-module(utils).
-export([stemming/2]).

stemming(Word, SuffixesList) when is_binary(Word) ->
  string_stemming(Word, SuffixesList);
stemming(Word, SuffixesList) ->
  string_stemming(Word, SuffixesList).

string_stemming(Word, []) ->
  Word;
string_stemming(Word, [H|T]) ->
  %check to see if Word ends with Head's key    
  Suffix = element(1, H),
  Replacement = element(2, H),  
  case word_ends_with(Word, Suffix) of 
    true ->
      case Replacement of 
        [] ->
          Word1 = string:substr(Word, 1, string:len(Word)  - string:len(Suffix)),
          string_stemming(Word1, []);
        _ -> 
          Word1 = string:concat(string:substr(Word, 1, string:len(Word)  - string:len(Suffix)), Replacement),
          string_stemming(Word1, [])
      end;
    _ ->
      string_stemming(Word, T)
  end.
  
word_ends_with(Word, Suffix) ->
  case string:len(Word) > string:len(Suffix) of
    true ->
      case (string:substr(Word, string:len(Word)  - string:len(Suffix) + 1)) =:= Suffix of
        true ->
          true;
        false ->
          false
      end;
    false ->
      false
  end.