## $Id: studylevel.py 9812 2012-12-20 06:59:26Z henrik $
##
## Copyright (C) 2011 Uli Fouquet & Henrik Bettermann
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program; if not, write to the Free Software
## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
##
"""
Container which holds the data of a student study level
and contains the course tickets.
"""
import grok
from zope.component.interfaces import IFactory
from zope.component import createObject
from zope.interface import implementedBy
from waeup.kofa.students.interfaces import (
    IStudentStudyLevel, IStudentNavigation, ICourseTicket)
from waeup.kofa.utils.helpers import attrs_to_fields
from waeup.kofa.students.vocabularies import StudyLevelSource

def getGradeWeightFromScore(score):
    if score is None:
        return (None, None)
    if score >= 70:
        return ('A',5)
    if score >= 60:
        return ('B',4)
    if score >= 50:
        return ('C',3)
    if score >= 45:
        return ('D',2)
    if score >= 40:
        return ('E',1)
    return ('F',0)

class StudentStudyLevel(grok.Container):
    """This is a container for course tickets.
    """
    grok.implements(IStudentStudyLevel, IStudentNavigation)
    grok.provides(IStudentStudyLevel)

    def __init__(self):
        super(StudentStudyLevel, self).__init__()
        self.level = None
        return

    @property
    def student(self):
        try:
            return self.__parent__.__parent__
        except AttributeError:
            return None

    @property
    def certcode(self):
        try:
            return self.__parent__.certificate.code
        except AttributeError:
            return None

    @property
    def number_of_tickets(self):
        return len(self)

    @property
    def total_credits(self):
        total = 0
        for ticket in self.values():
            total += ticket.credits
        return total

    @property
    def gpa(self):
        gpa = 0.0
        credits_counted = 0
        for ticket in self.values():
            if ticket.score:
                credits_counted += ticket.credits
                gpa += ticket.credits * ticket.weight
        if credits_counted:
            gpa = round(gpa/credits_counted, 2)
        return gpa

    @property
    def is_current_level(self):
        try:
            return self.__parent__.current_level == self.level
        except AttributeError:
            return False

    def writeLogMessage(self, view, message):
        return self.__parent__.__parent__.writeLogMessage(view, message)

    @property
    def level_title(self):
        studylevelsource = StudyLevelSource()
        return studylevelsource.factory.getTitle(self.__parent__, self.level)

    def addCourseTicket(self, ticket, course):
        """Add a course ticket object.
        """
        if not ICourseTicket.providedBy(ticket):
            raise TypeError(
                'StudentStudyLeves contain only ICourseTicket instances')
        ticket.code = course.code
        ticket.title = course.title
        ticket.fcode = course.__parent__.__parent__.__parent__.code
        ticket.dcode = course.__parent__.__parent__.code
        ticket.credits = course.credits
        ticket.passmark = course.passmark
        ticket.semester = course.semester
        self[ticket.code] = ticket
        return

    def addCertCourseTickets(self, cert):
        """Collect all certificate courses and create course
        tickets automatically.
        """
        if cert is not None:
            for key, val in cert.items():
                if val.level != self.level:
                    continue
                ticket = createObject(u'waeup.CourseTicket')
                ticket.automatic = True
                ticket.mandatory = val.mandatory
                ticket.carry_over = False
                self.addCourseTicket(ticket, val.course)
        return

StudentStudyLevel = attrs_to_fields(
    StudentStudyLevel, omit=['total_credits', 'gpa'])

class StudentStudyLevelFactory(grok.GlobalUtility):
    """A factory for student study levels.
    """
    grok.implements(IFactory)
    grok.name(u'waeup.StudentStudyLevel')
    title = u"Create a new student study level.",
    description = u"This factory instantiates new student study level instances."

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

    def getInterfaces(self):
        return implementedBy(StudentStudyLevel)

class CourseTicket(grok.Model):
    """This is a course ticket which allows the
    student to attend the course. Lecturers will enter scores and more at
    the end of the term.

    A course ticket contains a copy of the original course and
    certificate course data. If the courses and/or the referrin certificate
    courses are removed, the corresponding tickets remain unchanged.
    So we do not need any event
    triggered actions on course tickets.
    """
    grok.implements(ICourseTicket, IStudentNavigation)
    grok.provides(ICourseTicket)

    def __init__(self):
        super(CourseTicket, self).__init__()
        self.code = None
        return

    @property
    def student(self):
        """Get the associated student object.
        """
        try:
            return self.__parent__.__parent__.__parent__
        except AttributeError:
            return None

    @property
    def certcode(self):
        try:
            return self.__parent__.__parent__.certificate.code
        except AttributeError:
            return None

    @property
    def removable_by_student(self):
        return not self.mandatory

    def writeLogMessage(self, view, message):
        return self.__parent__.__parent__.__parent__.writeLogMessage(view, message)

    def getLevel(self):
        """Returns the id of the level the ticket has been added to.
        """
        # XXX: shouldn't that be an attribute?
        try:
            return self.__parent__.level
        except AttributeError:
            return None

    def getLevelSession(self):
        """Returns the session of the level the ticket has been added to.
        """
        # XXX: shouldn't that be an attribute?
        try:
            return self.__parent__.level_session
        except AttributeError:
            return None

    @property
    def grade(self):
        """Returns the grade calculated from score.
        """
        return getGradeWeightFromScore(self.score)[0]

    @property
    def weight(self):
        """Returns the weight calculated from score.
        """
        return getGradeWeightFromScore(self.score)[1]

CourseTicket = attrs_to_fields(CourseTicket)

class CourseTicketFactory(grok.GlobalUtility):
    """A factory for student study levels.
    """
    grok.implements(IFactory)
    grok.name(u'waeup.CourseTicket')
    title = u"Create a new course ticket.",
    description = u"This factory instantiates new course ticket instances."

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

    def getInterfaces(self):
        return implementedBy(CourseTicket)