import os
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy.pool import NullPool
from sqlalchemy import event, text
import logging

from database.models.generic_model import Base

logger = logging.getLogger(__name__)

DATABASE_URL = os.getenv("DATABASE_URL")


def _configure_sqlite_connection(dbapi_connection, connection_record):
    cursor = dbapi_connection.cursor()
    cursor.execute("PRAGMA journal_mode=WAL")
    cursor.execute("PRAGMA busy_timeout=30000")
    cursor.execute("PRAGMA synchronous=NORMAL")
    cursor.execute("PRAGMA cache_size=-64000")  # 64MB
    cursor.execute("PRAGMA foreign_keys=ON")
    cursor.execute("PRAGMA locking_mode=NORMAL")
    cursor.close()

    logger.debug("SQLite configuré avec WAL mode et busy_timeout=30s")


engine_kwargs = {
    "echo": False,
    "future": True,
    "poolclass": NullPool,
}

if DATABASE_URL and "sqlite" in DATABASE_URL:
    engine_kwargs["connect_args"] = {
        "check_same_thread": False,
        "timeout": 30,
    }

engine = create_async_engine(DATABASE_URL, **engine_kwargs)

if DATABASE_URL and "sqlite" in DATABASE_URL:

    @event.listens_for(engine.sync_engine, "connect")
    def set_sqlite_pragma(dbapi_connection, connection_record):
        _configure_sqlite_connection(dbapi_connection, connection_record)


async_session_factory = async_sessionmaker(
    engine,
    class_=AsyncSession,
    expire_on_commit=False,
    autoflush=False,
)


async def init_db():
    logger.info("Debut init_db")
    try:
        logger.info("Tentative de connexion")
        async with engine.begin() as conn:
            logger.info("Connexion etablie")

            if DATABASE_URL and "sqlite" in DATABASE_URL:
                result = await conn.execute(text("PRAGMA journal_mode"))
                journal_mode = result.scalar()
                logger.info(f"SQLite journal_mode: {journal_mode}")

            await conn.run_sync(Base.metadata.create_all)
            logger.info("create_all execute")

        logger.info("Base de données initialisée avec succès")
        logger.info(f"Fichier DB: {DATABASE_URL}")

    except Exception as e:
        logger.error(f"Erreur initialisation DB: {e}")
        raise


async def get_session() -> AsyncSession:
    async with async_session_factory() as session:
        yield session


async def close_db():
    await engine.dispose()
    logger.info("Connexions DB fermées")


async def execute_with_sqlite_retry(
    session: AsyncSession, statement, max_retries: int = 5, base_delay: float = 0.1
):
    import asyncio
    from sqlalchemy.exc import OperationalError

    last_error = None

    for attempt in range(max_retries):
        try:
            result = await session.execute(statement)
            return result
        except OperationalError as e:
            last_error = e
            if "database is locked" in str(e).lower():
                delay = base_delay * (2**attempt)
                logger.warning(
                    f"SQLite locked, tentative {attempt + 1}/{max_retries}, "
                    f"retry dans {delay:.2f}s"
                )
                await asyncio.sleep(delay)
            else:
                raise

    raise last_error


async def commit_with_retry(
    session: AsyncSession, max_retries: int = 5, base_delay: float = 0.1
):
    import asyncio
    from sqlalchemy.exc import OperationalError

    last_error = None

    for attempt in range(max_retries):
        try:
            await session.commit()
            return
        except OperationalError as e:
            last_error = e
            if "database is locked" in str(e).lower():
                delay = base_delay * (2**attempt)
                logger.warning(
                    f"SQLite locked lors du commit, tentative {attempt + 1}/{max_retries}, "
                    f"retry dans {delay:.2f}s"
                )
                await asyncio.sleep(delay)
            else:
                raise

    raise last_error