/**
 * 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/basic/ob_function_table_op.h"
#include "share/object/ob_obj_cast.h"
#include "common/sql_mode/ob_sql_mode_utils.h"
#include "sql/ob_sql_utils.h"
#include "sql/session/ob_sql_session_info.h"
#include "sql/engine/ob_physical_plan.h"
#include "sql/engine/ob_exec_context.h"
#include "pl/ob_pl_user_type.h"
#include "sql/engine/expr/ob_expr.h"
#include "sql/engine/expr/ob_expr_lob_utils.h"


namespace oceanbase
{
using namespace common;
namespace sql
{

OB_SERIALIZE_MEMBER((ObFunctionTableSpec, ObOpSpec), value_expr_, column_exprs_, has_correlated_expr_);

int ObFunctionTableOp::inner_open()
{
  int ret = OB_SUCCESS;
  node_idx_ = 0;
  already_calc_ = false;
  if (OB_ISNULL(MY_SPEC.value_expr_)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("value expr is not init", K(ret));
  } else if (ObExtendType == MY_SPEC.value_expr_->datum_meta_.type_) {
    next_row_func_ = &ObFunctionTableOp::inner_get_next_row_udf;
  } else {
    next_row_func_ = &ObFunctionTableOp::inner_get_next_row_sys_func;
  }
  return ret;
}

int ObFunctionTableOp::inner_rescan()
{
  int ret = OB_SUCCESS;
  if (OB_FAIL(ObOperator::inner_rescan())) {
    LOG_WARN("failed to inner rescan", K(ret));
  } else {
    node_idx_ = 0;
    if (MY_SPEC.has_correlated_expr_) {
      row_count_ = 0;
      col_count_ = 0;
      value_table_ = NULL;
      already_calc_ = false;
    }
  }
  return ret;
}

int ObFunctionTableOp::inner_close()
{
  int ret = OB_SUCCESS;
  node_idx_ = 0;
  row_count_ = 0;
  col_count_ = 0;
  value_table_ = NULL;
  return ret;
}

//ObFunctionTableOp has its own switch_iterator
int ObFunctionTableOp::switch_iterator()
{
  int ret = OB_SUCCESS;
  if (OB_FAIL(ObOperator::inner_switch_iterator())) {
    LOG_WARN("failed to switch iterator", K(ret));
  } else if (OB_ISNULL(ctx_.get_my_session())) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("failed to get session", K(ret));
  } else if (NULL == ctx_.get_my_session()->get_pl_implicit_cursor()
            || !ctx_.get_my_session()->get_pl_implicit_cursor()->get_in_forall()) {
    ret = OB_ITER_END;
  } else {
    node_idx_ = 0;
  }
  return ret;
}

void ObFunctionTableOp::destroy()
{
  ObOperator::destroy();
}


int ObFunctionTableOp::get_current_result(ObObj &result)
{
  int ret = OB_SUCCESS;
  void *data = NULL;
  CK (already_calc_);
  if (node_idx_ < 0 || node_idx_ >= row_count_ * col_count_) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("fail to get current result in table function",
              K(node_idx_), K(row_count_), K(col_count_));
  }
  do {
    CK (node_idx_ >= 0);
    if (OB_SUCC(ret) && node_idx_ >= row_count_) {
      ret = OB_ITER_END;
    }
    CK (OB_NOT_NULL(value_table_));
    OX (data = value_table_->get_data());
    CK (OB_NOT_NULL(data));
    OX (result = (static_cast<ObObj*>(data))[node_idx_++]);
  } while (OB_SUCC(ret) && result.get_meta().get_type() == ObMaxType);
  return ret;
}

int ObFunctionTableOp::inner_get_next_row()
{
  return (this->*next_row_func_)();
}

int ObFunctionTableOp::inner_get_next_row_udf()
{
  int ret = OB_SUCCESS;
  ObPhysicalPlanCtx *plan_ctx = nullptr;
  clear_evaluated_flag();
  if (OB_ISNULL(plan_ctx = ctx_.get_physical_plan_ctx())) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("failed to get plan ctx", K(ret), K(plan_ctx));
  } else if (OB_ISNULL(MY_SPEC.value_expr_)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("value expr is not init", K(ret));
  } else if (ObExtendType != MY_SPEC.value_expr_->datum_meta_.type_) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("get unexpected value", K(ret), K(MY_SPEC.value_expr_->datum_meta_.type_));
  } else if (FALSE_IT(plan_ctx->set_autoinc_id_tmp(0))) {
  } else if (OB_FAIL(ctx_.check_status())) {
    LOG_WARN("failed to check status ", K(ret));
  } else {
    ObDatum *value = nullptr;
    if (!already_calc_) {
      if (OB_FAIL(MY_SPEC.value_expr_->eval(eval_ctx_, value))) {
        LOG_WARN("failed to eval value expr", K(ret));
      } else if (value->is_null()) {
        //do nothing
      } else if (OB_ISNULL(value_table_ 
                 = reinterpret_cast<pl::ObPLCollection*>(value->get_ext()))) {
        ret = OB_ERR_UNEXPECTED;
        LOG_WARN("failed to get value table", K(ret));
      } else {
        row_count_ = value_table_->is_inited() ? value_table_->get_count() : 0;
        col_count_ = value_table_->get_column_count();
      }
      already_calc_ = true;
    }
    if (OB_SUCC(ret) && OB_UNLIKELY(node_idx_ >= row_count_)) {
      ret = OB_ITER_END;
    }
    CK (MY_SPEC.column_exprs_.count() >= col_count_);
    ObObj obj_stack[col_count_];
    if (OB_SUCC(ret)) {
      if (nullptr != value_table_ 
          && ObExtendType == value_table_->get_element_type().get_obj_type()) {
        pl::ObPLComposite *composite = NULL;
        pl::ObPLRecord *record = NULL;
        ObObj record_obj;
        OZ (get_current_result(record_obj));
        if (OB_SUCC(ret) && record_obj.is_pl_extend()) {
          CK (OB_NOT_NULL(composite = reinterpret_cast<pl::ObPLComposite*>(record_obj.get_ext())));
          CK (composite->is_record());
          OX (record = static_cast<pl::ObPLRecord*>(composite));
          CK (record->get_count() == col_count_);
          for (int64_t i = 0; OB_SUCC(ret) && i < col_count_; ++i) {
            OZ (record->get_element(i, obj_stack[i]));
          }
        } else {
          ret = OB_ERR_UNEXPECTED;
          LOG_ERROR("unexpected here", K(ret), K(record_obj), K(record_obj.meta_));
        }
      } else {
        for (int64_t i = 0; OB_SUCC(ret) && i < col_count_; ++i) {
          if (OB_FAIL(get_current_result(obj_stack[i]))) {
            LOG_WARN("failed to get current result", K(ret), K(i));
          }
        }
      }
    }
    if (OB_SUCC(ret)) {
      for (int64_t i = 0; OB_SUCC(ret) && i < col_count_; ++i) {
        if (obj_stack[i].is_null()) {
          MY_SPEC.column_exprs_.at(i)->locate_datum_for_write(eval_ctx_).set_null();
        } else {
          const ObObjDatumMapType &datum_map = MY_SPEC.column_exprs_.at(i)->obj_datum_map_;
          ObExpr * const &expr = MY_SPEC.column_exprs_.at(i);
          ObDatum &datum = expr->locate_datum_for_write(eval_ctx_);
          if (OB_FAIL(datum.from_obj(obj_stack[i], datum_map))) {
            LOG_WARN("failed to convert datum", K(ret));
          } else if (is_lob_storage(obj_stack[i].get_type()) &&
                     OB_FAIL(ob_adjust_lob_datum(obj_stack[i], expr->obj_meta_, datum_map,
                                                 get_exec_ctx().get_allocator(), datum))) {
            LOG_WARN("adjust lob datum failed", K(ret), K(obj_stack[i].get_meta()), K(expr->obj_meta_));
          }
        }
        if (OB_SUCC(ret)) {
          MY_SPEC.column_exprs_.at(i)->set_evaluated_projected(eval_ctx_);
        }
      }
    }
  }
  return ret;
}

int ObFunctionTableOp::inner_get_next_row_sys_func()
{
  int ret = OB_SUCCESS;
  ObPhysicalPlanCtx *plan_ctx = nullptr;
  ObDatum *value = nullptr;
  clear_evaluated_flag();
  if (OB_ISNULL(plan_ctx = ctx_.get_physical_plan_ctx())) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("failed to get plan ctx", K(ret), K(plan_ctx));
  } else if (OB_FAIL(ctx_.check_status())) {
    LOG_WARN("failed to check status ", K(ret));
  } else if (OB_FAIL(MY_SPEC.value_expr_->eval(eval_ctx_, value))) {
    if (OB_ITER_END != ret) {
      LOG_WARN("failed to eval value expr", K(ret));
    }
  } else {
    MY_SPEC.column_exprs_.at(0)->locate_datum_for_write(eval_ctx_).set_datum(*value);
    MY_SPEC.column_exprs_.at(0)->set_evaluated_projected(eval_ctx_);
  }
  return ret;
}


} // end namespace sql
} // end namespace oceanbase