from sqlalchemy import Column, String, Text, Integer, ForeignKey, JSON
from sqlalchemy.orm import relationship
from app.models.base import BaseModel


class Conversation(BaseModel):
    __tablename__ = "conversations"

    user_id = Column(String(36), ForeignKey("users.id"), nullable=False, index=True)
    title = Column(String(500), nullable=True)
    message_count = Column(Integer, default=0)

    messages = relationship("Message", back_populates="conversation", cascade="all, delete-orphan")


class Message(BaseModel):
    __tablename__ = "messages"

    conversation_id = Column(String(36), ForeignKey("conversations.id"), nullable=False, index=True)
    role = Column(String(20), nullable=False)  # user, assistant, system
    content = Column(Text, nullable=False)
    model = Column(String(100), nullable=True)
    tokens_used = Column(Integer, nullable=True)
    attachments = Column(JSON, nullable=True)  # 新增: [{file_id, filename, file_type, file_size}]

    conversation = relationship("Conversation", back_populates="messages")