/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

#include "config.h"

#include <cassert>
#include <mutex>
#include <sys/poll.h>

#include <Poco/Net/HTTPCookie.h>
#include <Poco/Net/HTTPRequest.h>
#include <Poco/Net/HTTPRequestHandler.h>
#include <Poco/Net/HTTPServerParams.h>
#include <Poco/Net/HTTPServerRequest.h>
#include <Poco/Net/HTTPServerResponse.h>
#include <Poco/Net/NetException.h>
#include <Poco/Net/SecureServerSocket.h>
#include <Poco/StringTokenizer.h>
#include <Poco/Util/ServerApplication.h>
#include <Poco/Util/Timer.h>

#include "Admin.hpp"
#include "AdminModel.hpp"
#include "Auth.hpp"
#include "Common.hpp"
#include "FileServer.hpp"
#include "IoUtil.hpp"
#include "Protocol.hpp"
#include "LOOLWSD.hpp"
#include "Log.hpp"
#include "Storage.hpp"
#include "TileCache.hpp"
#include "Unit.hpp"
#include "Util.hpp"

#include "net/Socket.hpp"
#include "net/WebSocketHandler.hpp"

#include "common/SigUtil.hpp"

using namespace LOOLProtocol;

using Poco::StringTokenizer;
using Poco::Net::HTTPRequestHandler;
using Poco::Net::HTTPResponse;
using Poco::Net::HTTPServerRequest;
using Poco::Net::HTTPServerResponse;
using Poco::Util::Application;

    /// Process incoming websocket messages
void AdminRequestHandler::handleMessage(bool /* fin */, WSOpCode /* code */, std::vector<char> &payload)
{
    // FIXME: check fin, code etc.
    const std::string firstLine = getFirstLine(payload.data(), payload.size());
    StringTokenizer tokens(firstLine, " ", StringTokenizer::TOK_IGNORE_EMPTY | StringTokenizer::TOK_TRIM);
    LOG_TRC("Recv: " << firstLine << " tokens " << tokens.count());

    if (tokens.count() < 1)
    {
        LOG_TRC("too few tokens");
        return;
    }

    std::unique_lock<std::mutex> modelLock(_admin->getLock());
    AdminModel& model = _admin->getModel();

    if (tokens.count() > 1 && tokens[0] == "auth")
    {
        std::string jwtToken;
        LOOLProtocol::getTokenString(tokens[1], "jwt", jwtToken);
        const auto& config = Application::instance().config();
        const auto sslKeyPath = config.getString("ssl.key_file_path", "");

        LOG_INF("Verifying JWT token: " << jwtToken);
        JWTAuth authAgent(sslKeyPath, "admin", "admin", "admin");
        if (authAgent.verify(jwtToken))
        {
            LOG_TRC("JWT token is valid");
            _isAuthenticated = true;
        }
        else
        {
            sendFrame("InvalidAuthToken");
            LOG_TRC("Invalid auth token");
            shutdown();
            return;
        }
    }

    if (!_isAuthenticated)
    {
        sendFrame("NotAuthenticated");
        LOG_TRC("Not authenticated");
        shutdown();
        return;
    }
    else if (tokens[0] == "documents" ||
             tokens[0] == "active_users_count" ||
             tokens[0] == "active_docs_count" ||
             tokens[0] == "mem_stats" ||
             tokens[0] == "cpu_stats")
    {
        const std::string result = model.query(tokens[0]);
        if (!result.empty())
        {
            sendTextFrame(tokens[0] + ' ' + result);
        }
    }
    else if (tokens[0] == "subscribe" && tokens.count() > 1)
    {
        for (std::size_t i = 0; i < tokens.count() - 1; i++)
        {
            model.subscribe(_sessionId, tokens[i + 1]);
        }
    }
    else if (tokens[0] == "unsubscribe" && tokens.count() > 1)
    {
        for (std::size_t i = 0; i < tokens.count() - 1; i++)
        {
            model.unsubscribe(_sessionId, tokens[i + 1]);
        }
    }
    else if (tokens[0] == "total_mem")
    {
        const auto totalMem = _admin->getTotalMemoryUsage();
        sendTextFrame("total_mem " + std::to_string(totalMem));
    }
    else if (tokens[0] == "kill" && tokens.count() == 2)
    {
        try
        {
            const auto pid = std::stoi(tokens[1]);
            LOG_INF("Admin request to kill PID: " << pid);
            SigUtil::killChild(pid);
        }
        catch (std::invalid_argument& exc)
        {
            LOG_WRN("Invalid PID to kill: " << tokens[1]);
        }
    }
    else if (tokens[0] == "settings")
    {
        // for now, we have only these settings
        std::ostringstream oss;
        oss << tokens[0] << " "
            << "mem_stats_size=" << model.query("mem_stats_size") << " "
            << "mem_stats_interval=" << std::to_string(_admin->getMemStatsInterval()) << " "
            << "cpu_stats_size="  << model.query("cpu_stats_size") << " "
            << "cpu_stats_interval=" << std::to_string(_admin->getCpuStatsInterval());

        std::string responseFrame = oss.str();
        sendTextFrame(responseFrame);
    }
    else if (tokens[0] == "shutdown")
    {
        LOG_INF("Shutdown requested by admin.");
        ShutdownRequestFlag = true;
        SocketPoll::wakeupWorld();
        return;
    }
    else if (tokens[0] == "set" && tokens.count() > 1)
    {
        for (size_t i = 1; i < tokens.count(); i++)
        {
            StringTokenizer setting(tokens[i], "=", StringTokenizer::TOK_IGNORE_EMPTY | StringTokenizer::TOK_TRIM);
            unsigned settingVal = 0;
            try
            {
                settingVal = std::stoi(setting[1]);
            }
            catch (const std::exception& exc)
            {
                LOG_WRN("Invalid setting value: " << setting[1] <<
                        " for " << setting[0]);
                return;
            }

            if (setting[0] == "mem_stats_size")
            {
                if (settingVal != static_cast<unsigned>(std::stoi(model.query(setting[0]))))
                {
                    model.setMemStatsSize(settingVal);
                }
            }
            else if (setting[0] == "mem_stats_interval")
            {
                if (settingVal != _admin->getMemStatsInterval())
                {
                    _admin->rescheduleMemTimer(settingVal);
                    model.clearMemStats();
                    model.notify("settings mem_stats_interval=" + std::to_string(settingVal));
                }
            }
            else if (setting[0] == "cpu_stats_size")
            {
                if (settingVal != static_cast<unsigned>(std::stoi(model.query(setting[0]))))
                {
                    model.setCpuStatsSize(settingVal);
                }
            }
            else if (setting[0] == "cpu_stats_interval")
            {
                if (settingVal != _admin->getCpuStatsInterval())
                {
                    _admin->rescheduleCpuTimer(settingVal);
                    model.clearCpuStats();
                    model.notify("settings cpu_stats_interval=" + std::to_string(settingVal));
                }
            }
        }
    }
}

AdminRequestHandler::AdminRequestHandler(Admin* adminManager,
                                         const std::weak_ptr<StreamSocket>& socket,
                                         const Poco::Net::HTTPRequest& request)
    : WebSocketHandler(socket, request),
      _admin(adminManager),
      _sessionId(0),
      _isAuthenticated(false)
{
}

void AdminRequestHandler::sendTextFrame(const std::string& message)
{
    UnitWSD::get().onAdminQueryMessage(message);
    std::cerr << "Admin: send text frame '" << message << "'\n";
    if (_isAuthenticated)
        sendFrame(message);
    else
        LOG_TRC("Skip sending message to non-authenticated client: '" << message << "'");
}

bool AdminRequestHandler::handleInitialRequest(
    const std::weak_ptr<StreamSocket> &socketWeak,
    const Poco::Net::HTTPRequest& request)
{
    auto socket = socketWeak.lock();

    // Different session id pool for admin sessions (?)
    const auto sessionId = Util::decodeId(LOOLWSD::GenSessionId());

    std::string requestURI = request.getURI();
    StringTokenizer pathTokens(requestURI, "/", StringTokenizer::TOK_IGNORE_EMPTY | StringTokenizer::TOK_TRIM);

    if (request.find("Upgrade") != request.end() && Poco::icompare(request["Upgrade"], "websocket") == 0)
    {
        Admin &admin = Admin::instance();
        auto handler = std::make_shared<AdminRequestHandler>(&admin, socketWeak, request);
        socket->setHandler(handler);

        { // FIXME: weird locking around subscribe ...
            std::unique_lock<std::mutex> modelLock(admin.getLock());
            // Subscribe the websocket of any AdminModel updates
            AdminModel& model = admin.getModel();
            handler->_sessionId = sessionId;
            model.subscribe(sessionId, handler);
        }
        return true;
    }

    HTTPResponse response;
    response.setStatusAndReason(HTTPResponse::HTTP_BAD_REQUEST);
    response.setContentLength(0);
    LOG_INF("Admin::handleInitialRequest bad request");
    socket->send(response);

    return false;
}

/// An admin command processor.
Admin::Admin() :
    SocketPoll("admin"),
    _model(AdminModel()),
    _forKitPid(-1),
    _lastTotalMemory(0),
    _memStatsTaskIntervalMs(5000),
    _cpuStatsTaskIntervalMs(5000)
{
    LOG_INF("Admin ctor.");

    std::unique_lock<std::mutex> modelLock(getLock());
    const auto totalMem = getTotalMemoryUsage();
    LOG_TRC("Total memory used: " << totalMem);
    _model.addMemStats(totalMem);
}

Admin::~Admin()
{
    LOG_INF("~Admin dtor.");
}

void Admin::pollingThread()
{
    std::chrono::steady_clock::time_point lastCPU, lastMem;

    lastCPU = std::chrono::steady_clock::now();
    lastMem = lastCPU;

    while (!_stop && !TerminationFlag && !ShutdownRequestFlag)
    {
        std::chrono::steady_clock::time_point now = std::chrono::steady_clock::now();
        int cpuWait = _cpuStatsTaskIntervalMs -
            std::chrono::duration_cast<std::chrono::milliseconds>(now - lastCPU).count();
        if (cpuWait < 0)
        {
            // TODO: implement me ...
            lastCPU = now;
            cpuWait += _cpuStatsTaskIntervalMs;
        }
        int memWait = _memStatsTaskIntervalMs -
            std::chrono::duration_cast<std::chrono::milliseconds>(now - lastCPU).count();
        if (memWait < 0)
        {
            std::unique_lock<std::mutex> modelLock(getLock());
            const auto totalMem = getTotalMemoryUsage();
            if (totalMem != _lastTotalMemory)
            {
                LOG_TRC("Total memory used: " << totalMem);
                _lastTotalMemory = totalMem;
            }

            _model.addMemStats(totalMem);

            lastMem = now;
            memWait += _memStatsTaskIntervalMs;
        }

        // Handle websockets & other work.
        int timeout = std::min(cpuWait, memWait);
        LOG_TRC("Admin poll for " << timeout << "ms");
        poll(timeout);
    }
}

void Admin::addDoc(const std::string& docKey, Poco::Process::PID pid, const std::string& filename, const std::string& sessionId)
{
    std::unique_lock<std::mutex> modelLock(_modelMutex);
    _model.addDocument(docKey, pid, filename, sessionId);
}

void Admin::rmDoc(const std::string& docKey, const std::string& sessionId)
{
    std::unique_lock<std::mutex> modelLock(_modelMutex);
    _model.removeDocument(docKey, sessionId);
}

void Admin::rmDoc(const std::string& docKey)
{
    std::unique_lock<std::mutex> modelLock(_modelMutex);
    LOG_INF("Removing complete doc [" << docKey << "] from Admin.");
    _model.removeDocument(docKey);
}

void Admin::rescheduleMemTimer(unsigned interval)
{
    _memStatsTaskIntervalMs = interval;
    LOG_INF("Memory stats interval changed - New interval: " << interval);
    wakeup();
}

void Admin::rescheduleCpuTimer(unsigned interval)
{
    _cpuStatsTaskIntervalMs = interval;
    LOG_INF("CPU stats interval changed - New interval: " << interval);
    wakeup();
}

unsigned Admin::getTotalMemoryUsage()
{
    Util::assertIsLocked(_modelMutex);

    // To simplify and clarify this; since load, link and pre-init all
    // inside the forkit - we should account all of our fixed cost of
    // memory to the forkit; and then count only dirty pages in the clients
    // since we know that they share everything else with the forkit.
    const size_t forkitRssKb = Util::getMemoryUsageRSS(_forKitPid);
    const size_t wsdPssKb = Util::getMemoryUsagePSS(Poco::Process::id());
    const size_t kitsDirtyKb = _model.getKitsMemoryUsage();
    const size_t totalMem = wsdPssKb + forkitRssKb + kitsDirtyKb;

    return totalMem;
}

unsigned Admin::getMemStatsInterval()
{
    return _memStatsTaskIntervalMs;
}

unsigned Admin::getCpuStatsInterval()
{
    return _cpuStatsTaskIntervalMs;
}

AdminModel& Admin::getModel()
{
    return _model;
}

void Admin::updateLastActivityTime(const std::string& docKey)
{
    std::unique_lock<std::mutex> modelLock(_modelMutex);
    _model.updateLastActivityTime(docKey);
}

void Admin::updateMemoryDirty(const std::string& docKey, int dirty)
{
    std::unique_lock<std::mutex> modelLock(_modelMutex);
    _model.updateMemoryDirty(docKey, dirty);
}

void Admin::dumpState(std::ostream& os)
{
    // FIXME: be more helpful ...
    SocketPoll::dumpState(os);
}

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