from sqlalchemy import create_engine, Column, Integer, String, DateTime
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from datetime import datetime
import hashlib

DATABASE_URL = "sqlite:///./hemo_users.db"

engine = create_engine(DATABASE_URL, connect_args={"check_same_thread": False})
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
Base = declarative_base()

class User(Base):
    __tablename__ = "users"

    id = Column(Integer, primary_key=True, index=True)
    username = Column(String, unique=True, index=True)
    email = Column(String, unique=True, index=True)
    hashed_password = Column(String)
    created_at = Column(DateTime, default=datetime.utcnow)

def init_db():
    Base.metadata.create_all(bind=engine)

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

def hash_password(password: str) -> str:
    return hashlib.sha256(password.encode()).hexdigest()

def verify_password(plain_password: str, hashed_password: str) -> bool:
    return hash_password(plain_password) == hashed_password