"""
This takes a MARCXML filename as an argument and converts it into
MARC records for the unglued edition (in .xml and .mrc formats).
Consider it a catalogolem: http://commons.wikimedia.org/wiki/File:Arcimboldo_Librarian_Stokholm.jpg
Use the MARCXML file for the non-unglued edition from Library of Congress.
"""

import pymarc
import logging
from datetime import datetime

from django.conf import settings
from django.urls import reverse

import regluit.core.cc as cc

def stub(edition):
    
    record = pymarc.Record(force_utf8=True)

    now = datetime.now()
    
    #mostly to identify this record as a stub
    field001 = pymarc.Field(tag='001', data='stb'+now.strftime('%y%m%d%H%M%S'))
    record.add_ordered_field(field001)
    
    add_stuff(record)
    
    # fun fun fun 008
    new_field_value= now.strftime('%y%m%d')+'s'
    if edition.publication_date and len(edition.publication_date)>3:
        new_field_value += edition.publication_date[0:4]
    else:
        new_field_value += '||||'
    new_field_value += '||||xx |||||o|||||||||||eng||'
    field008 = pymarc.Field(tag='008', data=new_field_value)
    record.add_ordered_field(field008)   
        
    # add IBSN for if available
    if edition.isbn_13:
        field020 = pymarc.Field(
            tag='020',
            indicators = [' ', ' '],
            subfields = ['a', edition.isbn_13]
        )
        record.add_ordered_field(field020)
    
    # OCLC number
    if edition.oclc:
        field035 = pymarc.Field(
            tag='035',
            indicators = [' ', ' '],
            subfields = ['a', '(OCoLC)' + edition.oclc]
        )
        record.add_ordered_field(field035)
        
    # author name
    num_auths = len(edition.authnames())
    if num_auths:
        field100 = pymarc.Field(
            tag='100',
            indicators = ['1', ' '],
            subfields = [
                'a', edition.authnames()[0],
            ]
        )
        record.add_ordered_field(field100)
    if num_auths > 1:
        for auth in edition.authnames()[1:]:
            field = pymarc.Field(
                tag='700',
                indicators = ['1', ' '],
                subfields = [
                    'a', auth,
                    'e', 'joint author.',
                ]
            )
            record.add_ordered_field(field)

    # add subfield to 245 indicating format
    field245 = pymarc.Field(
        tag='245',
        indicators = ['1', '0'],
        subfields = [
            'a', edition.title,
            'a', '[electronic resource]',
        ]
    )
    record.add_ordered_field(field245)
    
    #edition statement
    if edition.note:
        field250 = pymarc.Field(
            tag='250',
            indicators = [' ', ' '],
            subfields = [
                'a', str(edition.note),
            ]
        )
        record.add_ordered_field(field250)
    
    # publisher, date
    if edition.publisher:
        field260 = pymarc.Field(
            tag='260',
            indicators = [' ', ' '],
            subfields = [
                'b', edition.publisher,
            ]
        )
        if edition.publication_date:
            field260.add_subfield('c', str(edition.publication_date))
        record.add_ordered_field(field260)
    
    if edition.description:
        #add 520 field (description)
        field520 =  pymarc.Field(
            tag='520',
            indicators = [' ', ' '],
            subfields = [
                'a', edition.description,
            ]
        )
        record.add_ordered_field(field520)
        
    add_license(record, edition)
    
    return record

#load a with minimal change
def raw(marcfile,  edition):
    record = pymarc.parse_xml_to_array(marcfile)[0]
    for field in record:
        if field.tag in ('001', '003', '005', '006', '007', '856') or int( field.tag ) > 900:
            record.remove_field(field)
    add_stuff(record)
    return record
    
#load a record from library of Congress
def from_lc(marcfile,  edition):
    
    # save lccn for later (if there is one) before deleting it
    print_lccn = None
    record = pymarc.parse_xml_to_array(marcfile)[0]
    for lccn in record.get_fields('010'):
        for validlccn in lccn.get_subfields('a'):
            print_lccn = validlccn
    for field in record:
        if field.tag in ('001', '003', '005', '006', '007', '010', '040', '856') or int( field.tag ) > 900:
            record.remove_field(field)

    add_stuff(record)
    
    field008 = record.get_fields('008')[0]
    record.remove_field(field008)
    old_field_value = field008.value()
    new_field_value = old_field_value[:23] + 'o' + old_field_value[24:]
    field008 = pymarc.Field(tag='008', data=new_field_value)
    record.add_ordered_field(field008)   
        
    # add IBSN for ebook where applicable; relegate print ISBN to $z
    isbn = edition.isbn_13
    try:
        field020 = record.get_fields('020')[0]
        print_isbn = field020.get_subfields('a')[0]
        field020.delete_subfield('a')
        if isbn:
            field020.add_subfield('a', isbn)
        field020.add_subfield('z', print_isbn)
    except IndexError:
        print_isbn = None

    # change 050 and 082 indicators because LOC is no longer responsible for these
    # no easy indicator change function, so we'll just reconstruct the fields
    try:
        field050 = record.get_fields('050')[0]
        field050_new = field050
        field050_new.indicators = [' ', '4']
        record.remove_field(field050)
        record.add_ordered_field(field050_new)
    except:
        pass # if no 050 field, don't need to change indicator
    
    try:
        field082 = record.get_fields('082')[0]
        field082_new = field082
        field082_new.indicators = [' ', '4']
        record.remove_field(field082)
        record.add_ordered_field(field082_new)
    except:
        pass # if no 082 field, don't need to change indicator
    
    # add subfield to 245 indicating format
    try:
        field245 = record.get_fields('245')[0]
        field245.add_subfield('a', '[electronic resource]')
    except IndexError:
        pass
        
    # modify 300 field (physical description)
    try:
        field300 = record.get_fields('300')[0]
        subfield_a = field300.get_subfields('a')[0]
        if (
            subfield_a[-2:] == ' ;' or 
            subfield_a[-2:] == ' :' or 
            subfield_a[-2:] == ' +'
        ):
            subfield_a = subfield_a[:-2]
        new300a = '1 online resource (' + subfield_a + ')'
        if field300.get_subfields('b'):
            new300a += ' :'
        field300.delete_subfield('a')
        field300.add_subfield('a', new300a)
        field300.delete_subfield('c')
    except:
        pass
    
    add_license(record, edition)

    # add 588 field (source of description) - credit where credit is due
    if print_lccn:
        field588 = pymarc.Field(
            tag='588',
            indicators = [' ', ' '],
            subfields = [
                'a', 'Description based on print version record from the Library of Congress.',
            ]
        )
        record.add_ordered_field(field588)
    
    # add 776 field (related editions) - preserve pISBN, LCCN, OCLCnum
    title = record.get_fields('245')[0].get_subfields('a')[0]
    title = title.split('/')[0]
    
    subfields = ['i', 'Print version: ','t', title,]
    
    if print_isbn:
        subfields.extend(['z', print_isbn])
    elif isbn:
        subfields.extend(['z', isbn])
    if print_lccn:
        subfields.extend(['w', '(DLC) ' + print_lccn, ])
    if edition.oclc:
        subfields.extend(['w', '(OCoLC) ' + edition.oclc,])

    field776 = pymarc.Field(
        tag='776',
        indicators = ['0', '8'],
        subfields = subfields
    )
    
    record.add_ordered_field(field776)
        
    return record

def add_license(record, edition):
    if edition.license:
        # add 536 field (funding information)
        field536 = pymarc.Field(
            tag='536',
            indicators = [' ', ' '],
            subfields = [
                'a', edition.funding_info,
            ]
        )
        record.add_ordered_field(field536)
    
        # add 540 field (terms governing use)
        field540 = pymarc.Field(
            tag='540',
            indicators = [' ', ' '],
            subfields = [
                'a', dict(cc.CHOICES)[edition.license],
                'u', dict(cc.GRANTS)[edition.license], 
            ]
        )
        record.add_ordered_field(field540)

def add_stuff(record):
    # add field indicating record originator
    field003 = pymarc.Field(tag='003', data='UnglueIt')
    record.add_ordered_field(field003)
    
    # update timestamp of record
    datestamp = datetime.now().strftime('%Y%m%d%H%M%S') + '.0'
    field005 = pymarc.Field(tag='005', data=datestamp)
    record.add_ordered_field(field005)

    # change 006, 007, 008 because this is an online resource
    field006 = pymarc.Field(
        tag='006',
        data='m     o  d        '
    )
    record.add_ordered_field(field006)
    
    field007 = pymarc.Field(
        tag='007',
        data='cr'
    )
    record.add_ordered_field(field007)