import time
import asyncio
import ntplib
from datetime import datetime

class PrecisionTimer:
    def __init__(self):
        self.offset = 0 # 服务器时间 - 本地时间

    def sync_time(self):
        """
        同步 NTP 时间，计算偏移量
        """
        try:
            client = ntplib.NTPClient()
            response = client.request('pool.ntp.org', version=3)
            self.offset = response.tx_time - time.time()
            print(f"时间同步完成，偏移量: {self.offset:.3f}s")
        except Exception as e:
            print(f"NTP同步失败: {e}，将使用系统时间")

    def get_server_time(self):
        return time.time() + self.offset

    async def wait_until(self, target_time_str):
        """
        等待直到目标时间 (格式: 2026-02-01 10:00:00)
        """
        target_dt = datetime.strptime(target_time_str, "%Y-%m-%d %H:%M:%S")
        target_timestamp = target_dt.timestamp()
        
        print(f"正在等待目标时间: {target_time_str}")
        
        while True:
            current_time = self.get_server_time()
            remaining = target_timestamp - current_time
            
            if remaining <= 0:
                print("目标时间已到！触发抢购！")
                break
            
            # 动态调整调整休眠时间以节省 CPU 并保持精度
            if remaining > 1:
                await asyncio.sleep(remaining - 0.5)
            elif remaining > 0.1:
                await asyncio.sleep(0.01)
            else:
                # 最后一刻进入忙等以获取最高精度
                pass