from __future__ import annotations

from celery import Celery

from .settings import settings

celery = Celery(
    "multimailer",
    broker=settings.redis_url,
    backend=settings.redis_url,
)

celery.conf.update(
    task_default_queue="default",
    task_routes={
        "multimailer.send_email": {"queue": "send_email"},
        "multimailer.append_sent": {"queue": "append_sent"},
    },
    worker_prefetch_multiplier=1,
    task_acks_late=True,
    task_reject_on_worker_lost=True,
)


@celery.task(name="multimailer.ping")
def ping():
    return "pong"


@celery.task(name="multimailer.send_email", bind=True, max_retries=None)
def send_email(self, job_id: str):
    """Send one queued campaign job.

    The task records all state changes in the database. Temporary SMTP/network
    failures are retried with the campaign's configured backoff.
    """

    from app.db.models import CampaignVersion, JobSendStatus
    from app.db.session import SessionLocal
    from app.mailer.persistence.campaigns import load_version_config
    from app.mailer.sending.jobs import SendJobError, next_retry_delay, send_campaign_job
    from app.mailer.sending.smtp import SmtpSendError

    with SessionLocal() as session:
        try:
            return send_campaign_job(session, job_id=job_id, enqueue_imap_task=True).as_dict()
        except SmtpSendError as exc:
            # send_campaign_job has already updated the job attempt/status.
            from app.db.models import CampaignJob

            job = session.get(CampaignJob, job_id)
            if job and job.send_status == JobSendStatus.FAILED_TEMPORARY.value:
                version = session.get(CampaignVersion, job.campaign_version_id)
                delay = 60
                if version:
                    try:
                        _, _, config = load_version_config(session, version.id)
                        delay = next_retry_delay(config, job.attempt_count)
                    except Exception:
                        delay = 60
                raise self.retry(exc=exc, countdown=delay)
            raise
        except SendJobError:
            raise


@celery.task(name="multimailer.append_sent", bind=True, max_retries=None)
def append_sent(self, job_id: str):
    """Append the exact sent MIME to the configured IMAP Sent folder."""

    from app.db.session import SessionLocal
    from app.mailer.sending.imap import ImapAppendError
    from app.mailer.sending.jobs import append_sent_for_job

    with SessionLocal() as session:
        try:
            return append_sent_for_job(session, job_id=job_id).as_dict()
        except ImapAppendError as exc:
            if getattr(exc, "temporary", None) is True:
                raise self.retry(exc=exc, countdown=300)
            raise