#include "StorageMySQL.h"

#if USE_MYSQL

#include <Storages/StorageFactory.h>
#include <Storages/transformQueryForExternalDatabase.h>
#include <Storages/MySQL/MySQLHelpers.h>
#include <Storages/checkAndGetLiteralArgument.h>
#include <Processors/Sources/MySQLSource.h>
#include <Interpreters/evaluateConstantExpression.h>
#include <DataTypes/DataTypeString.h>
#include <Formats/FormatFactory.h>
#include <Processors/Formats/IOutputFormat.h>
#include <IO/Operators.h>
#include <IO/WriteHelpers.h>
#include <Parsers/ASTLiteral.h>
#include <Parsers/ASTCreateQuery.h>
#include <mysqlxx/Transaction.h>
#include <Processors/Sinks/SinkToStorage.h>
#include <QueryPipeline/Pipe.h>
#include <Common/parseRemoteDescription.h>
#include <Common/logger_useful.h>


namespace DB
{

namespace ErrorCodes
{
    extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
    extern const int BAD_ARGUMENTS;
}

static String backQuoteMySQL(const String & x)
{
    String res(x.size(), '\0');
    {
        WriteBufferFromString wb(res);
        writeBackQuotedStringMySQL(x, wb);
    }
    return res;
}

StorageMySQL::StorageMySQL(
    const StorageID & table_id_,
    mysqlxx::PoolWithFailover && pool_,
    const std::string & remote_database_name_,
    const std::string & remote_table_name_,
    const bool replace_query_,
    const std::string & on_duplicate_clause_,
    const ColumnsDescription & columns_,
    const ConstraintsDescription & constraints_,
    const String & comment,
    ContextPtr context_,
    const MySQLSettings & mysql_settings_)
    : IStorage(table_id_)
    , WithContext(context_->getGlobalContext())
    , remote_database_name(remote_database_name_)
    , remote_table_name(remote_table_name_)
    , replace_query{replace_query_}
    , on_duplicate_clause{on_duplicate_clause_}
    , mysql_settings(mysql_settings_)
    , pool(std::make_shared<mysqlxx::PoolWithFailover>(pool_))
    , log(&Poco::Logger::get("StorageMySQL (" + table_id_.table_name + ")"))
{
    StorageInMemoryMetadata storage_metadata;
    storage_metadata.setColumns(columns_);
    storage_metadata.setConstraints(constraints_);
    storage_metadata.setComment(comment);
    setInMemoryMetadata(storage_metadata);
}


Pipe StorageMySQL::read(
    const Names & column_names_,
    const StorageSnapshotPtr & storage_snapshot,
    SelectQueryInfo & query_info_,
    ContextPtr context_,
    QueryProcessingStage::Enum /*processed_stage*/,
    size_t /*max_block_size*/,
    unsigned)
{
    storage_snapshot->check(column_names_);
    String query = transformQueryForExternalDatabase(
        query_info_,
        storage_snapshot->metadata->getColumns().getOrdinary(),
        IdentifierQuotingStyle::BackticksMySQL,
        remote_database_name,
        remote_table_name,
        context_);
    LOG_TRACE(log, "Query: {}", query);

    Block sample_block;
    for (const String & column_name : column_names_)
    {
        auto column_data = storage_snapshot->metadata->getColumns().getPhysical(column_name);

        WhichDataType which(column_data.type);
        /// Convert enum to string.
        if (which.isEnum())
            column_data.type = std::make_shared<DataTypeString>();
        sample_block.insert({ column_data.type, column_data.name });
    }


    StreamSettings mysql_input_stream_settings(context_->getSettingsRef(),
        mysql_settings.connection_auto_close);
    return Pipe(std::make_shared<MySQLWithFailoverSource>(pool, query, sample_block, mysql_input_stream_settings));
}


class StorageMySQLSink : public SinkToStorage
{
public:
    explicit StorageMySQLSink(
        const StorageMySQL & storage_,
        const StorageMetadataPtr & metadata_snapshot_,
        const std::string & remote_database_name_,
        const std::string & remote_table_name_,
        const mysqlxx::PoolWithFailover::Entry & entry_,
        const size_t & mysql_max_rows_to_insert)
        : SinkToStorage(metadata_snapshot_->getSampleBlock())
        , storage{storage_}
        , metadata_snapshot{metadata_snapshot_}
        , remote_database_name{remote_database_name_}
        , remote_table_name{remote_table_name_}
        , entry{entry_}
        , max_batch_rows{mysql_max_rows_to_insert}
    {
    }

    String getName() const override { return "StorageMySQLSink"; }

    void consume(Chunk chunk) override
    {
        auto block = getHeader().cloneWithColumns(chunk.detachColumns());
        auto blocks = splitBlocks(block, max_batch_rows);
        mysqlxx::Transaction trans(entry);
        try
        {
            for (const Block & batch_data : blocks)
            {
                writeBlockData(batch_data);
            }
            trans.commit();
        }
        catch (...)
        {
            trans.rollback();
            throw;
        }
    }

    void writeBlockData(const Block & block)
    {
        WriteBufferFromOwnString sqlbuf;
        sqlbuf << (storage.replace_query ? "REPLACE" : "INSERT") << " INTO ";
        if (!remote_database_name.empty())
            sqlbuf << backQuoteMySQL(remote_database_name) << ".";
        sqlbuf << backQuoteMySQL(remote_table_name);
        sqlbuf << " (" << dumpNamesWithBackQuote(block) << ") VALUES ";

        auto writer = FormatFactory::instance().getOutputFormat("Values", sqlbuf, metadata_snapshot->getSampleBlock(), storage.getContext());
        writer->write(block);

        if (!storage.on_duplicate_clause.empty())
            sqlbuf << " ON DUPLICATE KEY " << storage.on_duplicate_clause;

        sqlbuf << ";";

        auto query = this->entry->query(sqlbuf.str());
        query.execute();
    }

    Blocks splitBlocks(const Block & block, const size_t & max_rows) const
    {
        /// Avoid Excessive copy when block is small enough
        if (block.rows() <= max_rows)
            return {block};

        const size_t split_block_size = ceil(block.rows() * 1.0 / max_rows);
        Blocks split_blocks(split_block_size);

        for (size_t idx = 0; idx < split_block_size; ++idx)
            split_blocks[idx] = block.cloneEmpty();

        const size_t columns = block.columns();
        const size_t rows = block.rows();
        size_t offsets = 0;
        UInt64 limits = max_batch_rows;
        for (size_t idx = 0; idx < split_block_size; ++idx)
        {
            /// For last batch, limits should be the remain size
            if (idx == split_block_size - 1) limits = rows - offsets;
            for (size_t col_idx = 0; col_idx < columns; ++col_idx)
            {
                split_blocks[idx].getByPosition(col_idx).column = block.getByPosition(col_idx).column->cut(offsets, limits);
            }
            offsets += max_batch_rows;
        }

        return split_blocks;
    }

    static std::string dumpNamesWithBackQuote(const Block & block)
    {
        WriteBufferFromOwnString out;
        for (auto it = block.begin(); it != block.end(); ++it)
        {
            if (it != block.begin())
                out << ", ";
            out << backQuoteMySQL(it->name);
        }
        return out.str();
    }

private:
    const StorageMySQL & storage;
    StorageMetadataPtr metadata_snapshot;
    std::string remote_database_name;
    std::string remote_table_name;
    mysqlxx::PoolWithFailover::Entry entry;
    size_t max_batch_rows;
};


SinkToStoragePtr StorageMySQL::write(const ASTPtr & /*query*/, const StorageMetadataPtr & metadata_snapshot, ContextPtr local_context)
{
    return std::make_shared<StorageMySQLSink>(
        *this,
        metadata_snapshot,
        remote_database_name,
        remote_table_name,
        pool->get(),
        local_context->getSettingsRef().mysql_max_rows_to_insert);
}


StorageMySQLConfiguration StorageMySQL::getConfiguration(ASTs engine_args, ContextPtr context_, MySQLBaseSettings & storage_settings)
{
    StorageMySQLConfiguration configuration;

    if (auto named_collection = getExternalDataSourceConfiguration(
            engine_args, context_, /* is_database_engine */false, /* throw_on_no_collection */true, storage_settings))
    {
        auto [common_configuration, storage_specific_args, settings_changes] = named_collection.value();
        configuration.set(common_configuration);
        configuration.addresses = {std::make_pair(configuration.host, configuration.port)};
        storage_settings.applyChanges(settings_changes);

        for (const auto & [arg_name, arg_value] : storage_specific_args)
        {
            if (arg_name == "replace_query")
                configuration.replace_query = checkAndGetLiteralArgument<bool>(arg_value, "replace_query");
            else if (arg_name == "on_duplicate_clause")
                configuration.on_duplicate_clause = checkAndGetLiteralArgument<String>(arg_value, "on_duplicate_clause");
            else
                throw Exception(ErrorCodes::BAD_ARGUMENTS,
                        "Unexpected key-value argument."
                        "Got: {}, but expected one of:"
                        "host, port, username, password, database, table, replace_query, on_duplicate_clause.", arg_name);
        }
    }
    else
    {
        if (engine_args.size() < 5 || engine_args.size() > 7)
            throw Exception(
                "Storage MySQL requires 5-7 parameters: MySQL('host:port' (or 'addresses_pattern'), database, table, 'user', 'password'[, replace_query, 'on_duplicate_clause']).",
                ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);

        for (auto & engine_arg : engine_args)
            engine_arg = evaluateConstantExpressionOrIdentifierAsLiteral(engine_arg, context_);

        const auto & host_port = checkAndGetLiteralArgument<String>(engine_args[0], "host:port");
        size_t max_addresses = context_->getSettingsRef().glob_expansion_max_elements;

        configuration.addresses = parseRemoteDescriptionForExternalDatabase(host_port, max_addresses, 3306);
        configuration.database = checkAndGetLiteralArgument<String>(engine_args[1], "database");
        configuration.table = checkAndGetLiteralArgument<String>(engine_args[2], "table");
        configuration.username = checkAndGetLiteralArgument<String>(engine_args[3], "username");
        configuration.password = checkAndGetLiteralArgument<String>(engine_args[4], "password");
        if (engine_args.size() >= 6)
            configuration.replace_query = checkAndGetLiteralArgument<UInt64>(engine_args[5], "replace_query");
        if (engine_args.size() == 7)
            configuration.on_duplicate_clause = checkAndGetLiteralArgument<String>(engine_args[6], "on_duplicate_clause");
    }
    for (const auto & address : configuration.addresses)
        context_->getRemoteHostFilter().checkHostAndPort(address.first, toString(address.second));
    if (configuration.replace_query && !configuration.on_duplicate_clause.empty())
        throw Exception(ErrorCodes::BAD_ARGUMENTS,
                        "Only one of 'replace_query' and 'on_duplicate_clause' can be specified, or none of them");

    return configuration;
}


void registerStorageMySQL(StorageFactory & factory)
{
    factory.registerStorage("MySQL", [](const StorageFactory::Arguments & args)
    {
        MySQLSettings mysql_settings; /// TODO: move some arguments from the arguments to the SETTINGS.
        auto configuration = StorageMySQL::getConfiguration(args.engine_args, args.getLocalContext(), mysql_settings);

        if (args.storage_def->settings)
            mysql_settings.loadFromQuery(*args.storage_def);

        if (!mysql_settings.connection_pool_size)
            throw Exception("connection_pool_size cannot be zero.", ErrorCodes::BAD_ARGUMENTS);

        mysqlxx::PoolWithFailover pool = createMySQLPoolWithFailover(configuration, mysql_settings);

        return std::make_shared<StorageMySQL>(
            args.table_id,
            std::move(pool),
            configuration.database,
            configuration.table,
            configuration.replace_query,
            configuration.on_duplicate_clause,
            args.columns,
            args.constraints,
            args.comment,
            args.getContext(),
            mysql_settings);
    },
    {
        .supports_settings = true,
        .source_access_type = AccessType::MYSQL,
    });
}

}

#endif