#pragma once

#include <DB/AggregateFunctions/IAggregateFunction.h>

#include <DB/DataTypes/IDataType.h>


namespace DB
{

using Poco::SharedPtr;

/** Тип - состояние агрегатной функции.
  * Параметры типа - это агрегатная функция, типы её аргументов и её параметры (для параметрических агрегатных функций).
  */
class DataTypeAggregateFunction : public IDataType
{
private:
	AggregateFunctionPtr function;
	DataTypes argument_types;
	Array parameters;
	
public:
	DataTypeAggregateFunction(const AggregateFunctionPtr & function_, const DataTypes & argument_types_, const Array & parameters_)
		: function(function_), argument_types(argument_types_), parameters(parameters_)
	{
	}

	std::string getFunctionName() const { return function->getName(); }
	
	std::string getName() const
	{
		std::stringstream stream;
		stream << "AggregateFunction(" << function->getName();

		if (!parameters.empty())
		{
			stream << "(";
			for (size_t i = 0; i < parameters.size(); ++i)
			{
				if (i)
					stream << ", ";
				stream << apply_visitor(DB::FieldVisitorToString(), parameters[i]);
			}
			stream << ")";
		}

		for (DataTypes::const_iterator it = argument_types.begin(); it != argument_types.end(); ++it)
			stream << ", " << (*it)->getName();
		
		stream << ")";
		return stream.str();
	}

	DataTypePtr getReturnType() const { return function->getReturnType(); };
	DataTypes getArgumentsDataTypes() const { return argument_types; }
	
	DataTypePtr clone() const { return new DataTypeAggregateFunction(function, argument_types, parameters); }

	void serializeBinary(const Field & field, WriteBuffer & ostr) const;
	void deserializeBinary(Field & field, ReadBuffer & istr) const;
	void serializeBinary(const IColumn & column, WriteBuffer & ostr, size_t offset = 0, size_t limit = 0) const;
	void deserializeBinary(IColumn & column, ReadBuffer & istr, size_t limit) const;
	void serializeText(const Field & field, WriteBuffer & ostr) const;
	void deserializeText(Field & field, ReadBuffer & istr) const;
	void serializeTextEscaped(const Field & field, WriteBuffer & ostr) const;
	void deserializeTextEscaped(Field & field, ReadBuffer & istr) const;
	void serializeTextQuoted(const Field & field, WriteBuffer & ostr) const;
	void deserializeTextQuoted(Field & field, ReadBuffer & istr) const;
	void serializeTextJSON(const Field & field, WriteBuffer & ostr) const;

	ColumnPtr createColumn() const;
	ColumnPtr createConstColumn(size_t size, const Field & field) const;

	Field getDefault() const
	{
		throw Exception("There is no default value for AggregateFunction data type", ErrorCodes::THERE_IS_NO_DEFAULT_VALUE);
	}
};


}