using PortScanner;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Networking.Pages
{
     public partial class WF_PortScanner : UserControl
     { 
          // Delegate to report back with one open port
          public delegate void ExecuteOnceCallback(int openPort);

          // Delegate to report back with one open port (Async)
          public delegate void ExecuteOnceAsyncCallback(int port, bool isOpen, bool isCancelled, bool isLast);

          // The manager instance
          IScannerManagerSingleton smc;

          // Cancellation token source for the cancel button
          private CancellationTokenSource cts;

          // Current mode of operation
          private ScannerManagerSingleton.ScanMode currentScanMode;

          public WF_PortScanner()
          {
               InitializeComponent();
               this.Load += WF_PortScanner_Load;
          }

          private void WF_PortScanner_Load(object sender, EventArgs e)
          {
               // Get the ScannerManagerSingleton instance
               smc = ScannerManagerSingleton.Instance;

               // Populate the timeout times list box
               PopulateTimeoutListBox();
          }

          private void PopulateTimeoutListBox()
          {
               // Assign the list to the ComboBox's DataSource property
               timeoutComboBox.DataSource = TimeoutListItem.CreateTimeoutListItems();
               timeoutComboBox.DisplayMember = "DisplayMember";
               timeoutComboBox.ValueMember = "ValueMember";

               // Set default value
               timeoutComboBox.SelectedValue = 2000;
          }

          // This method is used as a callback for portscanning - writes to the log box (text box)
          public void PortResult(int port, bool isOpen, bool isCancelled, bool isLast)
          {
               string status;

               // The operation has been cancelled by MainWindow
               if (isCancelled)
               {
                    status = "Operation cancelled." + Environment.NewLine;
               }

               // The port is open
               else if (isOpen)
               {
                    //status = String.Format("{0}, {1} port {2} is open.{3}", hostnameTextBox.Text, currentScanMode.ToString(), port, Environment.NewLine);
                    var item = new ListViewItem(new[] { port.ToString(), "Open" });
                    listview1.Items.Add(item);
               }

               // The port is closed
               else
               {
                    status = String.Format("{0}, {1} port {2} is closed.{3}", hostnameTextBox.Text, currentScanMode.ToString(), port, Environment.NewLine);

               }


               if (isLast || isCancelled)
                    ToggleInputs(true);
          }

          // Checks whether the timeout combo box has user input or not
          private bool IsTimeoutComboBoxUserInput()
          {
               var inputText = timeoutComboBox.Text;

               foreach (var displayMemberText in (List<TimeoutListItem>)timeoutComboBox.DataSource)
               {
                    if (displayMemberText.DisplayMember == inputText)
                    {
                         // Select the one that's in the box's list to prevent some problems
                         // This will return because the user input IS in the combo box's DataSource
                         // However it is still user input and does not have a ValueMember. Exception
                         // will be thrown.
                         timeoutComboBox.SelectedItem = displayMemberText;
                         return false;
                    }
               }

               return true;
          }

          // Executed when the Check Port button is clicked
          private void checkPortButton_Click(object sender, EventArgs e)
          {
               listview1.Items.Clear();

               // Get user inputs
               string hostname = hostnameTextBox.Text;
               if (hostname == "")
               {
                    MessageBox.Show("Please enter a valid hostname.",
                        "Input Error",
                        MessageBoxButtons.OK,
                        MessageBoxIcon.Error);
                    hostnameTextBox.Focus();
                    return;
               }

               // Check port
               int portMin = InputChecker.ParsePort(portTextBoxMin.Text);
               if (portMin == -1)
               {
                    MessageBox.Show((portRangeCheckBox.Checked ? "Lower limit of port range" : "Port") + " invalid.",
                        "Input Error",
                        MessageBoxButtons.OK,
                        MessageBoxIcon.Error);
                    portTextBoxMin.Focus();
                    return;
               }

               // Get scan mode
               ScannerManagerSingleton.ScanMode scanMode = ReadScanMode();

               // If custom timeout time, verify correct user input
               int timeout;
               if (IsTimeoutComboBoxUserInput())
               {
                    // If valid, proceed with that input as timeout
                    timeout = InputChecker.ParseTimeout(timeoutComboBox.Text);
                    if (timeout == -1)
                    {
                         MessageBox.Show("Timeout format: [time], [time]ms or [time] ms.\nTimeout must be between 250 ms and 20000 ms.",
                             "Timeout Error",
                             MessageBoxButtons.OK,
                             MessageBoxIcon.Error);
                         return;
                    }
               }
               else
               {
                    // Else, use the ValueMember of the selected Member
                    timeout = (int)timeoutComboBox.SelectedValue;
               }

               // Instantiate CTS
               cts = new CancellationTokenSource();

               // Simple one port check
               if (!portRangeCheckBox.Checked)
               {
                    // The callback for scan result
                    var callback = new ExecuteOnceAsyncCallback(PortResult);

                    // Send one check request and toggle user inputs
                    ToggleInputs(false);
                    smc.ExecuteOnceAsync(hostname, portMin, timeout, scanMode, callback, cts.Token);
               }

               // Port range check
               else
               {
                    // Verify input
                    int portMax = InputChecker.ParsePort(portTextBoxMax.Text);
                    if (portMax == -1)
                    {
                         MessageBox.Show("Upper limit of port range invalid.",
                             "Input Error",
                             MessageBoxButtons.OK,
                             MessageBoxIcon.Error);
                         portTextBoxMax.Focus();
                         return;
                    }

                    if (portMax < portMin)
                    {
                         MessageBox.Show("Port range invalid.",
                             "Input Error",
                             MessageBoxButtons.OK,
                             MessageBoxIcon.Error);
                         portTextBoxMax.Focus();
                         return;
                    }

                    // The callback for scan result
                    var callback = new ExecuteOnceAsyncCallback(PortResult);

                    // Set status box text
                    //var connectionText = String.Format("Connecting to {0}, port {1}...{2}", hostname, portMin,
                    //    Environment.NewLine);
                    //statusTextBox.AppendText(connectionText);
                    //Logger.Info(connectionText);
                    // Toggle inputs and begin operation
                    ToggleInputs(false);
                    smc.ExecuteRangeAsync(hostname, portMin, portMax, timeout, scanMode,progressBar1, callback, cts.Token);
               }
          }
          // Read scan mode radio button selection
          private ScannerManagerSingleton.ScanMode ReadScanMode()
          {
               if (tcpModeRadioButton.Checked)
               {
                    currentScanMode = ScannerManagerSingleton.ScanMode.TCP;
               }
               else
               {
                    currentScanMode = ScannerManagerSingleton.ScanMode.UDP;
               }
               return currentScanMode;
          }

          private void portRangeCheckBox_CheckedChanged(object sender, EventArgs e)
          {
               // This enables or disables the max. port input box
               if (portRangeCheckBox.Checked)
               {
                    portTextBoxMax.Enabled = true;
               }
               else
               {
                    portTextBoxMax.Enabled = false;
               }
          }

          // Toggle all inputs
          private void ToggleInputs(bool setting)
          {
               hostnameTextBox.Enabled = setting;
               portTextBoxMin.Enabled = setting;
               checkPortButton.Enabled = setting;
               portTextBoxMax.Enabled = setting;
               portRangeCheckBox.Enabled = setting;

               // Re-disable the portMax text box
               if (!portRangeCheckBox.Checked)
               {
                    portTextBoxMax.Enabled = false;
               }

               // Set focus to hostnameTextBox
               if (setting)
                    hostnameTextBox.Focus();
          }
          private void cancelButton_Click(object sender, EventArgs e)
          {
               // If cts is instantiated (i.e. the scanning operation is in progress, request cancellation
               if (cts != null)
               {
                    cts.Cancel();
                    progressBar1.Value = 0;
               }
          }
     }
}