#include <Storages/MergeTree/MergeTreeIndexSet.h>

#include <Interpreters/ExpressionActions.h>
#include <Interpreters/ExpressionAnalyzer.h>
#include <Interpreters/TreeRewriter.h>

#include <Parsers/ASTIdentifier.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/ASTLiteral.h>


namespace DB
{

namespace ErrorCodes
{
    extern const int LOGICAL_ERROR;
    extern const int INCORRECT_QUERY;
}

/// 0b11 -- can be true and false at the same time
static const Field UNKNOWN_FIELD(3u);


MergeTreeIndexGranuleSet::MergeTreeIndexGranuleSet(
    const String & index_name_,
    const Block & index_sample_block_,
    size_t max_rows_)
    : index_name(index_name_)
    , max_rows(max_rows_)
    , index_sample_block(index_sample_block_)
    , block(index_sample_block)
{
}

MergeTreeIndexGranuleSet::MergeTreeIndexGranuleSet(
    const String & index_name_,
    const Block & index_sample_block_,
    size_t max_rows_,
    MutableColumns && mutable_columns_)
    : index_name(index_name_)
    , max_rows(max_rows_)
    , index_sample_block(index_sample_block_)
    , block(index_sample_block.cloneWithColumns(std::move(mutable_columns_)))
{
}

void MergeTreeIndexGranuleSet::serializeBinary(WriteBuffer & ostr) const
{
    if (empty())
        throw Exception(
            "Attempt to write empty set index " + backQuote(index_name), ErrorCodes::LOGICAL_ERROR);

    const auto & size_type = DataTypePtr(std::make_shared<DataTypeUInt64>());

    if (max_rows != 0 && size() > max_rows)
    {
        size_type->serializeBinary(0, ostr);
        return;
    }

    size_type->serializeBinary(size(), ostr);

    for (size_t i = 0; i < index_sample_block.columns(); ++i)
    {
        const auto & type = index_sample_block.getByPosition(i).type;

        IDataType::SerializeBinaryBulkSettings settings;
        settings.getter = [&ostr](IDataType::SubstreamPath) -> WriteBuffer * { return &ostr; };
        settings.position_independent_encoding = false;
        settings.low_cardinality_max_dictionary_size = 0;

        IDataType::SerializeBinaryBulkStatePtr state;
        type->serializeBinaryBulkStatePrefix(settings, state);
        type->serializeBinaryBulkWithMultipleStreams(*block.getByPosition(i).column, 0, size(), settings, state);
        type->serializeBinaryBulkStateSuffix(settings, state);
    }
}

void MergeTreeIndexGranuleSet::deserializeBinary(ReadBuffer & istr)
{
    block.clear();

    Field field_rows;
    const auto & size_type = DataTypePtr(std::make_shared<DataTypeUInt64>());
    size_type->deserializeBinary(field_rows, istr);
    size_t rows_to_read = field_rows.get<size_t>();

    if (rows_to_read == 0)
        return;

    for (size_t i = 0; i < index_sample_block.columns(); ++i)
    {
        const auto & column = index_sample_block.getByPosition(i);
        const auto & type = column.type;
        auto new_column = type->createColumn();

        IDataType::DeserializeBinaryBulkSettings settings;
        settings.getter = [&](IDataType::SubstreamPath) -> ReadBuffer * { return &istr; };
        settings.position_independent_encoding = false;

        IDataType::DeserializeBinaryBulkStatePtr state;
        type->deserializeBinaryBulkStatePrefix(settings, state);
        type->deserializeBinaryBulkWithMultipleStreams(*new_column, rows_to_read, settings, state);

        block.insert(ColumnWithTypeAndName(new_column->getPtr(), type, column.name));
    }
}


MergeTreeIndexAggregatorSet::MergeTreeIndexAggregatorSet(const String & index_name_, const Block & index_sample_block_, size_t max_rows_)
    : index_name(index_name_)
    , max_rows(max_rows_)
    , index_sample_block(index_sample_block_)
    , columns(index_sample_block_.cloneEmptyColumns())
{
    ColumnRawPtrs column_ptrs;
    column_ptrs.reserve(index_sample_block.columns());
    Columns materialized_columns;
    for (const auto & column : index_sample_block.getColumns())
    {
        materialized_columns.emplace_back(column->convertToFullColumnIfConst()->convertToFullColumnIfLowCardinality());
        column_ptrs.emplace_back(materialized_columns.back().get());
    }

    data.init(ClearableSetVariants::chooseMethod(column_ptrs, key_sizes));

    columns = index_sample_block.cloneEmptyColumns();
}

void MergeTreeIndexAggregatorSet::update(const Block & block, size_t * pos, size_t limit)
{
    if (*pos >= block.rows())
        throw Exception(
                "The provided position is not less than the number of block rows. Position: "
                + toString(*pos) + ", Block rows: " + toString(block.rows()) + ".", ErrorCodes::LOGICAL_ERROR);

    size_t rows_read = std::min(limit, block.rows() - *pos);

    if (max_rows && size() > max_rows)
    {
        *pos += rows_read;
        return;
    }

    ColumnRawPtrs index_column_ptrs;
    index_column_ptrs.reserve(index_sample_block.columns());
    Columns materialized_columns;
    const Names index_columns = index_sample_block.getNames();
    for (const auto & column_name : index_columns)
    {
        materialized_columns.emplace_back(
                block.getByName(column_name).column->convertToFullColumnIfConst()->convertToFullColumnIfLowCardinality());
        index_column_ptrs.emplace_back(materialized_columns.back().get());
    }

    IColumn::Filter filter(block.rows(), 0);

    bool has_new_data = false;
    switch (data.type)
    {
        case ClearableSetVariants::Type::EMPTY:
            break;
#define M(NAME) \
        case ClearableSetVariants::Type::NAME: \
            has_new_data = buildFilter(*data.NAME, index_column_ptrs, filter, *pos, rows_read, data); \
            break;
        APPLY_FOR_SET_VARIANTS(M)
#undef M
    }

    if (has_new_data)
    {
        for (size_t i = 0; i < columns.size(); ++i)
        {
            auto filtered_column = block.getByName(index_columns[i]).column->filter(filter, block.rows());
            columns[i]->insertRangeFrom(*filtered_column, 0, filtered_column->size());
        }
    }

    *pos += rows_read;
}

template <typename Method>
bool MergeTreeIndexAggregatorSet::buildFilter(
    Method & method,
    const ColumnRawPtrs & column_ptrs,
    IColumn::Filter & filter,
    size_t pos,
    size_t limit,
    ClearableSetVariants & variants) const
{
    /// Like DistinctSortedBlockInputStream.
    typename Method::State state(column_ptrs, key_sizes, nullptr);

    bool has_new_data = false;
    for (size_t i = 0; i < limit; ++i)
    {
        auto emplace_result = state.emplaceKey(method.data, pos + i, variants.string_pool);

        if (emplace_result.isInserted())
            has_new_data = true;

        /// Emit the record if there is no such key in the current set yet.
        /// Skip it otherwise.
        filter[pos + i] = emplace_result.isInserted();
    }
    return has_new_data;
}

MergeTreeIndexGranulePtr MergeTreeIndexAggregatorSet::getGranuleAndReset()
{
    auto granule = std::make_shared<MergeTreeIndexGranuleSet>(index_name, index_sample_block, max_rows, std::move(columns));

    switch (data.type)
    {
        case ClearableSetVariants::Type::EMPTY:
            break;
#define M(NAME) \
        case ClearableSetVariants::Type::NAME: \
            data.NAME->data.clear(); \
            break;
        APPLY_FOR_SET_VARIANTS(M)
#undef M
    }

    columns = index_sample_block.cloneEmptyColumns();

    return granule;
}


MergeTreeIndexConditionSet::MergeTreeIndexConditionSet(
    const String & index_name_,
    const Block & index_sample_block_,
    size_t max_rows_,
    const SelectQueryInfo & query,
    const Context & context)
    : index_name(index_name_)
    , max_rows(max_rows_)
    , index_sample_block(index_sample_block_)
{
    for (const auto & name : index_sample_block.getNames())
        if (!key_columns.count(name))
            key_columns.insert(name);

    const auto & select = query.query->as<ASTSelectQuery &>();

    if (select.where() && select.prewhere())
        expression_ast = makeASTFunction(
                "and",
                select.where()->clone(),
                select.prewhere()->clone());
    else if (select.where())
        expression_ast = select.where()->clone();
    else if (select.prewhere())
        expression_ast = select.prewhere()->clone();

    useless = checkASTUseless(expression_ast);
    /// Do not proceed if index is useless for this query.
    if (useless)
        return;

    /// Replace logical functions with bit functions.
    /// Working with UInt8: last bit = can be true, previous = can be false (Like src/Storages/MergeTree/BoolMask.h).
    traverseAST(expression_ast);

    auto syntax_analyzer_result = TreeRewriter(context).analyze(
            expression_ast, index_sample_block.getNamesAndTypesList());
    actions = ExpressionAnalyzer(expression_ast, syntax_analyzer_result, context).getActions(true);
}

bool MergeTreeIndexConditionSet::alwaysUnknownOrTrue() const
{
    return useless;
}

bool MergeTreeIndexConditionSet::mayBeTrueOnGranule(MergeTreeIndexGranulePtr idx_granule) const
{
    if (useless)
        return true;

    auto granule = std::dynamic_pointer_cast<MergeTreeIndexGranuleSet>(idx_granule);
    if (!granule)
        throw Exception(
                "Set index condition got a granule with the wrong type.", ErrorCodes::LOGICAL_ERROR);

    if (useless || granule->empty() || (max_rows != 0 && granule->size() > max_rows))
        return true;

    Block result = granule->block;
    actions->execute(result);

    auto column
        = result.getByName(expression_ast->getColumnName()).column->convertToFullColumnIfConst()->convertToFullColumnIfLowCardinality();
    const auto * col_uint8 = typeid_cast<const ColumnUInt8 *>(column.get());

    const NullMap * null_map = nullptr;

    if (const auto * col_nullable = checkAndGetColumn<ColumnNullable>(*column))
    {
        col_uint8 = typeid_cast<const ColumnUInt8 *>(&col_nullable->getNestedColumn());
        null_map = &col_nullable->getNullMapData();
    }

    if (!col_uint8)
        throw Exception("ColumnUInt8 expected as Set index condition result.", ErrorCodes::LOGICAL_ERROR);

    const auto & condition = col_uint8->getData();

    for (size_t i = 0; i < column->size(); ++i)
        if ((!null_map || (*null_map)[i] == 0) && condition[i] & 1)
            return true;

    return false;
}

void MergeTreeIndexConditionSet::traverseAST(ASTPtr & node) const
{
    if (operatorFromAST(node))
    {
        auto & args = node->as<ASTFunction>()->arguments->children;

        for (auto & arg : args)
            traverseAST(arg);
        return;
    }

    if (atomFromAST(node))
    {
        if (node->as<ASTIdentifier>() || node->as<ASTFunction>())
            node = makeASTFunction("__bitWrapperFunc", node);
    }
    else
        node = std::make_shared<ASTLiteral>(UNKNOWN_FIELD);
}

bool MergeTreeIndexConditionSet::atomFromAST(ASTPtr & node) const
{
    /// Function, literal or column

    if (node->as<ASTLiteral>())
        return true;

    if (const auto * identifier = node->as<ASTIdentifier>())
        return key_columns.count(identifier->getColumnName()) != 0;

    if (auto * func = node->as<ASTFunction>())
    {
        if (key_columns.count(func->getColumnName()))
        {
            /// Function is already calculated.
            node = std::make_shared<ASTIdentifier>(func->getColumnName());
            return true;
        }

        auto & args = func->arguments->children;

        for (auto & arg : args)
            if (!atomFromAST(arg))
                return false;

        return true;
    }

    return false;
}

bool MergeTreeIndexConditionSet::operatorFromAST(ASTPtr & node)
{
    /// Functions AND, OR, NOT. Replace with bit*.
    auto * func = node->as<ASTFunction>();
    if (!func)
        return false;

    auto & args = func->arguments->children;

    if (func->name == "not")
    {
        if (args.size() != 1)
            return false;

        func->name = "__bitSwapLastTwo";
    }
    else if (func->name == "and")
    {
        auto last_arg = args.back();
        args.pop_back();

        ASTPtr new_func;
        if (args.size() > 1)
            new_func = makeASTFunction(
                    "__bitBoolMaskAnd",
                    node,
                    last_arg);
        else
            new_func = makeASTFunction(
                    "__bitBoolMaskAnd",
                    args.back(),
                    last_arg);

        node = new_func;
    }
    else if (func->name == "or")
    {
        auto last_arg = args.back();
        args.pop_back();

        ASTPtr new_func;
        if (args.size() > 1)
            new_func = makeASTFunction(
                    "__bitBoolMaskOr",
                    node,
                    last_arg);
        else
            new_func = makeASTFunction(
                    "__bitBoolMaskOr",
                    args.back(),
                    last_arg);

        node = new_func;
    }
    else
        return false;

    return true;
}

bool MergeTreeIndexConditionSet::checkASTUseless(const ASTPtr & node, bool atomic) const
{
    if (!node)
        return true;

    if (const auto * func = node->as<ASTFunction>())
    {
        if (key_columns.count(func->getColumnName()))
            return false;

        const ASTs & args = func->arguments->children;

        if (func->name == "and")
            return checkASTUseless(args[0], atomic) && checkASTUseless(args[1], atomic);
        else if (func->name == "or")
            return checkASTUseless(args[0], atomic) || checkASTUseless(args[1], atomic);
        else if (func->name == "not")
            return checkASTUseless(args[0], atomic);
        else
            return std::any_of(args.begin(), args.end(),
                [this](const auto & arg) { return checkASTUseless(arg, true); });
    }
    else if (const auto * literal = node->as<ASTLiteral>())
        return !atomic && literal->value.get<bool>();
    else if (const auto * identifier = node->as<ASTIdentifier>())
        return key_columns.find(identifier->getColumnName()) == std::end(key_columns);
    else
        return true;
}


MergeTreeIndexGranulePtr MergeTreeIndexSet::createIndexGranule() const
{
    return std::make_shared<MergeTreeIndexGranuleSet>(index.name, index.sample_block, max_rows);
}

MergeTreeIndexAggregatorPtr MergeTreeIndexSet::createIndexAggregator() const
{
    return std::make_shared<MergeTreeIndexAggregatorSet>(index.name, index.sample_block, max_rows);
}

MergeTreeIndexConditionPtr MergeTreeIndexSet::createIndexCondition(
    const SelectQueryInfo & query, const Context & context) const
{
    return std::make_shared<MergeTreeIndexConditionSet>(index.name, index.sample_block, max_rows, query, context);
};

bool MergeTreeIndexSet::mayBenefitFromIndexForIn(const ASTPtr &) const
{
    return false;
}

MergeTreeIndexPtr setIndexCreator(const IndexDescription & index)
{
    size_t max_rows = index.arguments[0].get<size_t>();
    return std::make_shared<MergeTreeIndexSet>(index, max_rows);
}

void setIndexValidator(const IndexDescription & index, bool /*attach*/)
{
    if (index.arguments.size() != 1)
        throw Exception("Set index must have exactly one argument.", ErrorCodes::INCORRECT_QUERY);
    else if (index.arguments[0].getType() != Field::Types::UInt64)
        throw Exception("Set index argument must be positive integer.", ErrorCodes::INCORRECT_QUERY);
}

}