"""Exporters for student related stuff.
"""
import grok
from zope.catalog.interfaces import ICatalog
from zope.component import queryUtility
from waeup.kofa.interfaces import ICSVExporter
from waeup.kofa.interfaces import MessageFactory as _
from waeup.kofa.students.interfaces import IStudent
from waeup.kofa.utils.batching import ExporterBase
from waeup.kofa.utils.helpers import iface_names

class StudentsExporter(grok.GlobalUtility, ExporterBase):
    """Exporter for Applicants.
    """
    grok.implements(ICSVExporter)
    grok.name('students')

    #: Fieldnames considered by this exporter
    fields = tuple(sorted(iface_names(IStudent, omit=['loggerInfo'])))

    #: The title under which this exporter will be displayed
    title = _(u'Students')

    def export(self, students, filepath=None):
        """Export `students`, an iterable, as CSV file.

        If `filepath` is ``None``, a raw string with CSV data is returned.
        """
        writer, outfile = self.get_csv_writer(filepath)
        for student in students:
            self.write_item(student, writer)
        return self.close_outfile(filepath, outfile)

    def export_all(self, site, filepath=None):
        """Export students into filepath as CSV data.

        If `filepath` is ``None``, a raw string with CSV data is returned.
        """
        catalog = queryUtility(
            ICatalog, context=site, name='students_catalog', default=None)
        if catalog is None:
            return self.export([], filepath)
        students = catalog.searchResults(
            student_id=(None, None))
        return self.export(students, filepath)