"""This command manages Closure Tables implementation

It adds new levels and cleans links between Educatives.
This way, it's relatively easy to fetch an entire tree with just one tiny request.

"""

from django.core.management.base import BaseCommand

from ultron.objective.models import Educative, PrerequisiteClosure


class Command(BaseCommand):
    def handle(self, *args, **options):
        educative_list = Educative.objects.all()
        count = 0
        for educative in educative_list:
            updated = False
            max_level = 0
            max_rank = 0
            count += 1
            print(str(count)  + ' - Traitement de ' + str(educative.long_label))
            breadcrumb = educative.breadcrumb()

            for path in range(0, len(breadcrumb)):
                tree = set(PrerequisiteClosure.objects.filter(descendant=educative, path=path))

                for position, ancestor in enumerate(breadcrumb[path]):
                    tree_path, _ = PrerequisiteClosure.objects.get_or_create(
                        ancestor=ancestor, descendant=educative, level=position, path=path
                    )
                    max_level = max(max_level, position)
                    max_rank = max(max_rank, ancestor.rank + 1)
    
                    if tree_path in tree:
                        tree.remove(tree_path)
    
                for tree_path in tree:
                    tree_path.delete()

            # Dans une condition pour espérer accélérer le traitement
            if educative.level != max_level:
                updated = True
                educative.level = max_level

            if educative.rank != max_rank:
                updated = True
                educative.rank = max_rank

            if updated:
                educative.save()