from __future__ import annotations

from functools import lru_cache

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

from app.core.config import get_settings


@lru_cache
def get_engine():
    settings = get_settings()
    return create_engine(
        settings.mysql_dsn,
        pool_pre_ping=True,
        future=True,
    )


SessionLocal = sessionmaker(bind=get_engine(), autoflush=False, autocommit=False, future=True)


def get_db() -> Session:
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def check_database_health() -> dict[str, object]:
    settings = get_settings()
    with get_engine().connect() as conn:
        current_db = conn.execute(text("SELECT DATABASE()")).scalar()
        version = conn.execute(text("SELECT VERSION()")).scalar()
        table_count = conn.execute(
            text(
                """
                SELECT COUNT(*)
                FROM information_schema.tables
                WHERE table_schema = :schema_name
                """
            ),
            {"schema_name": settings.mysql_database},
        ).scalar()
    return {
        "connected": True,
        "database": current_db,
        "version": version,
        "table_count": int(table_count or 0),
    }