//Copyright (c) Microsoft Corporation.  All rights reserved.

using System;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using System.Windows.Forms;
using Vanara.PInvoke;
using Vanara.Windows.Forms;
using Vanara.Windows.Shell;

namespace Microsoft.WindowsAPICodePack.Samples
{
	public partial class ExplorerBrowserTestForm : Form
	{
		private readonly AutoResetEvent itemsChanged = new AutoResetEvent(false);
		private readonly AutoResetEvent selectionChanged = new AutoResetEvent(false);
		private readonly System.Windows.Forms.Timer uiDecoupleTimer = new System.Windows.Forms.Timer();

		public ExplorerBrowserTestForm()
		{
			InitializeComponent();

			// initialize known folder combo box
			knownFolderCombo.Sorted = true;
			knownFolderCombo.Items.AddRange(KFItem.All);

			// initial property grids
			propertyGrid.SelectedObject = explorerBrowser;

			// setup ExplorerBrowser navigation events
			explorerBrowser.Navigating += new EventHandler<Vanara.Windows.Forms.ExplorerBrowser.NavigatingEventArgs>(explorerBrowser_Navigating);
			explorerBrowser.NavigationFailed += new EventHandler<Vanara.Windows.Forms.ExplorerBrowser.NavigationFailedEventArgs>(explorerBrowser_NavigationFailed);
			explorerBrowser.Navigated += new EventHandler<Vanara.Windows.Forms.ExplorerBrowser.NavigatedEventArgs>(explorerBrowser_Navigated);
			explorerBrowser.ItemsChanged += new EventHandler(explorerBrowser_ItemsChanged);
			explorerBrowser.SelectionChanged += new EventHandler(explorerBrowser_SelectionChanged);
			explorerBrowser.ItemsEnumerated += new EventHandler(explorerBrowser_ItemsEnumerated);
			explorerBrowser.Navigate(ShellFolder.Desktop);

			// set up Navigation log event and button state
			explorerBrowser.History.NavigationLogChanged += new EventHandler<Vanara.Windows.Forms.ExplorerBrowser.NavigationLogEventArgs>(NavigationLog_NavigationLogChanged);
			backButton.Enabled = false;
			forwardButton.Enabled = false;

			uiDecoupleTimer.Tick += new EventHandler(uiDecoupleTimer_Tick);
			uiDecoupleTimer.Interval = 100;
			uiDecoupleTimer.Start();
		}

		private void DebugEnterFunc([System.Runtime.CompilerServices.CallerMemberName] string func = "") => System.Diagnostics.Debug.WriteLine($"Entering {func}...");

		private void backButton_Click(object sender, EventArgs e) =>
			// Move backwards through navigation log
			explorerBrowser.NavigateFromHistory(NavigationLogDirection.Backward);

		private void clearHistoryButton_Click(object sender, EventArgs e) =>
			// clear navigation log
			explorerBrowser.History.Clear();

		private void explorerBrowser_ItemsChanged(object sender, EventArgs e)
		{
			DebugEnterFunc();
			itemsChanged.Set();
		}

		private void explorerBrowser_ItemsEnumerated(object sender, EventArgs e)
		{
			DebugEnterFunc();
			// This event is BeginInvoked to decouple the ExplorerBrowser UI from this UI
			BeginInvoke(new MethodInvoker(delegate ()
			{
				eventHistoryTextBox.Text =
					eventHistoryTextBox.Text +
					"View enumeration complete.\n";
			}));

			selectionChanged.Set();
			itemsChanged.Set();
		}

		private void explorerBrowser_Navigated(object sender, Vanara.Windows.Forms.ExplorerBrowser.NavigatedEventArgs args)
		{
			DebugEnterFunc();
			// This event is BeginInvoked to decouple the ExplorerBrowser UI from this UI
			BeginInvoke(new MethodInvoker(delegate ()
			{
				// update event history text box
				var location = (args.NewLocation == null) ? "(unknown)" : args.NewLocation.Name;
				eventHistoryTextBox.Text =
					eventHistoryTextBox.Text +
					"Navigation completed. New Location = " + location + "\n";
			}));
		}

		private void explorerBrowser_Navigating(object sender, Vanara.Windows.Forms.ExplorerBrowser.NavigatingEventArgs args)
		{
			DebugEnterFunc();
			// fail navigation if check selected (this must be synchronous)
			args.Cancel = failNavigationCheckBox.Checked;

			// This portion is BeginInvoked to decouple the ExplorerBrowser UI from this UI
			BeginInvoke(new MethodInvoker(delegate ()
			{
				// update event history text box
				var message = "";
				var location = (args.PendingLocation == null) ? "(unknown)" : args.PendingLocation.Name;
				if (args.Cancel)
				{
					message = "Navigation Failing. Pending Location = " + location;
				}
				else
				{
					message = "Navigation Pending. Pending Location = " + location;
				}
				eventHistoryTextBox.Text =
					eventHistoryTextBox.Text + message + "\n";
			}));
		}

		private void explorerBrowser_NavigationFailed(object sender, Vanara.Windows.Forms.ExplorerBrowser.NavigationFailedEventArgs args)
		{
			DebugEnterFunc();
			// This event is BeginInvoked to decouple the ExplorerBrowser UI from this UI
			BeginInvoke(new MethodInvoker(delegate ()
			{
				// update event history text box
				var location = (args.FailedLocation == null) ? "(unknown)" : args.FailedLocation.Name;
				eventHistoryTextBox.Text =
					eventHistoryTextBox.Text +
					"Navigation failed. Failed Location = " + location + "\n";

				if (explorerBrowser.History.CurrentLocationIndex == -1)
					navigationHistoryCombo.Text = "";
				else
					navigationHistoryCombo.SelectedIndex = explorerBrowser.History.CurrentLocationIndex;
			}));
		}

		private void explorerBrowser_SelectionChanged(object sender, EventArgs e)
		{
			DebugEnterFunc();
			selectionChanged.Set();
		}

		private void filePathEdit_TextChanged(object sender, EventArgs e) => filePathNavigate.Enabled = (filePathEdit.Text.Length > 0);

		private void filePathNavigate_Click(object sender, EventArgs e)
		{
			DebugEnterFunc();
			try
			{
				// Navigates to a specified file (must be a container file to work, i.e., ZIP, CAB)
				explorerBrowser.Navigate(new ShellFolder(filePathEdit.Text));
			}
			catch (COMException)
			{
				MessageBox.Show("Navigation not possible.");
			}
		}

		private void forwardButton_Click(object sender, EventArgs e)
		{
			DebugEnterFunc();
			explorerBrowser.NavigateFromHistory(NavigationLogDirection.Forward);
		}

		private void knownFolderCombo_SelectedIndexChanged(object sender, EventArgs e) => knownFolderNavigate.Enabled = (knownFolderCombo.Text.Length > 0);

		private void knownFolderNavigate_Click(object sender, EventArgs e)
		{
			try
			{
				// Navigate to a known folder
				explorerBrowser.Navigate(ShellItem.Open(((KFItem)knownFolderCombo.SelectedItem).ShellItem));
			}
			catch (COMException)
			{
				MessageBox.Show("Navigation not possible.");
			}
		}

		private void navigateButton_Click(object sender, EventArgs e)
		{
			DebugEnterFunc();
			try
			{
				// navigate to specific folder
				explorerBrowser.Navigate(new ShellFolder(pathEdit.Text));
			}
			catch (COMException)
			{
				MessageBox.Show("Navigation not possible.");
			}
		}

		private void navigationHistoryCombo_SelectedIndexChanged(object sender, EventArgs e) =>
			// navigating to specific index in navigation log
			explorerBrowser.NavigateToHistoryIndex(navigationHistoryCombo.SelectedIndex);

		private void NavigationLog_NavigationLogChanged(object sender, Vanara.Windows.Forms.ExplorerBrowser.NavigationLogEventArgs args)
		{
			DebugEnterFunc();
			// This event is BeginInvoked to decouple the ExplorerBrowser UI from this UI
			BeginInvoke(new MethodInvoker(delegate ()
			{
				// calculate button states
				if (args.CanNavigateBackwardChanged)
				{
					backButton.Enabled = explorerBrowser.History.CanNavigateBackward;
				}
				if (args.CanNavigateForwardChanged)
				{
					forwardButton.Enabled = explorerBrowser.History.CanNavigateForward;
				}

				// update history combo box
				if (args.LocationsChanged)
				{
					navigationHistoryCombo.Items.Clear();
					foreach (var shobj in explorerBrowser.History.Locations)
					{
						navigationHistoryCombo.Items.Add(shobj.Name);
					}
				}
				if (explorerBrowser.History.CurrentLocationIndex == -1)
					navigationHistoryCombo.Text = "";
				else
					navigationHistoryCombo.SelectedIndex = explorerBrowser.History.CurrentLocationIndex;
			}));
		}

		private void pathEdit_TextChanged(object sender, EventArgs e) => navigateButton.Enabled = (pathEdit.Text.Length > 0);

		private void uiDecoupleTimer_Tick(object sender, EventArgs e)
		{
			DebugEnterFunc();
			try
			{
				if (selectionChanged.WaitOne(1))
				{
					var itemsText = new StringBuilder();

					foreach (var item in explorerBrowser.SelectedItems)
					{
						if (item != null)
							itemsText.AppendLine("\tItem = " + item.Name);
					}

					selectedItemsTextBox.Text = itemsText.ToString();
					itemsTabControl.TabPages[1].Text = "Selected Items (Count=" + explorerBrowser.SelectedItems.Count.ToString() + ")";
				}

				if (itemsChanged.WaitOne(1))
				{
					// update items text box
					var itemsText = new StringBuilder();

					foreach (var item in explorerBrowser.Items)
					{
						if (item != null)
							itemsText.AppendLine("\tItem = " + item.Name);
					}

					itemsTextBox.Text = itemsText.ToString();
					itemsTabControl.TabPages[0].Text = "Items (Count=" + explorerBrowser.Items.Count.ToString() + ")";
				}
			}
			catch (Exception ex)
			{
				Debug.WriteLine(ex.Message);
			}
		}

		private class KFItem
		{
			private static readonly Shell32.IKnownFolderManager kfm = new Shell32.IKnownFolderManager();

			public KFItem(Guid id)
			{
				Id = id; Text = kfm.GetFolder(id).Name();
			}

			public static KFItem[] All => kfm.GetFolderIds().Select(g => new KFItem(g)).ToArray();

			public Guid Id { get; set; }

			public Shell32.IShellItem ShellItem => kfm.GetFolder(Id).GetShellItem<Shell32.IShellItem>();
			public string Text { get; set; }

			public override string ToString() => Text;
		}
	}
}