#ifndef FILEREADER_H
#define FILEREADER_H

#include <string>
#include <set>
#include <algorithm>

class FileReader {
 public:
  // Default constructor (doesn't do anything special)
  FileReader() {} 

  //----------------------------------------------------------------------------------
  // You implement these two

  // This version simply creates a set with all words in the file - it doesn't
  // select only the top N and doesn't use an exclusion list.  (It's used to
  // read in the exclusion list.)
  FileReader(const std::string & filename);

  // This version creates a set with the top_num most frequently occcuring words
  // from the file, ignoring all words in  the excluded FileReader's set
  FileReader(unsigned int top_num, const std::string filename, const FileReader &excluded);

  //----------------------------------------------------------------------------------


  // These are implemented already

  bool contains(const std::string &word) const {
    return word_set.find(word) != word_set.end();
  }

  // set difference
  FileReader operator-(const FileReader & other) const {
    FileReader result;
    std::set_difference(word_set.begin(), word_set.end(), other.word_set.begin(), other.word_set.end(),
			std::insert_iterator<std::set<std::string>>(result.word_set, result.word_set.begin()));
    return result;
  }

  // set intersection
  FileReader operator^(const FileReader & other) const {
    FileReader result;
    std::set_intersection(word_set.begin(), word_set.end(), other.word_set.begin(), other.word_set.end(),
			  std::insert_iterator<std::set<std::string>>(result.word_set, result.word_set.begin()));
    return result;
  }

  const std::set<std::string>& set() { return word_set; }

 private:
  std::set<std::string> word_set;
};

#endif // FILEREADER_H