import os
from typing import AsyncGenerator

from fastapi import Depends
from fastapi_users.db import SQLAlchemyBaseUserTableUUID, SQLAlchemyUserDatabase
from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
from sqlalchemy.ext.declarative import DeclarativeMeta, declarative_base
from sqlalchemy.orm import sessionmaker

DATABASE_URL = os.getenv("DATABASE_URL")
if not DATABASE_URL:
    mariadb_host = os.getenv("MARIADB_HOST", "localhost")
    mariadb_port = os.getenv("MARIADB_PORT", "3306")
    mariadb_db = os.getenv("MARIADB_DB", "group_project")
    mariadb_user = os.getenv("MARIADB_USER", "root")
    mariadb_password = os.getenv("MARIADB_PASSWORD", "strongpassword")
    #always use SSL except for localhost - i dont want to include certs
    ssl_param = "?ssl=true" if mariadb_host != "localhost" else ""

    if mariadb_host and mariadb_db and mariadb_user and mariadb_password:
        # Use MariaDB/MySQL over async driver
        DATABASE_URL = f"mysql+asyncmy://{mariadb_user}:{mariadb_password}@{mariadb_host}:{mariadb_port}/{mariadb_db}{ssl_param}"
    else:
        raise Exception("Only MariaDB is supported. Please set the DATABASE_URL environment variable.")

Base: DeclarativeMeta = declarative_base()


class User(SQLAlchemyBaseUserTableUUID, Base):
    pass


engine = create_async_engine(
    DATABASE_URL,
    pool_pre_ping=True,
    echo=os.getenv("SQL_ECHO", "0") == "1",
)
async_session_maker = sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)


async def create_db_and_tables():
    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)


async def get_async_session() -> AsyncGenerator[AsyncSession, None]:
    async with async_session_maker() as session:
        yield session


async def get_user_db(session: AsyncSession = Depends(get_async_session)):
    yield SQLAlchemyUserDatabase(session, User)