/*
 * Copyright (C) 2019-present ScyllaDB
 */

/*
 * SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.0
 */

#include "test/lib/scylla_tests_cmdline_options.hh"
#include "test/lib/test_services.hh"
#include "test/lib/sstable_test_env.hh"
#include "test/lib/cql_test_env.hh"
#include "test/lib/test_utils.hh"
#include "init.hh"
#include "db/config.hh"
#include "db/object_storage_endpoint_param.hh"
#include "db/large_data_handler.hh"
#include "db/corrupt_data_handler.hh"
#include "dht/i_partitioner.hh"
#include "gms/feature_service.hh"
#include "repair/row_level.hh"
#include "replica/compaction_group.hh"
#include "utils/assert.hh"
#include "utils/overloaded_functor.hh"
#include <boost/program_options.hpp>
#include <iostream>
#include <fmt/ranges.h>
#include <seastar/util/defer.hh>
#include "sstables/generation_type.hh"

static const sstring some_keyspace("ks");
static const sstring some_column_family("cf");

class table_for_tests::compaction_group_view : public compaction::compaction_group_view {
    table_for_tests::data& _data;
    sstables::sstables_manager& _sstables_manager;
    std::vector<sstables::shared_sstable> _compacted_undeleted;
    tombstone_gc_state _tombstone_gc_state;
    mutable compaction::compaction_backlog_tracker _backlog_tracker;
    compaction::compaction_strategy_state _compaction_strategy_state;
    std::string _group_id;
    seastar::condition_variable _staging_condition;
private:
    replica::table& table() const noexcept {
        return *_data.cf;
    }
public:
    explicit compaction_group_view(table_for_tests::data& data, sstables::sstables_manager& sstables_manager)
            : _data(data)
            , _sstables_manager(sstables_manager)
            , _tombstone_gc_state(nullptr)
            , _backlog_tracker(get_compaction_strategy().make_backlog_tracker())
            , _compaction_strategy_state(compaction::compaction_strategy_state::make(get_compaction_strategy()))
            , _group_id("table_for_tests::compaction_group_view")
    {
    }
    dht::token_range token_range() const noexcept override { return dht::token_range::make(dht::first_token(), dht::last_token()); }
    const schema_ptr& schema() const noexcept override {
        return table().schema();
    }
    unsigned min_compaction_threshold() const noexcept override {
        return schema()->min_compaction_threshold();
    }
    bool compaction_enforce_min_threshold() const noexcept override {
        return true;
    }
    future<lw_shared_ptr<const sstables::sstable_set>> main_sstable_set() const override {
        co_return co_await table().try_get_compaction_group_view_with_static_sharding().main_sstable_set();
    }
    future<lw_shared_ptr<const sstables::sstable_set>> maintenance_sstable_set() const override {
        co_return co_await table().try_get_compaction_group_view_with_static_sharding().maintenance_sstable_set();
    }
    lw_shared_ptr<const sstables::sstable_set> sstable_set_for_tombstone_gc() const override {
        return table().try_get_compaction_group_with_static_sharding()->main_sstables();
    }
    std::unordered_set<sstables::shared_sstable> fully_expired_sstables(const std::vector<sstables::shared_sstable>& sstables, gc_clock::time_point query_time) const override {
        return compaction::get_fully_expired_sstables(*this, sstables, query_time);
    }
    const std::vector<sstables::shared_sstable>& compacted_undeleted_sstables() const noexcept override {
        return _compacted_undeleted;
    }
    compaction::compaction_strategy& get_compaction_strategy() const noexcept override {
        return table().get_compaction_strategy();
    }
    compaction::compaction_strategy_state& get_compaction_strategy_state() noexcept override {
        return _compaction_strategy_state;
    }
    reader_permit make_compaction_reader_permit() const override {
        return table().compaction_concurrency_semaphore().make_tracking_only_permit(schema(), "table_for_tests::compaction_group_view", db::no_timeout, {});
    }
    sstables::sstables_manager& get_sstables_manager() noexcept override {
        return _sstables_manager;
    }
    sstables::shared_sstable make_sstable() const override {
        return table().make_sstable();
    }
    sstables::sstable_writer_config configure_writer(sstring origin) const override {
        return _sstables_manager.configure_writer(std::move(origin));
    }

    api::timestamp_type min_memtable_timestamp() const override {
        return table().min_memtable_timestamp();
    }
    api::timestamp_type min_memtable_live_timestamp() const override {
        return table().min_memtable_live_timestamp();
    }
    api::timestamp_type min_memtable_live_row_marker_timestamp() const override {
        return table().min_memtable_live_row_marker_timestamp();
    }
    bool memtable_has_key(const dht::decorated_key& key) const override { return false; }
    future<> on_compaction_completion(compaction::compaction_completion_desc desc, sstables::offstrategy offstrategy) override {
        return table().try_get_compaction_group_view_with_static_sharding().on_compaction_completion(std::move(desc), offstrategy);
    }
    bool is_auto_compaction_disabled_by_user() const noexcept override {
        return table().is_auto_compaction_disabled_by_user();
    }
    bool tombstone_gc_enabled() const noexcept override {
        return table().tombstone_gc_enabled();
    }
    const tombstone_gc_state& get_tombstone_gc_state() const noexcept override {
        return _tombstone_gc_state;
    }
    compaction::compaction_backlog_tracker& get_backlog_tracker() override {
        return _backlog_tracker;
    }
    const std::string get_group_id() const noexcept override {
        return _group_id;
    }
    seastar::condition_variable& get_staging_done_condition() noexcept override {
        return _staging_condition;
    }
    dht::token_range get_token_range_after_split(const dht::token& t) const noexcept override {
        return table().get_token_range_after_split(t);
    }
    int64_t get_sstables_repaired_at() const noexcept override { return 0; }
};

table_for_tests::data::data()
{ }

table_for_tests::data::~data() {}

schema_ptr table_for_tests::make_default_schema() {
    return schema_builder(some_keyspace, some_column_family)
        .with_column(utf8_type->decompose("p1"), utf8_type, column_kind::partition_key)
        .build();
}

table_for_tests::table_for_tests(sstables::sstables_manager& sstables_manager, compaction::compaction_manager& cm, schema_ptr s, replica::table::config cfg, data_dictionary::storage_options storage)
    : _data(make_lw_shared<data>())
{
    cfg.cf_stats = &_data->cf_stats;
    _data->s = s ? s : make_default_schema();
    _data->cf = make_lw_shared<replica::column_family>(_data->s, std::move(cfg), make_lw_shared<replica::storage_options>(storage), cm, sstables_manager, _data->cl_stats, sstables_manager.get_cache_tracker(), nullptr);
    _data->cf->mark_ready_for_writes(nullptr);
    _data->table_s = std::make_unique<compaction_group_view>(*_data, sstables_manager);
    cm.add(*_data->table_s);
    _data->storage = std::move(storage);
}

compaction::compaction_group_view& table_for_tests::as_compaction_group_view() noexcept {
    return *_data->table_s;
}

future<> table_for_tests::stop() {
    auto data = _data;
    co_await data->cf->get_compaction_manager().remove(*data->table_s);
    co_await data->cf->stop();
}

void table_for_tests::set_tombstone_gc_enabled(bool tombstone_gc_enabled) noexcept {
    _data->cf->set_tombstone_gc_enabled(tombstone_gc_enabled);
}

void table_for_tests::set_repair_sstable_classifier(replica::repair_classifier_func repair_sstable_classifier) {
    _data->cf->for_each_compaction_group([&] (replica::compaction_group& cg) {
        cg.set_repair_sstable_classifier(repair_sstable_classifier);
    });
}

namespace sstables {

std::vector<db::object_storage_endpoint_param> make_storage_options_config(const data_dictionary::storage_options& so) {
    std::vector<db::object_storage_endpoint_param> endpoints;
    std::visit(overloaded_functor {
        [] (const data_dictionary::storage_options::local& loc) mutable -> void {
        },
        [&endpoints] (const data_dictionary::storage_options::object_storage& os) mutable -> void {
            if (os.type == data_dictionary::storage_options::S3_NAME) {
                endpoints.emplace_back(os.endpoint, 
                    s3::endpoint_config {
                    .port = std::stoul(tests::getenv_safe("S3_SERVER_PORT_FOR_TEST")),
                    .use_https = ::getenv("AWS_DEFAULT_REGION") != nullptr,
                    .region = tests::getenv_or_default("AWS_DEFAULT_REGION", "local"),
                });
            }
            if (os.type == data_dictionary::storage_options::GS_NAME) {
                endpoints.emplace_back(db::object_storage_endpoint_param::gs_storage{
                    .endpoint = os.endpoint, 
                    .credentials_file = tests::getenv_or_default("GS_CREDENTIALS_FILE", "none")
                });
            }
        }
    }, so.value);
    return endpoints;
}

std::unique_ptr<db::config> make_db_config(sstring temp_dir, const data_dictionary::storage_options so) {
    auto cfg = std::make_unique<db::config>();
    cfg->data_file_directories.set({ temp_dir });
    cfg->object_storage_endpoints(make_storage_options_config(so));
    return cfg;
}

struct test_env::impl {
    std::optional<tmpdir> local_dir;
    tmpdir& dir;
    std::unique_ptr<db::config> db_config;
    directory_semaphore dir_sem;
    ::cache_tracker cache_tracker;
    gms::feature_service feature_service;
    db::nop_large_data_handler nop_ld_handler;
    db::nop_corrupt_data_handler nop_cd_handler;
    sstable_compressor_factory& scf;
    test_env_sstables_manager mgr;
    std::unique_ptr<test_env_compaction_manager> cmgr;
    reader_concurrency_semaphore semaphore;
    sstables::sstable_generation_generator gen;
    data_dictionary::storage_options storage;
    abort_source abort;

    impl(test_env_config cfg, sstable_compressor_factory&, sstables::storage_manager* sstm, tmpdir* tdir);
    impl(impl&&) = delete;
    impl(const impl&) = delete;

    sstables::generation_type new_generation() noexcept {
        return gen();
    }
};

test_env::impl::impl(test_env_config cfg, sstable_compressor_factory& scfarg, sstables::storage_manager* sstm, tmpdir* tdir)
    : local_dir(tdir == nullptr ? std::optional<tmpdir>(std::in_place) : std::optional<tmpdir>(std::nullopt))
    , dir(tdir == nullptr ? local_dir.value() : *tdir)
    , db_config(make_db_config(dir.path().native(), cfg.storage))
    , dir_sem(1)
    , feature_service({get_disabled_features_from_db_config(*db_config)})
    , nop_cd_handler(db::corrupt_data_handler::register_metrics::no)
    , scf(scfarg)
    , mgr(
            "test_env",
            cfg.large_data_handler == nullptr ? nop_ld_handler : *cfg.large_data_handler,
            cfg.corrupt_data_handler == nullptr ? nop_cd_handler : *cfg.corrupt_data_handler,
            sstables::sstables_manager::config{
                .available_memory = cfg.available_memory,
                .enable_sstable_key_validation = db_config->enable_sstable_key_validation(),
                .memory_reclaim_threshold = db_config->components_memory_reclaim_threshold,
                .data_file_directories = db_config->data_file_directories(),
                .format = db_config->sstable_format,
            },
            feature_service,
            cache_tracker,
            dir_sem,
            [host_id = locator::host_id::create_random_id()]{ return host_id; },
            scf,
            abort,
            {}, // extensions
            current_scheduling_group(),
            sstm)
    , semaphore(reader_concurrency_semaphore::no_limits{}, "sstables::test_env", reader_concurrency_semaphore::register_metrics::no)
    , storage(std::move(cfg.storage))
{
}

test_env::test_env(test_env_config cfg, sstable_compressor_factory& scf, sstables::storage_manager* sstm, tmpdir* tmp)
        : _impl(std::make_unique<impl>(std::move(cfg), scf, sstm, tmp))
{
}

test_env::test_env(test_env&&) noexcept = default;

test_env::~test_env() = default;

void test_env::maybe_start_compaction_manager(bool enable) {
    if (!_impl->cmgr) {
        _impl->cmgr = std::make_unique<test_env_compaction_manager>();
        if (enable) {
            _impl->cmgr->get_compaction_manager().enable();
        }
    }
}

future<> test_env::stop() {
    if (_impl->cmgr) {
        if (_impl->cmgr->get_compaction_manager().is_running()) {
            co_await _impl->cmgr->get_compaction_manager().stop();
        } else {
            co_await _impl->cmgr->get_compaction_manager().get_task_manager_module().stop();
        }
    }
    co_await _impl->mgr.close();
    co_await _impl->semaphore.stop();
}

class mock_sstables_registry : public sstables::sstables_registry {
    struct entry {
        sstring status;
        sstables::sstable_state state;
        sstables::entry_descriptor desc;
    };
    std::map<std::pair<table_id, generation_type>, entry> _entries;
public:
    virtual future<> create_entry(table_id owner, sstring status, sstable_state state, sstables::entry_descriptor desc) override {
        _entries.emplace(std::make_pair(owner, desc.generation), entry { status, state, desc });
        co_return;
    };
    virtual future<> update_entry_status(table_id owner, sstables::generation_type gen, sstring status) override {
        auto it = _entries.find(std::make_pair(owner, gen));
        if (it != _entries.end()) {
            it->second.status = status;
        } else {
            throw std::runtime_error("update_entry_status: not found");
        }
        co_return;
    }
    virtual future<> update_entry_state(table_id owner, sstables::generation_type gen, sstables::sstable_state state) override {
        auto it = _entries.find(std::make_pair(owner, gen));
        if (it != _entries.end()) {
            it->second.state = state;
        } else {
            throw std::runtime_error("update_entry_state: not found");
        }
        co_return;
    }
    virtual future<> delete_entry(table_id owner, sstables::generation_type gen) override {
        auto it = _entries.find(std::make_pair(owner, gen));
        if (it != _entries.end()) {
            _entries.erase(it);
        } else {
            throw std::runtime_error("delete_entry: not found");
        }
        co_return;
    }
    virtual future<> sstables_registry_list(table_id owner, entry_consumer consumer) override {
        for (auto& [loc_and_gen, e] : _entries) {
            if (loc_and_gen.first == owner) {
                co_await consumer(e.status, e.state, e.desc);
            }
        }
    }
};

future<> test_env::do_with_async(noncopyable_function<void (test_env&)> func, test_env_config cfg) {
    if (!cfg.storage.is_local_type()) {
        auto db_cfg = make_shared<db::config>();
        db_cfg->experimental_features({db::experimental_features_t::feature::KEYSPACE_STORAGE_OPTIONS});
        db_cfg->object_storage_endpoints(make_storage_options_config(cfg.storage));
        return seastar::async([func = std::move(func), cfg = std::move(cfg), db_cfg = std::move(db_cfg)] () mutable {
            sharded<sstables::storage_manager> sstm;
            sstm.start(std::ref(*db_cfg), sstables::storage_manager::config{}).get();
            auto stop_sstm = defer([&] { sstm.stop().get(); });
            auto scf = make_sstable_compressor_factory_for_tests_in_thread();
            test_env env(std::move(cfg), *scf, &sstm.local());
            auto close_env = defer([&] { env.stop().get(); });
            env.manager().plug_sstables_registry(std::make_unique<mock_sstables_registry>());
            auto unplu = defer([&env] { env.manager().unplug_sstables_registry(); });
            func(env);
        });
    }

    return seastar::async([func = std::move(func), cfg = std::move(cfg)] () mutable {
        auto scf = make_sstable_compressor_factory_for_tests_in_thread();
        test_env env(std::move(cfg), *scf);
        auto close_env = defer([&] { env.stop().get(); });
        func(env);
    });
}

sstables::generation_type
test_env::new_generation() noexcept {
    return _impl->new_generation();
}

shared_sstable
test_env::make_sstable(schema_ptr schema, sstring dir, sstables::generation_type generation,
        sstable::version_types v, sstable::format_types f,
        size_t buffer_size, db_clock::time_point now) {
    // FIXME -- most of the callers work with _impl->dir's path, so
    // test_env can initialize the .dir/.prefix only once, when constructed
    auto storage = _impl->storage;
    std::visit(overloaded_functor {
        [&dir] (data_dictionary::storage_options::local& o) { o.dir = dir; },
        [&schema] (data_dictionary::storage_options::object_storage& o) { o.location = schema->id(); },
    }, storage.value);
    return _impl->mgr.make_sstable(std::move(schema), storage, generation, sstables::sstable_state::normal, v, f, now, default_io_error_handler_gen(), buffer_size);
}

shared_sstable
test_env::make_sstable(schema_ptr schema, sstring dir, sstable::version_types v) {
    return make_sstable(std::move(schema), std::move(dir), new_generation(), std::move(v));
}

shared_sstable
test_env::make_sstable(schema_ptr schema, sstables::generation_type generation,
        sstable::version_types v, sstable::format_types f,
        size_t buffer_size, db_clock::time_point now) {
    return make_sstable(std::move(schema), _impl->dir.path().native(), generation, std::move(v), std::move(f), buffer_size, now);
}

shared_sstable
test_env::make_sstable(schema_ptr schema, sstable::version_types v) {
    return make_sstable(std::move(schema), _impl->dir.path().native(), std::move(v));
}

std::function<shared_sstable()>
test_env::make_sst_factory(schema_ptr s) {
    return [this, s = std::move(s)] {
        return make_sstable(s, new_generation());
    };
}

std::function<shared_sstable()>
test_env::make_sst_factory(schema_ptr s, sstable::version_types version) {
    return [this, s = std::move(s), version] {
        return make_sstable(s, new_generation(), version);
    };
}

future<shared_sstable>
test_env::reusable_sst(schema_ptr schema, sstring dir, sstables::generation_type generation,
        sstable::version_types version, sstable::format_types f, sstable_open_config cfg) {
    auto sst = make_sstable(std::move(schema), dir, generation, version, f);
    return sst->load(sst->get_schema()->get_sharder(), cfg).then([sst = std::move(sst)] {
        return make_ready_future<shared_sstable>(std::move(sst));
    });
}

future<shared_sstable>
test_env::reusable_sst(schema_ptr schema, sstring dir, sstables::generation_type::int_t gen_value,
        sstable::version_types version, sstable::format_types f) {
    return reusable_sst(std::move(schema), std::move(dir), sstables::generation_type(gen_value), version, f);
}

future<shared_sstable>
test_env::reusable_sst(schema_ptr schema, sstables::generation_type generation,
        sstable::version_types version, sstable::format_types f) {
    return reusable_sst(std::move(schema), _impl->dir.path().native(), std::move(generation), std::move(version), std::move(f));
}

future<shared_sstable>
test_env::reusable_sst(schema_ptr schema, shared_sstable sst) {
    return reusable_sst(std::move(schema), sst->get_storage().prefix(), sst->generation(), sst->get_version());
}

future<shared_sstable>
test_env::reusable_sst(shared_sstable sst) {
    return reusable_sst(sst->get_schema(), sst);
}

future<shared_sstable>
test_env::reusable_sst(schema_ptr schema, sstables::generation_type generation) {
    return reusable_sst(std::move(schema), _impl->dir.path().native(), generation);
}

test_env_sstables_manager&
test_env::manager() {
    return _impl->mgr;
}

test_env_compaction_manager&
test_env::test_compaction_manager() {
    return *_impl->cmgr;
}

reader_concurrency_semaphore&
test_env::semaphore() {
    return _impl->semaphore;
}

db::config&
test_env::db_config() {
    return *_impl->db_config;
}

tmpdir&
test_env::tempdir() noexcept {
    return _impl->dir;
}

data_dictionary::storage_options
test_env::get_storage_options() const noexcept {
    return _impl->storage;
}

reader_permit
test_env::make_reader_permit(const schema_ptr &s, const char* n, db::timeout_clock::time_point timeout) {
    return _impl->semaphore.make_tracking_only_permit(s, n, timeout, {});
}

reader_permit
test_env::make_reader_permit(db::timeout_clock::time_point timeout) {
    return _impl->semaphore.make_tracking_only_permit(nullptr, "test", timeout, {});
}

replica::table::config
test_env::make_table_config() {
    return replica::table::config{.compaction_concurrency_semaphore = &_impl->semaphore};
}

future<>
test_env::do_with_sharded_async(noncopyable_function<void (sharded<test_env>&)> func) {
    return seastar::async([func = std::move(func)] {
        tmpdir tdir;
        sharded<test_env> env;
        auto scf = make_sstable_compressor_factory_for_tests_in_thread();
        env.start(test_env_config{}, std::ref(*scf), nullptr, &tdir).get();
        auto stop = defer([&] { env.stop().get(); });
        func(env);
    });
}

table_for_tests
test_env::make_table_for_tests(schema_ptr s, sstring dir) {
    maybe_start_compaction_manager();
    auto cfg = make_table_config();
    cfg.enable_commitlog = false;
    auto storage = _impl->storage;
    std::visit(overloaded_functor {
        [&dir] (data_dictionary::storage_options::local& o) { o.dir = dir; },
        [&s] (data_dictionary::storage_options::object_storage& o) { o.location = s->id(); },
    }, storage.value);
    return table_for_tests(manager(), _impl->cmgr->get_compaction_manager(), s, std::move(cfg), std::move(storage));
}

table_for_tests
test_env::make_table_for_tests(schema_ptr s) {
    return make_table_for_tests(std::move(s), _impl->dir.path().native());
}

sstables::sstable_set test_env::make_sstable_set(compaction::compaction_strategy& cs, schema_ptr s) {
    auto t = make_table_for_tests(s);
    auto close_t = deferred_stop(t);
    return cs.make_sstable_set(t.as_compaction_group_view());
}

void test_env::request_abort() {
    _impl->abort.request_abort();
}

data_dictionary::storage_options make_test_object_storage_options(std::string_view type) {
    data_dictionary::storage_options ret;
    auto t = std::string(type);
    ret.value = data_dictionary::storage_options::object_storage {
        .bucket = tests::getenv_safe(t + "_BUCKET_FOR_TEST"),
        .endpoint = tests::getenv_safe(t + "_SERVER_ADDRESS_FOR_TEST"),
        .type = t
    };
    return ret;
}

static sstring toc_filename(const sstring& dir, schema_ptr schema, sstables::generation_type generation, sstable_version_types v) {
    return sstable::filename(dir, schema->ks_name(), schema->cf_name(), v, generation,
                             sstable_format_types::big, component_type::TOC);
}

future<shared_sstable> test_env::reusable_sst(schema_ptr schema, sstring dir, sstables::generation_type generation) {
    for (auto v : std::views::reverse(all_sstable_versions)) {
        if (co_await file_exists(toc_filename(dir, schema, generation, v))) {
            co_return co_await reusable_sst(schema, dir, generation, v);
        }
    }
    throw sst_not_found(dir, generation);
}

void test_env_compaction_manager::propagate_replacement(compaction::compaction_group_view& table_s, const std::vector<shared_sstable>& removed, const std::vector<shared_sstable>& added) {
    _cm.propagate_replacement(table_s, removed, added);
}

// Test version of compaction_manager::perform_compaction<>()
future<> test_env_compaction_manager::perform_compaction(shared_ptr<compaction::compaction_task_executor> task) {
    _cm._tasks.push_back(*task);
    auto unregister_task = defer([task] {
        if (!task->is_linked()) {
            testlog.error("compaction_manager_test: deregister_compaction uuid={}: task not found", task->compaction_data().compaction_uuid);
        }
        task->unlink();
        task->switch_state(compaction::compaction_task_executor::state::none);
    });
    co_await task->run_compaction();
}

}

static std::pair<int, char**> rebuild_arg_list_without(int argc, char** argv, const char* filter_out, bool exclude_positional_arg = false) {
    int new_argc = 0;
    char** new_argv = (char**) malloc(argc * sizeof(char*));
    std::memset(new_argv, 0, argc * sizeof(char*));
    bool exclude_next_arg = false;
    for (auto i = 0; i < argc; i++) {
        if (std::exchange(exclude_next_arg, false)) {
            continue;
        }
        if (strcmp(argv[i], filter_out) == 0) {
            // if arg filtered out has positional arg, that has to be excluded too.
            exclude_next_arg = exclude_positional_arg;
            continue;
        }
        new_argv[new_argc] = (char*) malloc(strlen(argv[i]) + 1);
        std::strcpy(new_argv[new_argc], argv[i]);
        new_argc++;
    }
    return std::make_pair(new_argc, new_argv);
}

static void free_arg_list(int argc, char** argv) {
    for (auto i = 0; i < argc; i++) {
        if (argv[i]) {
            free(argv[i]);
        }
    }
    free(argv);
}

scylla_tests_cmdline_options_processor::~scylla_tests_cmdline_options_processor() {
    if (_new_argv) {
        free_arg_list(_new_argc, _new_argv);
    }
}

std::pair<int, char**> scylla_tests_cmdline_options_processor::process_cmdline_options(int argc, char** argv) {
    namespace po = boost::program_options;

    // Removes -- (intended to separate boost suite args from seastar ones) which confuses boost::program_options.
    auto [new_argc, new_argv] = rebuild_arg_list_without(argc, argv, "--");
    auto _ = defer([argc = new_argc, argv = new_argv] {
        free_arg_list(argc, argv);
    });

    po::options_description desc("Scylla tests additional options");
    desc.add_options()
            ("help", "Produces help message")
            ("x-log2-compaction-groups", po::value<unsigned>()->default_value(0), "Controls static number of compaction groups per table per shard. For X groups, set the option to log (base 2) of X. Example: Value of 3 implies 8 groups.");
    po::variables_map vm;

    po::parsed_options parsed = po::command_line_parser(new_argc, new_argv).
            options(desc).
            allow_unregistered().
            run();

    po::store(parsed, vm);
    po::notify(vm);

    if (vm.count("help")) {
        std::cout << desc << std::endl;
        return std::make_pair(argc, argv);
    }

    unsigned x_log2_compaction_groups = vm["x-log2-compaction-groups"].as<unsigned>();
    if (x_log2_compaction_groups) {
        std::cout << "Setting x_log2_compaction_groups to " << x_log2_compaction_groups << std::endl;
        // TODO: perhaps we can later map it into initial_tablets.
        auto [_new_argc, _new_argv] = rebuild_arg_list_without(argc, argv, "--x-log2-compaction-groups", true);
        return std::make_pair(_new_argc, _new_argv);
    }

    return std::make_pair(argc, argv);
}