OpenRCT2/src/openrct2/network/ServerList.cpp

/*****************************************************************************
 * Copyright (c) 2014-2024 OpenRCT2 developers
 *
 * For a complete list of all authors, please refer to contributors.md
 * Interested in contributing? Visit https://github.com/OpenRCT2/OpenRCT2
 *
 * OpenRCT2 is licensed under the GNU General Public License version 3.
 *****************************************************************************/

#ifndef DISABLE_NETWORK

#    include "ServerList.h"

#    include "../Context.h"
#    include "../PlatformEnvironment.h"
#    include "../config/Config.h"
#    include "../core/File.h"
#    include "../core/FileStream.h"
#    include "../core/Guard.hpp"
#    include "../core/Http.h"
#    include "../core/Json.hpp"
#    include "../core/Memory.hpp"
#    include "../core/Path.hpp"
#    include "../core/String.hpp"
#    include "../platform/Platform.h"
#    include "Socket.h"
#    include "network.h"

#    include <algorithm>
#    include <numeric>
#    include <optional>

using namespace OpenRCT2;

int32_t ServerListEntry::CompareTo(const ServerListEntry& other) const
{
    const auto& a = *this;
    const auto& b = other;

    if (a.Favourite != b.Favourite)
    {
        return a.Favourite ? -1 : 1;
    }

    if (a.Local != b.Local)
    {
        return a.Local ? -1 : 1;
    }

    bool serverACompatible = a.Version == NetworkGetVersion();
    bool serverBCompatible = b.Version == NetworkGetVersion();
    if (serverACompatible != serverBCompatible)
    {
        return serverACompatible ? -1 : 1;
    }

    if (a.RequiresPassword != b.RequiresPassword)
    {
        return a.RequiresPassword ? 1 : -1;
    }

    if (a.Players != b.Players)
    {
        return a.Players > b.Players ? -1 : 1;
    }

    return String::Compare(a.Name, b.Name, true);
}

bool ServerListEntry::IsVersionValid() const noexcept
{
    return Version.empty() || Version == NetworkGetVersion();
}

std::optional<ServerListEntry> ServerListEntry::FromJson(json_t& server)
{
    Guard::Assert(server.is_object(), "ServerListEntry::FromJson expects parameter server to be object");

    const auto port = Json::GetNumber<int32_t>(server["port"]);
    const auto name = Json::GetString(server["name"]);
    const auto description = Json::GetString(server["description"]);
    const auto requiresPassword = Json::GetBoolean(server["requiresPassword"]);
    const auto version = Json::GetString(server["version"]);
    const auto players = Json::GetNumber<uint8_t>(server["players"]);
    const auto maxPlayers = Json::GetNumber<uint8_t>(server["maxPlayers"]);
    std::string ip;
    // if server["ip"] or server["ip"]["v4"] are values, this will throw an exception, so check first
    if (server["ip"].is_object() && server["ip"]["v4"].is_array())
    {
        ip = Json::GetString(server["ip"]["v4"][0]);
    }

    if (name.empty() || version.empty())
    {
        LOG_VERBOSE("Cowardly refusing to add server without name or version specified.");

        return std::nullopt;
    }

    ServerListEntry entry;

    entry.Address = ip + ":" + std::to_string(port);
    entry.Name = name;
    entry.Description = description;
    entry.Version = version;
    entry.RequiresPassword = requiresPassword;
    entry.Players = players;
    entry.MaxPlayers = maxPlayers;

    return entry;
}

void ServerList::Sort()
{
    _serverEntries.erase(
        std::unique(
            _serverEntries.begin(), _serverEntries.end(),
            [](const ServerListEntry& a, const ServerListEntry& b) {
                if (a.Favourite == b.Favourite)
                {
                    return String::IEquals(a.Address, b.Address);
                }
                return false;
            }),
        _serverEntries.end());
    std::sort(_serverEntries.begin(), _serverEntries.end(), [](const ServerListEntry& a, const ServerListEntry& b) {
        return a.CompareTo(b) < 0;
    });
}

ServerListEntry& ServerList::GetServer(size_t index)
{
    return _serverEntries[index];
}

size_t ServerList::GetCount() const
{
    return _serverEntries.size();
}

void ServerList::Add(const ServerListEntry& entry)
{
    _serverEntries.push_back(entry);
    Sort();
}

void ServerList::AddRange(const std::vector<ServerListEntry>& entries)
{
    _serverEntries.insert(_serverEntries.end(), entries.begin(), entries.end());
    Sort();
}

void ServerList::AddOrUpdateRange(const std::vector<ServerListEntry>& entries)
{
    for (auto& existsEntry : _serverEntries)
    {
        auto match = std::find_if(
            entries.begin(), entries.end(), [&](const ServerListEntry& entry) { return existsEntry.Address == entry.Address; });
        if (match != entries.end())
        {
            // Keep favourites
            auto fav = existsEntry.Favourite;

            existsEntry = *match;
            existsEntry.Favourite = fav;
        }
    }

    std::vector<ServerListEntry> newServers;
    std::copy_if(entries.begin(), entries.end(), std::back_inserter(newServers), [this](const ServerListEntry& entry) {
        return std::find_if(
                   _serverEntries.begin(), _serverEntries.end(),
                   [&](const ServerListEntry& existsEntry) { return existsEntry.Address == entry.Address; })
            == _serverEntries.end();
    });

    AddRange(newServers);
}

void ServerList::Clear() noexcept
{
    _serverEntries.clear();
}

std::vector<ServerListEntry> ServerList::ReadFavourites() const
{
    LOG_VERBOSE("server_list_read(...)");
    std::vector<ServerListEntry> entries;
    try
    {
        auto env = GetContext()->GetPlatformEnvironment();
        auto path = env->GetFilePath(PATHID::NETWORK_SERVERS);
        if (File::Exists(path))
        {
            auto fs = FileStream(path, FILE_MODE_OPEN);
            auto numEntries = fs.ReadValue<uint32_t>();
            for (size_t i = 0; i < numEntries; i++)
            {
                ServerListEntry serverInfo;
                serverInfo.Address = fs.ReadStdString();
                serverInfo.Name = fs.ReadStdString();
                serverInfo.RequiresPassword = false;
                serverInfo.Description = fs.ReadStdString();
                serverInfo.Version.clear();
                serverInfo.Favourite = true;
                serverInfo.Players = 0;
                serverInfo.MaxPlayers = 0;
                entries.push_back(std::move(serverInfo));
            }
        }
    }
    catch (const std::exception& e)
    {
        LOG_ERROR("Unable to read server list: %s", e.what());
        entries = std::vector<ServerListEntry>();
    }
    return entries;
}

void ServerList::ReadAndAddFavourites()
{
    _serverEntries.erase(
        std::remove_if(
            _serverEntries.begin(), _serverEntries.end(), [](const ServerListEntry& entry) { return entry.Favourite; }),
        _serverEntries.end());
    auto entries = ReadFavourites();
    AddRange(entries);
}

void ServerList::WriteFavourites() const
{
    // Save just favourite servers
    std::vector<ServerListEntry> favouriteServers;
    std::copy_if(
        _serverEntries.begin(), _serverEntries.end(), std::back_inserter(favouriteServers),
        [](const ServerListEntry& entry) { return entry.Favourite; });
    WriteFavourites(favouriteServers);
}

bool ServerList::WriteFavourites(const std::vector<ServerListEntry>& entries) const
{
    LOG_VERBOSE("server_list_write(%d, 0x%p)", entries.size(), entries.data());

    auto env = GetContext()->GetPlatformEnvironment();
    auto path = Path::Combine(env->GetDirectoryPath(DIRBASE::USER), u8"servers.cfg");

    try
    {
        auto fs = FileStream(path, FILE_MODE_WRITE);
        fs.WriteValue<uint32_t>(static_cast<uint32_t>(entries.size()));
        for (const auto& entry : entries)
        {
            fs.WriteString(entry.Address);
            fs.WriteString(entry.Name);
            fs.WriteString(entry.Description);
        }
        return true;
    }
    catch (const std::exception& e)
    {
        LOG_ERROR("Unable to write server list: %s", e.what());
        return false;
    }
}

std::future<std::vector<ServerListEntry>> ServerList::FetchLocalServerListAsync(const INetworkEndpoint& broadcastEndpoint) const
{
    auto broadcastAddress = broadcastEndpoint.GetHostname();
    return std::async(std::launch::async, [broadcastAddress] {
        constexpr auto RECV_DELAY_MS = 10;
        constexpr auto RECV_WAIT_MS = 2000;

        std::string_view msg = kNetworkLanBroadcastMsg;
        auto udpSocket = CreateUdpSocket();

        LOG_VERBOSE("Broadcasting %zu bytes to the LAN (%s)", msg.size(), broadcastAddress.c_str());
        auto len = udpSocket->SendData(broadcastAddress, kNetworkLanBroadcastPort, msg.data(), msg.size());
        if (len != msg.size())
        {
            throw std::runtime_error("Unable to broadcast server query.");
        }

        std::vector<ServerListEntry> entries;
        for (int i = 0; i < (RECV_WAIT_MS / RECV_DELAY_MS); i++)
        {
            try
            {
                // Start with initialised buffer in case we receive a non-terminated string
                char buffer[1024]{};
                size_t recievedLen{};
                std::unique_ptr<INetworkEndpoint> endpoint;
                auto p = udpSocket->ReceiveData(buffer, sizeof(buffer) - 1, &recievedLen, &endpoint);
                if (p == NetworkReadPacket::Success)
                {
                    auto sender = endpoint->GetHostname();
                    LOG_VERBOSE("Received %zu bytes back from %s", recievedLen, sender.c_str());
                    auto jinfo = Json::FromString(std::string_view(buffer));

                    if (jinfo.is_object())
                    {
                        jinfo["ip"] = { { "v4", { sender } } };

                        auto entry = ServerListEntry::FromJson(jinfo);
                        if (entry.has_value())
                        {
                            (*entry).Local = true;
                            entries.push_back(std::move(*entry));
                        }
                    }
                }
            }
            catch (const std::exception& e)
            {
                LOG_WARNING("Error receiving data: %s", e.what());
            }
            Platform::Sleep(RECV_DELAY_MS);
        }
        return entries;
    });
}

std::future<std::vector<ServerListEntry>> ServerList::FetchLocalServerListAsync() const
{
    return std::async(std::launch::async, [&] {
        // Get all possible LAN broadcast addresses
        auto broadcastEndpoints = GetBroadcastAddresses();

        // Spin off a fetch for each broadcast address
        std::vector<std::future<std::vector<ServerListEntry>>> futures;
        for (const auto& broadcastEndpoint : broadcastEndpoints)
        {
            auto f = FetchLocalServerListAsync(*broadcastEndpoint);
            futures.push_back(std::move(f));
        }

        // Wait and merge all results
        std::vector<ServerListEntry> mergedEntries;
        for (auto& f : futures)
        {
            try
            {
                auto entries = f.get();
                mergedEntries.insert(mergedEntries.begin(), entries.begin(), entries.end());
            }
            catch (...)
            {
                // Ignore any exceptions from a particular broadcast fetch
            }
        }
        return mergedEntries;
    });
}

std::future<std::vector<ServerListEntry>> ServerList::FetchOnlineServerListAsync() const
{
#    ifdef DISABLE_HTTP
    return {};
#    else

    auto p = std::make_shared<std::promise<std::vector<ServerListEntry>>>();
    auto f = p->get_future();

    std::string masterServerUrl = OPENRCT2_MASTER_SERVER_URL;
    if (!gConfigNetwork.MasterServerUrl.empty())
    {
        masterServerUrl = gConfigNetwork.MasterServerUrl;
    }

    Http::Request request;
    request.url = std::move(masterServerUrl);
    request.method = Http::Method::GET;
    request.header["Accept"] = "application/json";
    Http::DoAsync(request, [p](Http::Response& response) -> void {
        json_t root;
        try
        {
            if (response.status != Http::Status::Ok)
            {
                throw MasterServerException(STR_SERVER_LIST_NO_CONNECTION);
            }

            root = Json::FromString(response.body);
            if (root.is_object())
            {
                auto jsonStatus = root["status"];
                if (!jsonStatus.is_number_integer())
                {
                    throw MasterServerException(STR_SERVER_LIST_INVALID_RESPONSE_JSON_NUMBER);
                }

                auto status = Json::GetNumber<int32_t>(jsonStatus);
                if (status != 200)
                {
                    throw MasterServerException(STR_SERVER_LIST_MASTER_SERVER_FAILED);
                }

                auto jServers = root["servers"];
                if (!jServers.is_array())
                {
                    throw MasterServerException(STR_SERVER_LIST_INVALID_RESPONSE_JSON_ARRAY);
                }

                std::vector<ServerListEntry> entries;
                for (auto& jServer : jServers)
                {
                    if (jServer.is_object())
                    {
                        auto entry = ServerListEntry::FromJson(jServer);
                        if (entry.has_value())
                        {
                            entries.push_back(std::move(*entry));
                        }
                    }
                }

                p->set_value(entries);
            }
        }
        catch (...)
        {
            p->set_exception(std::current_exception());
        }
    });
    return f;
#    endif
}

uint32_t ServerList::GetTotalPlayerCount() const
{
    return std::accumulate(_serverEntries.begin(), _serverEntries.end(), 0, [](uint32_t acc, const ServerListEntry& entry) {
        return acc + entry.Players;
    });
}

#endif