/**
 * 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.
 */

#ifndef OCEANBASE_OBSERVER_VIRTUAL_TABLE_OB_TABLE_COLUMNS_
#define OCEANBASE_OBSERVER_VIRTUAL_TABLE_OB_TABLE_COLUMNS_
#include "lib/container/ob_se_array.h"
#include "share/ob_define.h"
#include "share/ob_virtual_table_scanner_iterator.h"
#include "common/ob_range.h"
#include "share/schema/ob_table_schema.h"
#include "share/schema/ob_schema_struct.h"

namespace oceanbase
{
namespace common
{
class ObRowkeyInfo;
}
namespace sql
{
class ObSQLSessionInfo;
class ObSelectStmt;
class ObRawExprFactory;
class ObStmtFactory;
struct SelectItem;
class ObRawExpr;
}
namespace observer
{
class ObTableColumns : public common::ObVirtualTableScannerIterator
{
public:
  enum KeyType
  {
    KEY_TYPE_EMPTY = 0,
    KEY_TYPE_PRIMARY = 1,
    KEY_TYPE_UNIQUE = 2,
    KEY_TYPE_MULTIPLE = 3,
    KEY_TYPE_MAX = 4
  };
  struct ColumnAttributes {
    common::ObString field_;
    common::ObString type_;
    common::ObString null_;
    common::ObString key_;
    common::ObString default_;
    common::ObString extra_;
    common::ObString privileges_;
    sql::ObExprResType result_type_;
    int64_t get_data_length() const;
  };
  ObTableColumns();
  virtual ~ObTableColumns();
  virtual int inner_get_next_row(common::ObNewRow *&row);
  virtual void reset();
  static int resolve_view_definition(
      common::ObIAllocator* allocator,
      sql::ObSQLSessionInfo *session,
      share::schema::ObSchemaGetterGuard* guard,
      const share::schema::ObTableSchema &table_schema,
      sql::ObSelectStmt *&select_stmt,
      sql::ObRawExprFactory &expr_factory,
      sql::ObStmtFactory &stmt_factory,
      bool throw_error);
  // skip inner added implicit cast and bool expr.
  static const sql::ObRawExpr *skip_inner_added_expr(const sql::ObRawExpr *expr);
  static int set_null_and_default_according_binary_expr(const uint64_t tenant_id,
                                                        const sql::ObSelectStmt *select_stmt,
                                                        const sql::ObRawExpr *expr,
                                                        share::schema::ObSchemaGetterGuard *schema_guard,
                                                        bool &nullable,
                                                        bool &has_default);
  static int deduce_column_attributes(const bool is_oracle_mode,
                                      const sql::ObSelectStmt *select_stmt,
                                      const sql::SelectItem &select_item,
                                      share::schema::ObSchemaGetterGuard *schema_guard,
                                      sql::ObSQLSessionInfo *session,
                                      char *column_type_str,
                                      int64_t column_type_str_len,
                                      ColumnAttributes &column_attributes,
                                      bool skip_type_str);  // skip_type_str : when use ObTableColumns::deduce_column_attributes in create_view_resolver,
                                                            // no field column_type_str, skip
private:

  enum DESC_COLUMN {
    TABLE_ID = 16,
    FIELD,
    TYPE,
    COLLATION,
    NULLABLE,
    KEY,
    DEFAULT,
    EXTRA,
    PRIVILEGES,
    COMMENT,
    IS_HIDDEN
  };
  int calc_show_table_id(uint64_t &show_table_id);
  int fill_row_cells(const share::schema::ObTableSchema &table_schema,
                     const share::schema::ObColumnSchemaV2 &column_schema);
  int fill_row_cells(const uint64_t tenant_id,
                     const uint64_t table_id,
                     const sql::ObSelectStmt *select_stmt,
                     const sql::SelectItem &select_item);
  int set_null_and_default_according_binary_expr(const sql::ObSelectStmt *select_stmt,
                                                 const sql::ObRawExpr *expr,
                                                 bool &nullable,
                                                 bool &has_default);
  int get_key_type(const share::schema::ObTableSchema &table_schema,
                   const share::schema::ObColumnSchemaV2 &column_schema,
                   KeyType &key_type) const;
  int is_primary_key(const share::schema::ObTableSchema &table_schema,
                     const share::schema::ObColumnSchemaV2 &column_schema,
                     bool &is_pri) const;
  int is_unique_key(const share::schema::ObTableSchema &table_schema,
                    const share::schema::ObColumnSchemaV2 &column_schema,
                    bool &is_uni) const;
  int is_multiple_key(const share::schema::ObTableSchema &table_schema,
                      const share::schema::ObColumnSchemaV2 &column_schema,
                      bool &is_mul) const;
  /**
   * If ob_sql_type_str failed to call, and the error code returned is OB_SIZE_OVERFLOW.
   * realloc memory to the size of OB_MAX_EXTENDED_TYPE_INFO_LENGTH, then try again
   */
  int get_type_str(const share::schema::ObColumnSchemaV2 &column_schema,
                   const int16_t default_length_semantics,
                   ObString &type_val);
  int fill_col_privs(
      ObSessionPrivInfo &session_priv,
      ObNeedPriv &need_priv, 
      ObPrivSet priv_set, 
      const char *priv_str,
      char* buf,
      const int64_t buf_len,
      int64_t &pos);
private:
  static bool can_rewrite_error_code(const int ret);
  char type_str_[common::OB_MAX_SYS_PARAM_NAME_LENGTH];
  char *column_type_str_;
  int64_t column_type_str_len_;
  DISALLOW_COPY_AND_ASSIGN(ObTableColumns);
};
}//observer
}//oceanbase
#endif /* OCEANBASE_OBSERVER_VIRTUAL_TABLE_OB_TABLE_COLUMNS_ */