"""消息模型"""
from typing import Optional, Union

from sqlalchemy import JSON, ForeignKey, String
from sqlalchemy.orm import Mapped, mapped_column

from src.models.base import BaseModel


class Message(BaseModel):
    """消息模型"""
    __tablename__ = "messages"

    ROLE_USER = "user"
    ROLE_ASSISTANT = "assistant"
    ROLE_SYSTEM = "system"
    VALID_ROLES = (ROLE_USER, ROLE_ASSISTANT, ROLE_SYSTEM)

    conversation_id: Mapped[str] = mapped_column(
        ForeignKey("conversations.id"),
        nullable=False,
        index=True,
    )
    role: Mapped[str] = mapped_column(String(20), nullable=False)
    content: Mapped[dict] = mapped_column(JSON, nullable=False)
    trace_id: Mapped[Optional[str]] = mapped_column(String(36), index=True, nullable=True)
    meta_info: Mapped[Optional[dict]] = mapped_column(JSON, default=None, nullable=True)