"""
按 Agent/工作流 + 会话键持久化的用户记忆（MySQL），与 Redis 热缓存配合实现长期记忆。
"""
import uuid

from sqlalchemy import Column, DateTime, String, UniqueConstraint, func
from sqlalchemy.dialects.mysql import CHAR, JSON

from app.core.database import Base


class PersistentUserMemory(Base):
    """会话级记忆快照：同一 scope 下 session_key 唯一。"""

    __tablename__ = "persistent_user_memories"
    __table_args__ = (
        UniqueConstraint("scope_kind", "scope_id", "session_key", name="uq_persistent_mem_scope_session"),
    )

    id = Column(CHAR(36), primary_key=True, default=lambda: str(uuid.uuid4()), comment="主键")
    scope_kind = Column(String(16), nullable=False, comment="agent 或 workflow")
    scope_id = Column(CHAR(36), nullable=False, comment="Agent ID 或 Workflow ID")
    session_key = Column(String(512), nullable=False, comment="调用方传入的 user_id 等会话键")
    payload = Column(JSON, nullable=False, comment="与 Redis 中 user_memory_* 结构一致的记忆 JSON")
    updated_at = Column(
        DateTime,
        server_default=func.now(),
        onupdate=func.now(),
        nullable=True,
        comment="更新时间",
    )

    def __repr__(self):
        return f"<PersistentUserMemory(scope={self.scope_kind}:{self.scope_id}, session={self.session_key[:32]})>"