except ComponentLookupError:
            # catalog not available. This might happen during tests.
            self[course.code] = course
            return 'Course added (for tests only).'
        results = list(cat.searchResults(code=(course.code,course.code)))
        if results:
            dep = results[0].__parent__.__parent__.longtitle()
            fac = results[0].__parent__.__parent__.__parent__.longtitle()
            return 'Course exists already in %s / %s.' % (fac,dep)
        self[course.code] = course
        return 'Course added.'

    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)