import os
from datetime import datetime
from sqlalchemy import create_engine, Column, Integer, String, DateTime, Text, ForeignKey, JSON
from sqlalchemy.orm import declarative_base, sessionmaker, relationship

DB_PATH = os.path.join(os.path.dirname(os.path.dirname(__file__)), "careerai.db")
engine = create_engine(f"sqlite:///{DB_PATH}", 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)
    email = Column(String, unique=True, index=True, nullable=False)
    name = Column(String, nullable=False)
    picture = Column(String, nullable=True)
    hashed_password = Column(String, nullable=True)
    google_id = Column(String, unique=True, index=True, nullable=True)
    created_at = Column(DateTime, default=datetime.utcnow)

    conversations = relationship("Conversation", back_populates="user", cascade="all, delete-orphan")

class Conversation(Base):
    __tablename__ = "conversations"

    id = Column(String, primary_key=True, index=True) # UUID string from frontend
    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    title = Column(String, nullable=False)
    messages = Column(JSON, nullable=False, default=list) # Store messages as JSON
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    user = relationship("User", back_populates="conversations")

# Create all tables
Base.metadata.create_all(bind=engine)

# Dependency to get DB session
def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()