/* Processed by ecpg (15.18 (Debian 15.18-0+deb12u1)) */
/* These include files are added by the preprocessor */
#include <ecpglib.h>
#include <ecpgerrno.h>
#include <sqlca.h>
/* End of automatic include section */

#line 1 "app/online/mg_ol_0015.pgc"
/* @tier medium @module mg @transform msg-gateway-online */
/*
 * mg_ol_0015.pgc - 전문게이트웨이 이중화 전환 서비스 (MG_OL_0015)  [tier=medium]
 *
 * Active/Standby 두 노드의 상태지표(CPU 부하/메모리 여유/세션수/응답지연/
 * 하트비트 경과초)를 요청 TXBUF 에서 읽어 헬스 점수를 산출하고, 점수가
 * 높은 노드로 라우팅한다. Active 가 임계 미만이면 Standby 로 절체(failover)
 * 하며 전환사유와 함께 선택노드/양측 점수를 응답한다.
 */
#include <stdio.h>
#include <string.h>

#include "txcore.h"
#include "acq_util.h"
#include "mg_core.h"


#line 1 "/usr/include/postgresql/sqlca.h"
#ifndef POSTGRES_SQLCA_H
#define POSTGRES_SQLCA_H

#ifndef PGDLLIMPORT
#if  defined(WIN32) || defined(__CYGWIN__)
#define PGDLLIMPORT __declspec (dllimport)
#else
#define PGDLLIMPORT
#endif							/* __CYGWIN__ */
#endif							/* PGDLLIMPORT */

#define SQLERRMC_LEN	150

#ifdef __cplusplus
extern "C"
{
#endif

struct sqlca_t
{
	char		sqlcaid[8];
	long		sqlabc;
	long		sqlcode;
	struct
	{
		int			sqlerrml;
		char		sqlerrmc[SQLERRMC_LEN];
	}			sqlerrm;
	char		sqlerrp[8];
	long		sqlerrd[6];
	/* Element 0: empty						*/
	/* 1: OID of processed tuple if applicable			*/
	/* 2: number of rows processed				*/
	/* after an INSERT, UPDATE or				*/
	/* DELETE statement					*/
	/* 3: empty						*/
	/* 4: empty						*/
	/* 5: empty						*/
	char		sqlwarn[8];
	/* Element 0: set to 'W' if at least one other is 'W'	*/
	/* 1: if 'W' at least one character string		*/
	/* value was truncated when it was			*/
	/* stored into a host variable.             */

	/*
	 * 2: if 'W' a (hopefully) non-fatal notice occurred
	 */	/* 3: empty */
	/* 4: empty						*/
	/* 5: empty						*/
	/* 6: empty						*/
	/* 7: empty						*/

	char		sqlstate[5];
};

struct sqlca_t *ECPGget_sqlca(void);

#ifndef POSTGRES_ECPG_INTERNAL
#define sqlca (*ECPGget_sqlca())
#endif

#ifdef __cplusplus
}
#endif

#endif

#line 17 "app/online/mg_ol_0015.pgc"


/* 노드 헬스 점수: 100 만점, 낮을수록 위험 (임계 = 40) */
#define HEALTH_THRESHOLD 40
#define HEARTBEAT_DEAD   15   /* 하트비트 15초 초과 = 다운 간주 */

static int health_score(long cpu, long memfree, long sess, long latency, long hb)
{
    long score = 100;

    /* 하트비트 단절이면 즉시 0점(다운) */
    if (hb > HEARTBEAT_DEAD)
        return 0;

    score -= cpu / 2;              /* CPU 사용률 가중 */
    score -= (100 - memfree) / 4;  /* 메모리 여유 부족 가중 */
    score -= sess / 50;            /* 동시세션 과다 가중 */
    score -= latency / 20;         /* 응답지연(ms) 가중 */

    if (score < 0)   score = 0;
    if (score > 100) score = 100;
    return (int)score;
}

TX_SERVICE(MG_OL_0015, ctx)
{
    long a_cpu = 0, a_mem = 0, a_sess = 0, a_lat = 0, a_hb = 0;
    long s_cpu = 0, s_mem = 0, s_sess = 0, s_lat = 0, s_hb = 0;
    int  a_score, s_score;
    const char *selected;
    const char *reason;

    tx_log(TX_LOG_INFO, "[MG_OL_0015] 이중화 전환 판정 서비스 진입");

    /* Active 노드 지표 */
    tx_buf_getlong(ctx->in, "A_CPU", &a_cpu);
    tx_buf_getlong(ctx->in, "A_MEMFREE", &a_mem);
    tx_buf_getlong(ctx->in, "A_SESS", &a_sess);
    tx_buf_getlong(ctx->in, "A_LATENCY", &a_lat);
    tx_buf_getlong(ctx->in, "A_HEARTBEAT", &a_hb);

    /* Standby 노드 지표 */
    tx_buf_getlong(ctx->in, "S_CPU", &s_cpu);
    tx_buf_getlong(ctx->in, "S_MEMFREE", &s_mem);
    tx_buf_getlong(ctx->in, "S_SESS", &s_sess);
    tx_buf_getlong(ctx->in, "S_LATENCY", &s_lat);
    tx_buf_getlong(ctx->in, "S_HEARTBEAT", &s_hb);

    a_score = health_score(a_cpu, a_mem, a_sess, a_lat, a_hb);
    s_score = health_score(s_cpu, s_mem, s_sess, s_lat, s_hb);

    tx_log(TX_LOG_INFO, "[MG_OL_0015] 헬스점수 active=%d standby=%d", a_score, s_score);

    /* 라우팅 판정: Active 우선, 임계 미만이거나 Standby 우세시 절체 */
    if (a_score == 0 && s_score == 0) {
        tx_log(TX_LOG_ERROR, "[MG_OL_0015] 양 노드 모두 다운 - 라우팅 불가");
        tx_buf_reset(ctx->out);
        tx_buf_sets(ctx->out, "RESPCODE", RESP_SYSERR);
        tx_buf_sets(ctx->out, "SELECTED", "NONE");
        tx_return(ctx, TX_FAIL, ctx->out);
        return;
    }

    if (a_score >= HEALTH_THRESHOLD && a_score >= s_score) {
        selected = "ACTIVE";
        reason   = "NORMAL";
    } else if (a_score < HEALTH_THRESHOLD && s_score >= HEALTH_THRESHOLD) {
        selected = "STANDBY";
        reason   = "FAILOVER";
    } else if (s_score > a_score) {
        selected = "STANDBY";
        reason   = "LOADBALANCE";
    } else {
        selected = "ACTIVE";
        reason   = "DEGRADED";
    }

    tx_buf_reset(ctx->out);
    tx_buf_sets(ctx->out, "RESPCODE", RESP_OK);
    tx_buf_sets(ctx->out, "SELECTED", selected);
    tx_buf_sets(ctx->out, "REASON", reason);
    tx_buf_setlong(ctx->out, "ASCORE", (long)a_score);
    tx_buf_setlong(ctx->out, "SSCORE", (long)s_score);
    tx_log(TX_LOG_INFO, "[MG_OL_0015] 라우팅 결정 node=%s reason=%s", selected, reason);
    tx_return(ctx, TX_OK, ctx->out);
}
