/**
 * 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_unix_timestamp.h"
#include "sql/engine/expr/ob_expr_util.h"
#include "lib/timezone/ob_time_convert.h"
#include "lib/allocator/ob_allocator.h"
#include "share/object/ob_obj_cast.h"
#include "sql/session/ob_sql_session_info.h"
#include "sql/engine/ob_exec_context.h"

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

namespace oceanbase {
namespace sql {

ObExprUnixTimestamp::ObExprUnixTimestamp(ObIAllocator& alloc)
    : ObFuncExprOperator(alloc, T_FUN_SYS_UNIX_TIMESTAMP, N_UNIX_TIMESTAMP, ZERO_OR_ONE, NOT_ROW_DIMENSION)
{}

ObExprUnixTimestamp::~ObExprUnixTimestamp()
{}

int ObExprUnixTimestamp::calc_result_typeN(
    ObExprResType& type, ObExprResType* type_array, int64_t param, ObExprTypeCtx& type_ctx) const
{
  /*  no argument - > int
   *  has argument & is literal :
   *  --> out_of_range date --> 0.000000
   *  --> (has usec) --> int
   *  --> (not has usec) --> number scale = -1
   *  has argument & is not literal :
   *  --> is string --> number scale = 6
   *  --> type.scale = 0 --> int
   *  --> type.scale != 0 --> number scale = type.scale
   */

  UNUSED(type_ctx);
  int ret = OB_SUCCESS;
  if (0 == param) {
    type.set_int();
    type.set_scale(ObAccuracy::DDL_DEFAULT_ACCURACY[ObIntType].scale_);
    type.set_precision(ObAccuracy::DDL_DEFAULT_ACCURACY[ObIntType].precision_);
    UNUSED(type_array);
  } else {
    ObExprResType& date_type = type_array[0];
    if (ObNullType == date_type.get_type()) {
      type.set_null();
    } else if (date_type.is_literal()) {  // literal
      ret = calc_result_type_literal(type, date_type);
    } else {  // column
      ret = calc_result_type_column(type, date_type);
    }
    date_type.set_calc_type(ObTimestampType);
  }
  ret = OB_SUCCESS;  // just let it go if error happened
  return ret;
}

int ObExprUnixTimestamp::calc_result_type_literal(ObExprResType& type, ObExprResType& type1) const
{
  int ret = OB_SUCCESS;
  ObObj date_obj = type1.get_param();
  bool is_number_res_type = false;
  int64_t utz_value = 0;
  if (date_obj.is_string_type()) {  // string
    int16_t scale = DEFAULT_SCALE_FOR_INTEGER;
    ObTimeConvertCtx cvrt_ctx(NULL, false);
    if (OB_FAIL(ObTimeConverter::str_to_datetime(date_obj.get_string(), cvrt_ctx, utz_value, &scale))) {
      LOG_WARN("failed to cast str to datetime", K(ret));
      is_number_res_type = true;
      type.set_scale(MAX_SCALE_FOR_TEMPORAL);
    } else {
      type.set_scale(scale);
    }
  } else {
    ObArenaAllocator oballocator(ObModIds::BLOCK_ALLOC);  // is this ok?
    ObCastCtx cast_ctx(&oballocator, NULL, 0, CM_NONE, CS_TYPE_INVALID, NULL);
    EXPR_GET_DATETIME_V2(date_obj, utz_value);
    if (OB_FAIL(ret)) {
      LOG_WARN("failed to cast date to datetime", K(ret), K(date_obj));
      utz_value = 0;
    }
  }
  // todo out-of-range date --> 0.000000
  if (is_number_res_type || utz_value % 1000000) {
    type.set_number();
    if (!type1.is_string_type()) {
      type.set_scale(type1.get_scale());
    }
    type.set_precision(static_cast<ObPrecision>(TIMESTAMP_VALUE_LENGTH + type.get_scale()));

  } else {
    type.set_int();
    type.set_precision(static_cast<ObPrecision>(TIMESTAMP_VALUE_LENGTH));
    type.set_scale(DEFAULT_SCALE_FOR_INTEGER);
  }
  return ret;
}

int ObExprUnixTimestamp::calc_result_type_column(ObExprResType& type, ObExprResType& type1) const
{
  int ret = OB_SUCCESS;
  if (type1.is_string_type() || type1.is_double()) {
    type.set_number();
    type.set_scale(MAX_SCALE_FOR_TEMPORAL);
    type.set_precision(static_cast<ObPrecision>(TIMESTAMP_VALUE_LENGTH + type.get_scale()));
  } else {
    if (DEFAULT_SCALE_FOR_INTEGER == type1.get_scale()) {
      type.set_int();
      type.set_precision(static_cast<ObPrecision>(TIMESTAMP_VALUE_LENGTH));
      type.set_scale(DEFAULT_SCALE_FOR_INTEGER);
    } else {
      type.set_number();
      type.set_scale(type1.get_scale());
      type.set_precision(static_cast<ObPrecision>(TIMESTAMP_VALUE_LENGTH + type.get_scale()));
    }
  }
  return ret;
}

int ObExprUnixTimestamp::calc_resultN(
    ObObj& result, const ObObj* date_array, int64_t param, common::ObExprCtx& expr_ctx) const
{
  int ret = OB_SUCCESS;
  if (OB_ISNULL(date_array) || OB_ISNULL(expr_ctx.phy_plan_ctx_)) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid argument.", K(ret));
  } else {
    ObObj date;
    if (0 == param) {
      if (!expr_ctx.phy_plan_ctx_->has_cur_time()) {
        ret = OB_ERR_UNEXPECTED;
        LOG_WARN("physical plan context don't have current time value", K(ret));
      } else {
        date = expr_ctx.phy_plan_ctx_->get_cur_time();
      }
    } else if (1 == param) {
      date = date_array[0];
    } else {
      ret = OB_ERR_UNEXPECTED;
      LOG_WARN("param is not right", K(ret));
    }
    EXPR_DEFINE_CAST_CTX(expr_ctx, CM_NONE);
    // here use result_type_
    if (OB_SUCCESS == ret && OB_FAIL(calc(result, date, result_type_, cast_ctx))) {
      LOG_WARN("calc date value failed", K(ret));
    }
  }
  return ret;
}
int ObExprUnixTimestamp::calc(ObObj& result, const ObObj& date, const ObExprResType& res_type, ObCastCtx& cast_ctx)
{
  int ret = OB_SUCCESS;
  if (date.is_null()) {
    result.set_null();
  } else if (ObTimestampType != date.get_type()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("type of date must be ObTimestampType", K(ret));
  } else {
    int64_t utz_value = 0;
    utz_value = date.get_timestamp();
    utz_value = utz_value < 0 ? 0 : utz_value;
    if (ObIntType == res_type.get_type()) {
      result.set_int(utz_value / 1000000);
    } else {
      number::ObNumber nmb;
      number::ObNumber usec;
      number::ObNumber res_nmb;
      nmb.from(utz_value, cast_ctx);
      int64_t v_usec = 1000000;
      usec.from(v_usec, cast_ctx);
      ret = nmb.div(usec, res_nmb, cast_ctx);
      if (OB_SUCC(ret)) {
        result.set_number(res_nmb);
      }
    }
  }
  return ret;
}

int ObExprUnixTimestamp::eval_unix_timestamp(const ObExpr& expr, ObEvalCtx& ctx, ObDatum& res)
{
  int ret = OB_SUCCESS;
  int64_t utz_value = 0;
  bool is_null = false;
  if (0 == expr.arg_cnt_) {
    CK(OB_NOT_NULL(ctx.exec_ctx_.get_physical_plan_ctx()));
    if (OB_SUCC(ret)) {
      const ObObj& date = ctx.exec_ctx_.get_physical_plan_ctx()->get_cur_time();
      utz_value = date.get_timestamp();
    }
  } else if (1 == expr.arg_cnt_) {
    ObDatum* arg = NULL;
    if (OB_FAIL(expr.eval_param_value(ctx, arg))) {
      LOG_WARN("eval arg failed", K(ret));
    } else if (arg->is_null()) {
      is_null = true;
      res.set_null();
    } else {
      utz_value = arg->get_timestamp();
    }
  } else {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("unexpected arg cnt", K(ret), K(expr.arg_cnt_));
  }

  if (OB_SUCC(ret) && !is_null) {
    ObObjType res_type = expr.datum_meta_.type_;
    utz_value = utz_value < 0 ? 0 : utz_value;
    if (ObIntType == res_type) {
      res.set_int(utz_value / 1000000);
    } else if (ObNumberType == res_type) {
      ObIAllocator& calc_alloc = ctx.get_reset_tmp_alloc();
      number::ObNumber tmp_nmb;
      number::ObNumber res_nmb;
      number::ObNumber usec_nmb;
      int64_t usec = 1000000;
      OZ(usec_nmb.from(usec, calc_alloc));
      OZ(tmp_nmb.from(utz_value, calc_alloc));
      OZ(tmp_nmb.div(usec_nmb, res_nmb, calc_alloc));
      OX(res.set_number(res_nmb));
    } else {
      ret = OB_ERR_UNEXPECTED;
      LOG_WARN("unexpected res type", K(ret), K(res_type));
    }
  }
  return ret;
}

int ObExprUnixTimestamp::cg_expr(ObExprCGCtx& expr_cg_ctx, const ObRawExpr& raw_expr, ObExpr& rt_expr) const
{
  int ret = OB_SUCCESS;
  UNUSED(expr_cg_ctx);
  UNUSED(raw_expr);
  rt_expr.eval_func_ = eval_unix_timestamp;
  return ret;
}
}  // namespace sql
}  // namespace oceanbase