#  Search.py  Copyright (c) Kari Laitinen

#  http://www.naturalprogramming.com

#  2006-05-15  File created.
#  2022-12-27  Converted to Python 3.

import sys   # needed when command line parameters are used


def search_string_in_file( file_name_from_caller,
                           string_to_be_searched ) :

   file_to_read  =  open( file_name_from_caller )  #  "r" is default

   print( "\n Searching ... \"%s\""  %  string_to_be_searched )

   line_counter  =  0
   end_of_file_encountered  =  False

   while  end_of_file_encountered  ==  False :

      text_line_from_file   =  file_to_read.readline()

      if  text_line_from_file  ==  ""  :

         end_of_file_encountered  =  True

      else  :

         line_counter  +=  1

         if  text_line_from_file.find( string_to_be_searched ) !=  -1  :

            print( "\n \"%s\" was found on line %d"  %    \
                   ( string_to_be_searched, line_counter ), end="" )

   file_to_read.close()


#  The main program begins.

command_line_parameters  =  sys.argv[ 1 : ]

if len( command_line_parameters )  ==  2 :

   search_string_in_file ( command_line_parameters[ 0 ],
                           command_line_parameters[ 1 ] )

else  :

   print( "\n This program can search a string in a "    \
          "\n text file. Give first the file name : ", end="" )

   file_name_given_by_user  =  input()

   print( "\n Type in the string to be searched: ", end="" )

   string_to_be_searched    =  input()

   search_string_in_file( file_name_given_by_user,
                          string_to_be_searched )


print( "\n" )