using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;


namespace RobvanderWoude
{
	internal class CheckVarsPHP
	{
		static readonly string progver = "1.02";

		
		static string scriptcode = String.Empty;


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

			SortedList<string, int> functions = new SortedList<string, int>( );
			SortedList<string, int> variables = new SortedList<string, int>( );
			bool showfuncs = true;
			bool showvars = true;
			bool unusedonly = false;
			Regex regex;
			string pattern;
			string scriptext = String.Empty;
			string scriptfile = String.Empty;
			int columnwidth = 12;
			int unusedfuncs = 0;
			int unusedvars = 0;

			#endregion Initialize Variables
			
			
			#region Command Line Parsing

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

			foreach ( string arg in args )
			{
				if ( arg[0] == '/' )
				{
					if ( arg.ToUpper( ) == "/?" )
					{
						return ShowHelp( );
					}
					else if ( arg.ToUpper( ) == "/F" )
					{
						if ( !showvars )
						{
							return ShowHelp( "Duplicate command line switch /F" );
						}
						if ( !showfuncs )
						{
							return ShowHelp( "Use /F or /V or neither, but not both" );
						}
						showvars = false;
					}
					else if ( arg.ToUpper( ) == "/U" )
					{
						if ( unusedonly )
						{
							return ShowHelp( "Duplicate command line switch /U" );
						}
						unusedonly = true;
					}
					else if ( arg.ToUpper( ) == "/V" )
					{
						if ( !showfuncs )
						{
							return ShowHelp( "Duplicate command line switch /V" );
						}
						if ( !showvars )
						{
							return ShowHelp( "Use /F or /V or neither, but not both" );
						}
						showfuncs = false;
					}
					else
					{
						return ShowHelp( "Invalid command line switch \"{0}\"", arg );
					}
				}
				else
				{
					if ( !String.IsNullOrWhiteSpace( scriptfile ) )
					{
						return ShowHelp( "Duplicate command line argument for PHP file" );
					}
					if ( !File.Exists( arg ) )
					{
						return ShowHelp( "Invalid file name or file not found: \"{0}\"", arg );
					}
					scriptext = Path.GetExtension( arg ).ToLower( );
					if ( scriptext != ".php" )
					{
						return ShowHelp( "Invalid file type \"{0}\"", arg );
					}
					scriptfile = Path.GetFullPath( arg );
				}

			}

			if ( String.IsNullOrWhiteSpace( scriptfile ) )
			{
				return ShowHelp( "Please specify a source file" );
			}

			#endregion Command Line Parsing


			#region Read File

			// Read the code from the file
			scriptcode = File.ReadAllText( scriptfile, Encoding.UTF8 );
			// Strip everything NOT PHP
			if ( scriptcode.Contains( "<?php" ) )
			{
				string purephp = string.Empty;
				pattern = @"<\?php[\w\W]*?\?>";
				regex = new Regex( pattern );
				if ( regex.IsMatch( scriptcode ) )
				{
					foreach ( Match match in regex.Matches( scriptcode ) )
					{
						purephp += match.Value + "\n\n";
					}
				}
				scriptcode = purephp;
			}
			// Remove comment lines from the code (does NOT strip comments starting halfway on a line)
			pattern = @"(^|\n|\r)[ \t]*//[^\n\r]+";
			regex = new Regex( pattern );
			scriptcode = regex.Replace( scriptcode, String.Empty );
			// Remove comment blocks from the code (does NOT strip comments starting halfway on a line)
			pattern = @"(^|\n|\r)[ \t]*/\*[\w\W]*\*/";
			regex = new Regex( pattern );
			scriptcode = regex.Replace( scriptcode, String.Empty );

			#endregion Read File


			#region List Functions

			// Create a list of subroutines found in the code
			// function names are NOT case sensitive
			if ( showfuncs )
			{
				pattern = @"(?:^|\n|\r)[ \t]*(?:function)[ \t]+([A-Z_][^\s\(]+)\(";
				regex = new Regex( pattern, RegexOptions.IgnoreCase );
				if ( regex.IsMatch( scriptcode ) )
				{
					MatchCollection matches = regex.Matches( scriptcode );
					if ( matches.Count > 0 )
					{
						foreach ( Match match in matches )
						{
							bool listed = false;
							string func = match.Groups[1].Value;
							foreach ( string key in functions.Keys )
							{
								if ( func.ToLower( ) == key.ToLower( ) )
								{
									listed = true;
								}
							}
							if ( !listed )
							{
								functions[func] = 0;
								columnwidth = Math.Max( func.Length, columnwidth );
							}
						}
					}
				}
			}

			#endregion List Functions


			#region Check for Nested Functions

			if ( showfuncs && functions.Count > 1 )
			{
				pattern = @"function[\t ]+([_A-Z]\w*)[\t ]*\([^\n\r\)]*\)([\w\W]*?)function[\t ]+[_A-Z]";
				regex = new Regex( pattern, RegexOptions.IgnoreCase );
				if ( regex.IsMatch( scriptcode ) )
				{
					foreach ( Match match in regex.Matches( scriptcode ) )
					{
						int errorcount = 0;
						string funcname = match.Groups[1].Value;
						string funccode = match.Groups[2].Value;
						int curlybraces = 0;
						foreach ( char chr in funccode.ToCharArray( ) )
						{
							if ( chr == '{' )
							{
								curlybraces++;
							}
							else if ( chr == '}' )
							{
								curlybraces--;
							}
							if ( curlybraces < 0 )
							{
								errorcount++;
							}
						}
						if ( curlybraces != 0 )
						{
							errorcount++;
						}
						if ( errorcount > 0 )
						{
							RedLine( "Nested function or unterminated curly braces detected in function \"{0}\"\n\n", funcname );
						}
					}
				}
			}

			#endregion Check for Nested Functions


			#region Check for Unterminated Curly Braces

			if ( !CheckCurlyBraces( ) )
			{
				RedLine( "Unterminated curly braces detected\n\n" );
			}

			#endregion Check for Unterminated Curly Braces


			#region List Variables

			// Create a list of variables found in the code and count their occurrence
			// Variable names ARE case sensitive
			if ( showvars )
			{
				pattern = @"\$[A-Z_][A-Z0-9_]*(\[([\$'\""]?[A-Z_][A-Z0-9_]*['\""]?)\])?";
				regex = new Regex( pattern, RegexOptions.IgnoreCase );
				if ( regex.IsMatch( scriptcode ) )
				{
					MatchCollection matches = regex.Matches( scriptcode );
					if ( matches.Count > 0 )
					{
						foreach ( Match match in matches )
						{
							string varstring = match.ToString( );
							if ( !variables.ContainsKey( varstring ) )
							{
								variables[varstring] = 1;
								if ( varstring.Length > columnwidth )
								{
									columnwidth = varstring.Length;
								}
							}
							else
							{
								variables[varstring] += 1;
							}
						}
					}
				}
			}

			#endregion List Variables


			#region Count and Display Functions Usage

			// Iterate through the list of subroutines and count the occurrences of its name
			if ( showfuncs )
			{
				List<string> keys = new List<string>( functions.Keys );
				foreach ( string func in keys )
				{
					pattern = string.Format( @"\b{0}\(", func );
					regex = new Regex( pattern );
					if ( regex.IsMatch( scriptcode ) )
					{
						functions[func] = regex.Matches( scriptcode ).Count - 1;
					}
				}
				// Show the results
				if ( unusedonly )
				{
					Console.WriteLine( "{0} Unused Function{1}{2}", unusedfuncs, ( unusedfuncs == 1 ? String.Empty : "s" ), ( unusedfuncs == 0 ? String.Empty : ":" ) );
					Console.WriteLine( "{0}==============={1}{2}", new String( '=', unusedfuncs.ToString( ).Length ), ( unusedfuncs == 1 ? String.Empty : "=" ), ( unusedfuncs == 0 ? String.Empty : "=" ) );
				}
				else
				{
					Console.WriteLine( "{0,-" + columnwidth + "}    Occurrences:", "Function:" );
					Console.WriteLine( "{0,-" + columnwidth + "}    ============", "=========" );
				}
				foreach ( string key in functions.Keys )
				{
					if ( functions[key] == 0 )
					{
						if ( unusedonly )
						{
							Console.WriteLine( key );
						}
						else
						{
							RedLine( string.Format( "{0,-" + columnwidth + "}    {1}", key, functions[key] ) );
						}
						unusedfuncs += 1;
					}
					else if ( !unusedonly )
					{
						Console.WriteLine( "{0,-" + columnwidth + "}    {1}", key, functions[key] );
					}
				}
				Console.WriteLine( );
			}

			#endregion Count and Display Functions Usage


			#region Count and Display Variables Usage

			if ( showvars )
			{
				// Show the results
				if ( unusedonly )
				{
					Console.WriteLine( "{0} Unused Variable{1}{2}", unusedvars, ( unusedvars == 1 ? String.Empty : "s" ), ( unusedvars == 0 ? String.Empty : ":" ) );
					Console.WriteLine( "{0}================{1}{2}", new String( '=', unusedvars.ToString( ).Length ), ( unusedvars == 1 ? String.Empty : "=" ), ( unusedvars == 0 ? String.Empty : "=" ) );
				}
				else
				{
					Console.WriteLine( "{0,-" + columnwidth + "}    Occurrences:", "Variable:" );
					Console.WriteLine( "{0,-" + columnwidth + "}    ============", "=========" );
				}
				foreach ( string key in variables.Keys )
				{
					if ( variables[key] == 1 && !IsSuperGlobal( key ) && key[0] != '$' )
					{
						if ( unusedonly )
						{
							Console.WriteLine( key );
						}
						else
						{
							RedLine( String.Format( "{0,-" + columnwidth + "}    {1}", key, variables[key] ) );
						}
						unusedvars += 1;
					}
					else if ( !unusedonly )
					{
						Console.WriteLine( "{0,-" + columnwidth + "}    {1}", key, variables[key] );
					}
				}
				Console.WriteLine( );
			}

			#endregion Count and Display Variables Usage


			int rc = 0;
			if ( showfuncs )
			{
				rc += unusedfuncs;
			}
			if ( showvars )
			{
				rc += unusedvars;
			}
			return rc;
		}


		static bool CheckCurlyBraces( )
		{
			if ( scriptcode.Count( o => ( o == '{' ) ) != scriptcode.Count( c => ( c == '}' ) ) )
			{
				return false;
			}
			string testtext = Regex.Replace( scriptcode, @"[^\{\}]", "" );
			int state = 0;
			for ( int i = 0; i < testtext.Length; i++ )
			{
				if ( testtext[i] == '{' )
				{
					state++;
				}
				else
				{
					state--;
				}
				if ( state < 0 )
				{
					return false;
				}
			}
			return true;
		}


		static bool IsSuperGlobal( string var )
		{
			string pattern = @"^\$(GLOBALS|_(SERVER|GET|POST|FILES|COOKIE|SESSION|REQUEST|ENV))(\[[^\]]+\])?$";
			Regex regex = new Regex( pattern );
			return regex.IsMatch( var.Trim( ) );
		}


		static void RedLine( string line, params object[] rlargs )
		{
			Console.ForegroundColor = ConsoleColor.Red;
			if ( rlargs.Length > 0 )
			{
				Console.WriteLine( line, rlargs );
			}
			else
			{
				Console.WriteLine( line );
			}
			Console.ResetColor( );
		}


		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

			/*
			CheckVarsPHP.exe,  Version 1.02
			Check PHP code for unused variables and functions
 
			Usage:    CheckVarsPHP.exe  "phpfile"  [ /F | /V ]  [ /U ]
 
			Where:    "phpfile"         is the PHP file to be examined
			          /F                tests Functions only
			                            (default: functions as well as variables)
			          /V                tests Variables only
			                            (default: functions as well as variables)
			          /U                list Unused functions and variables only
			                            (default: list all functions and variables)
 
			Notes:    If functions are tested, a (limited) test for nested functions
			          and unterminated curly braces is performed as well.
			          In PHP variables are not declared, so a single occurrence of a
			          variable means it is not used, unless it is a superglobal which
			          may be declared elsewhere. Keep in mind though, that this program
			          does not take into account the variables' scope, so a variable
			          name used once in two functions may in fact be unused but will
			          escape detection by this program.
			          The program's return code equals the number of unused functions
			          and/or variables, or -1 in case of (command line) errors.
 
			Written by Rob van der Woude
			https://www.robvanderwoude.com
			*/

			#endregion Help Text


			#region Display Help Text

			Console.Error.WriteLine( );

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

			Console.Error.WriteLine( "Check PHP code for unused variables and functions" );

			Console.Error.WriteLine( );

			Console.Error.Write( "Usage:    " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.WriteLine( "CheckVarsPHP.exe  \"phpfile\"  [ /F | /V ]  [ /U ]" );
			Console.ResetColor( );

			Console.Error.WriteLine( );

			Console.Error.Write( "Where:    " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "\"phpfile\"" );
			Console.ResetColor( );
			Console.Error.WriteLine( "         is the PHP file to be examined" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "          /F" );
			Console.ResetColor( );
			Console.Error.Write( "                tests " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "F" );
			Console.ResetColor( );
			Console.Error.WriteLine( "unctions only" );

			Console.Error.WriteLine( "                            (default: functions as well as variables)" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "          /V" );
			Console.ResetColor( );
			Console.Error.Write( "                tests " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "V" );
			Console.ResetColor( );
			Console.Error.WriteLine( "ariables only" );

			Console.Error.WriteLine( "                            (default: functions as well as variables)" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "          /U" );
			Console.ResetColor( );
			Console.Error.Write( "                list " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "U" );
			Console.ResetColor( );
			Console.Error.WriteLine( "nused functions and variables only" );

			Console.Error.WriteLine( "                            (default: list all functions and variables)" );

			Console.Error.WriteLine( );

			Console.Error.WriteLine( "Notes:    If functions are tested, a (limited) test for nested functions" );

			Console.Error.WriteLine( "          and unterminated curly braces is performed as well." );

			Console.Error.WriteLine( "          In PHP variables are not declared, so a single occurrence of a" );

			Console.Error.WriteLine( "          variable means it is not used, unless it is a superglobal which" );

			Console.Error.WriteLine( "          may be declared elsewhere. Keep in mind though, that this program" );

			Console.Error.WriteLine( "          does not take into account the variables' scope, so a variable" );

			Console.Error.WriteLine( "          name used once in two functions may in fact be unused but will" );

			Console.Error.WriteLine( "          escape detection by this program." );

			Console.Error.WriteLine( "          The program's return code equals the number of unused functions" );

			Console.Error.WriteLine( "          and/or variables, or -1 in case 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 Text


			return -1;
		}
	}
}