#include "stdio.h"
#include "stdlib.h"
#include "limits.h"
#include "sodium.h"
#include "strtoui.h"

int map(int i, int i_min, int i_max, int o_min, int o_max) {
    double r = (double)(o_max - o_min) / (double)(i_max - i_min);
    int j = (double) (i - i_min) * r + o_min;
    return j;
}

int main(int argc, char *argv[]) {
    if(argc == 1) {
        puts("Usage: chars [length]");
        puts("       Max length is 1024");
        exit(EXIT_SUCCESS);
    }

    unsigned int len;
    enum strtoui_error error = strtoui(&len, argv[1], 10);
    if(error != STRTOUI_SUCCESS){
        fputs("Bad input\n", stderr);
        exit(EXIT_FAILURE);
    }else if (len > 1024) {
        fputs("The length is to big\n", stderr);
        exit(EXIT_FAILURE);
    }

    char lower_range = 0x20;
    char upper_range= 0x7e;

    char data[len];
    randombytes_buf(data, sizeof len);

    for(int i = 0; i < len; i++) {
        int random = randombytes_uniform(upper_range);
        data[i] = map(random, 0, upper_range, lower_range, upper_range);
        printf("%c", data[i]);
    }
    printf("\n");

    exit(EXIT_SUCCESS);
}