import sqlite3
import json
from typing import List, Dict

class MemoryManager:
    def __init__(self, db_path: str = "memory.db"):
        self.db_path = db_path
        self._init_db()

    def _init_db(self):
        with sqlite3.connect(self.db_path) as conn:
            conn.execute("""
                CREATE TABLE IF NOT EXISTS sessions (
                    session_id TEXT PRIMARY KEY,
                    history TEXT
                )
            """)
            conn.commit()

    def get_history(self, session_id: str) -> List[Dict[str, str]]:
        with sqlite3.connect(self.db_path) as conn:
            cursor = conn.execute("SELECT history FROM sessions WHERE session_id = ?", (session_id,))
            row = cursor.fetchone()
            if row:
                return json.loads(row[0])
            return []

    def save_message(self, session_id: str, role: str, content: str):
        history = self.get_history(session_id)
        history.append({"role": role, "content": content})
        
        # Keep only last 10 messages for context window management if needed, 
        # but the prompt says persistent history.
        
        with sqlite3.connect(self.db_path) as conn:
            conn.execute("""
                INSERT OR REPLACE INTO sessions (session_id, history)
                VALUES (?, ?)
            """, (session_id, json.dumps(history)))
            conn.commit()

    def clear_session(self, session_id: str):
        with sqlite3.connect(self.db_path) as conn:
            conn.execute("DELETE FROM sessions WHERE session_id = ?", (session_id,))
            conn.commit()

memory_manager = MemoryManager()