from django.db.models import Prefetch, Q
from django.utils import timezone

import celery
from datetime import timedelta

from .models import DBBackup, DB
from .backup_engine import MySQLBackupEngine, PostgreSQLBackupEngine


@celery.shared_task
def start_backup(backup_id):
    backupdb = DBBackup.objects.get(id=backup_id)
    # task_id can be none if it's not a celery task (for ex : if running the function without apply it)
    task_id = start_backup.request.id

    klass = None
    match backupdb.db.db_type:
        case "mysql":
            klass = MySQLBackupEngine

        case "postgres":
            klass = PostgreSQLBackupEngine

        case _:
            pass

    if klass:
        be = klass(backupdb=backupdb)
        be.run(task_id)

    # if start_backup.request.id:
    #     # running from celery task
    #     pass
    # else:
    #     # running from standard function
    #     pass


@celery.shared_task
def job_check_daily_backup():
    now = timezone.now()

    for db in DB.objects.all():
        # check if need backup
        last_backup: DBBackup = (db.backups.order_by("-date_created")
                                 .filter(Q(status="ok") | Q(status="running") | Q(status="waiting"))
                                 .first())
        if not last_backup or last_backup.date_created < (now - timedelta(hours=24)):
            DBBackup.objects.create(db=db)

        for backup in db.backups.filter(date_created__lt=now - timedelta(days=30)):
            backup.set_expired()