/*
 * Copyright (C) 2017 ScyllaDB
 */

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

#include <seastar/core/future-util.hh>
#include "audit/audit.hh"
#include "db/config.hh"
#include "cql3/cql_statement.hh"
#include "cql3/statements/batch_statement.hh"
#include "cql3/statements/modification_statement.hh"
#include "storage_helper.hh"
#include "audit_cf_storage_helper.hh"
#include "audit_syslog_storage_helper.hh"
#include "audit_composite_storage_helper.hh"
#include "audit.hh"
#include "../db/config.hh"

#include <boost/algorithm/string/split.hpp>
#include <boost/algorithm/string/trim.hpp>
#include <boost/algorithm/string/classification.hpp>


namespace audit {

logging::logger logger("audit");

static std::set<sstring> parse_audit_modes(const sstring& data) {
    std::set<sstring> result;
    if (!data.empty()) {
        std::vector<sstring> audit_modes;
        boost::split(audit_modes, data, boost::is_any_of(","));
        if (audit_modes.empty()) {
            return {};
        }
        for (sstring& audit_mode : audit_modes) {
            boost::trim(audit_mode);
            if (audit_mode == "none") {
                return {};
            }
            if (audit_mode != "table" && audit_mode != "syslog") {
                throw audit_exception(fmt::format("Bad configuration: invalid 'audit': {}", audit_mode));
            }
            result.insert(std::move(audit_mode));
        }
    }
    return result;
}

static std::unique_ptr<storage_helper> create_storage_helper(const std::set<sstring>& audit_modes, cql3::query_processor& qp, service::migration_manager& mm) {
    SCYLLA_ASSERT(!audit_modes.empty() && !audit_modes.contains("none"));

    std::vector<std::unique_ptr<storage_helper>> helpers;
    for (const sstring& audit_mode : audit_modes) {
        if (audit_mode == "table") {
            helpers.emplace_back(std::make_unique<audit_cf_storage_helper>(qp, mm));
        } else if (audit_mode == "syslog") {
            helpers.emplace_back(std::make_unique<audit_syslog_storage_helper>(qp, mm));
        }
    }

    SCYLLA_ASSERT(!helpers.empty());
    if (helpers.size() == 1) {
        return std::move(helpers.front());
    }
    return std::make_unique<audit_composite_storage_helper>(std::move(helpers));
}

static sstring category_to_string(statement_category category)
{
    switch (category) {
        case statement_category::QUERY: return "QUERY";
        case statement_category::DML: return "DML";
        case statement_category::DDL: return "DDL";
        case statement_category::DCL: return "DCL";
        case statement_category::AUTH: return "AUTH";
        case statement_category::ADMIN: return "ADMIN";
    }
    return "";
}

sstring audit_info::category_string() const {
    return category_to_string(_category);
}

static category_set parse_audit_categories(const sstring& data) {
    category_set result;
    if (!data.empty()) {
        std::vector<sstring> tokens;
        boost::split(tokens, data, boost::is_any_of(","));
        for (sstring& category : tokens) {
            boost::trim(category);
            if (category == "QUERY") {
                result.set(statement_category::QUERY);
            } else if (category == "DML") {
                result.set(statement_category::DML);
            } else if (category == "DDL") {
                result.set(statement_category::DDL);
            } else if (category == "DCL") {
                result.set(statement_category::DCL);
            } else if (category == "AUTH") {
                result.set(statement_category::AUTH);
            } else if (category == "ADMIN") {
                result.set(statement_category::ADMIN);
            } else {
                throw audit_exception(fmt::format("Bad configuration: invalid 'audit_categories': {}", data));
            }
        }
    }
    return result;
}

static std::map<sstring, std::set<sstring>> parse_audit_tables(const sstring& data) {
    std::map<sstring, std::set<sstring>> result;
    if (!data.empty()) {
        std::vector<sstring> tokens;
        boost::split(tokens, data, boost::is_any_of(","));
        for (sstring& token : tokens) {
            std::vector<sstring> parts;
            boost::split(parts, token, boost::is_any_of("."));
            if (parts.size() != 2) {
                throw audit_exception(fmt::format("Bad configuration: invalid 'audit_tables': {}", data));
            }
            boost::trim(parts[0]);
            boost::trim(parts[1]);
            result[parts[0]].insert(std::move(parts[1]));
        }
    }
    return result;
}

static std::set<sstring> parse_audit_keyspaces(const sstring& data) {
    std::set<sstring> result;
    if (!data.empty()) {
        std::vector<sstring> tokens;
        boost::split(tokens, data, boost::is_any_of(","));
        for (sstring& token : tokens) {
            boost::trim(token);
            result.insert(std::move(token));
        }
    }
    return result;
}

audit::audit(locator::shared_token_metadata& token_metadata,
             cql3::query_processor& qp,
             service::migration_manager& mm,
             std::set<sstring>&& audit_modes,
             std::set<sstring>&& audited_keyspaces,
             std::map<sstring, std::set<sstring>>&& audited_tables,
             category_set&& audited_categories,
             const db::config& cfg)
    : _token_metadata(token_metadata)
    , _audited_keyspaces(std::move(audited_keyspaces))
    , _audited_tables(std::move(audited_tables))
    , _audited_categories(std::move(audited_categories))
    , _cfg(cfg)
    , _cfg_keyspaces_observer(cfg.audit_keyspaces.observe([this] (sstring const& new_value){ update_config<std::set<sstring>>(new_value, parse_audit_keyspaces, _audited_keyspaces); }))
    , _cfg_tables_observer(cfg.audit_tables.observe([this] (sstring const& new_value){ update_config<std::map<sstring, std::set<sstring>>>(new_value, parse_audit_tables, _audited_tables); }))
    , _cfg_categories_observer(cfg.audit_categories.observe([this] (sstring const& new_value){ update_config<category_set>(new_value, parse_audit_categories, _audited_categories); }))
{
    _storage_helper_ptr = create_storage_helper(std::move(audit_modes), qp, mm);
}

audit::~audit() = default;

future<> audit::start_audit(const db::config& cfg, sharded<locator::shared_token_metadata>& stm, sharded<cql3::query_processor>& qp, sharded<service::migration_manager>& mm) {
    std::set<sstring> audit_modes = parse_audit_modes(cfg.audit());
    if (audit_modes.empty()) {
        logger.info("Audit is disabled");
        return make_ready_future<>();
    }
    category_set audited_categories = parse_audit_categories(cfg.audit_categories());
    std::map<sstring, std::set<sstring>> audited_tables = parse_audit_tables(cfg.audit_tables());
    std::set<sstring> audited_keyspaces = parse_audit_keyspaces(cfg.audit_keyspaces());

    logger.info("Audit is enabled. Auditing to: \"{}\", with the following categories: \"{}\", keyspaces: \"{}\", and tables: \"{}\"",
                cfg.audit(), cfg.audit_categories(), cfg.audit_keyspaces(), cfg.audit_tables());

    return audit_instance().start(std::ref(stm),
                                  std::ref(qp),
                                  std::ref(mm),
                                  std::move(audit_modes),
                                  std::move(audited_keyspaces),
                                  std::move(audited_tables),
                                  std::move(audited_categories),
                                  std::cref(cfg))
    .then([&cfg] {
        if (!audit_instance().local_is_initialized()) {
            return make_ready_future<>();
        }
        return audit_instance().invoke_on_all([&cfg] (audit& local_audit) {
            return local_audit.start(cfg);
        });
    });
}

future<> audit::stop_audit() {
    if (!audit_instance().local_is_initialized()) {
        return make_ready_future<>();
    }
    return audit::audit::audit_instance().invoke_on_all([] (auto& local_audit) {
        return local_audit.shutdown();
    }).then([] {
        return audit::audit::audit_instance().stop();
    });
}

audit_info_ptr audit::create_audit_info(statement_category cat, const sstring& keyspace, const sstring& table, bool batch) {
    if (!audit_instance().local_is_initialized()) {
        return nullptr;
    }
    return std::make_unique<audit_info>(cat, keyspace, table, batch);
}

future<> audit::start(const db::config& cfg) {
    return _storage_helper_ptr->start(cfg);
}

future<> audit::stop() {
    return _storage_helper_ptr->stop();
}

future<> audit::shutdown() {
    return make_ready_future<>();
}

future<> audit::log(const audit_info* audit_info, service::query_state& query_state, const cql3::query_options& options, bool error) {
    const service::client_state& client_state = query_state.get_client_state();
    socket_address node_ip = _token_metadata.get()->get_topology().my_address().addr();
    db::consistency_level cl = options.get_consistency();
    thread_local static sstring no_username("undefined");
    static const sstring anonymous_username("anonymous");
    const sstring& username = client_state.user() ? client_state.user()->name.value_or(anonymous_username) : no_username;
    socket_address client_ip = client_state.get_client_address().addr();
    if (logger.is_enabled(logging::log_level::debug)) {
        logger.debug("Log written: node_ip {} category {} cl {} error {} keyspace {} query '{}' client_ip {} table {} username {}",
            node_ip, audit_info->category_string(), cl, error, audit_info->keyspace(),
            audit_info->query(), client_ip, audit_info->table(), username);
    }
    return futurize_invoke(std::mem_fn(&storage_helper::write), _storage_helper_ptr, audit_info, node_ip, client_ip, cl, username, error)
        .handle_exception([audit_info, node_ip, client_ip, cl, username, error] (auto ep) {
            logger.error("Unexpected exception when writing log with: node_ip {} category {} cl {} error {} keyspace {} query '{}' client_ip {} table {} username {} exception {}",
                node_ip, audit_info->category_string(), cl, error, audit_info->keyspace(),
                audit_info->query(), client_ip, audit_info->table(),username, ep);
    });
}

future<> audit::log_login(const sstring& username, socket_address client_ip, bool error) noexcept {
    socket_address node_ip = _token_metadata.get()->get_topology().my_address().addr();
    if (logger.is_enabled(logging::log_level::debug)) {
        logger.debug("Login log written: node_ip {}, client_ip {}, username {}, error {}",
            node_ip, client_ip, username, error ? "true" : "false");
    }
    return futurize_invoke(std::mem_fn(&storage_helper::write_login), _storage_helper_ptr, username, node_ip, client_ip, error)
        .handle_exception([username, node_ip, client_ip, error] (auto ep) {
            logger.error("Unexpected exception when writing login log with: node_ip {} client_ip {} username {} error {} exception {}",
                node_ip, client_ip, username, error, ep);
    });
}

future<> inspect(shared_ptr<cql3::cql_statement> statement, service::query_state& query_state, const cql3::query_options& options, bool error) {
    auto audit_info = statement->get_audit_info();
    if (!audit_info) {
        return make_ready_future<>();
    }
    if (audit_info->batch()) {
        cql3::statements::batch_statement* batch = static_cast<cql3::statements::batch_statement*>(statement.get());
        return do_for_each(batch->statements().begin(), batch->statements().end(), [&query_state, &options, error] (auto&& m) {
            return inspect(m.statement, query_state, options, error);
        });
    } else {
        if (audit::local_audit_instance().should_log(audit_info)) {
            return audit::local_audit_instance().log(audit_info, query_state, options, error);
        }
        return make_ready_future<>();
    }
}

future<> inspect_login(const sstring& username, socket_address client_ip, bool error) {
    if (!audit::audit_instance().local_is_initialized() || !audit::local_audit_instance().should_log_login()) {
        return make_ready_future<>();
    }
    return audit::local_audit_instance().log_login(username, client_ip, error);
}

bool audit::should_log_table(const sstring& keyspace, const sstring& name) const {
    auto keyspace_it = _audited_tables.find(keyspace);
    return keyspace_it != _audited_tables.cend() && keyspace_it->second.find(name) != keyspace_it->second.cend();
}

bool audit::should_log(const audit_info* audit_info) const {
    return _audited_categories.contains(audit_info->category())
           && (_audited_keyspaces.find(audit_info->keyspace()) != _audited_keyspaces.cend()
                         || should_log_table(audit_info->keyspace(), audit_info->table())
                         || audit_info->category() == statement_category::AUTH
                         || audit_info->category() == statement_category::ADMIN
                         || audit_info->category() == statement_category::DCL);
}

template<class T>
void audit::update_config(const sstring & new_value, std::function<T(const sstring&)> parse_func, T& cfg_parameter)
{
    try {
        cfg_parameter = parse_func(new_value);
    } catch (...) {
        logger.error("Audit configuration update failed because cannot parse value=\"{}\".", new_value);
        return;
    }

    // If update_config is called with an invalid new_value, this line is not reached.
    // But logging the invalid value must be avoided later, when a different configuration parameter is changed to a correct value.
    // That's why values from _audited_{categories, keyspaces, tables} are logged instead of _cfg.audit_{categories, keyspaces, tables}

    // Each table as "keyspace.table_name" like in the configuration file
    auto table_entries = _audited_tables | std::views::transform([](const auto& pair) {
        return pair.second | std::views::transform([&](const std::string& table_name) {
            return fmt::format("{}.{}", pair.first, table_name);
        });
    }) | std::views::join;

    logger.info(
        "Audit configuration is updated. Auditing to: \"{}\", with the following categories: \"{}\", keyspaces: \"{}\", and tables: \"{}\".",
        _cfg.audit(),
        fmt::join(std::views::transform(_audited_categories, category_to_string), ","),
        fmt::join(_audited_keyspaces, ","),
        fmt::join(table_entries, ","));
}

}