models.py

from pydantic import BaseModel
from typing import Optional
from sqlalchemy import create_engine, Column, Integer, String, Text, DateTime, ForeignKey
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker, relationship
from datetime import datetime

Base = declarative_base()
engine = create_engine('sqlite:///chat_history.db')
SessionLocal = sessionmaker(bind=engine)

class Conversation(Base):
    __tablename__ = 'conversations'
    
    id = Column(Integer, primary_key=True)
    pdf_name = Column(String(255))
    created_at = Column(DateTime, default=datetime.utcnow)
    messages = relationship("Message", back_populates="conversation")

class Message(Base):
    __tablename__ = 'messages'
    
    id = Column(Integer, primary_key=True)
    conversation_id = Column(Integer, ForeignKey('conversations.id'))
    role = Column(String(50))  # 'user' or 'assistant'
    content = Column(Text)
    created_at = Column(DateTime, default=datetime.utcnow)
    conversation = relationship("Conversation", back_populates="messages")

# Create tables
Base.metadata.create_all(engine)

class UserRequest(BaseModel):
    instruction: str
    pdf_file: bytes