"""Refresh listings_search_mv materialized view (daily 3 AM).

Currently tradein-mvp has no Celery infrastructure (verified — no celery_app.py exists
in tradein-mvp/backend/app/). This module provides both:
  - A Celery task wrapper (active only if celery is installed and celery_app present).
  - A plain async refresh_search_matview() callable for cron / one-shot invocation.

NEEDS COORDINATION: main session must decide whether to bootstrap Celery in tradein-mvp
or run via external scheduler (systemd timer / OS cron). Until then, no Beat schedule.
"""

from __future__ import annotations

import logging
import time

import psycopg

from app.core.config import settings

logger = logging.getLogger(__name__)


def refresh_search_matview() -> None:
    """REFRESH MATERIALIZED VIEW CONCURRENTLY listings_search_mv + premium_houses.

    psycopg v3, sync. Logs duration. Idempotent. Safe to run during read traffic
    (CONCURRENTLY). premium_houses (#2002) derives from `listings`, so it is refreshed
    right after the search MV in the same session. Each MV is refreshed independently —
    a failure on one is logged and does not abort the other (autocommit, so a failed
    REFRESH does not leave the connection in an aborted transaction).
    """
    start = time.monotonic()
    # DATABASE_URL is SQLAlchemy dialect form (postgresql+psycopg://...) in tradein-mvp
    # (see tradein-mvp/docker-compose.prod.yml). libpq / psycopg.connect() accepts only
    # postgresql:// or postgres:// — strip the +psycopg dialect prefix.
    dsn = settings.database_url.replace("postgresql+psycopg://", "postgresql://", 1)
    # CONCURRENTLY requires a UNIQUE index on each MV (listings_search_mv,
    # premium_houses_house_id_uidx). Order matters: premium_houses depends on the same
    # `listings` rows, so refresh it after the search MV is fresh.
    matviews = ("listings_search_mv", "premium_houses")
    with psycopg.connect(dsn, autocommit=True) as conn:
        for mv in matviews:
            mv_start = time.monotonic()
            try:
                with conn.cursor() as cur:
                    cur.execute(f"REFRESH MATERIALIZED VIEW CONCURRENTLY {mv}")
            except Exception:
                # Don't let one MV's failure skip the others; surface for alerting.
                logger.exception("%s refresh failed", mv)
            else:
                logger.info("%s refresh completed in %.2fs", mv, time.monotonic() - mv_start)
    logger.info("matview refresh batch completed in %.2fs", time.monotonic() - start)


# Celery-task wrapper — only registers if celery_app exists.
try:
    from app.celery_app import celery_app  # type: ignore[import-not-found]
except ImportError:
    logger.info(
        "Celery not configured in tradein-mvp — refresh_search_matview() callable directly. "
        "Bootstrap app/celery_app.py to enable scheduled execution.",
    )
else:

    @celery_app.task(name="tradein.refresh_search_matview")  # type: ignore[misc]
    def refresh_search_matview_task() -> None:
        """Celery wrapper for refresh_search_matview()."""
        refresh_search_matview()


# =============================================================================
# Beat schedule snippet — paste into app/celery_app.py if/when Celery is bootstrapped:
#
#   from celery.schedules import crontab
#
#   celery_app.conf.beat_schedule = {
#       'tradein-refresh-matview': {
#           'task':     'tradein.refresh_search_matview',
#           'schedule': crontab(hour=3, minute=0),
#       },
#       # ... other tradein beat entries
#   }
#
# Per master plan sec 10.1 ('refresh-search-matview-daily': crontab(minute=0, hour=3)).
# =============================================================================