using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.ComponentModel;
using System.Runtime.InteropServices;
using DTS.Common.Utilities.Logging;

namespace DTS.Common.Utilities
{
    public class PowerManagement
    {
        [DllImport("powrprof.dll")]
        static extern uint PowerGetActiveScheme(
            IntPtr UserRootPowerKey,
            ref IntPtr ActivePolicyGuid);

        [DllImport("powrprof.dll")]
        static extern uint PowerReadACValue(
            IntPtr RootPowerKey,
            IntPtr SchemeGuid,
            IntPtr SubGroupOfPowerSettingGuid,
            ref Guid PowerSettingGuid,
            ref int Type,
            ref IntPtr Buffer,
            ref uint BufferSize
            );

        [DllImport("powrprof.dll", CharSet = CharSet.Unicode)]
        static extern uint PowerReadFriendlyName(
            IntPtr RootPowerKey,
            IntPtr SchemeGuid,
            IntPtr SubGroupOfPowerSettingGuid,
            IntPtr PowerSettingGuid,
            StringBuilder Buffer,
            ref uint BufferSize
            );

        [DllImport("kernel32.dll")]
        static extern IntPtr LocalFree(
            IntPtr hMem
            );
        [DllImport("powrprof.dll")]
        static extern uint PowerEnumerate(
            IntPtr RootPowerKey,
            IntPtr SchemeGuid,
            ref Guid SubGroupOfPowerSetting,
            uint AccessFlags,
            uint Index,
            ref Guid Buffer,
            ref uint BufferSize);

        private const uint ERROR_MORE_DATA = 234;
        private static Guid HIGH_PERFORMANCE_GUID = new Guid("8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c");
        private static Guid MAX_PERFORMANCE_GUID = new Guid("01360e7e-525f-4625-ab94-f283dcfbd515");
        //private static Guid GUID_PROCESSOR_SETTINGS_SUBGROUP = new Guid("GUID_PROCESSOR_SETTINGS_SUBGROUP");
        //private static Guid GUID_POWERSCHEME_PERSONALITY = new Guid(0x245D8541, 0x3943, 0x4422, 0xB0, 0x25, 0x13, 0xA7, 0x84, 0xF6, 0x79, 0xB7);
        private static Guid GUID_PROCESSOR_SETTINGS_SUBGROUP = new Guid("54533251-82be-4824-96c1-47b60b740d00");
        private const uint ACCESS_INDIVIDUAL_SETTING = 18;
        public static bool IsInHighPowerMode()
        {
            var activeGuidPtr = IntPtr.Zero;
            try
            {
                uint res = 0;

                //8663 don't do power warning if performance/max performance power modes don't exist
                //enumerate all the schemes and look for either the high power guid or name, or max 
                //we could use this to determine the active one scheme, but for now we just want to log and
                //not continue on if we don't find high performance/max performance.
                var bContainsMaxOrHighPerformance = false;

                var p = new System.Diagnostics.Process
                {
                    StartInfo =
                    {
                        UseShellExecute = false,
                        RedirectStandardOutput = true,
                        RedirectStandardError = true,
                        CreateNoWindow = true,
                        WindowStyle = System.Diagnostics.ProcessWindowStyle.Minimized,
                        FileName = "powercfg",
                        Arguments = "/list"
                    }
                };

                p.Start();
                var output = p.StandardOutput.ReadToEnd();
                //APILogger.Log("Active Power Schemes", output);
                p.WaitForExit();

                if (output.Contains(HIGH_PERFORMANCE_GUID.ToString()) || (output.Contains(MAX_PERFORMANCE_GUID.ToString()))
                    || output.Contains("High performance") || output.Contains("Max performance")
                    )
                {
                    bContainsMaxOrHighPerformance = true;
                }


                //8663 don't do power warning if performance/max performance power modes don't exist
                if (!bContainsMaxOrHighPerformance)
                {
                    return true;
                }

                res = PowerGetActiveScheme(IntPtr.Zero, ref activeGuidPtr);
                if (res != 0)
                    throw new Win32Exception();

                var g = (Guid)System.Runtime.InteropServices.Marshal.PtrToStructure(activeGuidPtr, typeof(Guid));
                if (g == HIGH_PERFORMANCE_GUID || g == MAX_PERFORMANCE_GUID)
                {
                    return true;
                }



                //Get Friendly Name
                uint buffSize = 0;
                var buffer = new StringBuilder();
                var subGroupGuid = Guid.Empty;
                var powerSettingGuid = Guid.Empty;
                res = PowerReadFriendlyName(IntPtr.Zero, activeGuidPtr,
                    IntPtr.Zero, IntPtr.Zero, buffer, ref buffSize);

                if (res == ERROR_MORE_DATA)
                {
                    buffer.Capacity = (int)buffSize;
                    res = PowerReadFriendlyName(IntPtr.Zero, activeGuidPtr,
                        IntPtr.Zero, IntPtr.Zero, buffer, ref buffSize);
                }

                var name = buffer.ToString();
                name = name.ToLower();
                if (name.Contains("maximum performance") || name.Contains("high performance"))
                {
                    return true;
                }
                else
                {
                    APILogger.Log(string.Format("{0}\nProfile name:", APILogger.GetCurrentMethod()), name, "GUID:", g.ToString());
                    APILogger.Log("Active Power Schemes", output);
                    return false;
                }

            }
            catch (System.Exception ex)
            {
                APILogger.Log(ex);
            }
            finally
            {
                if (activeGuidPtr != IntPtr.Zero)
                {
                    var res = LocalFree(activeGuidPtr);
                    if (res != IntPtr.Zero)
                        throw new Win32Exception();
                }
            }
            //default to okay, so if there's an error, or if we can't read, just continue on
            return true;
        }
    }
}