//
// Implementation of insertion sort algorithm.
//
// Driver generates and sorts a random sequence of N integers.
// N and seed are passed as command-line arguments, with optional
// "--verbose" to request verbose output (intermediate results).
//
// const DATA_LIMIT specifies upper bound for random data.
//
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <vector>
#include <algorithm>

const int DATA_LIMIT = 100;
void fillWithRandom(int seed, std::vector<int> &v);
void printVector(std::vector<int> v);
void insertionSort(std::vector<int> &v, bool verbose);

/* main (driver) */
int main(int argc, char *argv[]) {

    if (argc < 3) {
        std::cerr << "usage:  " << argv[0] << " seed N [--verbose]" << std::endl;
        return EXIT_FAILURE;
    }

    char *endptr;
    long seed = strtol(argv[1], &endptr, 10);
    if (*endptr != '\0') {
        std::cerr << "non-numeric seed" << std::endl;
        return EXIT_FAILURE;
    }
    long n = strtol(argv[2], &endptr, 10);
    if (*endptr != '\0') {
        std::cerr << "non-numeric N" << std::endl;
        return EXIT_FAILURE;
    }
    bool verbose = (argc > 3) && (strcmp(argv[3], "--verbose") == 0);

    /* generate input */
    std::vector<int>v(n);
    fillWithRandom(seed, v);

    std::cout << "Data before sort:\n";
    printVector(v);

    insertionSort(v, verbose);

    std::cout << "\nData after sort:\n";
    printVector(v);
    return EXIT_SUCCESS;
}

/* fill vector with random data */
void fillWithRandom(int seed, std::vector<int> &v) {
    srand(seed);

    for (auto& iter : v) {
        iter = rand() % DATA_LIMIT;
    }
}

/* print vector */
void printVector(std::vector<int> v) {
    for (int val : v) {
        std::cout << val << " ";
    }
    std::cout << std::endl;
}

/* 
 * insertion sort:
 * sort vector of n ints
 */
void insertionSort(std::vector<int> &v, bool verbose) {
    if (verbose) {
            std::cout << "initially, sorted data:  "  
                << v[0] << " " << std::endl;
    }
 
    for (int i = 1; i < (int) v.size(); ++i) {
        // Insert v[i] in v[0 .. i-1] 
        int key = v[i];
        int j = i - 1;
        while (j >= 0 && v[j] > key) {
            v[j+1] = v[j];
            j -= 1;
        }
        v[j+1] = key;
        if (verbose) {
            std::cout << "after step " << i 
                << " key = " << key 
                << ", new key position = " << j+1 
                << ", sorted data:  ";
            for (int k = 0; k <= i; ++k) {
                std::cout << v[k] << " ";
            }
            std::cout << std::endl;
        }
    }
}