#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2011 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Security.Principal;
using System.ServiceProcess;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Windows.Forms.DataVisualization.Charting;
using HeuristicLab.Common;
using HeuristicLab.Core.Views;
using HeuristicLab.MainForm;


namespace HeuristicLab.Clients.Hive.SlaveCore.Views {

  [View("HeuristicLab Slave View")]
  [Content(typeof(SlaveItem), IsDefaultView = true)]
  public partial class SlaveView : ItemView {
    private SlaveDisplayStat lastSlaveDisplayStat;
    private const string serviceName = "HeuristicLab.Clients.Hive.SlaveCore.SlaveWindowsService";

    private const UInt32 BCM_SETSHIELD = 0x160C;
    [DllImport("user32", CharSet = CharSet.Auto, SetLastError = true)]
    static extern int SendMessage(IntPtr hWnd, UInt32 Msg, int wParam, IntPtr lParam);

    public new SlaveItem Content {
      get { return (SlaveItem)base.Content; }
      set {
        if (base.Content != value) {
          base.Content = value;
        }
      }
    }

    public SlaveView() {
      InitializeComponent();

      if (CheckRunAsAdmin()) {
        btnKill.ImageAlign = System.Drawing.ContentAlignment.MiddleLeft;
        btnKill.Image = HeuristicLab.Common.Resources.VSImageLibrary.BreakpointActive;
      } else {
        this.btnKill.FlatStyle = FlatStyle.System;
        SendMessage(btnKill.Handle, BCM_SETSHIELD, 0, (IntPtr)1);
      }

      lblSlaveState.Text = SlaveDisplayStat.NoService.ToString();
      lastSlaveDisplayStat = SlaveDisplayStat.NoService;
      Content_SlaveDisplayStateChanged(this, new EventArgs<SlaveDisplayStat>(lastSlaveDisplayStat));
    }

    #region Register Content Events
    protected override void DeregisterContentEvents() {
      Content.SlaveShutdown -= new System.EventHandler(Content_SlaveShutdown);
      Content.SlaveStatusChanged -= new System.EventHandler<EventArgs<StatusCommons>>(Content_SlaveStatusChanged);
      Content.SlaveDisplayStateChanged -= new EventHandler<EventArgs<SlaveDisplayStat>>(Content_SlaveDisplayStateChanged);
      Content.CoreConnectionChanged -= new EventHandler<EventArgs<CoreConnection>>(Content_CoreConnectionChanged);

      base.DeregisterContentEvents();
    }

    protected override void RegisterContentEvents() {
      base.RegisterContentEvents();

      Content.SlaveShutdown += new System.EventHandler(Content_SlaveShutdown);
      Content.SlaveStatusChanged += new System.EventHandler<EventArgs<StatusCommons>>(Content_SlaveStatusChanged);
      Content.SlaveDisplayStateChanged += new EventHandler<EventArgs<SlaveDisplayStat>>(Content_SlaveDisplayStateChanged);
      Content.CoreConnectionChanged += new EventHandler<EventArgs<CoreConnection>>(Content_CoreConnectionChanged);
    }
    #endregion

    protected override void OnContentChanged() {
      base.OnContentChanged();
      btnKill.Enabled = false;
      btnStart.Enabled = false;
      btnStop.Enabled = false;

      if (Content == null) {
        //nothing to do...         
      } else {
        //try to establish a connection to the slave service 
        if (base.Content != null) {
          ((SlaveItem)base.Content).Open();
          Task.Factory.StartNew(Connector);
        }
      }
    }

    private void Connector() {
      Content_SlaveDisplayStateChanged(this, new EventArgs<SlaveDisplayStat>(SlaveDisplayStat.NoService));
      bool connected = false;
      while (!connected) {
        this.Invoke(new Func<bool>(() => connected = ((SlaveItem)base.Content).ReconnectToSlaveCore()));

        if (!connected) {
          Thread.Sleep(1000);
        }
      }
      this.Invoke(new Action(SetEnabledStateOfControls));
    }

    protected override void SetEnabledStateOfControls() {
      base.SetEnabledStateOfControls();
      //do nothing at the moment, we have nothing editable
    }

    #region Event Handlers
    void Content_SlaveStatusChanged(object sender, EventArgs<StatusCommons> e) {
      RenderJobChart(e.Value);
      RenderCoreChart(e.Value);
    }

    void Content_SlaveShutdown(object sender, System.EventArgs e) {
      Task.Factory.StartNew(Connector);
    }

    void Content_SlaveDisplayStateChanged(object sender, EventArgs<SlaveDisplayStat> e) {
      lblSlaveState.Text = e.Value.ToString();
      lastSlaveDisplayStat = e.Value;

      if (e.Value == SlaveDisplayStat.Asleep || e.Value == SlaveDisplayStat.NoService) {
        btnKill.Enabled = false;
        btnStart.Enabled = true;
        btnStop.Enabled = false;
      }

      if (e.Value == SlaveDisplayStat.Busy || e.Value == SlaveDisplayStat.Idle || e.Value == SlaveDisplayStat.Offline) {
        btnKill.Enabled = true;
        btnStart.Enabled = false;
        btnStop.Enabled = true;
      }
    }

    void Content_CoreConnectionChanged(object sender, EventArgs<CoreConnection> e) {
      if (e.Value == CoreConnection.Offline) {
        btnKill.Enabled = false;
        btnStart.Enabled = false;
        btnStop.Enabled = false;
      }
    }
    #endregion

    private void RenderJobChart(StatusCommons status) {
      jobChart.Series[0].Points.Clear();
      jobChart.Series[1].Points.Clear();
      jobChart.Series[2].Points.Clear();
      jobChart.Series[3].Points.Clear();
      jobChart.Series[4].Points.Clear();


      DataPoint pJobs = new DataPoint(1, status.Jobs.Count);
      DataPoint pJobsAborted = new DataPoint(2, status.JobsAborted);
      DataPoint pJobsDone = new DataPoint(3, status.JobsFinished);
      DataPoint pJobsFetched = new DataPoint(4, status.JobsFetched);
      DataPoint pJobsFailed = new DataPoint(5, status.JobsFailed);

      pJobs.LegendText = "Current jobs: " + status.Jobs.Count;
      pJobs.Color = System.Drawing.Color.Yellow;
      pJobs.ToolTip = pJobs.LegendText;
      jobChart.Series[0].Color = System.Drawing.Color.Yellow;
      jobChart.Series[0].LegendText = pJobs.LegendText;
      jobChart.Series[0].Points.Add(pJobs);

      pJobsAborted.LegendText = "Aborted jobs: " + status.JobsAborted;
      pJobsAborted.Color = System.Drawing.Color.Orange;
      pJobsAborted.ToolTip = pJobsAborted.LegendText;
      jobChart.Series[1].Color = System.Drawing.Color.Orange;
      jobChart.Series[1].LegendText = pJobsAborted.LegendText;
      jobChart.Series[1].Points.Add(pJobsAborted);

      pJobsDone.LegendText = "Finished jobs: " + status.JobsFinished;
      pJobsDone.Color = System.Drawing.Color.Green;
      pJobsDone.ToolTip = pJobsDone.LegendText;
      jobChart.Series[2].Color = System.Drawing.Color.Green;
      jobChart.Series[2].LegendText = pJobsDone.LegendText;
      jobChart.Series[2].Points.Add(pJobsDone);

      pJobsFetched.LegendText = "Fetched jobs: " + status.JobsFetched;
      pJobsFetched.ToolTip = pJobsFetched.LegendText;
      pJobsFetched.Color = System.Drawing.Color.Blue;
      jobChart.Series[3].Color = System.Drawing.Color.Blue;
      jobChart.Series[3].LegendText = pJobsFetched.LegendText;
      jobChart.Series[3].Points.Add(pJobsFetched);

      pJobsFailed.LegendText = "Failed jobs: " + status.JobsFailed;
      pJobsFailed.ToolTip = pJobsFailed.LegendText;
      pJobsFailed.Color = System.Drawing.Color.Red;
      jobChart.Series[4].Color = System.Drawing.Color.Red;
      jobChart.Series[4].LegendText = pJobsFailed.LegendText;
      jobChart.Series[4].Points.Add(pJobsFailed);
    }

    private void RenderCoreChart(StatusCommons statusCommons) {
      int usedCores = statusCommons.TotalCores - statusCommons.FreeCores;
      DataPoint pFreeCores = new DataPoint(statusCommons.FreeCores, statusCommons.FreeCores);
      DataPoint pUsedCores = new DataPoint(usedCores, usedCores);

      coresChart.Series[0].Points.Clear();

      pFreeCores.LegendText = "Free cores: " + statusCommons.FreeCores;
      pFreeCores.Color = System.Drawing.Color.Green;
      pUsedCores.LegendText = "Used cores: " + usedCores;
      pUsedCores.Color = System.Drawing.Color.Red;

      coresChart.Series[0].Points.Add(pFreeCores);
      coresChart.Series[0].Points.Add(pUsedCores);
    }

    private bool CheckRunAsAdmin() {
      bool isRunAsAdmin = false;
      WindowsIdentity user = WindowsIdentity.GetCurrent();
      WindowsPrincipal principal = new WindowsPrincipal(user);

      try {
        isRunAsAdmin = principal.IsInRole(WindowsBuiltInRole.Administrator);
      }
      catch { }
      return isRunAsAdmin;
    }

    /// <summary>
    /// Shows the windows UAC dialog and restarts tray icon app
    /// </summary>
    private void ElevateApplication() {
      // launch itself as administrator
      ProcessStartInfo proc = new ProcessStartInfo(Application.ExecutablePath, "showui");
      proc.UseShellExecute = true;
      proc.WorkingDirectory = Environment.CurrentDirectory;
      proc.FileName = Application.ExecutablePath;
      proc.Verb = "runas";

      try {
        Process.Start(proc);
      }
      catch {
        // user refused to allow privileges elevation       
        return;
      }
      Application.Exit();
    }

    private void StartService() {
      TimeSpan timeout = TimeSpan.FromMilliseconds(5000);

      ServiceController service = new ServiceController(serviceName);
      try {
        if (service.Status == ServiceControllerStatus.Running) {
          service.Stop();
          service.WaitForStatus(ServiceControllerStatus.Stopped, timeout);
        }

        service.Start();
        service.WaitForStatus(ServiceControllerStatus.Running, timeout);
      }
      catch (InvalidOperationException ex) {
        MessageBox.Show("Error starting service: Hive Slave Service not found!" + Environment.NewLine + ex.ToString());
      }
      catch (Exception ex) {
        MessageBox.Show("Error starting service, exception is: " + Environment.NewLine + ex.ToString());
      }
    }

    private void StopService() {
      TimeSpan timeout = TimeSpan.FromMilliseconds(7000);

      ServiceController service = new ServiceController(serviceName);
      try {
        if (service.Status == ServiceControllerStatus.Running) {
          service.Stop();
          service.WaitForStatus(ServiceControllerStatus.Stopped, timeout);
        }
      }
      catch (InvalidOperationException ex) {
        MessageBox.Show("Error starting service: Hive Slave Service not found!" + Environment.NewLine + ex.ToString());
      }
      catch (Exception ex) {
        MessageBox.Show("Error starting service, exception is: " + Environment.NewLine + ex.ToString());
      }
    }

    private void btnKill_Click(object sender, EventArgs e) {
      if (CheckRunAsAdmin()) {
        StopService();
      } else {
        ElevateApplication();
      }
    }

    private void btnStop_Click(object sender, EventArgs e) {
      if (Content != null) {
        Content.Sleep();
      }
    }

    private void btnStart_Click(object sender, EventArgs e) {
      if (Content != null) {
        if (lastSlaveDisplayStat == SlaveDisplayStat.Asleep) {
          Content.RestartCore();
        } else if (lastSlaveDisplayStat == SlaveDisplayStat.NoService) {
          if (CheckRunAsAdmin()) {
            StartService();
          } else {
            ElevateApplication();
          }
        }
      }
    }
  }
}