/* @tier easy @module st @transform settlement-online */
/*
 * st_ol_0026.pgc - 캐시백/리워드 수수료 계산 (ST_OL_0026)  [tier=easy]
 *
 * 매출금액에 리워드 적립요율(만분율)을 적용해 캐시백을 산출하되,
 * 회차 적립한도(cap)로 상한을 적용한다. 요율/한도 미입력 시 리워드
 * 정책(st_reward_policy)에서 조회한다.
 */
#include <stdio.h>
#include <string.h>

#include "txcore.h"
#include "txcore_dbio.h"
#include "acq_util.h"
#include "st_core.h"

EXEC SQL INCLUDE sqlca;


static long st_fee_round(long amount, long rate_bp)
{
    /* 요율(만분율, basis point) x 금액 -> 원단위 반올림 (BigDecimal HALF_UP 대응) */
    if (amount < 0)
        return -(((-amount) * rate_bp + 5000) / 10000);
    return (amount * rate_bp + 5000) / 10000;
}

TX_SERVICE(ST_OL_0026, ctx)
{
    EXEC SQL BEGIN DECLARE SECTION;
    char h_merch[16];
    long h_reward_bp;
    long h_cap;
    EXEC SQL END DECLARE SECTION;

    char merch[16];
    long amount = 0, reward_bp = 0, cap = 0, cashback;

    tx_log(TX_LOG_INFO, "[ST_OL_0026] 캐시백/리워드 계산 진입");

    if (tx_buf_get(ctx->in, "MERCHID", merch, sizeof(merch)) != TX_OK) {
        tx_return(ctx, TX_EINVAL, ctx->out);
        return;
    }
    tx_buf_getlong(ctx->in, "AMOUNT", &amount);
    tx_buf_getlong(ctx->in, "REWARDBP", &reward_bp);
    tx_buf_getlong(ctx->in, "CAP", &cap);

    /* 리워드 정책 조회 */
    if (reward_bp <= 0 || cap <= 0) {
        strncpy(h_merch, merch, sizeof(h_merch) - 1);
        h_merch[sizeof(h_merch) - 1] = '\0';
        h_reward_bp = 0;
        h_cap = 0;
        EXEC SQL SELECT reward_bp, cap_amt
            INTO :h_reward_bp, :h_cap
            FROM st_reward_policy
            WHERE merch_id = :h_merch;
        if (sqlca.sqlcode == TX_SQL_OK) {
            if (reward_bp <= 0) reward_bp = h_reward_bp;
            if (cap <= 0)       cap       = h_cap;
        } else if (sqlca.sqlcode != TX_SQL_NOTFOUND) {
            TX_DBIO_LOG_ERR("SELECT st_reward_policy");
        }
    }
    if (reward_bp <= 0) reward_bp = 100;   /* 1% 적립 */
    if (cap <= 0) cap = 20000;             /* 회차 한도 2만원 */

    if (!amount_is_valid(amount)) {
        tx_buf_reset(ctx->out);
        tx_buf_sets(ctx->out, "RESPCODE", RESP_INVALID);
        tx_return(ctx, TX_EINVAL, ctx->out);
        return;
    }

    cashback = st_fee_round(amount, reward_bp);
    if (cashback > cap) cashback = cap;

    tx_buf_reset(ctx->out);
    tx_buf_sets(ctx->out, "RESPCODE", RESP_OK);
    tx_buf_sets(ctx->out, "MERCHID", merch);
    tx_buf_setlong(ctx->out, "AMOUNT", amount);
    tx_buf_setlong(ctx->out, "REWARDBP", reward_bp);
    tx_buf_setlong(ctx->out, "CASHBACK", cashback);
    tx_buf_setlong(ctx->out, "CAP", cap);
    tx_log(TX_LOG_INFO, "[ST_OL_0026] 캐시백 amount=%ld bp=%ld cashback=%ld",
           amount, reward_bp, cashback);
    tx_return(ctx, TX_OK, ctx->out);
}