// SPDX-FileCopyrightText: Matteo Settenvini <matteo.settenvini@montecristosoftware.eu>
// SPDX-License-Identifier: GPL-3.0-or-later

#include "user_policy.hh"

#include "logger.hh"
#include "resolver.hh"

#include "parentalcontrol-dns.h"

#include <mutex>
#include <string>
#include <vector>

#include <unistd.h>

namespace /* anonymous */ {

struct GObjectDeletor {
    auto operator() (void *gobj) const noexcept -> void {
        g_object_unref(gobj);
    }
};

} // ~ namespace anonymous


using ProxyPtr = std::unique_ptr<ParentalControlsDns, GObjectDeletor>;

auto malcontent::UserPolicy::resolver(std::optional<uid_t> maybe_uid) const -> std::shared_ptr<Resolver> {
    auto uid = maybe_uid.value_or(getuid());
    if (uid == 0) {
        return nullptr; // no restrictions for root!
    }

    // If cached, let's return this immediately
    {
        std::shared_lock lock { _cache_mutex };
        auto it = _resolver_cache.find(uid);
        if (it != _resolver_cache.cend()) {
            return it->second;
        }
    }

    // Missing from cache, insert if still needed
    std::unique_lock lock { _cache_mutex };
    auto it = _resolver_cache.find(uid);
    if (it != _resolver_cache.cend()) {
        return it->second;
    }

    GError *error = nullptr;
    auto dbus_proxy = ProxyPtr {
        parental_controls_dns_proxy_new_for_bus_sync(
            G_BUS_TYPE_SYSTEM,
            // right now we check the property value at start
            // and we never update during runtime.
            G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS,
            "com.endlessm.ParentalControls.Dns",
            "/com/endlessm/ParentalControls/Dns",
            nullptr,
            &error
        )
    };

    if (error != nullptr) {
        malcontent::Logger::warn(error->message);
        return nullptr;
    }

    std::vector<std::string> dns;
    for (auto it = parental_controls_dns_get_dns(dbus_proxy.get()); it != nullptr; ++it) {
        dns.push_back(*it);
    }

    it = _resolver_cache.insert(it, { uid, std::make_shared<Resolver>(std::move(dns)) });
    return it->second;
}