const char rodata[] = "abcd";
#include <stdio.h>
#include <stdlib.h>
#define _GNU_SOURCE
#include <string.h>


struct account {
    long money;
    const char *name;
};
void retrieve_account(struct account *acc);
void check_flag(const struct account *acc);

int main(int argc, char **argv){
    struct account acc; // current user and their money
    retrieve_account(&acc);

    /////////// INTERESTING CODE BELOW //////////////

    // these are the interesting local variables, packed in a struct so the layout doesn't change
    struct {
        char buffer[16];
        int nDucks;
    } order; 
    const long price_per_duck = 20;

    setbuf(stdout, NULL); // turn off output buffering
    printf("Hi, %s! Welcome to *Acme Rubber Ducks, Inc.*! We sell rubber ducks for the low price of $%ld per duck. You have $%ld. How many rubber ducks would you like to order? ", acc.name, price_per_duck, acc.money);

    fgets(order.buffer, 512, stdin); 
    order.nDucks = atoi(order.buffer); // atoi converts a string to an int

    if(order.nDucks < 1) { // we're certainly not going to get tricked by anyone ordering a negative amount of ducks!
        printf("Sorry, minimum order size is 1\n");
        return 0;
    }

    printf("And what is your shipping address? ");
    fgets(order.buffer, 512, stdin); // read up to 512 bytes into our 16 byte buffer (what could possibly go wrong?)
    strchrnul(order.buffer, '\n')[0] = '\0'; // replace newline with end-of-string

    long total = order.nDucks*price_per_duck;
    if(total > acc.money) { // input validation is important. we're checking everything here!
        printf("Sorry! You don't have enough money!\n");
    } else {
        acc.money -= total;
        printf("Thank you for your order of %d ducks!\nWe have charged your account $%ld, and you now have $%ld left.\n", order.nDucks, total, acc.money);
        check_flag(&acc);
    }

    return 0;
}


void retrieve_account(struct account *acc) {
    const char* m = getenv("MONEY");
    if(m != NULL)
        acc->money = atol(m);
    else
        acc->money = 1000;
    acc->name = getenv("USER");
    // ^^^ the arrow operator (->) gets a field value from a *pointer to a struct*; it is
    // equivalent to dereferencing the pointer (*acc) and then selecting the field: (*acc).name
}

// check if the flag was captured
// ctf.py will check if money > 1000 and if so issue a success token
void check_flag(const struct account *acc) {
    if(getenv("TASK_NAME")) {
        char cmdline[48];
        snprintf(cmdline, 47, "python ctf.py check %ld", acc->money);
        system(cmdline);
    } else {
        printf("Success!");
    }
}