"""Batch processing components for academics objects.

Batch processors eat CSV files to add, update or remove large numbers
of certain kinds of objects at once.

Here we define the processors for academics specific objects like
faculties, departments and the like.
"""
import grok
from zope.interface import Interface
from waeup.sirp.interfaces import IBatchProcessor
from waeup.sirp.students.interfaces import IStudent
from waeup.sirp.utils.batching import BatchProcessor

class StudentProcessor(BatchProcessor):
    """A batch processor for IStudent objects.
    """
    grok.implements(IBatchProcessor)
    grok.provides(IBatchProcessor)
    grok.context(Interface)
    util_name = 'studentimporter'
    grok.name(util_name)

    name = u'Student Importer'
    iface = IStudent

    location_fields = ['student_id',]
    factory_name = 'waeup.Student'

    mode = None

    @property
    def req(self):
        result = dict(
            create = self.required_fields,
            update = self.location_fields,
            remove = self.location_fields,
        )
        return result

    def parentsExist(self, row, site):
        return 'students' in site.keys()

    # The entry never exists in create mode.
    def entryExists(self, row, site):
        if row.has_key('student_id'):
            return row['student_id'] in site['students'].keys()
        return False

    def getParent(self, row, site):
        return site['students']

    def getEntry(self, row, site):
        if not self.entryExists(row, site):
            return None
        parent = self.getParent(row, site)
        return parent.get(row['student_id'])

    def addEntry(self, obj, row, site):
        parent = self.getParent(row, site)
        parent.addStudent(obj)
        return

    def delEntry(self, row, site):
        parent = self.getParent(row, site)
        del parent[row['student_id']]
        pass