"""
Database utilities for chat history.
"""

from typing import Iterator

from psycopg_pool import ConnectionPool

from app.core.chatbot.config import DATABASE_URL

# Connection pool for efficient connection management
# min_size=1 keeps at least 1 connection ready
# max_size=10 limits concurrent connections
_connection_pool = None


def get_connection_pool() -> ConnectionPool:
    """Get or create the connection pool (lazy initialization)."""

    global _connection_pool
    if _connection_pool is None:
        _connection_pool = ConnectionPool(
            DATABASE_URL,
            min_size=1,
            max_size=10,
            kwargs={"connect_timeout": 10},
        )
    return _connection_pool


def get_db_connection():
    """Get a database connection from the pool."""

    return get_connection_pool().connection()


def db_connection_dependency() -> Iterator:
    """FastAPI dependency that yields a pooled DB connection."""

    with get_db_connection() as conn:
        yield conn