"""Punto de entrada del servicio de migraciones.

Se ejecuta como init container antes de que arranquen los demás servicios.
Aplica todas las migraciones pendientes hasta 'head' con bloqueo advisory
para evitar condiciones de carrera en despliegues con múltiples réplicas.
"""
from __future__ import annotations

import os
import sys
import logging

from sqlalchemy import create_engine, text
from alembic.config import Config as AlembicConfig
from alembic import command as alembic_command

logging.basicConfig(level=logging.INFO, format="%(levelname)s %(message)s")
log = logging.getLogger(__name__)

DATABASE_URL = os.environ.get(
    "DATABASE_URL",
    "postgresql+psycopg://ipsextractor:ipsextractor@database:5432/ipsextractor",
)


def main() -> None:
    log.info("Conectando a la base de datos…")
    engine = create_engine(DATABASE_URL, pool_pre_ping=True)

    alembic_cfg = AlembicConfig()
    alembic_cfg.set_main_option("script_location", "alembic")
    alembic_cfg.set_main_option("sqlalchemy.url", DATABASE_URL)

    if DATABASE_URL.startswith("postgresql"):
        with engine.connect().execution_options(isolation_level="AUTOCOMMIT") as conn:
            conn.execute(text("SELECT pg_advisory_lock(74512001)"))
            log.info("Bloqueo advisory adquirido — ejecutando migraciones…")
            try:
                alembic_command.upgrade(alembic_cfg, "head")
                log.info("Migraciones completadas.")
            finally:
                conn.execute(text("SELECT pg_advisory_unlock(74512001)"))
    else:
        alembic_command.upgrade(alembic_cfg, "head")
        log.info("Migraciones completadas.")

    engine.dispose()


if __name__ == "__main__":
    try:
        main()
    except Exception as exc:
        log.error("Migraciones fallidas: %s", exc)
        sys.exit(1)