# This file is part of Wolne Lektury, licensed under GNU Affero GPLv3 or later.
# Copyright © Fundacja Wolne Lektury. See NOTICE for more information.
#
from django.core.management.base import BaseCommand
from librarian import ParseError
from catalogue.models import Book


class Command(BaseCommand):
    help = 'Checks integrity of catalogue data.'

    def add_arguments(self, parser):
        parser.add_argument(
                '-q', '--quiet', action='store_false', dest='verbose',
                default=True, help='Suppress output')
        parser.add_argument(
                '-d', '--dry-run', action='store_true', dest='dry_run',
                default=False, help="Just check for problems, don't fix them")

    def handle(self, **options):
        from django.db import transaction

        verbose = options['verbose']

        with transaction.atomic():
            for book in Book.objects.all().iterator():
                try:
                    info = book.wldocument().book_info
                except ParseError:
                    if verbose:
                        print("ERROR! Bad XML for book:", book.slug)
                        print("To resolve: republish.")
                        print()
                else:
                    should_be = [p.slug for p in info.parts]
                    is_now = [p.slug for p in book.children.all().order_by('parent_number')]
                    if should_be != is_now:
                        if verbose:
                            print("ERROR! Wrong children for book:", book.slug)
                            # print("Is:       ", is_now)
                            # print("Should be:", should_be)
                            from difflib import ndiff
                            print('\n'.join(ndiff(is_now, should_be)))
                            print("To resolve: republish parent book.")
                            print()

                # Check for ancestry.
                parents = []
                parent = book.parent
                while parent:
                    parents.append(parent)
                    parent = parent.parent
                ancestors = list(book.ancestor.all())
                if set(ancestors) != set(parents):
                    if options['verbose']:
                        print("Wrong ancestry for book:", book)
                        print("Is:       ", ", ".join(ancestors))
                        print("Should be:", ", ".join(parents))
                    if not options['dry_run']:
                        book.repopulate_ancestors()
                        if options['verbose']:
                            print("Fixed.")
                    if options['verbose']:
                        print()

                # TODO: check metadata tags, reset counters