using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace Common
{
    public class CPUData
    {
        public static PerformanceCounter cpuCounter = new PerformanceCounter("Processor", "% Processor Time", "_Total");
        public static double GetCPU()
        {
            try
            {
                cpuCounter.NextValue(); // 初始化计数器，让它开始计数
                System.Threading.Thread.Sleep(1000); // 等待一秒
                double cpuUsage = cpuCounter.NextValue(); // 获取CPU使用率
                return cpuUsage;
            }
            catch (Exception ex)
            {
                throw;
            }
        }

        [DllImport("kernel32.dll")]
        private static extern void GetSystemTimePreciseAsFileTime(out long fileTime);

        // 将 FILETIME (long) 转换为 DateTime
        public static DateTime GetNowPrecise()
        {
            long fileTime;
            GetSystemTimePreciseAsFileTime(out fileTime);
            DateTime localTime = DateTime.FromFileTimeUtc(fileTime).ToLocalTime();
            return localTime;

        }
    }
    public class CpuMonitor
    {
        // 将静态初始化改为延迟加载，并将异常处理移至初始化时
        private static PerformanceCounter _cpuCounter = null;
        private static readonly object _lock = new object();
        private static Exception _initException = null;

        private static void InitializeCounter()
    {
        if (_initException != null) throw _initException;
        if (_cpuCounter != null) return;

        lock (_lock)
        {
            if (_cpuCounter != null) return;

            try
            {
                // 尝试创建计数器
                _cpuCounter = new PerformanceCounter("Processor", "% Processor Time", "_Total");
                // 立即调用一次 NextValue 来初始化
                _cpuCounter.NextValue();
            }
            catch (Exception ex)
            {
                throw _initException;
            }
        }
    }

        public static double GetCurrentCpuUsage()
        {
            try
            {
                CpuMonitor.InitializeCounter(); // 确保计数器已初始化
                _cpuCounter.NextValue(); // 首次调用返回0，用于初始化本次采样
                System.Threading.Thread.Sleep(1000); // 等待采样间隔
                return _cpuCounter.NextValue(); // 返回过去一秒内的平均使用率
            }
            catch
            {
                // 记录日志或返回一个错误标识值，例如 -1
                return -1;
            }
        }
    }
}
