/**
 * 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_RESV
#include "sql/resolver/ddl/ob_explain_resolver.h"
#include "sql/resolver/ob_resolver.h"

using namespace oceanbase;
using namespace sql;
using namespace common;
const static int64_t EXPLAIN_FORMAT = 0;
const static int64_t EXPLAIN_DISPLAY_OPTION = 1;
const static int64_t EXPLAIN_CHILD_STMT = 2;
const static int64_t EXPLAIN_INTO_TABLE = 3;
const static int64_t EXPLAIN_STMT_ID = 4;
int ObExplainResolver::resolve(const ParseNode &parse_tree)
{
  int ret = OB_SUCCESS;
  ObExplainStmt *explain_stmt = NULL;
  if (!(T_EXPLAIN == parse_tree.type_  && 5 == parse_tree.num_child_)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("invalid EXPLAIN syntax",
             "type", parse_tree.type_,
             "# of child", parse_tree.num_child_);
  } else if (NULL == (explain_stmt = create_stmt<ObExplainStmt>())) {
    ret = OB_SQL_RESOLVER_NO_MEMORY;
    LOG_WARN("failed to create explain stmt");
  } else {
    ParseNode *child_node = parse_tree.children_[EXPLAIN_CHILD_STMT];
    ObStmt *child_stmt = NULL;
    ObExplainDisplayOpt opt;
    opt.with_tree_line_ = true;
    if (OB_ISNULL(child_node)) {
      ret = OB_ERR_UNEXPECTED;
      LOG_WARN("empty parse tree for stmt");
    } else if (!(T_SELECT == child_node->type_
                 || T_DELETE == child_node->type_
                 || T_INSERT == child_node->type_
                 || T_MERGE == child_node->type_
                 || T_UPDATE == child_node->type_
                 || T_REPLACE == child_node->type_
                 || T_MULTI_INSERT == child_node->type_)) {
      ret = OB_NOT_SUPPORTED;
      LOG_WARN("invalid stmt type for EXPLAIN", "type", child_node->type_);
      LOG_USER_ERROR(OB_NOT_SUPPORTED, "stmt type for EXPLAIN");
    } else {
      ObResolver resolver(params_);
      if (OB_FAIL(resolver.resolve(ObResolver::IS_NOT_PREPARED_STMT,
                                   *child_node,
                                   child_stmt))) {
        LOG_WARN("failed to resolve child stmt", K(ret));
      } else if (OB_ISNULL(child_stmt)) {
        ret = OB_ERR_UNEXPECTED;
        LOG_WARN("failed to generate stmt for child stmt");
      } else {
        explain_stmt->set_explain_query_stmt(static_cast<ObDMLStmt *>(child_stmt));
        ParseNode *format = parse_tree.children_[EXPLAIN_FORMAT];
        if (NULL != format) {
          switch (format->type_) {
          case T_OUTLINE:
          {
            explain_stmt->set_explain_format(EXPLAIN_OUTLINE);
            opt.with_tree_line_ = true;
          } break;
          case T_EXTENDED:
          {
            explain_stmt->set_explain_format(EXPLAIN_EXTENDED);
            opt.with_tree_line_ = true;
          } break;
          case T_PARTITIONS:
          {
            explain_stmt->set_explain_format(EXPLAIN_PARTITIONS);
            opt.with_tree_line_ = true;
          } break;
          case T_TRADITIONAL:
          {
            explain_stmt->set_explain_format(EXPLAIN_TRADITIONAL);
            opt.with_tree_line_ = true;
          } break;
          case T_FORMAT_JSON:
          {
            explain_stmt->set_explain_format(EXPLAIN_FORMAT_JSON);
            opt.with_tree_line_ = false;
          } break;
          case T_BASIC: {
            explain_stmt->set_explain_format(EXPLAIN_BASIC);
            opt.with_tree_line_ = true;
            break;
          }
          case T_EXTENDED_NOADDR: {
            explain_stmt->set_explain_format(EXPLAIN_EXTENDED_NOADDR);
            opt.with_tree_line_ = true;
            break;
          }
          case T_PLANREGRESS: {
            explain_stmt->set_explain_format(EXPLAIN_PLANREGRESS);
            opt.with_tree_line_ = true;
            break;
          }
          default:
            ret = OB_ERROR;
            LOG_WARN("unknown explain format", "format", format->type_);
            break;
          }
        }
      }
    }
    ParseNode *opt_node = parse_tree.children_[EXPLAIN_DISPLAY_OPTION];
    if (OB_SUCC(ret) && NULL != opt_node) {
      switch (opt_node->type_) {
      case T_PRETTY_COLOR:
        opt.with_color_ = true;
        // pass
      case T_PRETTY:
        opt.with_tree_line_ = true;
        break;
      default:
        ret = OB_ERR_UNEXPECTED;
        LOG_WARN("unexpected display option", K(ret), K(opt_node->type_));
      }
    }
    if (OB_SUCC(ret)) {
      explain_stmt->set_display_opt(opt);
    }
    ParseNode *into_table_node = parse_tree.children_[EXPLAIN_INTO_TABLE];
    if (OB_SUCC(ret) && NULL != into_table_node) {
      ObString into_table(into_table_node->str_len_, into_table_node->str_value_);
      explain_stmt->set_into_table(into_table);
    }
    ParseNode *statement_id_node = parse_tree.children_[EXPLAIN_STMT_ID];
    if (OB_SUCC(ret) && NULL != statement_id_node) {
      ObString statement_id(statement_id_node->str_len_, statement_id_node->str_value_);
      explain_stmt->set_statement_id(statement_id);
    }
  }

  return ret;
}