/*
* Author:		Bradlee Hall
* Title:	    Grouping App
* Description:  This program reads in names from a file, randomly groups the
*				names and displays them
* Date Created:           1/20/2017
* Date Last Modified:     5/25/2017
*/

#include <algorithm>
#include <fstream>
#include <iostream>
#include <string>
#include <time.h>
#include <vector>

using namespace std;

struct person {

	string firstName;
	int group;
};

bool compareByGroup(const person &, const person &);

int main() {

	int numGroups = 0, groupSize = 0, roundStud = 0;

	vector<person> names;

	fstream file;
	string throwAway;
	person student;

	srand(time(NULL));

	//Open the file
	file.open("names.txt");

	if (!file) {
		cerr << "Cannot read file" << endl;
		return 1;
	}

	//Query the user for the amount of students in the groups
	cout << "How many students would you like in a group? ";

	cin >> groupSize;

	//Load the names into a vector array
	while (!file.eof()) {

		file >> student.firstName;
		names.push_back(student);

		//throw away the last names and the rest of the line
		getline(file, throwAway);
	}

	//Randomly shuffle them
	random_shuffle(names.begin(), names.end());

	//Query the user as to group size
	while (groupSize != 2 && groupSize != 3 && groupSize != 4 && groupSize != 5) {
		cerr << "Please enter 2, 3, 4 or 5: ";
		cin >> groupSize;
	}

	roundStud = names.size();

	//If the number of of students that cannot be divided evenly into a group
	//is less than the size of a little more than half the size of a group
	//just make groups a little bigger
	if ((names.size() % groupSize) < ((groupSize / 2) + 1)) {

		//Round down to the next lowest group number multiple
		while ((roundStud % groupSize != 0)) {

			roundStud--;
		}

	}
	//Otherwise make a few slightly smaller groups
	else{

		//Round up to the next highest group number multiple
		while ((roundStud % groupSize != 0)) {

			roundStud++;
		}
	}

	numGroups = (roundStud / groupSize);

	//Assign groups one-by-one for equal distribution
	for(int i = 0; i < names.size(); i++)
		names[i].group = ((i % numGroups) + 1);

	//Sort the vector based on the groups
	sort(names.begin(), names.end(), compareByGroup);

	cout << endl;

	int currGroup = 1;

	//Display the groups
	while (!names.empty()) {

		cout << "Group " << currGroup << " consists of: " << endl;

		while((names.size() != 0) && (names.back().group == currGroup)) {

			cout << names.back().firstName << endl;
			names.pop_back();
		}

		cout << endl;

		currGroup++;
	}

	system("pause");

	return 0;
}

bool compareByGroup(const person &a, const person &b)
{
	return (a.group > b.group);
}