#include <Storages/MergeTree/ReplicatedMergeTreeTableMetadata.h>
#include <Storages/MergeTree/MergeTreeData.h>
#include <Parsers/formatAST.h>
#include <Parsers/parseQuery.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/ExpressionListParsers.h>
#include <IO/Operators.h>
#include <Interpreters/FunctionNameNormalizer.h>


namespace DB
{

namespace ErrorCodes
{
    extern const int METADATA_MISMATCH;
}

static String formattedAST(const ASTPtr & ast)
{
    if (!ast)
        return "";
    WriteBufferFromOwnString buf;
    formatAST(*ast, buf, false, true);
    return buf.str();
}

static String formattedASTNormalized(const ASTPtr & ast)
{
    if (!ast)
        return "";
    auto ast_normalized = ast->clone();
    FunctionNameNormalizer().visit(ast_normalized.get());
    WriteBufferFromOwnString buf;
    formatAST(*ast_normalized, buf, false, true);
    return buf.str();
}

ReplicatedMergeTreeTableMetadata::ReplicatedMergeTreeTableMetadata(const MergeTreeData & data, const StorageMetadataPtr & metadata_snapshot)
{
    if (data.format_version < MERGE_TREE_DATA_MIN_FORMAT_VERSION_WITH_CUSTOM_PARTITIONING)
    {
        auto minmax_idx_column_names = data.getMinMaxColumnsNames(metadata_snapshot->getPartitionKey());
        date_column = minmax_idx_column_names[data.minmax_idx_date_column_pos];
    }

    const auto data_settings = data.getSettings();
    sampling_expression = formattedASTNormalized(metadata_snapshot->getSamplingKeyAST());
    index_granularity = data_settings->index_granularity;
    merging_params_mode = static_cast<int>(data.merging_params.mode);
    sign_column = data.merging_params.sign_column;

    /// This code may looks strange, but previously we had only one entity: PRIMARY KEY (or ORDER BY, it doesn't matter)
    /// Now we have two different entities ORDER BY and it's optional prefix -- PRIMARY KEY.
    /// In most cases user doesn't specify PRIMARY KEY and semantically it's equal to ORDER BY.
    /// So rules in zookeeper metadata is following:
    /// - When we have only ORDER BY, than store it in "primary key:" row of /metadata
    /// - When we have both, than store PRIMARY KEY in "primary key:" row and ORDER BY in "sorting key:" row of /metadata

    primary_key = formattedASTNormalized(metadata_snapshot->getPrimaryKey().expression_list_ast);
    if (metadata_snapshot->isPrimaryKeyDefined())
    {
        /// We don't use preparsed AST `sorting_key.expression_list_ast` because
        /// it contain version column for VersionedCollapsingMergeTree, which
        /// is not stored in ZooKeeper for compatibility reasons. So the best
        /// compatible way is just to convert definition_ast to list and
        /// serialize it. In all other places key.expression_list_ast should be
        /// used.
        sorting_key = formattedASTNormalized(extractKeyExpressionList(metadata_snapshot->getSortingKey().definition_ast));
    }

    data_format_version = data.format_version;

    if (data.format_version >= MERGE_TREE_DATA_MIN_FORMAT_VERSION_WITH_CUSTOM_PARTITIONING)
        partition_key = formattedASTNormalized(metadata_snapshot->getPartitionKey().expression_list_ast);

    ttl_table = formattedASTNormalized(metadata_snapshot->getTableTTLs().definition_ast);

    skip_indices = metadata_snapshot->getSecondaryIndices().toString();

    projections = metadata_snapshot->getProjections().toString();

    if (data.canUseAdaptiveGranularity())
        index_granularity_bytes = data_settings->index_granularity_bytes;
    else
        index_granularity_bytes = 0;

    constraints = metadata_snapshot->getConstraints().toString();
}

void ReplicatedMergeTreeTableMetadata::write(WriteBuffer & out) const
{
    out << "metadata format version: 1\n"
        << "date column: " << date_column << "\n"
        << "sampling expression: " << sampling_expression << "\n"
        << "index granularity: " << index_granularity << "\n"
        << "mode: " << merging_params_mode << "\n"
        << "sign column: " << sign_column << "\n"
        << "primary key: " << primary_key << "\n";

    if (data_format_version >= MERGE_TREE_DATA_MIN_FORMAT_VERSION_WITH_CUSTOM_PARTITIONING)
    {
        out << "data format version: " << data_format_version.toUnderType() << "\n"
            << "partition key: " << partition_key << "\n";
    }

    if (!sorting_key.empty())
        out << "sorting key: " << sorting_key << "\n";

    if (!ttl_table.empty())
        out << "ttl: " << ttl_table << "\n";

    if (!skip_indices.empty())
        out << "indices: " << skip_indices << "\n";

    if (!projections.empty())
        out << "projections: " << projections << "\n";

    if (index_granularity_bytes != 0)
        out << "granularity bytes: " << index_granularity_bytes << "\n";

    if (!constraints.empty())
        out << "constraints: " << constraints << "\n";
}

String ReplicatedMergeTreeTableMetadata::toString() const
{
    WriteBufferFromOwnString out;
    write(out);
    return out.str();
}

void ReplicatedMergeTreeTableMetadata::read(ReadBuffer & in)
{
    in >> "metadata format version: 1\n";
    in >> "date column: " >> date_column >> "\n";
    in >> "sampling expression: " >> sampling_expression >> "\n";
    in >> "index granularity: " >> index_granularity >> "\n";
    in >> "mode: " >> merging_params_mode >> "\n";
    in >> "sign column: " >> sign_column >> "\n";
    in >> "primary key: " >> primary_key >> "\n";

    if (in.eof())
        data_format_version = 0;
    else if (checkString("data format version: ", in))
        in >> data_format_version.toUnderType() >> "\n";

    if (data_format_version >= MERGE_TREE_DATA_MIN_FORMAT_VERSION_WITH_CUSTOM_PARTITIONING)
        in >> "partition key: " >> partition_key >> "\n";

    if (checkString("sorting key: ", in))
        in >> sorting_key >> "\n";

    if (checkString("ttl: ", in))
        in >> ttl_table >> "\n";

    if (checkString("indices: ", in))
        in >> skip_indices >> "\n";

    if (checkString("projections: ", in))
        in >> projections >> "\n";

    if (checkString("granularity bytes: ", in))
    {
        in >> index_granularity_bytes >> "\n";
        index_granularity_bytes_found_in_zk = true;
    }
    else
        index_granularity_bytes = 0;

    if (checkString("constraints: ", in))
        in >> constraints >> "\n";
}

ReplicatedMergeTreeTableMetadata ReplicatedMergeTreeTableMetadata::parse(const String & s)
{
    ReplicatedMergeTreeTableMetadata metadata;
    ReadBufferFromString buf(s);
    metadata.read(buf);
    return metadata;
}


void ReplicatedMergeTreeTableMetadata::checkImmutableFieldsEquals(const ReplicatedMergeTreeTableMetadata & from_zk, const ColumnsDescription & columns, ContextPtr context) const
{
    if (data_format_version < MERGE_TREE_DATA_MIN_FORMAT_VERSION_WITH_CUSTOM_PARTITIONING)
    {
        if (date_column != from_zk.date_column)
            throw Exception(ErrorCodes::METADATA_MISMATCH, "Existing table metadata in ZooKeeper differs in date index column. "
                "Stored in ZooKeeper: {}, local: {}", from_zk.date_column, date_column);
    }
    else if (!from_zk.date_column.empty())
    {
        throw Exception(ErrorCodes::METADATA_MISMATCH, "Existing table metadata in ZooKeeper differs in date index column. "
            "Stored in ZooKeeper: {}, local is custom-partitioned.", from_zk.date_column);
    }

    if (index_granularity != from_zk.index_granularity)
        throw Exception(ErrorCodes::METADATA_MISMATCH, "Existing table metadata in ZooKeeper differs "
                        "in index granularity. Stored in ZooKeeper: {}, local: {}",
                        DB::toString(from_zk.index_granularity), DB::toString(index_granularity));

    if (merging_params_mode != from_zk.merging_params_mode)
        throw Exception(ErrorCodes::METADATA_MISMATCH,
                        "Existing table metadata in ZooKeeper differs in mode of merge operation. "
                        "Stored in ZooKeeper: {}, local: {}", DB::toString(from_zk.merging_params_mode),
                        DB::toString(merging_params_mode));

    if (sign_column != from_zk.sign_column)
        throw Exception(ErrorCodes::METADATA_MISMATCH, "Existing table metadata in ZooKeeper differs in sign column. "
            "Stored in ZooKeeper: {}, local: {}", from_zk.sign_column, sign_column);

    /// NOTE: You can make a less strict check of match expressions so that tables do not break from small changes
    ///    in formatAST code.
    String parsed_zk_primary_key = formattedAST(KeyDescription::parse(from_zk.primary_key, columns, context).expression_list_ast);
    if (primary_key != parsed_zk_primary_key)
        throw Exception(ErrorCodes::METADATA_MISMATCH, "Existing table metadata in ZooKeeper differs in primary key. "
            "Stored in ZooKeeper: {}, parsed from ZooKeeper: {}, local: {}",
            from_zk.primary_key, parsed_zk_primary_key, primary_key);

    if (data_format_version != from_zk.data_format_version)
        throw Exception(ErrorCodes::METADATA_MISMATCH,
                        "Existing table metadata in ZooKeeper differs in data format version. "
                        "Stored in ZooKeeper: {}, local: {}", DB::toString(from_zk.data_format_version.toUnderType()),
                        DB::toString(data_format_version.toUnderType()));

    String parsed_zk_partition_key = formattedAST(KeyDescription::parse(from_zk.partition_key, columns, context).expression_list_ast);
    if (partition_key != parsed_zk_partition_key)
        throw Exception(ErrorCodes::METADATA_MISMATCH,
                        "Existing table metadata in ZooKeeper differs in partition key expression. "
                        "Stored in ZooKeeper: {}, parsed from ZooKeeper: {}, local: {}",
                        from_zk.partition_key, parsed_zk_partition_key, partition_key);
}

void ReplicatedMergeTreeTableMetadata::checkEquals(const ReplicatedMergeTreeTableMetadata & from_zk, const ColumnsDescription & columns, ContextPtr context) const
{

    checkImmutableFieldsEquals(from_zk, columns, context);

    String parsed_zk_sampling_expression = formattedAST(KeyDescription::parse(from_zk.sampling_expression, columns, context).definition_ast);
    if (sampling_expression != parsed_zk_sampling_expression)
    {
        throw Exception(ErrorCodes::METADATA_MISMATCH, "Existing table metadata in ZooKeeper differs in sample expression. "
            "Stored in ZooKeeper: {}, parsed from ZooKeeper: {}, local: {}",
            from_zk.sampling_expression, parsed_zk_sampling_expression, sampling_expression);
    }

    String parsed_zk_sorting_key = formattedAST(extractKeyExpressionList(KeyDescription::parse(from_zk.sorting_key, columns, context).definition_ast));
    if (sorting_key != parsed_zk_sorting_key)
    {
        throw Exception(ErrorCodes::METADATA_MISMATCH,
                        "Existing table metadata in ZooKeeper differs in sorting key expression. "
                        "Stored in ZooKeeper: {}, parsed from ZooKeeper: {}, local: {}",
                        from_zk.sorting_key, parsed_zk_sorting_key, sorting_key);
    }

    auto parsed_primary_key = KeyDescription::parse(primary_key, columns, context);
    String parsed_zk_ttl_table = formattedAST(TTLTableDescription::parse(from_zk.ttl_table, columns, context, parsed_primary_key).definition_ast);
    if (ttl_table != parsed_zk_ttl_table)
    {
        throw Exception(ErrorCodes::METADATA_MISMATCH, "Existing table metadata in ZooKeeper differs in TTL. "
            "Stored in ZooKeeper: {}, parsed from ZooKeeper: {}, local: {}",
            from_zk.ttl_table, parsed_zk_ttl_table, ttl_table);
    }

    String parsed_zk_skip_indices = IndicesDescription::parse(from_zk.skip_indices, columns, context).toString();
    if (skip_indices != parsed_zk_skip_indices)
    {
        throw Exception(ErrorCodes::METADATA_MISMATCH, "Existing table metadata in ZooKeeper differs in skip indexes. "
                "Stored in ZooKeeper: {}, parsed from ZooKeeper: {}, local: {}",
                from_zk.skip_indices, parsed_zk_skip_indices, skip_indices);
    }

    String parsed_zk_projections = ProjectionsDescription::parse(from_zk.projections, columns, context).toString();
    if (projections != parsed_zk_projections)
    {
        throw Exception(ErrorCodes::METADATA_MISMATCH, "Existing table metadata in ZooKeeper differs in projections. "
                "Stored in ZooKeeper: {}, parsed from ZooKeeper: {}, local: {}",
                from_zk.projections, parsed_zk_projections, projections);
    }

    String parsed_zk_constraints = ConstraintsDescription::parse(from_zk.constraints).toString();
    if (constraints != parsed_zk_constraints)
    {
        throw Exception(ErrorCodes::METADATA_MISMATCH, "Existing table metadata in ZooKeeper differs in constraints. "
                "Stored in ZooKeeper: {}, parsed from ZooKeeper: {}, local: {}",
                from_zk.constraints, parsed_zk_constraints, constraints);
    }

    if (from_zk.index_granularity_bytes_found_in_zk && index_granularity_bytes != from_zk.index_granularity_bytes)
        throw Exception(ErrorCodes::METADATA_MISMATCH,
                        "Existing table metadata in ZooKeeper differs in index granularity bytes. "
                        "Stored in ZooKeeper: {}, local: {}", from_zk.index_granularity_bytes, index_granularity_bytes);
}

ReplicatedMergeTreeTableMetadata::Diff
ReplicatedMergeTreeTableMetadata::checkAndFindDiff(const ReplicatedMergeTreeTableMetadata & from_zk, const ColumnsDescription & columns, ContextPtr context) const
{

    checkImmutableFieldsEquals(from_zk, columns, context);

    Diff diff;

    if (sorting_key != from_zk.sorting_key)
    {
        diff.sorting_key_changed = true;
        diff.new_sorting_key = from_zk.sorting_key;
    }

    if (sampling_expression != from_zk.sampling_expression)
    {
        diff.sampling_expression_changed = true;
        diff.new_sampling_expression = from_zk.sampling_expression;
    }

    if (ttl_table != from_zk.ttl_table)
    {
        diff.ttl_table_changed = true;
        diff.new_ttl_table = from_zk.ttl_table;
    }

    if (skip_indices != from_zk.skip_indices)
    {
        diff.skip_indices_changed = true;
        diff.new_skip_indices = from_zk.skip_indices;
    }

    if (projections != from_zk.projections)
    {
        diff.projections_changed = true;
        diff.new_projections = from_zk.projections;
    }

    if (constraints != from_zk.constraints)
    {
        diff.constraints_changed = true;
        diff.new_constraints = from_zk.constraints;
    }

    return diff;
}

StorageInMemoryMetadata ReplicatedMergeTreeTableMetadata::Diff::getNewMetadata(const ColumnsDescription & new_columns, ContextPtr context, const StorageInMemoryMetadata & old_metadata) const
{
    StorageInMemoryMetadata new_metadata = old_metadata;
    new_metadata.columns = new_columns;

    if (!empty())
    {
        auto parse_key_expr = [] (const String & key_expr)
        {
            ParserNotEmptyExpressionList parser(false);
            auto new_sorting_key_expr_list = parseQuery(parser, key_expr, 0, DBMS_DEFAULT_MAX_PARSER_DEPTH);

            ASTPtr order_by_ast;
            if (new_sorting_key_expr_list->children.size() == 1)
                order_by_ast = new_sorting_key_expr_list->children[0];
            else
            {
                auto tuple = makeASTFunction("tuple");
                tuple->arguments->children = new_sorting_key_expr_list->children;
                order_by_ast = tuple;
            }
            return order_by_ast;
        };

        if (sorting_key_changed)
        {
            auto order_by_ast = parse_key_expr(new_sorting_key);

            new_metadata.sorting_key.recalculateWithNewAST(order_by_ast, new_metadata.columns, context);

            if (new_metadata.primary_key.definition_ast == nullptr)
            {
                /// Primary and sorting key become independent after this ALTER so we have to
                /// save the old ORDER BY expression as the new primary key.
                auto old_sorting_key_ast = old_metadata.getSortingKey().definition_ast;
                new_metadata.primary_key = KeyDescription::getKeyFromAST(
                    old_sorting_key_ast, new_metadata.columns, context);
            }
        }

        if (sampling_expression_changed)
        {
            if (!new_sampling_expression.empty())
            {
                auto sample_by_ast = parse_key_expr(new_sampling_expression);
                new_metadata.sampling_key.recalculateWithNewAST(sample_by_ast, new_metadata.columns, context);
            }
            else /// SAMPLE BY was removed
            {
                new_metadata.sampling_key = {};
            }
        }

        if (skip_indices_changed)
            new_metadata.secondary_indices = IndicesDescription::parse(new_skip_indices, new_columns, context);

        if (constraints_changed)
            new_metadata.constraints = ConstraintsDescription::parse(new_constraints);

        if (projections_changed)
            new_metadata.projections = ProjectionsDescription::parse(new_projections, new_columns, context);

        if (ttl_table_changed)
        {
            if (!new_ttl_table.empty())
            {
                ParserTTLExpressionList parser;
                auto ttl_for_table_ast = parseQuery(parser, new_ttl_table, 0, DBMS_DEFAULT_MAX_PARSER_DEPTH);
                new_metadata.table_ttl = TTLTableDescription::getTTLForTableFromAST(
                    ttl_for_table_ast, new_metadata.columns, context, new_metadata.primary_key);
            }
            else /// TTL was removed
            {
                new_metadata.table_ttl = TTLTableDescription{};
            }
        }
    }

    /// Changes in columns may affect following metadata fields
    new_metadata.column_ttls_by_name.clear();
    for (const auto & [name, ast] : new_metadata.columns.getColumnTTLs())
    {
        auto new_ttl_entry = TTLDescription::getTTLFromAST(ast, new_metadata.columns, context, new_metadata.primary_key);
        new_metadata.column_ttls_by_name[name] = new_ttl_entry;
    }

    if (new_metadata.partition_key.definition_ast != nullptr)
        new_metadata.partition_key.recalculateWithNewColumns(new_metadata.columns, context);

    if (!sorting_key_changed) /// otherwise already updated
        new_metadata.sorting_key.recalculateWithNewColumns(new_metadata.columns, context);

    /// Primary key is special, it exists even if not defined
    if (new_metadata.primary_key.definition_ast != nullptr)
    {
        new_metadata.primary_key.recalculateWithNewColumns(new_metadata.columns, context);
    }
    else
    {
        new_metadata.primary_key = KeyDescription::getKeyFromAST(new_metadata.sorting_key.definition_ast, new_metadata.columns, context);
        new_metadata.primary_key.definition_ast = nullptr;
    }

    if (!sampling_expression_changed && new_metadata.sampling_key.definition_ast != nullptr)
        new_metadata.sampling_key.recalculateWithNewColumns(new_metadata.columns, context);

    if (!skip_indices_changed) /// otherwise already updated
    {
        for (auto & index : new_metadata.secondary_indices)
            index.recalculateWithNewColumns(new_metadata.columns, context);
    }

    if (!ttl_table_changed && new_metadata.table_ttl.definition_ast != nullptr)
        new_metadata.table_ttl = TTLTableDescription::getTTLForTableFromAST(
            new_metadata.table_ttl.definition_ast, new_metadata.columns, context, new_metadata.primary_key);

    if (!projections_changed)
    {
        ProjectionsDescription recalculated_projections;
        for (const auto & projection : new_metadata.projections)
            recalculated_projections.add(ProjectionDescription::getProjectionFromAST(projection.definition_ast, new_metadata.columns, context));
        new_metadata.projections = std::move(recalculated_projections);
    }

    return new_metadata;
}

}