using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Management;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace IOTContainer.Common
{
    public static class SystemUsage
    {
        #region 获取CPU使用率

        #region AIP声明 
        [DllImport("IpHlpApi.dll")]
        extern static public uint GetIfTable(byte[] pIfTable, ref uint pdwSize, bool bOrder);

        [DllImport("User32")]
        private extern static int GetWindow(int hWnd, int wCmd);

        [DllImport("User32")]
        private extern static int GetWindowLongA(int hWnd, int wIndx);

        [DllImport("user32.dll")]
        private static extern bool GetWindowText(int hWnd, StringBuilder title, int maxBufSize);

        [DllImport("user32", CharSet = CharSet.Auto)]
        private extern static int GetWindowTextLength(IntPtr hWnd);
        #endregion

        public static float? GetCpuUsedRate()
        {
            try
            {
                PerformanceCounter pcCpuLoad;
                pcCpuLoad = new PerformanceCounter("Processor", "% Processor Time", "_Total")
                {
                    MachineName = "."
                };
                pcCpuLoad.NextValue();
                Thread.Sleep(1500);
                float CpuLoad = pcCpuLoad.NextValue();

                return CpuLoad;
            }
            catch
            {
            }
            return 0;
        }
        #endregion
        #region 获取内存使用率
        #region 可用内存

        /// <summary>
        ///     获取可用内存
        /// </summary>
        internal static long? GetMemoryAvailable()
        {

            long availablebytes = 0;
            var managementClassOs = new ManagementClass("Win32_OperatingSystem");
            foreach (var managementBaseObject in managementClassOs.GetInstances())
                if (managementBaseObject["FreePhysicalMemory"] != null)
                    availablebytes = 1024 * long.Parse(managementBaseObject["FreePhysicalMemory"].ToString());
            return availablebytes / MbDiv;

        }

        #endregion
        internal static double? GetMemoryUsed()
        {
            float? PhysicalMemory = GetPhysicalMemory();
            float? MemoryAvailable = GetMemoryAvailable();
            double? MemoryUsed = (double?)(PhysicalMemory - MemoryAvailable);
            double currentMemoryUsed = (double)MemoryUsed;
            return currentMemoryUsed;
        }
        private static long? GetPhysicalMemory()
        {
            //获得物理内存
            var managementClass = new ManagementClass("Win32_ComputerSystem");
            var managementObjectCollection = managementClass.GetInstances();
            long PhysicalMemory;
            foreach (var managementBaseObject in managementObjectCollection)
                if (managementBaseObject["TotalPhysicalMemory"] != null)
                {
                    return long.Parse(managementBaseObject["TotalPhysicalMemory"].ToString()) / MbDiv;
                }
            return null;

        }
        public static double? GetMemoryUsedRate()
        {
            float? PhysicalMemory = GetPhysicalMemory();
            float? MemoryAvailable = GetMemoryAvailable();
            double? MemoryUsedRate = (double?)(PhysicalMemory - MemoryAvailable) / PhysicalMemory;
            return MemoryUsedRate.HasValue ? Convert.ToDouble(MemoryUsedRate * 100) : 0;
        }
        #endregion

        #region 单位转换进制

        private const int KbDiv = 1024;
        private const int MbDiv = 1024 * 1024;
        private const int GbDiv = 1024 * 1024 * 1024;

        #endregion
        #region 获取磁盘占用率
        internal static double GetUsedDiskPercent()
        {
            float? usedSize = GetUsedDiskSize();
            float? totalSize = GetTotalSize();
            double? percent = (double?)usedSize / totalSize;
            return percent.HasValue ? Convert.ToDouble(percent * 100) : 0;
        }

        internal static float? GetUsedDiskSize()
        {
            var currentDrive = GetCurrentDrive();
            float UsedDiskSize = (long)currentDrive?.TotalSize - (long)currentDrive?.TotalFreeSpace;
            return UsedDiskSize / MbDiv;
        }

        internal static float? GetTotalSize()
        {
            var currentDrive = GetCurrentDrive();

            float TotalSize = (long)currentDrive?.TotalSize / MbDiv;
            return TotalSize;
        }

        /// <summary>
        /// 获取当前执行的盘符信息
        /// </summary>
        /// <returns></returns>
        private static DriveInfo GetCurrentDrive()
        {
            string path = Application.StartupPath.ToString().Substring(0, 3);
            return DriveInfo.GetDrives().FirstOrDefault<DriveInfo>(p => p.Name.Equals(path));
        }
        #endregion

    }
}