"""Utility for applying Alembic migrations before application startup."""
from __future__ import annotations

import logging
from pathlib import Path

from alembic import command
from alembic.config import Config
from dotenv import load_dotenv

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)


def _load_env() -> None:
    """Ensure environment variables from .env are available."""
    load_dotenv()


def _alembic_config(project_root: Path) -> Config:
    config_path = project_root / "alembic.ini"
    if not config_path.exists():
        raise FileNotFoundError(f"Missing alembic.ini at {config_path}")

    config = Config(str(config_path))
    config.set_main_option("script_location", str(project_root / "alembic"))
    return config


def run_migrations(target_revision: str = "head") -> None:
    """Apply Alembic migrations up to the given revision."""
    project_root = Path(__file__).resolve().parent.parent
    _load_env()

    config = _alembic_config(project_root)
    logger.info("Applying database migrations up to %s", target_revision)
    command.upgrade(config, target_revision)
    logger.info("Database migrations applied successfully")


if __name__ == "__main__":
    run_migrations()