from django.core.management.base import BaseCommand, CommandParser, CommandError
from django.db.models import DecimalField, F, Sum, Func, Q

from decimal import Decimal

from services.models import Service, ServiceType


class Command(BaseCommand):
    help = 'Gestion des types de services'

    def add_arguments(self, parser):
        cmd = self
        class SubParser(CommandParser):
            def __init__(self, **kwargs):
                super().__init__(cmd, **kwargs)
        subparsers = parser.add_subparsers(dest='command', parser_class=SubParser)
        subparsers.required = True

        parser_list = subparsers.add_parser('list', help='Lister les types de services')

        parser_add = subparsers.add_parser('add', help='Ajouter un nouveau type de service')
        parser_add.add_argument('name', help='Nom du nouveau type de service')

        parser_change = subparsers.add_parser('change', help='Renomer un type de service')
        parser_change.add_argument('old_name', help='Ancien nom')
        parser_change.add_argument('new_name', help='Nouveau nom')

        parser_delete = subparsers.add_parser('delete', help='Supprimer un type de service')
        parser_delete.add_argument('name', help='Nom du type de service')

    def handle(self, *args, **options):
        cmd = options.pop('command')
        getattr(self, 'handle_{cmd}'.format(cmd=cmd))(*args, **options)

    def handle_list(self, *args, **options):
        for st in ServiceType.objects.all():
            self.stdout.write('{:<30} {:4d} services'.format(st.name, st.services.count()))

    def handle_add(self, *args, **options):
        if ServiceType.objects.filter(name=options['name']).exists():
            raise CommandError('Le type de service "%s" existe déjà' % options['name'])
        st = ServiceType.objects.create(name=options['name'])
        self.stdout.write(self.style.SUCCESS('Nouveau type de service "%s" créé avec succès' % st.name))

    def handle_change(self, *args, **options):
        try:
            st = ServiceType.objects.get(name=options['old_name'])
        except ServiceType.DoesNotExist:
            raise CommandError('Le type de service "%s" n’existe pas' % options['old_name'])
        if ServiceType.objects.filter(name=options['new_name']).exists():
            raise CommandError('Le type de service "%s" existe déjà' % options['new_name'])
        st.name = options['new_name']
        st.save()
        self.stdout.write(self.style.SUCCESS('Type de service renommé en "%s"' % options['new_name']))

    def handle_delete(self, *args, **options):
        try:
            st = ServiceType.objects.get(name=options['name'])
        except ServiceType.DoesNotExist:
            raise CommandError('Le type de service "%s" n’existe pas' % options['name'])
        if Service.objects.filter(service_type=st).exists():
            raise CommandError('Il existe des services de type "%s", suppression refusé' % options['name'])
        st.delete()
        self.stdout.write(self.style.SUCCESS('Le type de service "%s" a été supprimé' % options['name']))