/*
 ******************************************************************************
 * file name  : vec_sort.cpp
 * author     : Hung Q. Ngo
 * description: how to sort vectors, this is a quick hack just to show you how
 *              you might do it; in your project 1, it might be best to design
 *              a class Table, make "col_index" a member of that class, 
 ******************************************************************************
 */
#include <iostream>
#include <vector>
#include <iomanip>  // for setw()
#include <cstdlib>  // for rand() and srand()
#include <ctime>    // for time()

#include "cb_sort.h"

using namespace std;

struct Record {
    size_t col_index; // the column used for indexing the record
    vector<int> row;
    friend ostream& operator<<(ostream&, const Record&);
};

/**
 * -----------------------------------------------------------------------------
 * generate a random table with m rows and n columns, indexed by i <= n
 * -----------------------------------------------------------------------------
 */
vector<Record> get_table(size_t m, size_t n, size_t index) {
    vector<Record> ret(m);
    vector<int> row(n);
    srand(static_cast<unsigned int>(time(0)));
    for (size_t i=0; i<m; i++) {
        ret[i].col_index = index;
        ret[i].row = row;
        for (size_t j=0; j<n; j++) {
            ret[i].row[j] = rand() % m;
        }
    }
    return ret;
}

/**
 * -----------------------------------------------------------------------------
 * print a vector of Item_Type, finish with a new line
 * assumes compiler knows how to cout << Item_Type 
 * -----------------------------------------------------------------------------
 */
template <typename Item_Type>
void print_vec(vector<Item_Type>& vec) {
    for (int i=0; i<vec.size(); i++) {
        cout << vec[i] << " ";
    }
    cout << endl;
}

/**
 * -----------------------------------------------------------------------------
 * overload the extraction operator << so that we can cout a Record
 * -----------------------------------------------------------------------------
 */
ostream& operator<<(ostream& out, const Record& rec) {
    for (size_t i=0; i<rec.row.size(); i++) {
        out << rec.row[i] << " ";
    }
    out << endl;
    return out;
}

/**
 * -----------------------------------------------------------------------------
 * compare records
 * -----------------------------------------------------------------------------
 */
int rec_cmp(Record a, Record b) {
    return a.row[a.col_index] < b.row[b.col_index] ? -1 :
           a.row[a.col_index] == b.row[b.col_index] ? 0 : 1;
}

/**
 * -----------------------------------------------------------------------------
 *  sort rows of a matrix on a given column
 * -----------------------------------------------------------------------------
 */
int main() {
    vector<Record> vec = get_table(10, 3, 0);
    cout << "Before: \n";
    print_vec(vec);
    randomized_quick_sort(vec, rec_cmp);
    cout << "After: \n";
    print_vec(vec);
    return 0;
}