"""
KeyvalDB - 键值数据库（简化版，仅使用 aiosqlite）
"""

import aiosqlite
from loguru import logger
from utils.singleton import Singleton


class KeyvalDB(metaclass=Singleton):
    """键值存储数据库"""

    def __init__(self):
        self.db_path = "database/keyval.db"
        self.conn = None

    async def initialize(self):
        """初始化数据库"""
        self.conn = await aiosqlite.connect(self.db_path)
        await self.conn.execute("""
            CREATE TABLE IF NOT EXISTS keyval (
                key TEXT PRIMARY KEY,
                value TEXT
            )
        """)
        await self.conn.commit()
        logger.debug("KeyvalDB 初始化完成")

    async def set(self, key: str, value: str):
        """设置键值"""
        await self.conn.execute(
            "INSERT OR REPLACE INTO keyval (key, value) VALUES (?, ?)",
            (key, value)
        )
        await self.conn.commit()

    async def get(self, key: str):
        """获取值"""
        cursor = await self.conn.execute(
            "SELECT value FROM keyval WHERE key = ?",
            (key,)
        )
        row = await cursor.fetchone()
        return row[0] if row else None

    async def delete(self, key: str):
        """删除键"""
        await self.conn.execute("DELETE FROM keyval WHERE key = ?", (key,))
        await self.conn.commit()

    async def close(self):
        """关闭连接"""
        if self.conn:
            await self.conn.close()