## $Id: batching.py 7429 2011-12-21 15:06:34Z 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
##
"""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 students specific objects like
students, studycourses, payment tickets and accommodation tickets.
"""
import grok
import csv
from zope.interface import Interface
from zope.schema import getFields
from zope.component import queryUtility
from zope.event import notify
from zope.catalog.interfaces import ICatalog
from waeup.sirp.interfaces import (
    IBatchProcessor, FatalCSVError, IObjectConverter)
from waeup.sirp.students.interfaces import (
    IStudent, IStudentStudyCourseImport,
    IStudentUpdateByRegNo, IStudentUpdateByMatricNo)
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 = []
    factory_name = 'waeup.Student'

    mode = None

    @property
    def available_fields(self):
        return sorted(list(set(
            ['student_id','reg_number','matric_number'] + getFields(
                self.iface).keys())))

    def checkHeaders(self, headerfields, mode='create'):
        if not 'reg_number' in headerfields and not 'student_id' \
            in headerfields and not 'matric_number' in headerfields:
            raise FatalCSVError(
                "Need at least columns student_id or reg_number " +
                "or matric_number for import!")
        if mode == 'create':
            for field in self.required_fields:
                if not field in headerfields:
                    raise FatalCSVError(
                        "Need at least columns %s for import!" %
                        ', '.join(["'%s'" % x for x in self.required_fields]))
        # Check for fields to be ignored...
        not_ignored_fields = [x for x in headerfields
                              if not x.startswith('--')]
        if len(set(not_ignored_fields)) < len(not_ignored_fields):
            raise FatalCSVError(
                "Double headers: each column name may only appear once.")
        return True

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

    def getLocator(self, row):
        if row.get('student_id',None):
            return 'student_id'
        elif row.get('reg_number',None):
            return 'reg_number'
        elif row.get('matric_number',None):
            return 'matric_number'
        else:
            return None

    # The entry never exists in create mode.
    def entryExists(self, row, site):
        return self.getEntry(row, site) is not None

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

    def getEntry(self, row, site):
        if not 'students' in site.keys():
            return None
        if self.getLocator(row) == 'student_id':
            if row['student_id'] in site['students']:
                student = site['students'][row['student_id']]
                return student
        elif self.getLocator(row) == 'reg_number':
            reg_number = row['reg_number']
            cat = queryUtility(ICatalog, name='students_catalog')
            results = list(
                cat.searchResults(reg_number=(reg_number, reg_number)))
            if results:
                return results[0]
        elif self.getLocator(row) == 'matric_number':
            matric_number = row['matric_number']
            cat = queryUtility(ICatalog, name='students_catalog')
            results = list(
                cat.searchResults(matric_number=(matric_number, matric_number)))
            if results:
                return results[0]
        return None

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

    def delEntry(self, row, site):
        student = self.getEntry(row, site)
        if student is not None:
            parent = self.getParent(row, site)
            del parent[student.student_id]
        pass

    def getMapping(self, path, headerfields, mode):
        """Get a mapping from CSV file headerfields to actually used fieldnames.
        """
        result = dict()
        reader = csv.reader(open(path, 'rb'))
        raw_header = reader.next()
        for num, field in enumerate(headerfields):
            if field not in [
                'student_id', 'reg_number', 'matric_number'] and mode == 'remove':
                continue
            if field == u'--IGNORE--':
                # Skip ignored columns in failed and finished data files.
                continue
            result[raw_header[num]] = field
        return result

    def checkConversion(self, row, mode='create'):
        """Validates all values in row.
        """
        if mode in ['update', 'remove']:
            if self.getLocator(row) == 'reg_number':
                iface = IStudentUpdateByRegNo
            elif self.getLocator(row) == 'matric_number':
                iface = IStudentUpdateByMatricNo
        else:
            iface = self.iface
        converter = IObjectConverter(iface)
        errs, inv_errs, conv_dict =  converter.fromStringDict(
            row, self.factory_name)
        return errs, inv_errs, conv_dict

class StudentStudyCourseProcessor(BatchProcessor):
    """A batch processor for IStudentStudyCourse objects.
    """
    grok.implements(IBatchProcessor)
    grok.provides(IBatchProcessor)
    grok.context(Interface)
    util_name = 'studycourseupdater'
    grok.name(util_name)

    name = u'StudentStudyCourse Importer (update only)'
    iface = IStudentStudyCourseImport
    factory_name = 'waeup.StudentStudyCourse'

    location_fields = []

    mode = None

    @property
    def available_fields(self):
        return sorted(list(set(
            ['student_id','reg_number','matric_number'] + getFields(
                self.iface).keys())))

    def checkHeaders(self, headerfields, mode='ignore'):
        if not 'reg_number' in headerfields and not 'student_id' \
            in headerfields and not 'matric_number' in headerfields:
            raise FatalCSVError(
                "Need at least columns student_id " +
                "or reg_number or matric_number for import!")
        # Check for fields to be ignored...
        not_ignored_fields = [x for x in headerfields
                              if not x.startswith('--')]
        if len(set(not_ignored_fields)) < len(not_ignored_fields):
            raise FatalCSVError(
                "Double headers: each column name may only appear once.")
        return True

    def getParent(self, row, site):
        if not 'students' in site.keys():
            return None
        if 'student_id' in row.keys() and row['student_id']:
            if row['student_id'] in site['students']:
                student = site['students'][row['student_id']]
                return student
        elif 'reg_number' in row.keys() and row['reg_number']:
            reg_number = row['reg_number']
            #import pdb; pdb.set_trace()
            cat = queryUtility(ICatalog, name='students_catalog')
            results = list(
                cat.searchResults(reg_number=(reg_number, reg_number)))
            if results:
                return results[0]
        elif 'matric_number' in row.keys() and row['matric_number']:
            matric_number = row['matric_number']
            cat = queryUtility(ICatalog, name='students_catalog')
            results = list(
                cat.searchResults(matric_number=(matric_number, matric_number)))
            if results:
                return results[0]
        return None

    def parentsExist(self, row, site):
        return self.getParent(row, site) is not None

    def entryExists(self, row, site):
        student = self.getParent(row, site)
        if not student:
            return None
        if 'studycourse' in student:
            return student
        return None

    def getEntry(self, row, site):
        student = self.entryExists(row, site)
        if not student:
            return None
        return student.get('studycourse')

    def updateEntry(self, obj, row, site):
        """Update obj to the values given in row.
        """
        for key, value in row.items():
            # Skip fields not declared in interface.
            if hasattr(obj, key):
                setattr(obj, key, value)
        # Update the students_catalog
        notify(grok.ObjectModifiedEvent(obj.__parent__))
        return