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):
        """多次 NTP 同步取中位数，提高精度"""
        offsets = []
        servers = ['ntp.aliyun.com', 'ntp.tencent.com', 'pool.ntp.org']
        for server in servers:
            try:
                client = ntplib.NTPClient()
                resp = client.request(server, version=3)
                offsets.append(resp.tx_time - time.time())
            except Exception:
                continue
        if offsets:
            offsets.sort()
            self.offset = offsets[len(offsets) // 2]
            print(f"时间同步完成，偏移量: {self.offset:.3f}s (采样{len(offsets)}个)")
        else:
            print("NTP同步失败，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，最后阶段忙等保证精度"""
        target_dt = datetime.strptime(target_time_str, "%Y-%m-%d %H:%M:%S")
        target_ts = target_dt.timestamp()

        print(f"等待目标时间: {target_time_str}")

        while True:
            now = self.get_server_time()
            remaining = target_ts - now

            if remaining <= 0:
                print("目标时间已到！")
                break
            elif remaining > 10:
                await asyncio.sleep(remaining - 10)
            elif remaining > 2:
                await asyncio.sleep(0.5)
            elif remaining > 0.1:
                await asyncio.sleep(0.01)
            # remaining <= 0.1: 忙等，不 sleep

    async def wait_until_early(self, target_time_str, early_ms=500):
        """提前 early_ms 毫秒触发，用于需要预操作的场景"""
        target_dt = datetime.strptime(target_time_str, "%Y-%m-%d %H:%M:%S")
        target_ts = target_dt.timestamp() - (early_ms / 1000.0)

        while True:
            now = self.get_server_time()
            remaining = target_ts - now
            if remaining <= 0:
                break
            elif remaining > 10:
                await asyncio.sleep(remaining - 10)
            elif remaining > 2:
                await asyncio.sleep(0.5)
            elif remaining > 0.1:
                await asyncio.sleep(0.01)