"""
Memory Service - Robust memory management
"""

from datetime import datetime, timezone
from typing import Dict, List
from database import long_term_memory_col, chat_history_col

class MemoryService:
    @staticmethod
    def load_long_memory(user_id: str) -> Dict:
        try:
            return long_term_memory_col.find_one({"user_id": user_id}) or {}
        except Exception as e:
            logging.error(f"[Memory] Load failed: {e}")
            return {}

    @staticmethod
    def save_fact(user_id: str, key: str, value: str):
        try:
            long_term_memory_col.update_one(
                {"user_id": user_id},
                {"$set": {key: value, "last_updated": datetime.now(timezone.utc)}},
                upsert=True
            )
        except Exception as e:
            logging.error(f"[Memory] Save failed: {e}")

    @staticmethod
    def load_recent_memory(user_id: str, limit: int = 8) -> List[Dict]:
        try:
            cursor = chat_history_col.find({"user_id": user_id}).sort("timestamp", -1).limit(limit * 2)
            msgs = list(cursor)
            msgs.reverse()
            pairs = []
            for msg in msgs:
                if msg["role"] == "user":
                    pairs.append({"user": msg["content"], "ai": ""})
                elif msg["role"] == "assistant" and pairs:
                    pairs[-1]["ai"] = msg["content"]
            return [p for p in pairs if p["ai"]]
        except Exception as e:
            logging.error(f"[Memory] Load recent failed: {e}")
            return []