/* @tier hard @module st @transform settlement-online */
/*
 * st_ol_0013.pgc - 정산금 분할(N분할) 계산 (ST_OL_0013)  [tier=hard]
 *
 * 총 정산금을 N 회차로 균등 분할하되, 원단위 잔여(remainder)를 마지막
 * 회차에 몰아 합계가 원금과 일치하도록 배분한다. 산출된 회차 스케줄을
 * 분할지급 예정(st_installment)에 적재한다.
 */
#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;


TX_SERVICE(ST_OL_0013, ctx)
{
    EXEC SQL BEGIN DECLARE SECTION;
    char h_merch[16];
    long h_seq;
    long h_part_amt;
    long h_total_ins;
    EXEC SQL END DECLARE SECTION;

    char merch[16];
    long total = 0, parts = 0, base_part, last_part, i, acc = 0;

    tx_log(TX_LOG_INFO, "[ST_OL_0013] 정산금 분할 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, "TOTAL", &total);
    tx_buf_getlong(ctx->in, "PARTS", &parts);

    if (total <= 0 || parts <= 0 || parts > 60) {
        tx_buf_reset(ctx->out);
        tx_buf_sets(ctx->out, "RESPCODE", RESP_INVALID);
        tx_return(ctx, TX_EINVAL, ctx->out);
        return;
    }

    base_part = total / parts;
    for (i = 0; i < parts - 1; i++)
        acc += base_part;
    last_part = total - acc;            /* 잔여 마지막 회차 흡수 */

    /* 회차 스케줄 적재 (트랜잭션 경계) : 기존 예정 삭제 후 재적재 */
    strncpy(h_merch, merch, sizeof(h_merch) - 1);
    h_merch[sizeof(h_merch) - 1] = '\0';

    if (tx_begin() != TX_OK)
        tx_log(TX_LOG_WARN, "[ST_OL_0013] tx_begin 경고");

    EXEC SQL DELETE FROM st_installment WHERE merch_id = :h_merch;
    if (sqlca.sqlcode != TX_SQL_OK && sqlca.sqlcode != TX_SQL_NOTFOUND) {
        TX_DBIO_LOG_ERR("DELETE st_installment");
        tx_abort();
        tx_return(ctx, TX_EDB, ctx->out);
        return;
    }

    for (i = 0; i < parts; i++) {
        h_seq      = i + 1;
        h_part_amt = (i == parts - 1) ? last_part : base_part;
        EXEC SQL INSERT INTO st_installment
                (merch_id, seq_no, part_amt, reg_ts)
            VALUES
                (:h_merch, :h_seq, :h_part_amt, now());
        if (sqlca.sqlcode != TX_SQL_OK) {
            TX_DBIO_LOG_ERR("INSERT st_installment");
            tx_abort();
            tx_return(ctx, TX_EDB, ctx->out);
            return;
        }
    }

    /* 적재 검증: 합계 대조 */
    h_total_ins = 0;
    EXEC SQL SELECT coalesce(sum(part_amt), 0)
        INTO :h_total_ins
        FROM st_installment
        WHERE merch_id = :h_merch;
    if (sqlca.sqlcode != TX_SQL_OK || h_total_ins != total) {
        tx_log(TX_LOG_ERROR, "[ST_OL_0013] 분할합 불일치 적재=%ld 원금=%ld",
               (long)h_total_ins, total);
        tx_abort();
        tx_return(ctx, TX_FAIL, ctx->out);
        return;
    }
    tx_commit();

    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, "TOTAL", total);
    tx_buf_setlong(ctx->out, "PARTS", parts);
    tx_buf_setlong(ctx->out, "BASEPART", base_part);
    tx_buf_setlong(ctx->out, "LASTPART", last_part);
    tx_log(TX_LOG_INFO, "[ST_OL_0013] 분할 total=%ld parts=%ld base=%ld last=%ld",
           total, parts, base_part, last_part);
    tx_return(ctx, TX_OK, ctx->out);
}
