"""
memory/memory_store.py
Agent 记忆模块：管理对话历史（短期）与关键事实（长期）
新增: add_chain_result() 记录完整多步骤调用链
"""

from collections import deque
from dataclasses import dataclass, field
from datetime import datetime
from typing import TYPE_CHECKING, Literal

from utils.logger import get_logger

if TYPE_CHECKING:
    from mcp.mcp_protocol import ChainResult


# ── 消息数据结构 ───────────────────────────────────────────────
@dataclass
class Message:
    """单条对话消息"""
    role:      Literal["user", "assistant", "tool", "chain"]
    content:   str
    timestamp: str = field(default_factory=lambda: datetime.now().strftime("%H:%M:%S"))
    metadata:  dict = field(default_factory=dict)

    def to_dict(self) -> dict:
        return {
            "role":      self.role,
            "content":   self.content,
            "timestamp": self.timestamp,
        }


# ── 记忆存储 ───────────────────────────────────────────────────
class MemoryStore:
    """
    对话记忆存储

    短期记忆: deque 保存最近 N 轮对话，自动滚动淘汰
    长期记忆: 关键事实列表（生产环境可替换为向量数据库）
    链路记录: 完整的多步骤调用链历史

    使用示例:
        memory = MemoryStore(max_history=20)
        memory.add_user_message("你好")
        memory.add_chain_result(chain_result)
    """

    def __init__(self, max_history: int = 20):
        self.logger      = get_logger("MEMORY")
        self.max_history = max_history
        self._history:   deque[Message] = deque(maxlen=max_history)
        self._facts:     list[str]      = []
        self._chains:    list[dict]     = []   # 调用链历史记录

        self.logger.info(f"💾 Memory 初始化，最大历史: {max_history} 条")

    # ── 写入接口 ────────────────────────────────────────────────

    def add_user_message(self, content: str) -> None:
        self._add(Message(role="user", content=content))

    def add_assistant_message(self, content: str) -> None:
        self._add(Message(role="assistant", content=content))

    def add_tool_result(self, tool_name: str, result: str) -> None:
        self._add(Message(
            role="tool",
            content=result,
            metadata={"tool": tool_name},
        ))

    def add_chain_result(self, chain_result: "ChainResult") -> None:
        """
        记录完整的多步骤调用链结果

        Args:
            chain_result: ChainResult 实例
        """
        # 写入对话历史（assistant 角色）
        self._add(Message(
            role="chain",
            content=chain_result.final_reply,
            metadata={
                "goal":            chain_result.goal,
                "total_steps":     chain_result.total_steps,
                "completed_steps": chain_result.completed_steps,
                "success":         chain_result.success,
                "tools_used":      [r.tool_name for r in chain_result.step_results],
            },
        ))

        # 写入链路追踪记录
        chain_record = {
            "timestamp":  datetime.now().isoformat(),
            "goal":       chain_result.goal,
            "steps":      [
                {
                    "step_id":   r.step_id,
                    "tool_name": r.tool_name,
                    "success":   r.success,
                    "output":    r.output[:200],
                    "error":     r.error,
                }
                for r in chain_result.step_results
            ],
            "success":    chain_result.success,
        }
        self._chains.append(chain_record)
        self.logger.info(
            f"🔗 调用链已记录: {chain_result.completed_steps}/{chain_result.total_steps} 步成功"
        )

    def add_fact(self, fact: str) -> None:
        self._facts.append(fact)
        self.logger.debug(f"📌 长期记忆新增: {fact}")

    # ── 读取接口 ────────────────────────────────────────────────

    def get_history(self, last_n: int | None = None) -> list[dict]:
        messages = list(self._history)
        if last_n:
            messages = messages[-last_n:]
        return [m.to_dict() for m in messages]

    def get_facts(self) -> list[str]:
        return list(self._facts)

    def get_chain_history(self) -> list[dict]:
        """获取所有调用链历史记录"""
        return list(self._chains)

    def get_context_summary(self) -> str:
        """生成上下文摘要，供 LLM Prompt 使用"""
        history = self.get_history(last_n=6)
        lines   = [f"[{m['role'].upper()}] {m['content'][:80]}" for m in history]
        return "\n".join(lines) if lines else "（暂无对话历史）"

    # ── 管理接口 ────────────────────────────────────────────────

    def clear_history(self) -> None:
        self._history.clear()
        self.logger.info("🗑 对话历史已清空")

    def stats(self) -> dict:
        return {
            "history_count": len(self._history),
            "facts_count":   len(self._facts),
            "chain_count":   len(self._chains),
            "max_history":   self.max_history,
        }

    def _add(self, message: Message) -> None:
        self._history.append(message)
        self.logger.debug(f"💬 [{message.role.upper()}] {message.content[:60]}...")