92 lines
3.0 KiB
Python
92 lines
3.0 KiB
Python
"""记忆上下文组装与检索结果数据结构（纯领域，无 IO）。
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``MemoryRetrievalResult`` 持有已加载的 Memory ORM 实例（由 services/memory 检索后传入），
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``build_memory_context`` 把它组装成注入上下文的文本。本模块只接收已加载数据、输出结构化对象。
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"""
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from __future__ import annotations
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from datetime import UTC, datetime
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from pydantic import BaseModel, ConfigDict
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from app.core.time import utc_now
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from app.models.memory import Memory
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class MemoryRetrievalResult(BaseModel):
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"""记忆检索结果（持有已加载的 Memory ORM 实例列表）。"""
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model_config = ConfigDict(arbitrary_types_allowed=True)
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memories: list[Memory]
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def _to_aware(dt: datetime | None) -> datetime | None:
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"""确保 datetime 有时区信息，naive 视为 UTC。"""
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if dt is None:
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return None
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if dt.tzinfo is None:
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return dt.replace(tzinfo=UTC)
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return dt
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def build_memory_context(result: MemoryRetrievalResult, *, max_length: int = 3000) -> str | None:
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"""把检索到的记忆组装成注入上下文的文本；无记忆时返回 None。
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按**重要性降序**排列，每条附带重要性标签和相对时间。
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超过 ``max_length`` 字符时截断，避免上下文窗口膨胀。
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"""
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if not result.memories:
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return None
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now = utc_now()
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def _mem_sort_key(m: Memory) -> float:
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"""排序键：重要性（越高越优先），同时辅助时间衰减。"""
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ca = _to_aware(m.created_at)
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hours_ago = (now - ca).total_seconds() / 3600 if ca else 0
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decay = max(0.5, 1.0 - hours_ago / 720) # 30 天内缓慢衰减
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return (m.importance or 0.5) * decay
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sorted_mems = sorted(result.memories, key=_mem_sort_key, reverse=True)
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lines: list[str] = []
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total_chars = 0
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for idx, item in enumerate(sorted_mems):
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importance_label = _importance_label(item.importance)
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ca = _to_aware(item.created_at)
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hours_ago = (now - ca).total_seconds() / 3600 if ca else 0
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time_label = _time_ago_str(hours_ago)
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line = f"- 「{item.title}」{time_label} [{importance_label}]\n {item.content}"
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line_len = len(line) + 1 # +1 for newline
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if total_chars + line_len > max_length:
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remaining = len(sorted_mems) - idx
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if remaining > 0:
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lines.append(f"…以及 {remaining} 条其他记忆（已截断）")
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break
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lines.append(line)
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total_chars += line_len
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return "相关记忆：\n" + "\n".join(lines)
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def _importance_label(importance: float) -> str:
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if importance >= 0.8:
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return "★重要"
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if importance >= 0.5:
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return "●一般"
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return "○参考"
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def _time_ago_str(hours_ago: float) -> str:
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if hours_ago < 1:
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return "刚刚"
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if hours_ago < 24:
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return f"{int(hours_ago)}小时前"
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days = int(hours_ago / 24)
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if days < 30:
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return f"{days}天前"
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months = int(days / 30)
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return f"{months}个月前"
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