//  JavaToPython.java  Copyright (c) 2006 Kari Laitinen

//  http://www.naturalprogramming.com

//  2006-04-28   File created.
//  2006-05-28   Last modification.

//  This program helps to convert Java programs to Python programs.
//  This is not a fully automatic converter. After a conversion, the
//  conversion result usually needs to be modified by hand.

//  This program is specifically tailored to convert the programs of
//  Kari Laitinen's books.

//  DO NOT USE THIS PROGRAM TO CONVERT THIS PROGRAM TO A
//  PYTHON PROGRAM. THE CONVERSION OPERATION DESTROYS ALL THE
//  STRINGS THAT NEED TO BE REPLACED.

//  The best way to execute this program is to run it in a
//  command prompt window where command line parameters can
//  be given. It may be difficult, and even impossible, to
//  supply the command line parameters if this program is 
//  executed with a modern development tool such as JCreator
//  or Eclipse.

import java.util.* ;
import java.io.* ;  // Classes for file handling.

class JavaToPython
{
   static void
   store_text_lines_to_file( ArrayList<String> given_array_of_text_lines,
                             String            given_file_name )
   {
      try
      {
         PrintWriter output_file  = 
                new PrintWriter( new FileWriter( given_file_name ) ) ;

         for ( int line_index  =  0 ;
                   line_index  <  given_array_of_text_lines.size() ;
                   line_index  ++ )
         {
            output_file.println(
                      given_array_of_text_lines.get( line_index ) ) ;
         }

         output_file.close() ;
      }
      catch ( IOException caught_io_exception )
      {
         System.out.print( "\n\n Cannot write to file \""
                        +  given_file_name  +  "\"\n" ) ;
      }
   }


   static void replace_names_in_file( String  original_file_name )
   {

      ArrayList<String> names_to_replace  =  new  ArrayList<String>() ;
      ArrayList<String> replacement_names  =  new  ArrayList<String>() ;


      names_to_replace.add( "System.out.print(" ) ;
      replacement_names.add( "print" ) ;

      names_to_replace.add( "System.out.printf(" ) ;
      replacement_names.add( "print" ) ;

//      names_to_replace.add( "using System.IO" ) ;
//      replacement_names.add( "import java.io.*" ) ;

//      names_to_replace.add( "using System" ) ;
//      replacement_names.add( "import java.util.*" ) ;

      names_to_replace.add( "public static void main( String[] not_in_use )");
      replacement_names.add( "" ) ;

      names_to_replace.add(
              "public static void main( String[] command_line_parameters )" ) ;
      replacement_names.add( "" ) ;

      names_to_replace.add( "keyboard.nextInt(" ) ;
      replacement_names.add( "int( raw_input() " ) ;

      names_to_replace.add( "keyboard.nextDouble(" ) ;
      replacement_names.add( "float( raw_input() " ) ;

      names_to_replace.add( "keyboard.nextLine().charAt( 0" ) ;
      replacement_names.add( "raw_input(" ) ;

      names_to_replace.add( "keyboard.nextLine()" ) ;
      replacement_names.add( "raw_input()" ) ;

      names_to_replace.add( " String " ) ;
      replacement_names.add( " " ) ;

      names_to_replace.add( " public " ) ;
      replacement_names.add( " " ) ;

      names_to_replace.add( " protected " ) ;
      replacement_names.add( " " ) ;

      names_to_replace.add( " void " ) ;
      replacement_names.add( " def " ) ;

//      names_to_replace.add( " this" ) ;
//      replacement_names.add( " self" ) ;

      names_to_replace.add( " boolean " ) ;
      replacement_names.add( "" ) ;

      names_to_replace.add( " true" ) ;
      replacement_names.add( " True" ) ;

      names_to_replace.add( " false" ) ;
      replacement_names.add( " False" ) ;

      names_to_replace.add( " &&" ) ;
      replacement_names.add( " and" ) ;

      names_to_replace.add( " ||" ) ;
      replacement_names.add( " or" ) ;

      names_to_replace.add( " ++" ) ;
      replacement_names.add( " +=  1" ) ;

      names_to_replace.add( " --" ) ;
      replacement_names.add( " -=  1" ) ;

      names_to_replace.add( ".java" ) ;
      replacement_names.add( ".py" ) ;

//      names_to_replace.add( "string.Length" ) ;
//      replacement_names.add( "string.length()" ) ;

//      names_to_replace.add( ".Length" ) ;
//      replacement_names.add( ".length" ) ;

      names_to_replace.add( ".charAt( character_index )" ) ;
      replacement_names.add( "[ character_index ]" ) ;

      names_to_replace.add( ".charAt(" ) ;
      replacement_names.add( "[" ) ;

      names_to_replace.add( "indexOf(" ) ;
      replacement_names.add( "find(" ) ;

      names_to_replace.add( ".substring(" ) ;
      replacement_names.add( "[" ) ;

      names_to_replace.add( "toUpperCase(" ) ;
      replacement_names.add( "upper(" ) ;

//      names_to_replace.add( "ToCharArray(" ) ;
//      replacement_names.add( "toCharArray(" ) ;

//      names_to_replace.add( "Close(" ) ;
//      replacement_names.add( "close(" ) ;

      names_to_replace.add( "toLowerCase(" ) ;
      replacement_names.add( "lower(" ) ;

      names_to_replace.add( "Integer.parseInt(" ) ;
      replacement_names.add( "int(" ) ;

      names_to_replace.add( "if (" ) ;
      replacement_names.add( "if " ) ;

      names_to_replace.add( "if  (" ) ;
      replacement_names.add( "if " ) ;

      names_to_replace.add( "else if (" ) ;
      replacement_names.add( "elif " ) ;

      names_to_replace.add( "else if  (" ) ;
      replacement_names.add( "elif " ) ;

      names_to_replace.add( "else" ) ;
      replacement_names.add( "else  :" ) ;

      names_to_replace.add( "while (" ) ;
      replacement_names.add( "while " ) ;

      names_to_replace.add( "for (" ) ;
      replacement_names.add( "for " ) ;

      names_to_replace.add( " int " ) ;
      replacement_names.add( " " ) ;

      names_to_replace.add( "int[] " ) ;
      replacement_names.add( "" ) ;

      names_to_replace.add( " char " ) ;
      replacement_names.add( " " ) ;

      names_to_replace.add( "char[] " ) ;
      replacement_names.add( "" ) ;

      names_to_replace.add( " float " ) ;
      replacement_names.add( " " ) ;

      names_to_replace.add( " double " ) ;
      replacement_names.add( " " ) ;

      names_to_replace.add( "double[] " ) ;
      replacement_names.add( "" ) ;

      names_to_replace.add( " long " ) ;
      replacement_names.add( " " ) ;

      names_to_replace.add( "            {" ) ;
      replacement_names.add( "" ) ;

      names_to_replace.add( "         {" ) ;
      replacement_names.add( "" ) ;

      names_to_replace.add( "      {" ) ;
      replacement_names.add( "" ) ;

      names_to_replace.add( "   {" ) ;
      replacement_names.add( "" ) ;

      names_to_replace.add( "{" ) ;
      replacement_names.add( "" ) ;

      names_to_replace.add( "            }" ) ;
      replacement_names.add( "" ) ;

      names_to_replace.add( "         }" ) ;
      replacement_names.add( "" ) ;

      names_to_replace.add( "      }" ) ;
      replacement_names.add( "" ) ;

      names_to_replace.add( "   }" ) ;
      replacement_names.add( "" ) ;

      names_to_replace.add( "}" ) ;
      replacement_names.add( "" ) ;


      names_to_replace.add( " extends " ) ;
      replacement_names.add( " ( " ) ;




//      names_to_replace.add( "Equals(" ) ;
//      replacement_names.add( "equals(" ) ;

//      names_to_replace.add( "Add(" ) ;
//      replacement_names.add( "add(" ) ;

//      names_to_replace.add( "ToString(" ) ;
//      replacement_names.add( "toString(" ) ;

      try
      {
         BufferedReader original_file  =
              new BufferedReader( new FileReader( original_file_name ) ) ;

         ArrayList<String>  original_text_lines  =  new  ArrayList<String>() ;
         ArrayList<String>  modified_text_lines  =  new  ArrayList<String>() ;

         Calendar  current_date  =  new  GregorianCalendar() ;

         //  The following statements add some Kari-Laitinen-style 
         //  comments at the beginning of the modified program file.

         modified_text_lines.add( "" ) ;

         modified_text_lines.add( String.format( 
                     "#  %s  Copyright (c) %d Kari Laitinen",
                     original_file_name,
                     current_date.get( Calendar.YEAR ) ) ) ;

         modified_text_lines.add( "" ) ;

         modified_text_lines.add( "#  http://www.naturalprogramming.com" ) ;

         modified_text_lines.add( "" ) ;

         modified_text_lines.add( 
              String.format( "#  %tF  File created.", current_date ) ) ;

         modified_text_lines.add(
              String.format( "#  %tF  Last modification.", current_date ) ) ;

         boolean opening_brace_of_main_method_found  =  false ;
         boolean start_of_main_method_found  =  false ;

         int  line_counter  =  0 ;
         boolean end_of_file_encountered  =  false ;

         while ( end_of_file_encountered  ==  false )
         {
            String  text_line_from_file   =  original_file.readLine() ;

            if ( text_line_from_file  ==  null )
            {
               end_of_file_encountered  =  true ;
            }
            else
            {
               line_counter  ++ ;
               original_text_lines.add( text_line_from_file ) ;

               //  The following three if constructs are used to find
               //  out when the main() method begins.

               if ( opening_brace_of_main_method_found  ==  true )
               {
                  //  This program works only when the main() method is
                  //  the last method in a program.

                  //  Because in Python programs the main "method"
                  //  is just statements at the end of a program,
                  //  we need to unindent the lines of a Java
                  //  main() method

                  if ( text_line_from_file.startsWith( "      " ) )
                  {
                     //  Two 3-space indentation steps will be removed.

                     text_line_from_file  =  text_line_from_file.substring( 6 ) ;
                  }
               }

               if ( start_of_main_method_found  ==  true )
               {
                  if ( text_line_from_file.indexOf( "{" ) != -1 )
                  {
                     opening_brace_of_main_method_found  =  true ;
                  }
               }

               if ( text_line_from_file.indexOf( "void main(" ) !=  -1 )
               {
                  start_of_main_method_found  =  true ;
               }


               //  The loop that replaces method names etc.


               for ( int name_index  =  0 ;
                         name_index  <  names_to_replace.size() ;
                         name_index  ++ )
               {
                  if ( text_line_from_file.indexOf(
                            names_to_replace.get( name_index  ) )  !=  -1 )
                  {
                     text_line_from_file  =
                          text_line_from_file.replace(
                              names_to_replace.get( name_index ),
                              replacement_names.get( name_index ) ) ;

                     System.out.print( "\n \""
                          +  names_to_replace.get( name_index )
                          +  "\" was replaced with \"" 
                          +  replacement_names.get( name_index )
                          +  "\" on line "  +  line_counter  ) ;

                  }
               }

               //  Unnecessary space characters and semicolons will be removed
               //  from the end of line.

               while( text_line_from_file.endsWith( " " ) ||
                      text_line_from_file.endsWith( ";" ) )
               {
                  text_line_from_file  =  text_line_from_file.substring( 0,
                                            text_line_from_file.length() - 1 ) ;
               }


               modified_text_lines.add( text_line_from_file ) ;
            }
         }

         original_file.close() ;

         String  backup_file_name  =  original_file_name  +  ".bak" ;

         store_text_lines_to_file( original_text_lines,
                                   backup_file_name   ) ; 
         store_text_lines_to_file( modified_text_lines,
                                   original_file_name ) ;
      }
      catch ( FileNotFoundException caught_file_not_found_exception )
      {
         System.out.print( "\n Cannot open file " + original_file_name ) ;
      }
      catch ( IOException  caught_io_exception )
      {
         System.out.print( "\n Error in reading " + original_file_name ) ;
      }
   }


   public static void main( String[] command_line_parameters )
   {
      Scanner keyboard = new Scanner( System.in ) ;

      String  file_name_given_by_user ;

      if ( command_line_parameters.length  ==  1 )
      {
         file_name_given_by_user  =  command_line_parameters[ 0 ] ;
      }
      else
      {
         System.out.print( "\n This program helps you to convert a Java "
                        +  "\n program to a Python program. Please,"
                        +  "\n type the name of the program file:  " ) ;

         file_name_given_by_user  =  keyboard.nextLine() ;
      }

      replace_names_in_file( file_name_given_by_user ) ;
   }
}