# ============================================
# Projet   : API-KA
# Fichier  : src/database/db.py
# Node     : m3u96b
# Author   : Simon-Pierre Boucher
# Contact  : contact@spboucher.ai
# Date     : 2026-08-16
# ============================================
"""Engine SQLAlchemy, sessions, initialisation du schéma et healthcheck DB."""

from __future__ import annotations

import argparse
from collections.abc import Iterator
from contextlib import contextmanager

from sqlalchemy import Engine, create_engine, text
from sqlalchemy.orm import Session, sessionmaker

from src.config import get_settings, verify_node
from src.database.models import Base

_engine: Engine | None = None
_session_factory: sessionmaker[Session] | None = None


def get_engine() -> Engine:
    """Retourne l'engine SQLAlchemy (créé paresseusement, pool_pre_ping actif)."""
    global _engine
    if _engine is None:
        settings = get_settings()
        kwargs: dict = {"pool_pre_ping": True}
        if settings.database_url.startswith("sqlite"):
            kwargs["connect_args"] = {"check_same_thread": False}
        _engine = create_engine(settings.database_url, **kwargs)
    return _engine


def get_session_factory() -> sessionmaker[Session]:
    """Retourne la fabrique de sessions liée à l'engine courant."""
    global _session_factory
    if _session_factory is None:
        _session_factory = sessionmaker(bind=get_engine(), expire_on_commit=False)
    return _session_factory


def reset_engine() -> None:
    """Réinitialise l'engine (utilisé par les tests après changement de config)."""
    global _engine, _session_factory
    if _engine is not None:
        _engine.dispose()
    _engine = None
    _session_factory = None


@contextmanager
def session_scope() -> Iterator[Session]:
    """Session transactionnelle : commit en sortie, rollback sur exception."""
    session = get_session_factory()()
    try:
        yield session
        session.commit()
    except Exception:
        session.rollback()
        raise
    finally:
        session.close()


def get_db() -> Iterator[Session]:
    """Dépendance FastAPI fournissant une session par requête."""
    session = get_session_factory()()
    try:
        yield session
    finally:
        session.close()


def init_db() -> None:
    """Crée toutes les tables si elles n'existent pas (idempotent)."""
    Base.metadata.create_all(get_engine())


def healthcheck() -> bool:
    """Vérifie que la base répond (SELECT 1)."""
    try:
        with get_engine().connect() as conn:
            conn.execute(text("SELECT 1"))
        return True
    except Exception:
        return False


def main() -> None:
    """Point d'entrée CLI : ``python -m src.database.db --init``."""
    from src.utils.logger import get_logger

    parser = argparse.ArgumentParser(description="Gestion de la base API-KA (m3u96b)")
    parser.add_argument("--init", action="store_true", help="Créer les tables")
    args = parser.parse_args()

    verify_node()
    logger = get_logger("apika.db")
    if args.init:
        init_db()
        logger.info("Base initialisée", extra={"database_ok": healthcheck()})
    else:
        logger.info("Healthcheck base", extra={"database_ok": healthcheck()})


if __name__ == "__main__":
    main()