初始化提交

backend/app/models/chat.py

@@ -0,0 +1,52 @@
+"""聊天会话与消息模型。"""
+
+from datetime import datetime
+
+from sqlalchemy import DateTime, ForeignKey, Integer, String, Text
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.core.ids import new_message_id, new_session_id
+from app.core.time import utc_now
+from app.db.base import Base
+
+
+class ChatSession(Base):
+    __tablename__ = "chat_sessions"
+
+    id: Mapped[str] = mapped_column(String(80), primary_key=True, default=new_session_id)
+    character_id: Mapped[str] = mapped_column(String(80), ForeignKey("characters.id"), index=True)
+    title: Mapped[str | None] = mapped_column(String(200))
+    status: Mapped[str] = mapped_column(String(40), nullable=False, default="active", index=True)
+    owner_scope: Mapped[str] = mapped_column(String(80), nullable=False, default="", index=True)
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=utc_now)
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), default=utc_now, onupdate=utc_now
+    )
+
+
+class ChatMessage(Base):
+    __tablename__ = "chat_messages"
+
+    id: Mapped[str] = mapped_column(String(80), primary_key=True, default=new_message_id)
+    character_id: Mapped[str] = mapped_column(String(80), ForeignKey("characters.id"), index=True)
+    session_id: Mapped[str] = mapped_column(String(80), ForeignKey("chat_sessions.id"), index=True)
+    role: Mapped[str] = mapped_column(String(40), nullable=False)
+    content: Mapped[str] = mapped_column(Text, nullable=False)
+    modality: Mapped[str] = mapped_column(String(40), nullable=False, default="text")
+    run_id: Mapped[str | None] = mapped_column(String(80), ForeignKey("runs.id"), index=True)
+    metadata_json: Mapped[str] = mapped_column(Text, nullable=False, default="{}")
+    sensitivity: Mapped[str] = mapped_column(String(40), nullable=False, default="low")
+    versions_json: Mapped[str] = mapped_column(
+        Text,
+        nullable=False,
+        default="[]",
+        comment="版本历史 JSON 数组：[{content, created_at}]，按生成顺序排列，末尾最新",
+    )
+    active_version_idx: Mapped[int] = mapped_column(
+        Integer,
+        nullable=False,
+        default=0,
+        comment="当前活跃版本在 versions_json 中的索引（0-based）",
+    )
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=utc_now)
+    deleted_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))