#include <Common/DNSResolver.h>
#include <DataTypes/DataTypeString.h>
#include <DataTypes/DataTypesNumber.h>
#include <Interpreters/Cluster.h>
#include <Interpreters/Context.h>
#include <Storages/System/StorageSystemClusters.h>

namespace DB
{

NamesAndTypesList StorageSystemClusters::getNamesAndTypes()
{
    return {
        {"cluster", std::make_shared<DataTypeString>()},
        {"shard_num", std::make_shared<DataTypeUInt32>()},
        {"shard_weight", std::make_shared<DataTypeUInt32>()},
        {"replica_num", std::make_shared<DataTypeUInt32>()},
        {"host_name", std::make_shared<DataTypeString>()},
        {"host_address", std::make_shared<DataTypeString>()},
        {"port", std::make_shared<DataTypeUInt16>()},
        {"is_local", std::make_shared<DataTypeUInt8>()},
        {"user", std::make_shared<DataTypeString>()},
        {"default_database", std::make_shared<DataTypeString>()},
    };
}

void StorageSystemClusters::fillData(MutableColumns & res_columns, const Context & context, const SelectQueryInfo &) const
{
    auto updateColumns = [&](const std::string & cluster_name, const Cluster::ShardInfo & shard_info, const Cluster::Address & address)
    {
        size_t i = 0;
        res_columns[i++]->insert(cluster_name);
        res_columns[i++]->insert(static_cast<UInt64>(shard_info.shard_num));
        res_columns[i++]->insert(static_cast<UInt64>(shard_info.weight));
        res_columns[i++]->insert(static_cast<UInt64>(address.replica_num));
        res_columns[i++]->insert(address.host_name);
        res_columns[i++]->insert(DNSResolver::instance().resolveHost(address.host_name).toString());
        res_columns[i++]->insert(static_cast<UInt64>(address.port));
        res_columns[i++]->insert(static_cast<UInt64>(shard_info.isLocal()));
        res_columns[i++]->insert(address.user);
        res_columns[i++]->insert(address.default_database);
    };

    auto clusters = context.getClusters().getContainer();
    for (const auto & entry : clusters)
    {
        const std::string cluster_name = entry.first;
        const ClusterPtr cluster = entry.second;
        const auto & addresses_with_failover = cluster->getShardsAddresses();
        const auto & shards_info = cluster->getShardsInfo();

        if (!addresses_with_failover.empty())
        {
            auto it1 = addresses_with_failover.cbegin();
            auto it2 = shards_info.cbegin();

            while (it1 != addresses_with_failover.cend())
            {
                const auto & addresses = *it1;
                const auto & shard_info = *it2;

                for (const auto & address : addresses)
                    updateColumns(cluster_name, shard_info, address);

                ++it1;
                ++it2;
            }
        }
    }
}
}