using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Net;
using System.Threading;
using System.Xml;


namespace RobvanderWoude
{
	internal class TestSitemap
	{
		static readonly string progver = "1.04";

		static int delay = 250;


		static int Main( string[] args )
		{
			#region Initialize Variables

			string sitemap = string.Empty;
			string title = Console.Title;
			int urlcount = 0;
			int errorcount = 0;
			int redirectscount = 0;
			bool countredirectsaserrors = false;
			bool excludequeries = false;
			bool excludelanguage = false;
			bool quietmode = false;
			Stopwatch stopwatch = new Stopwatch( );


			#endregion Initialize Variables


			#region Command Line Arguments

			if ( args.Length == 0 || args.Length > 4 )
			{
				return ShowHelp( );
			}

			foreach ( string arg in args )
			{
				if ( arg[0] != '/' )
				{
					if ( !string.IsNullOrWhiteSpace( sitemap ) )
					{
						return ShowHelp( "Duplicate sitemap argument \"{0}\"", arg );
					}
					if ( !File.Exists( arg ) )
					{
						return ShowHelp( "File \"{0}\" not found", arg );
					}
					if ( !QuickTestXML( arg ) )
					{
						return ShowHelp( "File \"{0}\" is not a valid XML file", arg );
					}
					sitemap = arg;
				}
				else if ( arg == "/?" )
				{
					return ShowHelp( );
				}
				else if ( arg.Length > 3 && arg.ToUpper( ).StartsWith( "/D:" ) )
				{
					if ( delay != 250 )
					{
						return ShowHelp( "Duplicate command line switch /D" );
					}
					if ( !Int32.TryParse( arg.Substring( 3 ), out delay ) )
					{
						return ShowHelp( "Invalid delay value \"{0}\"", arg );
					}
					delay = Math.Max( delay, 250 );
				}
				else if ( arg.ToUpper( ) == "/Q" )
				{
					if ( quietmode )
					{
						return ShowHelp( "Duplicate command line switch /Q" );
					}
					quietmode = true;
				}
				else if ( arg.ToUpper( ) == "/R" )
				{
					if ( countredirectsaserrors )
					{
						return ShowHelp( "Duplicate command line switch /R" );
					}
					countredirectsaserrors = true;
				}
				else if ( arg.ToUpper( ) == "/XL" )
				{
					if ( excludelanguage )
					{
						return ShowHelp( "Duplicate command line switch /XL" );
					}
					excludelanguage = true;
				}
				else if ( arg.ToUpper( ) == "/XQ" )
				{
					if ( excludequeries )
					{
						return ShowHelp( "Duplicate command line switch /XQ" );
					}
					excludequeries = true;
				}
				else
				{
					return ShowHelp( "Invalid command line switch \"{0}\'", arg );
				}
			}

			// No queries? No language
			excludelanguage = excludelanguage || excludequeries;

			#endregion Command Line Arguments


			stopwatch.Start( );


			#region Read XML and Test URLs

			Console.Title = "Reading sitemap";
			int matchingurls = 0;
			XmlReader testxml = XmlReader.Create( sitemap );
			while ( testxml.Read( ) )
			{
				if ( testxml.NodeType == XmlNodeType.Text )
				{
					if ( testxml.Value.StartsWith( "http" ) )
					{
						string url = testxml.Value;
						if ( !( excludequeries && url.Contains( "?" ) ) )
						{
							if ( !( excludelanguage && ( url.Contains( "?lang=" ) || url.Contains( "&lang=" ) || url.Contains( "&lang=" ) ) ) )
							{
								matchingurls++;
							}
						}
					}
				}
			}
			testxml.Close( );

			Console.Title = string.Format( "  0% tested, 0 errors and 0 redirections in 0 of {0} URLs so far", matchingurls );
			int percentage = 0;
			SortedList<string, int> results = new SortedList<string, int>( );
			XmlReader xml = XmlReader.Create( sitemap );
			while ( xml.Read( ) )
			{
				if ( xml.NodeType == XmlNodeType.Text )
				{
					if ( xml.Value.StartsWith( "http" ) )
					{
						string url = xml.Value;
						if ( !( excludequeries && url.Contains( "?" ) ) )
						{
							if ( !( excludelanguage && ( url.Contains( "?lang=" ) || url.Contains( "&lang=" ) || url.Contains( "&amp;lang=" ) ) ) )
							{
								int result = WebTest( url );
								urlcount++;
								results[url] = result;
								if ( result == 200 )
								{
									if ( !quietmode )
									{
										Console.ForegroundColor = ConsoleColor.Green;
										Console.WriteLine( "{0}\t{1}", result, url );
									}
								}
								else if ( result > 300 && result < 400 )
								{
									redirectscount++;
									Console.ForegroundColor = ConsoleColor.DarkYellow;
									Console.WriteLine( "{0}\t{1}", result, url );
								}
								else
								{
									errorcount++;
									Console.ForegroundColor = ConsoleColor.Red;
									Console.WriteLine( "{0}\t{1}", result, url );
								}
								Console.ResetColor( );
							}
						}
						percentage = (int) ( urlcount * 100 / matchingurls );
						Console.Title = string.Format( "{0,3}% tested, {1} errors and {2} redirections in {3} of {4} URLs so far", percentage, errorcount, redirectscount, urlcount, matchingurls );
					}
				}
			}

			xml.Close( );
			Console.Title = title;

			#endregion Read XML and Test URLs


			#region Show Summary

			stopwatch.Stop( );
			Console.WriteLine( "\nTesting {0} URLs took {1:0.0} seconds, {2} errors and {3} redirections encountered", urlcount, stopwatch.Elapsed.TotalSeconds, errorcount, redirectscount );

			if ( errorcount > 0 || ( redirectscount > 0 && countredirectsaserrors ) )
			{
				string message = string.Format( "\n{0} error{1} and {2} redirection{3} encountered:", errorcount, ( errorcount == 1 ? "" : "s" ), redirectscount, ( redirectscount == 1 ? "" : "s" ) );
				Console.WriteLine( "\n" );
				Console.WriteLine( message );
				Console.WriteLine( new string( '=', message.Length ) );
				foreach ( KeyValuePair<string, int> result in results )
				{
					if ( result.Value != 200 )
					{
						Console.WriteLine( "{0}\t{1}", result.Value, result.Key );
					}
				}
			}

			#endregion Show Summary


			int rc = errorcount;
			if ( countredirectsaserrors )
			{
				rc += redirectscount;
			}
			return rc;
		}


		static bool QuickTestXML( string file )
		{
			// Check if the file starts with "<?xml"
			StreamReader test = new StreamReader( file );
			string firstline = test.ReadLine( );
			test.Close( );
			return ( firstline.StartsWith( "<?xml", StringComparison.OrdinalIgnoreCase ) );
		}


		static int WebTest( string url )
		{
			Thread.Sleep( 250 );
			try
			{
				// Next 3 lines allow secure connections
				ServicePointManager.Expect100Continue = true;
				ServicePointManager.SecurityProtocol |= SecurityProtocolType.Tls12;
				ServicePointManager.SecurityProtocol |= SecurityProtocolType.Ssl3;

				HttpWebRequest webrequest = (HttpWebRequest)WebRequest.Create( url );
				webrequest.AllowAutoRedirect = false;
				HttpWebResponse response = (HttpWebResponse)webrequest.GetResponse( );
				webrequest.Abort( );
				
				return (int)response.StatusCode;
			}
			catch ( Exception e )
			{
				Console.Error.WriteLine( e.Message );
				return 0;
			}
		}


		#region Error handling

		public static int ShowHelp( params string[] errmsg )
		{
			#region Error Message

			if ( errmsg.Length > 0 )
			{
				List<string> errargs = new List<string>( errmsg );
				errargs.RemoveAt( 0 );
				Console.Error.WriteLine( );
				Console.ForegroundColor = ConsoleColor.Red;
				Console.Error.Write( "ERROR:\t" );
				Console.ForegroundColor = ConsoleColor.White;
				Console.Error.WriteLine( errmsg[0], errargs.ToArray( ) );
				Console.ResetColor( );
			}

			#endregion Error Message


			#region Help Text

			/*
			TestSitemap.exe,  Version 1.04
			Test all URLs encountered in an XML sitemap
 
			Usage:   TestSitemap.exe  sitemap  [ options ]

			Where:   sitemap    path of XML sitemap file

			Options: /D:nn      Delay of nn milliseconds between URL tests
			                    (default: 250 ms)
			         /Q         Quiet mode: display errors and redirections only
			                    (default: show all)
			         /R         Redirects count as errors (default: redirects are
			                    displayed as such but not counted as errors)
			         /XL        eXclude Language specifications, e.g. ?lang=en
			         /XQ        eXclude all Queries, i.e. "?" and everything after that
			                    (/XQ automatically implies /XL as well)

			Note:    Return code equals the number of failed URL tests, or -1 in case
			         of command line errors.

			Written by Rob van der Woude
			https://www.robvanderwoude.com
			*/

			#endregion Help Text


			#region Display help

			Console.Error.WriteLine( );

			Console.Error.WriteLine( "TestSitemap.exe,  Version {0}", progver );

			Console.Error.WriteLine( "Test all URLs encountered in an XML sitemap" );

			Console.Error.WriteLine( );

			Console.Error.Write( "Usage:   " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.WriteLine( "TestSitemap.exe  sitemap  [ options ]" );
			Console.ResetColor( );

			Console.Error.WriteLine( );

			Console.Error.Write( "Where:   " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "sitemap" );
			Console.ResetColor( );
			Console.Error.Write( "    path of XML " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "sitemap" );
			Console.ResetColor( );
			Console.Error.WriteLine( " file" );

			Console.Error.WriteLine( );

			Console.Error.Write( "Options: " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "/D:nn      D" );
			Console.ResetColor( );
			Console.Error.Write( "elay of " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "nn" );
			Console.ResetColor( );
			Console.Error.WriteLine( " milliseconds between URL tests" );

			Console.Error.WriteLine( "                    (default: 250 ms)" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "         /Q         Q" );
			Console.ResetColor( );
			Console.Error.WriteLine( "uiet mode: display errors and redirections only" );

			Console.Error.WriteLine( "                    (default: show all)" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "         /R         R" );
			Console.ResetColor( );
			Console.Error.WriteLine( "edirects count as errors (default: redirects are" );

			Console.Error.WriteLine( "                    displayed as such but not counted as errors)" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "         /XL" );
			Console.ResetColor( );
			Console.Error.Write( "        e" );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "X" );
			Console.ResetColor( );
			Console.Error.Write( "clude " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "L" );
			Console.ResetColor( );
			Console.Error.WriteLine( "anguage specifications, e.g. ?lang=en" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "         /XQ" );
			Console.ResetColor( );
			Console.Error.Write( "        e" );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "X" );
			Console.ResetColor( );
			Console.Error.Write( "clude all " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "Q" );
			Console.ResetColor( );
			Console.Error.WriteLine( "ueries, i.e. \"?\" and everything after that" );

			Console.Error.Write( "                    (" );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "/XQ" );
			Console.ResetColor( );
			Console.Error.Write( " automatically implies " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "/XL" );
			Console.ResetColor( );
			Console.Error.WriteLine( " as well)" );

			Console.Error.WriteLine( );

			Console.Error.WriteLine( "Note:    Return code equals the number of failed URL tests, or -1 in case" );

			Console.Error.WriteLine( "         of command line errors." );

			Console.Error.WriteLine( );

			Console.Error.WriteLine( "Written by Rob van der Woude" );

			Console.Error.WriteLine( "https://www.robvanderwoude.com" );

			#endregion Display Help


			return -1;
		}

		#endregion Error handling
	}
}