#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#define AMOUNT_BUF_SIZE 64

typedef struct {
    long long units;
    int cents;
    char currency[4];
} amount_t;

int amount_parse(const char* str, amount_t* out) {
    if (!str || !out) return -1;
    long long units = 0;
    int cents = 0;
    char currency[4] = "KRW";
    const char* p = str;
    while (*p && !isdigit(*p) && *p != '.' && *p != '-') p++;
    if (sscanf(p, "%lld.%2d", &units, &cents) >= 1) {
        out->units = units;
        out->cents = cents;
        strcpy(out->currency, currency);
        return 0;
    }
    return -1;
}

int amount_format(const amount_t* a, char* buf, size_t len) {
    if (!a || !buf) return -1;
    return snprintf(buf, len, "%s %lld.%02d", a->currency, a->units, a->cents);
}

int amount_add(const amount_t* a, const amount_t* b, amount_t* out) {
    if (!a || !b || !out) return -1;
    long long total_cents = a->units * 100 + a->cents + b->units * 100 + b->cents;
    out->units = total_cents / 100;
    out->cents = (int)(total_cents % 100);
    strcpy(out->currency, a->currency);
    return 0;
}

int amount_subtract(const amount_t* a, const amount_t* b, amount_t* out) {
    if (!a || !b || !out) return -1;
    long long total_cents = (a->units * 100 + a->cents) - (b->units * 100 + b->cents);
    out->units = total_cents / 100;
    out->cents = (int)(total_cents % 100);
    if (total_cents < 0) out->cents = -out->cents;
    strcpy(out->currency, a->currency);
    return 0;
}

int amount_multiply(const amount_t* a, int factor, amount_t* out) {
    if (!a || !out) return -1;
    long long total_cents = (a->units * 100 + a->cents) * factor;
    out->units = total_cents / 100;
    out->cents = (int)(total_cents % 100);
    strcpy(out->currency, a->currency);
    return 0;
}