#pragma once

#include <DataTypes/IDataType.h>

namespace DB

{

/// Dynamic type allows to store values of any type inside it and to read

/// subcolumns with any type without knowing all of them in advance.

class DataTypeDynamic final : public IDataType

{

public:

static constexpr bool is_parametric = true;

/// Don't change this constant, it can break backward compatibility.

static constexpr size_t DEFAULT_MAX_DYNAMIC_TYPES = 32;

explicit DataTypeDynamic(size_t max_dynamic_types_ = DEFAULT_MAX_DYNAMIC_TYPES);

TypeIndex getTypeId() const override { return TypeIndex::Dynamic; }

const char * getFamilyName() const override { return "Dynamic"; }

bool isParametric() const override { return true; }

bool canBeInsideNullable() const override { return false; }

bool supportsSparseSerialization() const override { return false; }

bool canBeInsideSparseColumns() const override { return false; }

bool isComparable() const override { return true; }

MutableColumnPtr createColumn() const override;

Field getDefault() const override;

/// 2 Dynamic types with different max_dynamic_types parameters are considered as different.

bool equals(const IDataType & rhs) const override

{

if (const auto * rhs_dynamic_type = typeid_cast<const DataTypeDynamic *>(&rhs))

return max_dynamic_types == rhs_dynamic_type->max_dynamic_types;

return false;

}

bool haveSubtypes() const override { return false; }

bool hasDynamicSubcolumnsData() const override { return true; }

bool hasDynamicStructure() const override { return true; }

std::unique_ptr<SubstreamData> getDynamicSubcolumnData(std::string_view subcolumn_name, const SubstreamData & data, size_t initial_array_level, bool throw_if_null) const override;

size_t getMaxDynamicTypes() const { return max_dynamic_types; }

void updateHashImpl(SipHash & hash) const override;

private:

SerializationPtr doGetSerialization(const SerializationInfoSettings & settings) const override;

String doGetName() const override;

size_t max_dynamic_types;

};

/// Returns true if provided type is Dynamic or has Dynamic type as a nested type.

bool hasDynamicType(const DataTypePtr & type);

}