/*
 
  This Source Code Form is subject to the terms of the Mozilla Public
  License, v. 2.0. If a copy of the MPL was not distributed with this
  file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
  Copyright (C) 2009-2020 Michael Möller <mmoeller@openhardwaremonitor.org>
	
*/

using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.InteropServices;
using System.Security;
using System.Security.Principal;
using System.Windows.Forms;
using Microsoft.Win32;
using OpenHardwareMonitor.TaskScheduler;

namespace OpenHardwareMonitor.GUI {
  public class StartupManager {

    private TaskSchedulerClass scheduler;
    private bool startup;
    private bool isAvailable;

    private const string REGISTRY_RUN =
      @"Software\Microsoft\Windows\CurrentVersion\Run";

    private bool IsAdministrator() {
      try {
        WindowsIdentity identity = WindowsIdentity.GetCurrent();
        WindowsPrincipal principal = new WindowsPrincipal(identity);
        return principal.IsInRole(WindowsBuiltInRole.Administrator);
      } catch {
        return false;
      }
    }

    public StartupManager() {
      int p = (int)System.Environment.OSVersion.Platform;
      if ((p == 4) || (p == 128)) {
        scheduler = null;        
        isAvailable = false;
        return;
      }

      if (IsAdministrator()) {
        try {
          scheduler = new TaskSchedulerClass();
          scheduler.Connect(null, null, null, null);
        } catch {
          scheduler = null;
        }

        if (scheduler != null) {
          try {
            try {
              // check if the taskscheduler is running
              IRunningTaskCollection collection = scheduler.GetRunningTasks(0);
            } catch (ArgumentException) { }            

            ITaskFolder folder = scheduler.GetFolder("\\Open Hardware Monitor");
            IRegisteredTask task = folder.GetTask("Startup");
            startup = (task != null) && 
              (task.Definition.Triggers.Count > 0) &&
              (task.Definition.Triggers[1].Type == 
                TASK_TRIGGER_TYPE2.TASK_TRIGGER_LOGON) &&
              (task.Definition.Actions.Count > 0) &&
              (task.Definition.Actions[1].Type ==
                TASK_ACTION_TYPE.TASK_ACTION_EXEC) &&
              (task.Definition.Actions[1] as IExecAction != null) &&
              ((task.Definition.Actions[1] as IExecAction).Path ==
                Application.ExecutablePath);
              
          } catch (IOException) {
            startup = false;
          } catch (UnauthorizedAccessException) {
            scheduler = null;
          } catch (COMException) {
            scheduler = null;
          } catch (NotImplementedException) {
            scheduler = null;
          }
        } 
      } else {
        scheduler = null;
      }

      if (scheduler == null) {
        try {
          using (RegistryKey key =
            Registry.CurrentUser.OpenSubKey(REGISTRY_RUN)) {
            startup = false;
            if (key != null) {
              string value = (string)key.GetValue("OpenHardwareMonitor");
              if (value != null)
                startup = value == Application.ExecutablePath;
            }            
          }
          isAvailable = true;
        } catch (SecurityException) {
          isAvailable = false;
        }
      } else {
        isAvailable = true;
      }
    }

    private void CreateSchedulerTask() {
      ITaskDefinition definition = scheduler.NewTask(0);
      definition.RegistrationInfo.Description =
        "This task starts the Open Hardware Monitor on Windows startup.";
      definition.Principal.RunLevel =
        TASK_RUNLEVEL.TASK_RUNLEVEL_HIGHEST;
      definition.Settings.DisallowStartIfOnBatteries = false;
      definition.Settings.StopIfGoingOnBatteries = false;
      definition.Settings.ExecutionTimeLimit = "PT0S";

      ILogonTrigger trigger = (ILogonTrigger)definition.Triggers.Create(
        TASK_TRIGGER_TYPE2.TASK_TRIGGER_LOGON);

      IExecAction action = (IExecAction)definition.Actions.Create(
        TASK_ACTION_TYPE.TASK_ACTION_EXEC);
      action.Path = Application.ExecutablePath;
      action.WorkingDirectory =
        Path.GetDirectoryName(Application.ExecutablePath);

      ITaskFolder root = scheduler.GetFolder("\\");
      ITaskFolder folder;
      try {
        folder = root.GetFolder("Open Hardware Monitor");
      } catch (IOException) {
        folder = root.CreateFolder("Open Hardware Monitor", "");
      }
      folder.RegisterTaskDefinition("Startup", definition,
        (int)TASK_CREATION.TASK_CREATE_OR_UPDATE, null, null,
        TASK_LOGON_TYPE.TASK_LOGON_INTERACTIVE_TOKEN, "");
    }

    private void DeleteSchedulerTask() {
      ITaskFolder root = scheduler.GetFolder("\\");
      try {
        ITaskFolder folder = root.GetFolder("Open Hardware Monitor");
        folder.DeleteTask("Startup", 0);
      } catch (IOException) { }
      try {
        root.DeleteFolder("Open Hardware Monitor", 0);
      } catch (IOException) { }
    }

    private void CreateRegistryRun() {
      RegistryKey key = Registry.CurrentUser.CreateSubKey(REGISTRY_RUN);     
      key.SetValue("OpenHardwareMonitor", Application.ExecutablePath);
    }

    private void DeleteRegistryRun() {
      RegistryKey key = Registry.CurrentUser.CreateSubKey(REGISTRY_RUN);
      key.DeleteValue("OpenHardwareMonitor");
    }

    public bool IsAvailable {
      get { return isAvailable; }
    }

    public bool Startup {
      get {
        return startup;
      }
      set {
        if (startup != value) {          
          if (isAvailable) {
            if (scheduler != null) {
              if (value)
                CreateSchedulerTask();
              else
                DeleteSchedulerTask();
              startup = value;
            } else {
              try {
                if (value)
                  CreateRegistryRun();
                else
                  DeleteRegistryRun();
                startup = value;
              } catch (UnauthorizedAccessException) {
                throw new InvalidOperationException();
              }
            }
          } else {
            throw new InvalidOperationException();
          }
        }
      }
    }
  }

}