#include <map>
#include <Poco/Path.h>

#include <DB/Common/escapeForFileName.h>

#include <DB/Core/Exception.h>
#include <DB/Core/ErrorCodes.h>

#include <DB/IO/ReadHelpers.h>
#include <DB/IO/WriteHelpers.h>

#include <DB/DataTypes/DataTypeArray.h>
#include <DB/DataTypes/DataTypeNested.h>

#include <DB/Columns/ColumnArray.h>
#include <DB/Columns/ColumnNested.h>

#include <DB/Storages/StorageLog.h>


#define DBMS_STORAGE_LOG_DATA_FILE_EXTENSION 	".bin"
#define DBMS_STORAGE_LOG_MARKS_FILE_EXTENSION	".mrk"
#define DBMS_STORAGE_LOG_MARKS_FILE_NAME 		"__marks.mrk"


namespace DB
{

using Poco::SharedPtr;


LogBlockInputStream::LogBlockInputStream(size_t block_size_, const Names & column_names_, StoragePtr owned_storage, size_t mark_number_, size_t rows_limit_)
	: IProfilingBlockInputStream(owned_storage), block_size(block_size_), column_names(column_names_), storage(dynamic_cast<StorageLog &>(*owned_storage)), mark_number(mark_number_), rows_limit(rows_limit_), rows_read(0)
{
}


Block LogBlockInputStream::readImpl()
{
	Block res;

	if (rows_read == rows_limit)
		return res;

	/// Если файлы не открыты, то открываем их.
	if (streams.empty())
	{
		Poco::ScopedReadRWLock lock(storage.rwlock);
		
		for (Names::const_iterator it = column_names.begin(); it != column_names.end(); ++it)
			addStream(*it, *storage.getDataTypeByName(*it));
	}

	/// Сколько строк читать для следующего блока.
	size_t max_rows_to_read = std::min(block_size, rows_limit - rows_read);

	/// Указатели на столбцы смещений, общие для столбцов из вложенных структур данных
	typedef std::map<std::string, ColumnPtr> OffsetColumns;
	OffsetColumns offset_columns;

	for (Names::const_iterator it = column_names.begin(); it != column_names.end(); ++it)
	{
		ColumnWithNameAndType column;
		column.name = *it;
		column.type = storage.getDataTypeByName(*it);
		
		bool read_offsets = true;
		
		/// Для вложенных структур запоминаем указатели на столбцы со смещениями
		if (const DataTypeArray * type_arr = dynamic_cast<const DataTypeArray *>(&*column.type))
		{
			String name = DataTypeNested::extractNestedTableName(column.name);
			
			if (offset_columns.count(name) == 0)
				offset_columns[name] = new ColumnArray::ColumnOffsets_t;
			else
				read_offsets = false; /// на предыдущих итерациях смещения уже считали вызовом readData
			
			column.column = new ColumnArray(type_arr->getNestedType()->createColumn(), offset_columns[name]);
		}
		else
			column.column = column.type->createColumn();
		
		readData(*it, *column.type, *column.column, max_rows_to_read, 0, read_offsets);

		if (column.column->size())
			res.insert(column);
	}

	if (res)
		rows_read += res.rows();

	if (!res || rows_read == rows_limit)
	{
		/** Закрываем файлы (ещё до уничтожения объекта).
		  * Чтобы при создании многих источников, но одновременном чтении только из нескольких,
		  *  буферы не висели в памяти.
		  */
		streams.clear();
	}
		
	return res;
}


void LogBlockInputStream::addStream(const String & name, const IDataType & type, size_t level)
{
	/// Для массивов используются отдельные потоки для размеров.
	if (const DataTypeArray * type_arr = dynamic_cast<const DataTypeArray *>(&type))
	{
		String size_name = DataTypeNested::extractNestedTableName(name) + ARRAY_SIZES_COLUMN_NAME_SUFFIX + toString(level);
		streams.insert(std::make_pair(size_name, new Stream(
			storage.files[size_name].data_file.path(),
			mark_number
				? storage.files[size_name].marks[mark_number].offset
				: 0)));

		addStream(name, *type_arr->getNestedType(), level + 1);
	}
	else if (const DataTypeNested * type_nested = dynamic_cast<const DataTypeNested *>(&type))
	{
		String size_name = name + ARRAY_SIZES_COLUMN_NAME_SUFFIX + toString(level);
		streams.insert(std::make_pair(size_name, new Stream(
			storage.files[size_name].data_file.path(),
			mark_number
				? storage.files[size_name].marks[mark_number].offset
				: 0)));

		const NamesAndTypesList & columns = *type_nested->getNestedTypesList();
		for (NamesAndTypesList::const_iterator it = columns.begin(); it != columns.end(); ++it)
			addStream(DataTypeNested::concatenateNestedName(name, it->first), *it->second, level + 1);
	}
	else
		streams.insert(std::make_pair(name, new Stream(
			storage.files[name].data_file.path(),
			mark_number
				? storage.files[name].marks[mark_number].offset
				: 0)));
}


void LogBlockInputStream::readData(const String & name, const IDataType & type, IColumn & column, size_t max_rows_to_read,
									size_t level, bool read_offsets)
{
	/// Для массивов требуется сначала десериализовать размеры, а потом значения.
	if (const DataTypeArray * type_arr = dynamic_cast<const DataTypeArray *>(&type))
	{
		if (read_offsets)
		{
			type_arr->deserializeOffsets(
				column,
				streams[DataTypeNested::extractNestedTableName(name) + ARRAY_SIZES_COLUMN_NAME_SUFFIX + toString(level)]->compressed,
				max_rows_to_read);
		}

		if (column.size())
			readData(
				name,
				*type_arr->getNestedType(),
				dynamic_cast<ColumnArray &>(column).getData(),
				dynamic_cast<const ColumnArray &>(column).getOffsets()[column.size() - 1],
				level + 1);
	}
	else if (const DataTypeNested * type_nested = dynamic_cast<const DataTypeNested *>(&type))
	{
		type_nested->deserializeOffsets(
			column,
			streams[name + ARRAY_SIZES_COLUMN_NAME_SUFFIX + toString(level)]->compressed,
			max_rows_to_read);

		if (column.size())
		{
			ColumnNested & column_nested = dynamic_cast<ColumnNested &>(column);
			
			NamesAndTypesList::const_iterator it = type_nested->getNestedTypesList()->begin();
			for (size_t i = 0; i < column_nested.getData().size(); ++i, ++it)
			{
				readData(
					DataTypeNested::concatenateNestedName(name, it->first),
					*it->second,
					*column_nested.getData()[i],
					column_nested.getOffsets()[column.size() - 1],
					level + 1);
			}
		}
	}
	else
		type.deserializeBinary(column, streams[name]->compressed, max_rows_to_read);
}


LogBlockOutputStream::LogBlockOutputStream(StoragePtr owned_storage)
	: IBlockOutputStream(owned_storage), storage(dynamic_cast<StorageLog &>(*owned_storage)),
	lock(storage.rwlock), marks_stream(storage.marks_file.path(), 4096, O_APPEND | O_CREAT | O_WRONLY)
{
	for (NamesAndTypesList::const_iterator it = storage.columns->begin(); it != storage.columns->end(); ++it)
		addStream(it->first, *it->second);
}


void LogBlockOutputStream::write(const Block & block)
{
	storage.check(block, true);
	
	/// Множество записанных столбцов со смещениями, чтобы не писать общие для вложенных структур столбцы несколько раз
	OffsetColumns offset_columns;

	MarksForColumns marks;
	marks.reserve(storage.files.size());
	for (size_t i = 0; i < block.columns(); ++i)
	{
		const ColumnWithNameAndType & column = block.getByPosition(i);
		writeData(column.name, *column.type, *column.column, marks, offset_columns);
	}
	writeMarks(marks);
}


void LogBlockOutputStream::writeSuffix()
{
	/// Заканчиваем запись.
	marks_stream.next();

	for (FileStreams::iterator it = streams.begin(); it != streams.end(); ++it)
		it->second->finalize();

	streams.clear();
}


void LogBlockOutputStream::addStream(const String & name, const IDataType & type, size_t level)
{
	/// Для массивов используются отдельные потоки для размеров.
	if (const DataTypeArray * type_arr = dynamic_cast<const DataTypeArray *>(&type))
	{
		String size_name = DataTypeNested::extractNestedTableName(name) + ARRAY_SIZES_COLUMN_NAME_SUFFIX + toString(level);
		streams.insert(std::make_pair(size_name, new Stream(
			storage.files[size_name].data_file.path())));

		addStream(name, *type_arr->getNestedType(), level + 1);
	}
	else if (const DataTypeNested * type_nested = dynamic_cast<const DataTypeNested *>(&type))
	{
		String size_name = name + ARRAY_SIZES_COLUMN_NAME_SUFFIX + toString(level);
		streams.insert(std::make_pair(size_name, new Stream(
			storage.files[size_name].data_file.path())));

		const NamesAndTypesList & columns = *type_nested->getNestedTypesList();
		for (NamesAndTypesList::const_iterator it = columns.begin(); it != columns.end(); ++it)
			addStream(DataTypeNested::concatenateNestedName(name, it->first), *it->second, level + 1);
	}
	else
		streams.insert(std::make_pair(name, new Stream(
			storage.files[name].data_file.path())));
}


void LogBlockOutputStream::writeData(const String & name, const IDataType & type, const IColumn & column, MarksForColumns & out_marks,
										OffsetColumns & offset_columns, size_t level)
{
	/// Для массивов требуется сначала сериализовать размеры, а потом значения.
	if (const DataTypeArray * type_arr = dynamic_cast<const DataTypeArray *>(&type))
	{
		String size_name = DataTypeNested::extractNestedTableName(name) + ARRAY_SIZES_COLUMN_NAME_SUFFIX + toString(level);
		
		if (offset_columns.count(size_name) == 0)
		{
			offset_columns.insert(size_name);
			
			Mark mark;
			mark.rows = (storage.files[size_name].marks.empty() ? 0 : storage.files[size_name].marks.back().rows) + column.size();
			mark.offset = streams[size_name]->plain_offset + streams[size_name]->plain.count();

			out_marks.push_back(std::make_pair(storage.files[size_name].column_index, mark));
			
			type_arr->serializeOffsets(column, streams[size_name]->compressed);
			streams[size_name]->compressed.next();
		}

		writeData(name, *type_arr->getNestedType(), dynamic_cast<const ColumnArray &>(column).getData(), out_marks, offset_columns, level + 1);
	}
	else if (const DataTypeNested * type_nested = dynamic_cast<const DataTypeNested *>(&type))
	{
		String size_name = name + ARRAY_SIZES_COLUMN_NAME_SUFFIX + toString(level);

		Mark mark;
		mark.rows = (storage.files[size_name].marks.empty() ? 0 : storage.files[size_name].marks.back().rows) + column.size();
		mark.offset = streams[size_name]->plain_offset + streams[size_name]->plain.count();

		out_marks.push_back(std::make_pair(storage.files[size_name].column_index, mark));
		
		type_nested->serializeOffsets(column, streams[size_name]->compressed);
		streams[size_name]->compressed.next();
		
		const ColumnNested & column_nested = dynamic_cast<const ColumnNested &>(column);
			
		NamesAndTypesList::const_iterator it = type_nested->getNestedTypesList()->begin();
		for (size_t i = 0; i < column_nested.getData().size(); ++i, ++it)
		{
			writeData(
				DataTypeNested::concatenateNestedName(name, it->first),
				*it->second,
				*column_nested.getData()[i],
				out_marks,
				offset_columns,
				level + 1);
		}
	}
	else
	{
		Mark mark;
		mark.rows = (storage.files[name].marks.empty() ? 0 : storage.files[name].marks.back().rows) + column.size();
		mark.offset = streams[name]->plain_offset + streams[name]->plain.count();

		out_marks.push_back(std::make_pair(storage.files[name].column_index, mark));

		type.serializeBinary(column, streams[name]->compressed);
		streams[name]->compressed.next();
	}
}

static bool ColumnIndexLess(const std::pair<size_t, Mark> & a, const std::pair<size_t, Mark> & b)
{
	return a.first < b.first;
}

void LogBlockOutputStream::writeMarks(MarksForColumns marks)
{
	if (marks.size() != storage.files.size())
		throw Exception("Wrong number of marks generated from block. Makes no sense.", ErrorCodes::LOGICAL_ERROR);
	
	sort(marks.begin(), marks.end(), ColumnIndexLess);
	
	for (size_t i = 0; i < marks.size(); ++i)
	{
		if (marks[i].first != i)
			throw Exception("Invalid marks generated from block. Makes no sense.", ErrorCodes::LOGICAL_ERROR);
		
		Mark mark = marks[i].second;
		
		writeIntBinary(mark.rows, marks_stream);
		writeIntBinary(mark.offset, marks_stream);
		
		storage.files[storage.column_names[i]].marks.push_back(mark);
	}
}


StorageLog::StorageLog(const std::string & path_, const std::string & name_, NamesAndTypesListPtr columns_)
	: path(path_), name(name_), columns(columns_), loaded_marks(false)
{
	if (columns->empty())
		throw Exception("Empty list of columns passed to StorageLog constructor", ErrorCodes::EMPTY_LIST_OF_COLUMNS_PASSED);
	
	/// создаём файлы, если их нет
	Poco::File(path + escapeForFileName(name) + '/').createDirectories();

	for (NamesAndTypesList::const_iterator it = columns->begin(); it != columns->end(); ++it)
		addFile(it->first, *it->second);
	
	marks_file = Poco::File(path + escapeForFileName(name) + '/' + DBMS_STORAGE_LOG_MARKS_FILE_NAME);
}

StoragePtr StorageLog::create(const std::string & path_, const std::string & name_, NamesAndTypesListPtr columns_)
{
	return (new StorageLog(path_, name_, columns_))->thisPtr();
}


void StorageLog::addFile(const String & column_name, const IDataType & type, size_t level)
{
	if (files.end() != files.find(column_name))
		throw Exception("Duplicate column with name " + column_name + " in constructor of StorageLog.",
			ErrorCodes::DUPLICATE_COLUMN);

	if (const DataTypeArray * type_arr = dynamic_cast<const DataTypeArray *>(&type))
	{
		String size_column_suffix = ARRAY_SIZES_COLUMN_NAME_SUFFIX + toString(level);
		String size_name = DataTypeNested::extractNestedTableName(column_name) + size_column_suffix;

		if (files.end() == files.find(size_name))
		{
			ColumnData & column_data = files.insert(std::make_pair(size_name, ColumnData())).first->second;
			column_data.column_index = column_names.size();
			column_data.data_file = Poco::File(
				path + escapeForFileName(name) + '/' + escapeForFileName(DataTypeNested::extractNestedTableName(column_name)) + size_column_suffix + DBMS_STORAGE_LOG_DATA_FILE_EXTENSION);
			
			column_names.push_back(size_name);
		}

		addFile(column_name, *type_arr->getNestedType(), level + 1);
	}
	else if (const DataTypeNested * type_nested = dynamic_cast<const DataTypeNested *>(&type))
	{
		String size_column_suffix = ARRAY_SIZES_COLUMN_NAME_SUFFIX + toString(level);

		ColumnData & column_data = files.insert(std::make_pair(column_name + size_column_suffix, ColumnData())).first->second;
		column_data.column_index = column_names.size();
		column_data.data_file = Poco::File(
			path + escapeForFileName(name) + '/' + escapeForFileName(column_name) + size_column_suffix + DBMS_STORAGE_LOG_DATA_FILE_EXTENSION);
		
		column_names.push_back(column_name + size_column_suffix);

		const NamesAndTypesList & columns = *type_nested->getNestedTypesList();
		for (NamesAndTypesList::const_iterator it = columns.begin(); it != columns.end(); ++it)
			addFile(DataTypeNested::concatenateNestedName(name, it->first), *it->second, level + 1);
	}
	else
	{
		ColumnData & column_data = files.insert(std::make_pair(column_name, ColumnData())).first->second;
		column_data.column_index = column_names.size();
		column_data.data_file = Poco::File(
			path + escapeForFileName(name) + '/' + escapeForFileName(column_name) + DBMS_STORAGE_LOG_DATA_FILE_EXTENSION);
		
		column_names.push_back(column_name);
	}
}


void StorageLog::loadMarks()
{
	Poco::ScopedWriteRWLock lock(rwlock);
	
	if (loaded_marks)
		return;
	
	typedef std::vector<Files_t::iterator> FilesByIndex;
	FilesByIndex files_by_index(files.size());
	for (Files_t::iterator it = files.begin(); it != files.end(); ++it)
	{
		files_by_index[it->second.column_index] = it;
	}
	
	if (marks_file.exists())
	{
		size_t file_size = marks_file.getSize();
		if (file_size % (files.size() * sizeof(Mark)) != 0)
			throw Exception("Size of marks file is inconsistent", ErrorCodes::SIZES_OF_MARKS_FILES_ARE_INCONSISTENT);
		
		int marks_count = file_size / (files.size() * sizeof(Mark));

		for (size_t i = 0; i < files_by_index.size(); ++i)
		{
			files_by_index[i]->second.marks.reserve(marks_count);
		}
		
		ReadBufferFromFile marks_rb(marks_file.path(), 32768);
		while (!marks_rb.eof())
		{
			for (size_t i = 0; i < files_by_index.size(); ++i)
			{
				Mark mark;
				readIntBinary(mark.rows, marks_rb);
				readIntBinary(mark.offset, marks_rb);
				files_by_index[i]->second.marks.push_back(mark);
			}
		}
	}
	else
	{
		/// Сконвертируем засечки из старого формата (по файлу для каждого столбца) в новый (один файл для всех столбцов).
		ssize_t size_of_marks_file = -1;
		for (Files_t::iterator it = files.begin(); it != files.end(); ++it)
		{
			Poco::File marks_file(path + escapeForFileName(name) + '/' + Poco::Path(it->second.data_file.path()).getBaseName() + DBMS_STORAGE_LOG_MARKS_FILE_EXTENSION);
			if (marks_file.exists())
			{
				ssize_t size_of_current_marks_file = marks_file.getSize();

				if (size_of_current_marks_file % sizeof(Mark) != 0)
					throw Exception("Sizes of marks files are inconsistent", ErrorCodes::SIZES_OF_MARKS_FILES_ARE_INCONSISTENT);

				if (-1 == size_of_marks_file)
					size_of_marks_file = size_of_current_marks_file;
				else if (size_of_marks_file != size_of_current_marks_file)
					throw Exception("Sizes of marks files are inconsistent", ErrorCodes::SIZES_OF_MARKS_FILES_ARE_INCONSISTENT);

				it->second.marks.reserve(marks_file.getSize() / sizeof(Mark));
				ReadBufferFromFile marks_rb(marks_file.path(), 32768);
				while (!marks_rb.eof())
				{
					Mark mark;
					readIntBinary(mark.rows, marks_rb);
					readIntBinary(mark.offset, marks_rb);
					it->second.marks.push_back(mark);
				}
			}
		}
		
		if (size_of_marks_file != -1)
		{
			/// Запишем засечки в новом формате.
			WriteBufferFromFile marks_wb(marks_file.path(), 4096, O_APPEND | O_CREAT | O_WRONLY);
			size_t marks_count = marksCount();
			for (size_t mark_index = 0; mark_index < marks_count; ++mark_index)
			{
				for (size_t i = 0; i < files_by_index.size(); ++i)
				{
					Mark mark = files_by_index[i]->second.marks[mark_index];
					writeIntBinary(mark.rows, marks_wb);
					writeIntBinary(mark.offset, marks_wb);
				}
			}
			
			/// Удалим файлы с засечками.
			for (Files_t::iterator it = files.begin(); it != files.end(); ++it)
			{
				Poco::File marks_file(path + escapeForFileName(name) + '/' + Poco::Path(it->second.data_file.path()).getBaseName() + DBMS_STORAGE_LOG_MARKS_FILE_EXTENSION);
				
				marks_file.remove();
			}
		}
	}

	loaded_marks = true;
}


size_t StorageLog::marksCount()
{
	return files.begin()->second.marks.size();
}


void StorageLog::rename(const String & new_path_to_db, const String & new_name)
{
	Poco::ScopedWriteRWLock lock(rwlock);
	
	/// Переименовываем директорию с данными.
	Poco::File(path + escapeForFileName(name)).renameTo(new_path_to_db + escapeForFileName(new_name));
	
	path = new_path_to_db;
	name = new_name;

	for (Files_t::iterator it = files.begin(); it != files.end(); ++it)
	{
		it->second.data_file = Poco::File(path + escapeForFileName(name) + '/' + Poco::Path(it->second.data_file.path()).getFileName());
	}
	
	marks_file = Poco::File(path + escapeForFileName(name) + '/' + DBMS_STORAGE_LOG_MARKS_FILE_NAME);
}


BlockInputStreams StorageLog::read(
	size_t from_mark,
	size_t to_mark,
	const Names & column_names,
	ASTPtr query,
	const Settings & settings,
	QueryProcessingStage::Enum & processed_stage,
	size_t max_block_size,
	unsigned threads)
{
	/** Если читаем все данные в один поток, то засечки не требуются.
	  * Отсутствие необходимости загружать засечки позволяет уменьшить потребление памяти при использовании таблицы типа ChunkMerger.
	  */
	bool read_all_data_in_one_thread = (threads == 1 && from_mark == 0 && to_mark == std::numeric_limits<size_t>::max());
	if (!read_all_data_in_one_thread)
		loadMarks();
	
	check(column_names);
	processed_stage = QueryProcessingStage::FetchColumns;

	Poco::ScopedReadRWLock lock(rwlock);

	BlockInputStreams res;
	
	if (read_all_data_in_one_thread)
	{
		res.push_back(new LogBlockInputStream(
			max_block_size,
			column_names,
			thisPtr(),
			0, std::numeric_limits<size_t>::max()));
	}
	else
	{
		const Marks & marks = files.begin()->second.marks;
		size_t marks_size = marks.size();

		if (to_mark == std::numeric_limits<size_t>::max())
			to_mark = marks_size;

		if (to_mark > marks_size || to_mark < from_mark)
			throw Exception("Marks out of range in StorageLog::read", ErrorCodes::LOGICAL_ERROR);

		if (threads > to_mark - from_mark)
			threads = to_mark - from_mark;

		for (size_t thread = 0; thread < threads; ++thread)
		{
			res.push_back(new LogBlockInputStream(
				max_block_size,
				column_names,
				thisPtr(),
				from_mark + thread * (to_mark - from_mark) / threads,
				marks[from_mark + (thread + 1) * (to_mark - from_mark) / threads - 1].rows -
					((thread == 0 && from_mark == 0)
						? 0
						: marks[from_mark + thread * (to_mark - from_mark) / threads - 1].rows)));
		}
	}

	return res;
}


BlockInputStreams StorageLog::read(
	const Names & column_names,
	ASTPtr query,
	const Settings & settings,
	QueryProcessingStage::Enum & processed_stage,
	size_t max_block_size,
	unsigned threads)
{
	return read(0, std::numeric_limits<size_t>::max(), column_names, query, settings, processed_stage, max_block_size, threads);
}


BlockOutputStreamPtr StorageLog::write(
	ASTPtr query)
{
	loadMarks();
	return new LogBlockOutputStream(thisPtr());
}


}