#include <ext/size.hpp>
#include <DB/Dictionaries/HashedDictionary.h>


namespace DB
{

namespace ErrorCodes
{
	extern const int TYPE_MISMATCH;
	extern const int ARGUMENT_OUT_OF_BOUND;
	extern const int BAD_ARGUMENTS;
	extern const int DICTIONARY_IS_EMPTY;
}


HashedDictionary::HashedDictionary(const std::string & name, const DictionaryStructure & dict_struct,
	DictionarySourcePtr source_ptr, const DictionaryLifetime dict_lifetime, bool require_nonempty)
	: name{name}, dict_struct(dict_struct), source_ptr{std::move(source_ptr)}, dict_lifetime(dict_lifetime),
		require_nonempty(require_nonempty)
{
	createAttributes();

	try
	{
		loadData();
		calculateBytesAllocated();
	}
	catch (...)
	{
		creation_exception = std::current_exception();
	}

	creation_time = std::chrono::system_clock::now();
}

HashedDictionary::HashedDictionary(const HashedDictionary & other)
	: HashedDictionary{other.name, other.dict_struct, other.source_ptr->clone(), other.dict_lifetime, other.require_nonempty}
{
}


void HashedDictionary::toParent(const PaddedPODArray<Key> & ids, PaddedPODArray<Key> & out) const
{
	const auto null_value = std::get<UInt64>(hierarchical_attribute->null_values);

	getItemsNumber<UInt64>(*hierarchical_attribute, ids,
		[&] (const std::size_t row, const UInt64 value) { out[row] = value; },
		[&] (const std::size_t) { return null_value; });
}


/// Allow to use single value in same way as array.
static inline HashedDictionary::Key getAt(const PaddedPODArray<HashedDictionary::Key> & arr, const size_t idx) { return arr[idx]; }
static inline HashedDictionary::Key getAt(const HashedDictionary::Key & value, const size_t idx) { return value; }

template <typename ChildType, typename AncestorType>
void HashedDictionary::isInImpl(
	const ChildType & child_ids,
	const AncestorType & ancestor_ids,
	PaddedPODArray<UInt8> & out) const
{
	const auto null_value = std::get<UInt64>(hierarchical_attribute->null_values);
	const auto & attr = *std::get<CollectionPtrType<Key>>(hierarchical_attribute->maps);
	const auto rows = out.size();

	for (const auto row : ext::range(0, rows))
	{
		auto id = getAt(child_ids, row);
		const auto ancestor_id = getAt(ancestor_ids, row);

		while (id != null_value && id != ancestor_id)
		{
			auto it = attr.find(id);
			if (it != std::end(attr))
				id = it->second;
			else
				break;
		}

		out[row] = id == ancestor_id;
	}

	query_count.fetch_add(rows, std::memory_order_relaxed);
}

void HashedDictionary::isInVectorVector(
	const PaddedPODArray<Key> & child_ids,
	const PaddedPODArray<Key> & ancestor_ids,
	PaddedPODArray<UInt8> & out) const
{
	isInImpl(child_ids, ancestor_ids, out);
}

void HashedDictionary::isInVectorConstant(
	const PaddedPODArray<Key> & child_ids,
	const Key ancestor_id,
	PaddedPODArray<UInt8> & out) const
{
	isInImpl(child_ids, ancestor_id, out);
}

void HashedDictionary::isInConstantVector(
	const Key child_id,
	const PaddedPODArray<Key> & ancestor_ids,
	PaddedPODArray<UInt8> & out) const
{
	isInImpl(child_id, ancestor_ids, out);
}


#define DECLARE(TYPE)\
void HashedDictionary::get##TYPE(const std::string & attribute_name, const PaddedPODArray<Key> & ids, PaddedPODArray<TYPE> & out) const\
{\
	const auto & attribute = getAttribute(attribute_name);\
	if (!isAttributeTypeConvertibleTo(attribute.type, AttributeUnderlyingType::TYPE))\
		throw Exception{\
			name + ": type mismatch: attribute " + attribute_name + " has type " + toString(attribute.type),\
			ErrorCodes::TYPE_MISMATCH};\
	\
	const auto null_value = std::get<TYPE>(attribute.null_values);\
	\
	getItemsNumber<TYPE>(attribute, ids,\
		[&] (const std::size_t row, const auto value) { out[row] = value; },\
		[&] (const std::size_t) { return null_value; });\
}
DECLARE(UInt8)
DECLARE(UInt16)
DECLARE(UInt32)
DECLARE(UInt64)
DECLARE(Int8)
DECLARE(Int16)
DECLARE(Int32)
DECLARE(Int64)
DECLARE(Float32)
DECLARE(Float64)
#undef DECLARE

void HashedDictionary::getString(const std::string & attribute_name, const PaddedPODArray<Key> & ids, ColumnString * out) const
{
	const auto & attribute = getAttribute(attribute_name);
	if (!isAttributeTypeConvertibleTo(attribute.type, AttributeUnderlyingType::String))
		throw Exception{
			name + ": type mismatch: attribute " + attribute_name + " has type " + toString(attribute.type),
			ErrorCodes::TYPE_MISMATCH};

	const auto & null_value = StringRef{std::get<String>(attribute.null_values)};

	getItemsImpl<StringRef, StringRef>(attribute, ids,
		[&] (const std::size_t row, const StringRef value) { out->insertData(value.data, value.size); },
		[&] (const std::size_t) { return null_value; });
}

#define DECLARE(TYPE)\
void HashedDictionary::get##TYPE(\
	const std::string & attribute_name, const PaddedPODArray<Key> & ids, const PaddedPODArray<TYPE> & def,\
	PaddedPODArray<TYPE> & out) const\
{\
	const auto & attribute = getAttribute(attribute_name);\
	if (!isAttributeTypeConvertibleTo(attribute.type, AttributeUnderlyingType::TYPE))\
		throw Exception{\
			name + ": type mismatch: attribute " + attribute_name + " has type " + toString(attribute.type),\
			ErrorCodes::TYPE_MISMATCH};\
	\
	getItemsNumber<TYPE>(attribute, ids,\
		[&] (const std::size_t row, const auto value) { out[row] = value; },\
		[&] (const std::size_t row) { return def[row]; });\
}
DECLARE(UInt8)
DECLARE(UInt16)
DECLARE(UInt32)
DECLARE(UInt64)
DECLARE(Int8)
DECLARE(Int16)
DECLARE(Int32)
DECLARE(Int64)
DECLARE(Float32)
DECLARE(Float64)
#undef DECLARE

void HashedDictionary::getString(
	const std::string & attribute_name, const PaddedPODArray<Key> & ids, const ColumnString * const def,
	ColumnString * const out) const
{
	const auto & attribute = getAttribute(attribute_name);
	if (!isAttributeTypeConvertibleTo(attribute.type, AttributeUnderlyingType::String))
		throw Exception{
			name + ": type mismatch: attribute " + attribute_name + " has type " + toString(attribute.type),
			ErrorCodes::TYPE_MISMATCH};

	getItemsImpl<StringRef, StringRef>(attribute, ids,
		[&] (const std::size_t row, const StringRef value) { out->insertData(value.data, value.size); },
		[&] (const std::size_t row) { return def->getDataAt(row); });
}

#define DECLARE(TYPE)\
void HashedDictionary::get##TYPE(\
	const std::string & attribute_name, const PaddedPODArray<Key> & ids, const TYPE & def, PaddedPODArray<TYPE> & out) const\
{\
	const auto & attribute = getAttribute(attribute_name);\
	if (!isAttributeTypeConvertibleTo(attribute.type, AttributeUnderlyingType::TYPE))\
		throw Exception{\
			name + ": type mismatch: attribute " + attribute_name + " has type " + toString(attribute.type),\
			ErrorCodes::TYPE_MISMATCH};\
	\
	getItemsNumber<TYPE>(attribute, ids,\
		[&] (const std::size_t row, const auto value) { out[row] = value; },\
		[&] (const std::size_t) { return def; });\
}
DECLARE(UInt8)
DECLARE(UInt16)
DECLARE(UInt32)
DECLARE(UInt64)
DECLARE(Int8)
DECLARE(Int16)
DECLARE(Int32)
DECLARE(Int64)
DECLARE(Float32)
DECLARE(Float64)
#undef DECLARE

void HashedDictionary::getString(
	const std::string & attribute_name, const PaddedPODArray<Key> & ids, const String & def,
	ColumnString * const out) const
{
	const auto & attribute = getAttribute(attribute_name);
	if (!isAttributeTypeConvertibleTo(attribute.type, AttributeUnderlyingType::String))
		throw Exception{
			name + ": type mismatch: attribute " + attribute_name + " has type " + toString(attribute.type),
			ErrorCodes::TYPE_MISMATCH};

	getItemsImpl<StringRef, StringRef>(attribute, ids,
		[&] (const std::size_t row, const StringRef value) { out->insertData(value.data, value.size); },
		[&] (const std::size_t) { return StringRef{def}; });
}

void HashedDictionary::has(const PaddedPODArray<Key> & ids, PaddedPODArray<UInt8> & out) const
{
	const auto & attribute = attributes.front();

	switch (attribute.type)
	{
		case AttributeUnderlyingType::UInt8: has<UInt8>(attribute, ids, out); break;
		case AttributeUnderlyingType::UInt16: has<UInt16>(attribute, ids, out); break;
		case AttributeUnderlyingType::UInt32: has<UInt32>(attribute, ids, out); break;
		case AttributeUnderlyingType::UInt64: has<UInt64>(attribute, ids, out); break;
		case AttributeUnderlyingType::Int8: has<Int8>(attribute, ids, out); break;
		case AttributeUnderlyingType::Int16: has<Int16>(attribute, ids, out); break;
		case AttributeUnderlyingType::Int32: has<Int32>(attribute, ids, out); break;
		case AttributeUnderlyingType::Int64: has<Int64>(attribute, ids, out); break;
		case AttributeUnderlyingType::Float32: has<Float32>(attribute, ids, out); break;
		case AttributeUnderlyingType::Float64: has<Float64>(attribute, ids, out); break;
		case AttributeUnderlyingType::String: has<StringRef>(attribute, ids, out); break;
	}
}

void HashedDictionary::createAttributes()
{
	const auto size = dict_struct.attributes.size();
	attributes.reserve(size);

	for (const auto & attribute : dict_struct.attributes)
	{
		attribute_index_by_name.emplace(attribute.name, attributes.size());
		attributes.push_back(createAttributeWithType(attribute.underlying_type, attribute.null_value));

		if (attribute.hierarchical)
		{
			hierarchical_attribute = &attributes.back();

			if (hierarchical_attribute->type != AttributeUnderlyingType::UInt64)
				throw Exception{
					name + ": hierarchical attribute must be UInt64.",
					ErrorCodes::TYPE_MISMATCH};
		}
	}
}

void HashedDictionary::loadData()
{
	auto stream = source_ptr->loadAll();
	stream->readPrefix();

	while (const auto block = stream->read())
	{
		const auto & id_column = *block.safeGetByPosition(0).column;

		element_count += id_column.size();

		for (const auto attribute_idx : ext::range(0, attributes.size()))
		{
			const auto & attribute_column = *block.safeGetByPosition(attribute_idx + 1).column;
			auto & attribute = attributes[attribute_idx];

			for (const auto row_idx : ext::range(0, id_column.size()))
				setAttributeValue(attribute, id_column[row_idx].get<UInt64>(), attribute_column[row_idx]);
		}
	}

	stream->readSuffix();

	if (require_nonempty && 0 == element_count)
		throw Exception{
			name + ": dictionary source is empty and 'require_nonempty' property is set.",
			ErrorCodes::DICTIONARY_IS_EMPTY};
}

template <typename T>
void HashedDictionary::addAttributeSize(const Attribute & attribute)
{
	const auto & map_ref = std::get<CollectionPtrType<T>>(attribute.maps);
	bytes_allocated += sizeof(CollectionType<T>) + map_ref->getBufferSizeInBytes();
	bucket_count = map_ref->getBufferSizeInCells();
}

void HashedDictionary::calculateBytesAllocated()
{
	bytes_allocated += attributes.size() * sizeof(attributes.front());

	for (const auto & attribute : attributes)
	{
		switch (attribute.type)
		{
			case AttributeUnderlyingType::UInt8: addAttributeSize<UInt8>(attribute); break;
			case AttributeUnderlyingType::UInt16: addAttributeSize<UInt16>(attribute); break;
			case AttributeUnderlyingType::UInt32: addAttributeSize<UInt32>(attribute); break;
			case AttributeUnderlyingType::UInt64: addAttributeSize<UInt64>(attribute); break;
			case AttributeUnderlyingType::Int8: addAttributeSize<Int8>(attribute); break;
			case AttributeUnderlyingType::Int16: addAttributeSize<Int16>(attribute); break;
			case AttributeUnderlyingType::Int32: addAttributeSize<Int32>(attribute); break;
			case AttributeUnderlyingType::Int64: addAttributeSize<Int64>(attribute); break;
			case AttributeUnderlyingType::Float32: addAttributeSize<Float32>(attribute); break;
			case AttributeUnderlyingType::Float64: addAttributeSize<Float64>(attribute); break;
			case AttributeUnderlyingType::String:
			{
				addAttributeSize<StringRef>(attribute);
				bytes_allocated += sizeof(Arena) + attribute.string_arena->size();

				break;
			}
		}
	}
}

template <typename T>
void HashedDictionary::createAttributeImpl(Attribute & attribute, const Field & null_value)
{
	std::get<T>(attribute.null_values) = null_value.get<typename NearestFieldType<T>::Type>();
	std::get<CollectionPtrType<T>>(attribute.maps) = std::make_unique<CollectionType<T>>();
}

HashedDictionary::Attribute HashedDictionary::createAttributeWithType(const AttributeUnderlyingType type, const Field & null_value)
{
	Attribute attr{type};

	switch (type)
	{
		case AttributeUnderlyingType::UInt8: createAttributeImpl<UInt8>(attr, null_value); break;
		case AttributeUnderlyingType::UInt16: createAttributeImpl<UInt16>(attr, null_value); break;
		case AttributeUnderlyingType::UInt32: createAttributeImpl<UInt32>(attr, null_value); break;
		case AttributeUnderlyingType::UInt64: createAttributeImpl<UInt64>(attr, null_value); break;
		case AttributeUnderlyingType::Int8: createAttributeImpl<Int8>(attr, null_value); break;
		case AttributeUnderlyingType::Int16: createAttributeImpl<Int16>(attr, null_value); break;
		case AttributeUnderlyingType::Int32: createAttributeImpl<Int32>(attr, null_value); break;
		case AttributeUnderlyingType::Int64: createAttributeImpl<Int64>(attr, null_value); break;
		case AttributeUnderlyingType::Float32: createAttributeImpl<Float32>(attr, null_value); break;
		case AttributeUnderlyingType::Float64: createAttributeImpl<Float64>(attr, null_value); break;
		case AttributeUnderlyingType::String:
		{
			std::get<String>(attr.null_values) = null_value.get<String>();
			std::get<CollectionPtrType<StringRef>>(attr.maps) = std::make_unique<CollectionType<StringRef>>();
			attr.string_arena = std::make_unique<Arena>();
			break;
		}
	}

	return attr;
}


template <typename OutputType, typename ValueSetter, typename DefaultGetter>
void HashedDictionary::getItemsNumber(
	const Attribute & attribute,
	const PaddedPODArray<Key> & ids,
	ValueSetter && set_value,
	DefaultGetter && get_default) const
{
	if (false) {}
#define DISPATCH(TYPE) \
	else if (attribute.type == AttributeUnderlyingType::TYPE) \
		getItemsImpl<TYPE, OutputType>(attribute, ids, std::forward<ValueSetter>(set_value), std::forward<DefaultGetter>(get_default));
	DISPATCH(UInt8)
	DISPATCH(UInt16)
	DISPATCH(UInt32)
	DISPATCH(UInt64)
	DISPATCH(Int8)
	DISPATCH(Int16)
	DISPATCH(Int32)
	DISPATCH(Int64)
	DISPATCH(Float32)
	DISPATCH(Float64)
#undef DISPATCH
	else
		throw Exception("Unexpected type of attribute: " + toString(attribute.type), ErrorCodes::LOGICAL_ERROR);
}

template <typename AttributeType, typename OutputType, typename ValueSetter, typename DefaultGetter>
void HashedDictionary::getItemsImpl(
	const Attribute & attribute,
	const PaddedPODArray<Key> & ids,
	ValueSetter && set_value,
	DefaultGetter && get_default) const
{
	const auto & attr = *std::get<CollectionPtrType<AttributeType>>(attribute.maps);
	const auto rows = ext::size(ids);

	for (const auto i : ext::range(0, rows))
	{
		const auto it = attr.find(ids[i]);
		set_value(i, it != attr.end() ? it->second : get_default(i));
	}

	query_count.fetch_add(rows, std::memory_order_relaxed);
}


template <typename T>
void HashedDictionary::setAttributeValueImpl(Attribute & attribute, const Key id, const T value)
{
	auto & map = *std::get<CollectionPtrType<T>>(attribute.maps);
	map.insert({ id, value });
}

void HashedDictionary::setAttributeValue(Attribute & attribute, const Key id, const Field & value)
{
	switch (attribute.type)
	{
		case AttributeUnderlyingType::UInt8: setAttributeValueImpl<UInt8>(attribute, id, value.get<UInt64>()); break;
		case AttributeUnderlyingType::UInt16: setAttributeValueImpl<UInt16>(attribute, id, value.get<UInt64>()); break;
		case AttributeUnderlyingType::UInt32: setAttributeValueImpl<UInt32>(attribute, id, value.get<UInt64>()); break;
		case AttributeUnderlyingType::UInt64: setAttributeValueImpl<UInt64>(attribute, id, value.get<UInt64>()); break;
		case AttributeUnderlyingType::Int8: setAttributeValueImpl<Int8>(attribute, id, value.get<Int64>()); break;
		case AttributeUnderlyingType::Int16: setAttributeValueImpl<Int16>(attribute, id, value.get<Int64>()); break;
		case AttributeUnderlyingType::Int32: setAttributeValueImpl<Int32>(attribute, id, value.get<Int64>()); break;
		case AttributeUnderlyingType::Int64: setAttributeValueImpl<Int64>(attribute, id, value.get<Int64>()); break;
		case AttributeUnderlyingType::Float32: setAttributeValueImpl<Float32>(attribute, id, value.get<Float64>()); break;
		case AttributeUnderlyingType::Float64: setAttributeValueImpl<Float64>(attribute, id, value.get<Float64>()); break;
		case AttributeUnderlyingType::String:
		{
			auto & map = *std::get<CollectionPtrType<StringRef>>(attribute.maps);
			const auto & string = value.get<String>();
			const auto string_in_arena = attribute.string_arena->insert(string.data(), string.size());
			map.insert({ id, StringRef{string_in_arena, string.size()} });
			break;
		}
	}
}

const HashedDictionary::Attribute & HashedDictionary::getAttribute(const std::string & attribute_name) const
{
	const auto it = attribute_index_by_name.find(attribute_name);
	if (it == std::end(attribute_index_by_name))
		throw Exception{
			name + ": no such attribute '" + attribute_name + "'",
			ErrorCodes::BAD_ARGUMENTS};

	return attributes[it->second];
}

template <typename T>
void HashedDictionary::has(const Attribute & attribute, const PaddedPODArray<Key> & ids, PaddedPODArray<UInt8> & out) const
{
	const auto & attr = *std::get<CollectionPtrType<T>>(attribute.maps);
	const auto rows = ext::size(ids);

	for (const auto i : ext::range(0, rows))
		out[i] = attr.find(ids[i]) != std::end(attr);

	query_count.fetch_add(rows, std::memory_order_relaxed);
}

}