Fixed issues with special characters in the file name

PlaylistDownloader/PlaylistDownloader/App.config

@@ -11,4 +11,7 @@
       </dependentAssembly>
     </assemblyBinding>
   </runtime>
+  <appSettings>
+    <add key="debug" value="false" />
+  </appSettings>
 </configuration>

PlaylistDownloader/PlaylistDownloader/Downloader.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
+using System.Configuration;
 using System.Diagnostics;
 using System.IO;
 using System.Linq;
@@ -14,13 +15,15 @@ public class Downloader : BackgroundWorker
 	{
 
 		private readonly ICollection<PlaylistItem> _playlist;
+        private readonly bool _isDebugMode = bool.Parse(ConfigurationManager.AppSettings.Get("debug"));
 
-		//[download]   0.9% of 3.45MiB at 553.57KiB/s ETA 00:06
-		private readonly Regex _extractDownloadProgress = new Regex(@"\[download\][\s]*([0-9\.]+)%");
+        //[download]   0.9% of 3.45MiB at 553.57KiB/s ETA 00:06
+        private readonly Regex _extractDownloadProgress = new Regex(@"\[download\][\s]*([0-9\.]+)%");
 		private int _progress;
 		private readonly int _totalSongs;
 		private readonly CancellationTokenSource _cts;
 
+
         public Downloader(ICollection<PlaylistItem> playlist)
 		{
 			_playlist = playlist;
@@ -91,12 +94,9 @@ private void DownloadPlaylistItem(PlaylistItem item, ParallelOptions po)
 							StartInfo =
 							{
 								FileName = "youtube-dl.exe",
-								Arguments =
-									string.Format(
-                                         " --ffmpeg-location ./ffmpeg --extract-audio --audio-format mp3 -o \"{2}/{0}.%(ext)s\" {1}",
-										item.FileName, youtubeLink.Url, SettingsWindow.SONGS_FOLDER),
-								CreateNoWindow = true,
-								WindowStyle = ProcessWindowStyle.Hidden,
+								Arguments = string.Format(" --ffmpeg-location ./ffmpeg --extract-audio --audio-format mp3 -o \"{2}\\{0}.%(ext)s\" {1}", item.FileName, youtubeLink.Url, SettingsWindow.SONGS_FOLDER),
+								CreateNoWindow = !_isDebugMode,
+								WindowStyle = _isDebugMode ? ProcessWindowStyle.Normal : ProcessWindowStyle.Hidden,
 								RedirectStandardOutput = true,
 								UseShellExecute = false
 							}
@@ -142,10 +142,11 @@ private void DownloadPlaylistItem(PlaylistItem item, ParallelOptions po)
 
 		private static string MakeValidFileName(string name)
 		{
-			string invalidChars = Regex.Escape(new string(Path.GetInvalidFileNameChars()));
-			string invalidRegStr = string.Format(@"([{0}]*\.+$)|([{0}]+)", invalidChars);
-
-			return Regex.Replace(name, invalidRegStr, "_");
-		}
+            return Regex.Replace(
+                name,
+                "[\\W-]+",  /*Matches any nonword character. Equivalent to '[^A-Za-z0-9_]'*/
+                "-",
+                RegexOptions.IgnoreCase);
+        }
 	}
 }

PlaylistDownloader/PlaylistDownloader/PlaylistDownloader.csproj

@@ -69,6 +69,7 @@
       <Private>True</Private>
     </Reference>
     <Reference Include="System" />
+    <Reference Include="System.Configuration" />
     <Reference Include="System.Data" />
     <Reference Include="System.Web" />
     <Reference Include="System.Xml" />

PlaylistDownloader/PlaylistDownloader/SettingsWindow.xaml.cs

@@ -7,6 +7,7 @@
 using System.Windows.Input;
 using PlaylistDownloader.Annotations;
 using System;
+using System.Configuration;
 
 namespace PlaylistDownloader
 {
@@ -33,6 +34,7 @@ public partial class SettingsWindow : INotifyPropertyChanged
 		private bool _isQueryValid;
 		private const string INSTRUCTIONS = "Enter songs (one per line)";
         public static readonly string SONGS_FOLDER = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.MyMusic), "PlaylistDownloader");
+        private readonly bool _isDebugMode = bool.Parse(ConfigurationManager.AppSettings.Get("debug"));
 
         public SettingsWindow()
 		{
@@ -53,7 +55,7 @@ public SettingsWindow()
 		            FileName = "youtube-dl.exe",
 		            Arguments = " -U",
 		            CreateNoWindow = true,
-		            WindowStyle = ProcessWindowStyle.Hidden,
+		            WindowStyle = _isDebugMode ? ProcessWindowStyle.Normal : ProcessWindowStyle.Hidden,
 		            RedirectStandardOutput = true,
 		            UseShellExecute = false
 		        }

PlaylistDownloader/PlaylistDownloader/YoutubeSearcher.cs

@@ -11,13 +11,13 @@ namespace PlaylistDownloader
 {
 	public static class YoutubeSearcher
 	{
-		const string URL = "http://www.youtube.com/results?search_query={0}&page={1}";
+		private const string URL = "http://www.youtube.com/results?search_query={0}&page={1}";
 
 		public static IEnumerable<YoutubeLink> GetYoutubeLinks(string query, int numberOfResults = 1)
 		{
 			List<YoutubeLink> links = new List<YoutubeLink>();
 			int page = 1;
-			while (page < 20 && links.Count() < numberOfResults)
+			while (page < 20 && links.Count < numberOfResults)
 			{
 				string requestUrl = string.Format(URL, HttpUtility.UrlEncode(query)?.Replace("%20", "+"), page);
 				HtmlDocument doc = new HtmlDocument();
@@ -28,7 +28,7 @@ public static IEnumerable<YoutubeLink> GetYoutubeLinks(string query, int numberO
 				page++;
 			}
 			return links;
-			//TODO 040 make sure program correctly stops if page is not existent => message to user
+			// TODO 040 make sure program correctly stops if page is not existent => message to user
 		}
 
 		private static string GetWebPageCode(string url)