#include <iostream>
#include <iomanip>
#include <string>
#include <vector>
#include "stats.h"
#include "student.h"
// note: this next #include is unnecessary because student.h already includes name.h,
// but it would not cause an error, because name.h has "include guards".
// #include "name.h"

// Read information about a student, returning true if the information was read correctly.
bool Student::read(std::istream& in_str, unsigned int num_homeworks, unsigned int num_tests) {

  // If we don't find an id, we've reached the end of the file & silently return false. 
  if (!(in_str >> id_number_)) return false;
  // Once we have an id number, any other failure in reading is treated as an error.  

  // read and construct the name
  std::string first_name,last_name;
  if (! (in_str >> first_name >> last_name)) {
    std::cerr << "Failed reading name for student " << id_number_ << std::endl;
    return false;
  }
  name_ = Name(first_name,last_name);

  // Read the homework scores
  unsigned int i;
  int score;
  hw_scores_.clear();
  for (i=0; i<num_homeworks && (in_str >> score); ++i) { hw_scores_.push_back(score); }
  if (hw_scores_.size() != num_homeworks) {
    std::cerr << "ERROR: end of file or invalid input reading hw scores for " << id_number_ << std::endl;
    return false;
  }

  // Read the test scores
  test_scores_.clear();
  for (i=0; i<num_tests && (in_str >> score); ++i) { test_scores_.push_back(score); }
  if (test_scores_.size() != num_tests) {
    std::cerr << "ERROR: end of file or invalid input reading test scores for" << id_number_ << std::endl;
    return false;
  }
  return true;  // everything was fine
}

// Compute and store the hw, test and final average for the student. 
void Student::compute_averages(double hw_weight) {
  double dummy_stddev;
  avg_and_std_dev(hw_scores_, hw_avg_, dummy_stddev);
  avg_and_std_dev(test_scores_, test_avg_, dummy_stddev);
  final_avg_ = hw_weight * hw_avg_ + (1 - hw_weight) * test_avg_;
}

std::ostream& Student::output_name(std::ostream& out_str) const {
  out_str << last_name() << ", " << first_name();
  return out_str;
}

std::ostream& Student::output_averages(std::ostream& out_str) const {
  out_str << std::fixed << std::setprecision(1);
  out_str << hw_avg_ << " " << test_avg_ << " " << final_avg_ << std::endl;
  return out_str;
}
          
// Boolean function to define alphabetical ordering of names.  The vector sort 
// function requires that the objects be passed by CONSTANT REFERENCE.
bool less_names(const Student& stu1, const Student& stu2) {
  return stu1.last_name() < stu2.last_name() || 
         (stu1.last_name() == stu2.last_name() && stu1.first_name() < stu2.first_name());
}