/**
 * Copyright (c) 2021 OceanBase
 * OceanBase CE is licensed under Mulan PubL v2.
 * You can use this software according to the terms and conditions of the Mulan PubL v2.
 * You may obtain a copy of Mulan PubL v2 at:
 *          http://license.coscl.org.cn/MulanPubL-2.0
 * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
 * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
 * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
 * See the Mulan PubL v2 for more details.
 */

#define USING_LOG_PREFIX SQL_ENG
#include "sql/engine/expr/ob_expr_uid.h"
#include "sql/engine/ob_physical_plan_ctx.h"
#include "lib/mysqlclient/ob_mysql_result.h"
#include "lib/mysqlclient/ob_mysql_transaction.h"
#include "lib/string/ob_sql_string.h"
#include "lib/mysqlclient/ob_mysql_proxy.h"
#include "lib/oblog/ob_log_module.h"
#include "sql/session/ob_sql_session_info.h"
#include "share/schema/ob_schema_getter_guard.h"
#include "sql/engine/ob_exec_context.h"

using namespace oceanbase::common;
using namespace oceanbase::sql;

namespace oceanbase {
namespace sql {

ObExprUid::ObExprUid(ObIAllocator& alloc) : ObFuncExprOperator(alloc, T_FUN_SYS_UID, N_UID, 0, NOT_ROW_DIMENSION)
{}

ObExprUid::~ObExprUid()
{}

int ObExprUid::calc_result_type0(ObExprResType& type, ObExprTypeCtx& type_ctx) const
{
  UNUSED(type_ctx);
  if (share::is_oracle_mode()) {
    type.set_number();
    type.set_precision(PRECISION_UNKNOWN_YET);
    type.set_scale(ORA_NUMBER_SCALE_UNKNOWN_YET);
  } else {
    type.set_uint64();
  }
  return OB_SUCCESS;
}

int ObExprUid::calc_result0(ObObj& result, ObExprCtx& expr_ctx) const
{
  int ret = OB_SUCCESS;
  const ObSQLSessionInfo* session_info = NULL;
  if (OB_ISNULL(session_info = expr_ctx.my_session_)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("session info is null", K(ret));
  } else if (!share::is_oracle_mode()) {
    ret = OB_NOT_SUPPORTED;
    LOG_WARN("UID function is supported by Oracle mode", K(ret), K(share::is_oracle_mode()));
  } else {
    const uint64_t sess_uid = session_info->get_user_id();
    // result.set_uint64_value(sess_uid);
    number::ObNumber num;
    if (OB_FAIL(num.from(sess_uid, *(expr_ctx.calc_buf_)))) {
      LOG_WARN("convert int to number failed", K(ret), K(sess_uid));
    } else {
      result.set_number(num);
    }
  }
  return ret;
}

int ObExprUid::eval_uid(const ObExpr& expr, ObEvalCtx& ctx, ObDatum& expr_datum)
{
  int ret = OB_SUCCESS;
  UNUSED(expr);
  const ObBasicSessionInfo* session_info = NULL;
  if (OB_ISNULL(session_info = ctx.exec_ctx_.get_my_session())) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("session info is null", K(ret));
  } else {
    char local_buff[number::ObNumber::MAX_BYTE_LEN];
    ObDataBuffer local_alloc(local_buff, number::ObNumber::MAX_BYTE_LEN);
    number::ObNumber num;
    if (OB_FAIL(num.from(session_info->get_user_id(), local_alloc))) {
      LOG_WARN("failed to convert int to number", K(ret));
    } else {
      expr_datum.set_number(num);
    }
  }
  return ret;
}

int ObExprUid::cg_expr(ObExprCGCtx& op_cg_ctx, const ObRawExpr& raw_expr, ObExpr& rt_expr) const
{
  UNUSED(raw_expr);
  UNUSED(op_cg_ctx);
  rt_expr.eval_func_ = ObExprUid::eval_uid;
  return OB_SUCCESS;
}

}  // namespace sql
}  // namespace oceanbase
