#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <time.h>
double eps = 1;

struct vector {
    int x;
    int y;
    int z;
};

struct abc {
    struct vector vect;
    double len;
};

int intRand(int min, int max) {
    double r = (double) rand()/RAND_MAX;
    return (int) (r*(max-min) + 1);
}

double vect_len(struct vector a) {
    double result = pow(a.x*a.x + a.y*a.y + a.z*a.z, 0.5);
    return result;
}

void f_d(struct abc *a, int n) {
    for (int i = 0; i < n; i++)
        (*(a + i)).len = vect_len((*(a + i)).vect);
}

void print_struct(struct abc st) {
    printf("X: %d, Y: %d, Z: %d \n", st.vect.x, st.vect.y, st.vect.z);
    printf("vector's length: %lf \n", st.len);
}

int vector_cmp(const void *a, const void *b) {
    struct abc *as = (struct abc *) a;
    struct abc *bs = (struct abc *) b;
    return ((*as).len > (*bs).len) - ((*as).len < (*bs).len);
}

int vector_cmp_eps(const void *a, const void *b) {
    double *as = (double *) a;
    struct abc *bs = (struct abc *) b;
    return (*as > ((*bs).len - eps)) - (*as < ((*bs).len + eps));

}

void vect_find_eps(struct abc *V, int n, double len) {
    struct abc *el = bsearch(&len, V, n, sizeof(struct abc), vector_cmp_eps);
    if (el == NULL) {
        printf("Wektor o podanej dlugoci nie istnieje. \n");
        return;
    }
    struct abc *ptr = el;
    while(ptr > V) {
        if (ptr->len >= len - eps) print_struct(*ptr);
        ptr--;
    }
    ptr = el;
    ptr++;
    while(ptr < V + n) {
        if (ptr->len <= len + eps) print_struct(*ptr);
        ptr++;
    }
}

void vect_find(struct abc *V, int n, double len) {
    double a = len - eps;
    double b = len + eps;
    int min;
    int max;
    for (int i = 0; i < n; i++) {
        if ( (*(V + i)).len >= a) {
            min = i;
            break;
        }
    }
    for (int i = n - 1; i >= 0; i--) {
        if ( (*(V + i)).len <= b) {
            max = i;
            break;
        }
    }
    for(int i = min; i < max + 1; i++)
        print_struct(*(V+i));


}

int main(int argc, char **argv) {
    srand(time(0));
    int n = atoi(argv[1]);
    struct abc *TAB = (struct abc *) malloc(n*sizeof(struct abc));
    if (TAB == NULL) {
        printf("Alokacja pamieci sie nie powiodla. \n");
        return 0;
    }

    for (int i = 0; i < n; i++) {
        TAB[i].vect.x = intRand(0, 21) - 1;
        TAB[i].vect.y = intRand(0, 21) - 1;
        TAB[i].vect.z = intRand(0, 21) - 1;
    }
    f_d(TAB, n);

    printf("Wektory przed sortowaniem: \n");
    for (int i = 0; i < n; i++)
        print_struct(TAB[i]);

    qsort(TAB, n, sizeof(TAB[0]), vector_cmp);
    printf("\n");

    printf("Wektory po sortowaniu: \n");
    for (int i = 0; i < n; i++)
        print_struct(TAB[i]);

    printf("Podaj szukana dlugosc: \n");
    double slen;
    scanf("%lf", &slen);

    printf("\nWektory o podanej dlugosci +/- eps = 1(metoda liniowa) // Dla sprawdzenia poprawnosci ponizszego wyszukiwania z bsearch: \n");

    vect_find(TAB, n, slen);
    printf("\nWektory o podanej dlugosci +/- eps = 1(metoda z uzyciem bsearch): \n");
    vect_find_eps(TAB, n, slen);
    free(TAB);
    return 0;
}