from sqlalchemy import create_engine, event
from sqlalchemy.orm import sessionmaker
from sqlalchemy.pool import QueuePool
import backend.config.settings as settings

engine = create_engine(
    settings.DATABASE_URL,
    poolclass=QueuePool,
    pool_size=20,
    max_overflow=30,
    pool_pre_ping=True,
    pool_recycle=1800,
    pool_timeout=30,
    connect_args={} if 'postgresql' in settings.DATABASE_URL else {"check_same_thread": False}
)

@event.listens_for(engine, "connect")
def set_sqlite_pragma(dbapi_connection, connection_record):
    if "sqlite" in settings.DATABASE_URL:
        cursor = dbapi_connection.cursor()
        cursor.execute("PRAGMA journal_mode=WAL")
        cursor.execute("PRAGMA synchronous=NORMAL")
        cursor.execute("PRAGMA busy_timeout=5000")
        cursor.close()

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

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

import hashlib
from datetime import datetime

def hash_phone(phone: str) -> str:
    return hashlib.sha256(phone.encode()).hexdigest()[:32]

def get_language_preference(user_hash, db):
  from backend.database.postgres.models.users import User
  user = db.query(User).filter(User.user_hash == user_hash).first()
  return user.language_preference if user else None

def save_language_preference(
  user_hash, language, db
):
  from backend.database.postgres.models.users import User
  existing = db.query(User).filter(User.user_hash == user_hash).first()
  if existing:
    existing.language_preference = language
    existing.updated_at = datetime.utcnow()
  else:
    from core.auth import hash_password
    db.add(User(
      user_hash=user_hash,
      language_preference=language,
      pin_hash=hash_password("changeme"),  # Requires password reset on first login
    ))
  db.commit()

def delete_language_preference(user_hash, db):
  from backend.database.postgres.models.users import User
  user = db.query(User).filter(User.user_hash == user_hash).first()
  if user:
    user.language_preference = "en"
    db.commit()