/* @tier easy @module cl @transform closing-util */
/*
 * cl_cu_0008.c - 마감 공통 유틸리티 (plain C)  [tier=easy]
 */
#include "cl_cu_0008.h"

#include <string.h>

/* 상·하한 적용 정률 수수료 */
long cl_cu_0008_fee(long amount, int rate_bp)
{
    long fee;
    const long floor_fee = 100L;
    const long cap_fee = 500000L;
    if (amount <= 0 || rate_bp < 0)
        return 0;
    fee = (amount * (long)rate_bp) / 10000L;
    if (fee < floor_fee)
        fee = floor_fee;
    if (fee > cap_fee)
        fee = cap_fee;
    return fee;
}

/* 최근접 배수 선택: 아래/위 배수 중 더 가까운 쪽으로 정규화 */
long cl_cu_0008_round_unit(long amount, long unit)
{
    long down, up, dd, du;
    if (unit <= 0)
        return amount;
    if (amount % unit == 0)
        return amount;
    down = (amount / unit) * unit;
    if (amount > 0)
        up = down + unit;
    else
        up = down - unit;
    dd = amount - down; if (dd < 0) dd = -dd;
    du = up - amount;   if (du < 0) du = -du;
    return dd <= du ? down : up;
}

/* amount 를 YYYYMMDD 로 보고 월말/윤년 유효성 분류: 0=무효 1=정상 2=월말 */
int cl_cu_0008_classify(long amount)
{
    int y = (int)(amount / 10000L);
    int m = (int)((amount / 100L) % 100L);
    int d = (int)(amount % 100L);
    int dim[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
    int leap, last;
    if (m < 1 || m > 12 || d < 1)
        return 0;
    leap = (y % 4 == 0 && y % 100 != 0) || (y % 400 == 0);
    last = dim[m - 1];
    if (m == 2 && leap)
        last = 29;
    if (d > last)
        return 0;
    if (d == last)
        return 2;
    return 1;
}
