//  Findreplace.kt  (c) Kari Laitinen

//  http://www.naturalprogramming.com

//  2024-02-21  File created.

/*  Compilation and execution:

      c:\freeware\kotlinc\bin\kotlinc Findreplace.kt -include-runtime -d RunThis.jar

      java -jar RunThis.jar

*/

import java.io.*

fun store_text_lines_to_file( given_array_of_text_lines : ArrayList<String>,
                              given_file_name : String )
{
   try
   {
     val output_file  =  PrintWriter( FileWriter( given_file_name ) )

      for ( text_line in given_array_of_text_lines )
      {
         output_file.println( text_line )
      }

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

fun replace_string_in_file( original_file_name : String,
                            string_to_replace : String,
                            replacement_string : String )
{
   try
   {
      val original_file = BufferedReader( FileReader( original_file_name ) )
      
      val original_text_lines  =  ArrayList<String>()
      val modified_text_lines  =  ArrayList<String>()

      var line_counter  =  0 
      var end_of_file_encountered  =  false

      while ( end_of_file_encountered  ==  false )
      {
         var 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 )

            if ( text_line_from_file.contains( string_to_replace ) )
            {
               text_line_from_file  =
                       text_line_from_file.replace( string_to_replace,
                                                    replacement_string )

               print( "\n \""  +  string_to_replace
                    +  "\" was replaced with \""  +  replacement_string
                    +  "\" on line "  +  line_counter  ) ;
            }

            modified_text_lines.add( text_line_from_file )
         }
      }

      original_file.close()

      val 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 ( caught_file_not_found_exception : FileNotFoundException )
   {
      print( "\n Cannot open \"" + original_file_name + "\"")
   }
   catch ( caught_io_exception : IOException )
   {
      print( "\n Error in reading " + original_file_name )
   }
}


fun main( command_line_parameters : Array<String> )
{
   var file_name_given_by_user : String
   var string_to_replace : String
   var replacement_string : String
      
   if ( command_line_parameters.size  ==  3 )
   {
      file_name_given_by_user  =  command_line_parameters[ 0 ]
      string_to_replace        =  command_line_parameters[ 1 ]
      replacement_string       =  command_line_parameters[ 2 ]
   }
   else
   {
      print( "\n This program can replace a string in a "
          +  "\n text file. Give first the file name :  " )

      file_name_given_by_user  =  readLine()!!

      print( "\n Type in the string to be replaced: " )

      string_to_replace   =  readLine()!!

      print( "\n Type in the replacement string:    " )

      replacement_string   =  readLine()!!

   }
   
   if ( string_to_replace.equals( "" )  ||
        string_to_replace.equals( replacement_string ) )
   {
      print( "\n Cannot replace \""  +  string_to_replace
          +  "\" with \""  +  replacement_string  +  "\"\n\n" )
   }
   else
   {
      replace_string_in_file( file_name_given_by_user,
                              string_to_replace,
                              replacement_string )
   }
}