import logging
import os

from alembic import command
from alembic.config import Config
from alembic.runtime.migration import MigrationContext
from sqlalchemy import create_engine, inspect, text
from sqlalchemy.orm import Session, sessionmaker

logger = logging.getLogger("pops")


def _db_url() -> str:
    return (
        f"mysql+pymysql://{os.environ['MYSQL_USER']}:{os.environ['MYSQL_PASSWORD']}"
        f"@{os.environ['MYSQL_HOST']}:{os.environ.get('MYSQL_PORT', 3306)}"
        f"/{os.environ['MYSQL_DATABASE']}"
    )


engine = create_engine(_db_url(), pool_pre_ping=True)
SessionLocal = sessionmaker(bind=engine)


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


def run_migrations() -> None:
    alembic_cfg = Config("alembic.ini")
    with engine.connect() as conn:
        current_rev = MigrationContext.configure(conn).get_current_revision()
    if current_rev is None:
        if "printers" in inspect(engine).get_table_names():
            logger.info("Existing schema detected, stamping Alembic to head")
            command.stamp(alembic_cfg, "head")
        else:
            logger.info("Fresh database, running migrations")
            command.upgrade(alembic_cfg, "head")
    else:
        command.upgrade(alembic_cfg, "head")


def check_db() -> tuple[bool, str]:
    try:
        with engine.connect() as conn:
            conn.execute(text("SELECT 1"))
        return True, "ok"
    except Exception as e:
        return False, str(e)