"""
Database configuration for scheduled downloads.
Uses SQLite with SQLAlchemy ORM for persistent storage.
"""

from sqlalchemy import create_engine, event
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from pathlib import Path
import logging

logger = logging.getLogger(__name__)

# Database file location - uses /app/data in Docker container
# This directory should be mounted as a volume for persistence
DATA_DIR = Path(__file__).parent.parent / "data"
DB_PATH = DATA_DIR / "scheduled_tasks.db"

# Ensure data directory exists (will be mounted volume in Docker)
DATA_DIR.mkdir(parents=True, exist_ok=True)

# Create engine with proper settings for SQLite in Docker
engine = create_engine(
    f"sqlite:///{DB_PATH}",
    echo=False,
    connect_args={
        "check_same_thread": False,  # Allow multi-threaded access
        "timeout": 30  # Longer timeout for container I/O
    },
    pool_pre_ping=True,  # Verify connections before using
)

# Enable foreign keys for SQLite
@event.listens_for(engine, "connect")
def set_sqlite_pragma(dbapi_conn, connection_record):
    cursor = dbapi_conn.cursor()
    cursor.execute("PRAGMA foreign_keys=ON")
    cursor.close()

# Create session factory
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

# Base class for models
Base = declarative_base()


def init_database():
    """Initialize database - called on container startup"""
    try:
        Base.metadata.create_all(bind=engine)
        logger.info(f"Database initialized at {DB_PATH}")
    except Exception as e:
        logger.error(f"Failed to initialize database: {e}")
        raise


def get_db():
    """
    Dependency for FastAPI to get database session.
    
    Usage:
        @app.get("/endpoint")
        def endpoint(db: Session = Depends(get_db)):
            ...
    """
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()