//------------------------------------------------------------------------------
/*
    This file is part of rippled: https://github.com/ripple/rippled
    Copyright (c) 2012, 2013 Ripple Labs Inc.

    Permission to use, copy, modify, and/or distribute this software for any
    purpose  with  or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.

    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================

#include <ripple/app/ledger/LedgerMaster.h>
#include <ripple/app/misc/HashRouter.h>
#include <ripple/app/misc/NetworkOPs.h>
#include <ripple/app/misc/ValidatorList.h>
#include <ripple/basics/base64.h>
#include <ripple/basics/make_SSLContext.h>
#include <ripple/beast/core/LexicalCast.h>
#include <ripple/core/DatabaseCon.h>
#include <ripple/nodestore/DatabaseShard.h>
#include <ripple/overlay/Cluster.h>
#include <ripple/overlay/predicates.h>
#include <ripple/overlay/impl/ConnectAttempt.h>
#include <ripple/overlay/impl/PeerImp.h>
#include <ripple/peerfinder/make_Manager.h>
#include <ripple/rpc/json_body.h>
#include <ripple/server/SimpleWriter.h>

#include <boost/utility/in_place_factory.hpp>

namespace ripple {

/** A functor to visit all active peers and retrieve their JSON data */
struct get_peer_json
{
    using return_type = Json::Value;

    Json::Value json;

    get_peer_json() = default;

    void operator() (std::shared_ptr<Peer> const& peer)
    {
        json.append (peer->json ());
    }

    Json::Value operator() ()
    {
        return json;
    }
};

//------------------------------------------------------------------------------

OverlayImpl::Child::Child (OverlayImpl& overlay)
    : overlay_(overlay)
{
}

OverlayImpl::Child::~Child()
{
    overlay_.remove(*this);
}

//------------------------------------------------------------------------------

OverlayImpl::Timer::Timer (OverlayImpl& overlay)
    : Child(overlay)
    , timer_(overlay_.io_service_)
{
}

void
OverlayImpl::Timer::stop()
{
    error_code ec;
    timer_.cancel(ec);
}

void
OverlayImpl::Timer::run()
{
    timer_.expires_from_now (std::chrono::seconds(1));
    timer_.async_wait(overlay_.strand_.wrap(
        std::bind(&Timer::on_timer, shared_from_this(),
            std::placeholders::_1)));
}

void
OverlayImpl::Timer::on_timer (error_code ec)
{
    if (ec || overlay_.isStopping())
    {
        if (ec && ec != boost::asio::error::operation_aborted)
        {
            JLOG(overlay_.journal_.error()) << "on_timer: " << ec.message();
        }
        return;
    }

    overlay_.m_peerFinder->once_per_second();
    overlay_.sendEndpoints();
    overlay_.autoConnect();

    if ((++overlay_.timer_count_ % Tuning::checkSeconds) == 0)
        overlay_.check();

    timer_.expires_from_now (std::chrono::seconds(1));
    timer_.async_wait(overlay_.strand_.wrap(std::bind(
        &Timer::on_timer, shared_from_this(),
            std::placeholders::_1)));
}

//------------------------------------------------------------------------------

OverlayImpl::OverlayImpl (
    Application& app,
    Setup const& setup,
    Stoppable& parent,
    ServerHandler& serverHandler,
    Resource::Manager& resourceManager,
    Resolver& resolver,
    boost::asio::io_service& io_service,
    BasicConfig const& config)
    : Overlay (parent)
    , app_ (app)
    , io_service_ (io_service)
    , work_ (boost::in_place(std::ref(io_service_)))
    , strand_ (io_service_)
    , setup_(setup)
    , journal_ (app_.journal("Overlay"))
    , serverHandler_(serverHandler)
    , m_resourceManager (resourceManager)
    , m_peerFinder (PeerFinder::make_Manager (*this, io_service,
        stopwatch(), app_.journal("PeerFinder"), config))
    , m_resolver (resolver)
    , next_id_(1)
    , timer_count_(0)
{
    beast::PropertyStream::Source::add (m_peerFinder.get());
}

OverlayImpl::~OverlayImpl ()
{
    stop();

    // Block until dependent objects have been destroyed.
    // This is just to catch improper use of the Stoppable API.
    //
    std::unique_lock <decltype(mutex_)> lock (mutex_);
    cond_.wait (lock, [this] { return list_.empty(); });
}

//------------------------------------------------------------------------------

Handoff
OverlayImpl::onHandoff (std::unique_ptr <beast::asio::ssl_bundle>&& ssl_bundle,
    http_request_type&& request,
        endpoint_type remote_endpoint)
{
    auto const id = next_id_++;
    beast::WrappedSink sink (app_.logs()["Peer"], makePrefix(id));
    beast::Journal journal (sink);

    Handoff handoff;
    if (processRequest(request, handoff))
        return handoff;
    if (! isPeerUpgrade(request))
        return handoff;

    handoff.moved = true;

    JLOG(journal.debug()) << "Peer connection upgrade from " << remote_endpoint;

    error_code ec;
    auto const local_endpoint (ssl_bundle->socket.local_endpoint(ec));
    if (ec)
    {
        JLOG(journal.debug()) << remote_endpoint << " failed: " << ec.message();
        return handoff;
    }

    auto consumer = m_resourceManager.newInboundEndpoint(
        beast::IPAddressConversion::from_asio(remote_endpoint));
    if (consumer.disconnect())
        return handoff;

    auto const slot = m_peerFinder->new_inbound_slot (
        beast::IPAddressConversion::from_asio(local_endpoint),
            beast::IPAddressConversion::from_asio(remote_endpoint));

    if (slot == nullptr)
    {
        // self-connect, close
        handoff.moved = false;
        return handoff;
    }

    // TODO Validate HTTP request

    {
        auto const types = beast::rfc2616::split_commas(
            request["Connect-As"]);
        if (std::find_if(types.begin(), types.end(),
                [](std::string const& s)
                {
                    return boost::beast::detail::iequals(s, "peer");
                }) == types.end())
        {
            handoff.moved = false;
            handoff.response = makeRedirectResponse(slot, request,
                remote_endpoint.address());
            handoff.keep_alive = beast::rfc2616::is_keep_alive(request);
            return handoff;
        }
    }

    auto hello = parseHello (true, request, journal);
    if(! hello)
    {
        m_peerFinder->on_closed(slot);
        handoff.moved = false;
        handoff.response = makeErrorResponse (slot, request,
            remote_endpoint.address(),
            "Unable to parse HELLO message");
        handoff.keep_alive = false;
        return handoff;
    }

    auto sharedValue = makeSharedValue(
        ssl_bundle->stream.native_handle(), journal);
    if(! sharedValue)
    {
        m_peerFinder->on_closed(slot);
        handoff.moved = false;
        handoff.response = makeErrorResponse (slot, request,
            remote_endpoint.address(),
            "Incorrect security cookie (possible MITM detected)");
        handoff.keep_alive = false;
        return handoff;
    }

    auto publicKey = verifyHello (*hello,
        *sharedValue,
        setup_.public_ip,
        beast::IPAddressConversion::from_asio(
            remote_endpoint), journal, app_);
    if(! publicKey)
    {
        m_peerFinder->on_closed(slot);
        handoff.moved = false;
        handoff.response = makeErrorResponse (slot, request,
            remote_endpoint.address(),
            "Unable to verify HELLO message");
        handoff.keep_alive = false;
        return handoff;
    }

    auto const result = m_peerFinder->activate (slot, *publicKey,
        static_cast<bool>(app_.cluster().member(*publicKey)));
    if (result != PeerFinder::Result::success)
    {
        m_peerFinder->on_closed(slot);
        JLOG(journal.debug()) <<
            "Peer " << remote_endpoint << " redirected, slots full";
        handoff.moved = false;
        handoff.response = makeRedirectResponse(slot, request,
            remote_endpoint.address());
        handoff.keep_alive = beast::rfc2616::is_keep_alive(request);
        return handoff;
    }

    auto const peer = std::make_shared<PeerImp>(app_, id,
        remote_endpoint, slot, std::move(request), *hello,
            *publicKey, consumer, std::move(ssl_bundle), *this);
    {
        // As we are not on the strand, run() must be called
        // while holding the lock, otherwise new I/O can be
        // queued after a call to stop().
        std::lock_guard <decltype(mutex_)> lock (mutex_);
        {
            auto const result =
                m_peers.emplace (peer->slot(), peer);
            assert (result.second);
            (void) result.second;
        }
        list_.emplace(peer.get(), peer);

        peer->run();
    }
    handoff.moved = true;
    return handoff;
}

//------------------------------------------------------------------------------

bool
OverlayImpl::isPeerUpgrade(http_request_type const& request)
{
    if (! is_upgrade(request))
        return false;
    auto const versions = parse_ProtocolVersions(
        request["Upgrade"]);
    if (versions.size() == 0)
        return false;
    return true;
}

std::string
OverlayImpl::makePrefix (std::uint32_t id)
{
    std::stringstream ss;
    ss << "[" << std::setfill('0') << std::setw(3) << id << "] ";
    return ss.str();
}

std::shared_ptr<Writer>
OverlayImpl::makeRedirectResponse (PeerFinder::Slot::ptr const& slot,
    http_request_type const& request, address_type remote_address)
{
    boost::beast::http::response<json_body> msg;
    msg.version(request.version());
    msg.result(boost::beast::http::status::service_unavailable);
    msg.insert("Server", BuildInfo::getFullVersionString());
    msg.insert("Remote-Address", remote_address);
    msg.insert("Content-Type", "application/json");
    msg.insert(boost::beast::http::field::connection, "close");
    msg.body() = Json::objectValue;
    {
        auto const result = m_peerFinder->redirect(slot);
        Json::Value& ips = (msg.body()["peer-ips"] = Json::arrayValue);
        for (auto const& _ : m_peerFinder->redirect(slot))
            ips.append(_.address.to_string());
    }
    msg.prepare_payload();
    return std::make_shared<SimpleWriter>(msg);
}

std::shared_ptr<Writer>
OverlayImpl::makeErrorResponse (PeerFinder::Slot::ptr const& slot,
    http_request_type const& request,
    address_type remote_address,
    std::string text)
{
    boost::beast::http::response<boost::beast::http::string_body> msg;
    msg.version(request.version());
    msg.result(boost::beast::http::status::bad_request);
    msg.insert("Server", BuildInfo::getFullVersionString());
    msg.insert("Remote-Address", remote_address.to_string());
    msg.insert(boost::beast::http::field::connection, "close");
    msg.body() = text;
    msg.prepare_payload();
    return std::make_shared<SimpleWriter>(msg);
}

//------------------------------------------------------------------------------

void
OverlayImpl::connect (beast::IP::Endpoint const& remote_endpoint)
{
    assert(work_);

    auto usage = resourceManager().newOutboundEndpoint (remote_endpoint);
    if (usage.disconnect())
    {
        JLOG(journal_.info()) << "Over resource limit: " << remote_endpoint;
        return;
    }

    auto const slot = peerFinder().new_outbound_slot(remote_endpoint);
    if (slot == nullptr)
    {
        JLOG(journal_.debug()) << "Connect: No slot for " << remote_endpoint;
        return;
    }

    auto const p = std::make_shared<ConnectAttempt>(app_,
        io_service_, beast::IPAddressConversion::to_asio_endpoint(remote_endpoint),
            usage, setup_.context, next_id_++, slot,
                app_.journal("Peer"), *this);

    std::lock_guard<decltype(mutex_)> lock(mutex_);
    list_.emplace(p.get(), p);
    p->run();
}

//------------------------------------------------------------------------------

// Adds a peer that is already handshaked and active
void
OverlayImpl::add_active (std::shared_ptr<PeerImp> const& peer)
{
    std::lock_guard <decltype(mutex_)> lock (mutex_);

    {
        auto const result =
            m_peers.emplace (peer->slot(), peer);
        assert (result.second);
        (void) result.second;
    }

    {
        auto const result = ids_.emplace (
            std::piecewise_construct,
                std::make_tuple (peer->id()),
                    std::make_tuple (peer));
        assert(result.second);
        (void) result.second;
    }

    list_.emplace(peer.get(), peer);

    JLOG(journal_.debug()) <<
        "activated " << peer->getRemoteAddress() <<
        " (" << peer->id() << ":" <<
        toBase58 (
            TokenType::NodePublic,
            peer->getNodePublic()) << ")";

    // As we are not on the strand, run() must be called
    // while holding the lock, otherwise new I/O can be
    // queued after a call to stop().
    peer->run();
}

void
OverlayImpl::remove (PeerFinder::Slot::ptr const& slot)
{
    std::lock_guard <decltype(mutex_)> lock (mutex_);
    auto const iter = m_peers.find (slot);
    assert(iter != m_peers.end ());
    m_peers.erase (iter);
}

//------------------------------------------------------------------------------
//
// Stoppable
//
//------------------------------------------------------------------------------

// Caller must hold the mutex
void
OverlayImpl::checkStopped ()
{
    if (isStopping() && areChildrenStopped () && list_.empty())
        stopped();
}

void
OverlayImpl::onPrepare()
{
    PeerFinder::Config config;

    if (app_.config().PEERS_MAX != 0)
        config.maxPeers = app_.config().PEERS_MAX;

    config.outPeers = config.calcOutPeers();

    auto const port = serverHandler_.setup().overlay.port;

    config.peerPrivate = app_.config().PEER_PRIVATE;
    config.wantIncoming =
        (! config.peerPrivate) && (port != 0);
    // if it's a private peer or we are running as standalone
    // automatic connections would defeat the purpose.
    config.autoConnect =
        !app_.config().standalone() &&
        !app_.config().PEER_PRIVATE;
    config.listeningPort = port;
    config.features = "";
    config.ipLimit = setup_.ipLimit;

    // Enforce business rules
    config.applyTuning();

    m_peerFinder->setConfig (config);

    // Populate our boot cache: if there are no entries in [ips] then we use
    // the entries in [ips_fixed]. If both are empty, we resort to a round-robin
    // pool.
    auto bootstrapIps = app_.config().IPS.empty()
        ? app_.config().IPS_FIXED
        : app_.config().IPS;
    if (bootstrapIps.empty ())
        bootstrapIps.push_back ("r.ripple.com 51235");

    m_resolver.resolve (bootstrapIps,
        [this](std::string const& name,
            std::vector <beast::IP::Endpoint> const& addresses)
        {
            std::vector <std::string> ips;
            ips.reserve(addresses.size());
            for (auto const& addr : addresses)
            {
                if (addr.port () == 0)
                {
                    Throw<std::runtime_error> ("Port not specified for "
                        "address:" + addr.to_string ());
                }

                ips.push_back (to_string (addr));
            }

            std::string const base ("config: ");
            if (!ips.empty ())
                m_peerFinder->addFallbackStrings (base + name, ips);
        });

    // Add the ips_fixed from the rippled.cfg file
    if (! app_.config().standalone() && !app_.config().IPS_FIXED.empty ())
    {
        m_resolver.resolve (app_.config().IPS_FIXED,
            [this](
                std::string const& name,
                std::vector <beast::IP::Endpoint> const& addresses)
            {
                if (!addresses.empty ())
                    m_peerFinder->addFixedPeer (name, addresses);
            });
    }
}

void
OverlayImpl::onStart ()
{
    auto const timer = std::make_shared<Timer>(*this);
    std::lock_guard <decltype(mutex_)> lock (mutex_);
    list_.emplace(timer.get(), timer);
    timer_ = timer;
    timer->run();
}

void
OverlayImpl::onStop ()
{
    strand_.dispatch(std::bind(&OverlayImpl::stop, this));
}

void
OverlayImpl::onChildrenStopped ()
{
    std::lock_guard <decltype(mutex_)> lock (mutex_);
    checkStopped ();
}

//------------------------------------------------------------------------------
//
// PropertyStream
//
//------------------------------------------------------------------------------

void
OverlayImpl::onWrite (beast::PropertyStream::Map& stream)
{
    beast::PropertyStream::Set set ("traffic", stream);
    auto stats = m_traffic.getCounts();
    for (auto& i : stats)
    {
        if (! i.second.messagesIn && ! i.second.messagesOut)
            continue;

        beast::PropertyStream::Map item (set);
        item["category"] = i.first;
        item["bytes_in"] =
            beast::lexicalCast<std::string>
                (i.second.bytesIn.load());
        item["messages_in"] =
            beast::lexicalCast<std::string>
                (i.second.messagesIn.load());
        item["bytes_out"] =
            beast::lexicalCast<std::string>
                (i.second.bytesOut.load());
        item["messages_out"] =
            beast::lexicalCast<std::string>
                (i.second.messagesOut.load());
    }
}

//------------------------------------------------------------------------------
/** A peer has connected successfully
    This is called after the peer handshake has been completed and during
    peer activation. At this point, the peer address and the public key
    are known.
*/
void
OverlayImpl::activate (std::shared_ptr<PeerImp> const& peer)
{
    // Now track this peer
    {
        std::lock_guard <decltype(mutex_)> lock (mutex_);
        auto const result (ids_.emplace (
            std::piecewise_construct,
                std::make_tuple (peer->id()),
                    std::make_tuple (peer)));
        assert(result.second);
        (void) result.second;
    }

    JLOG(journal_.debug()) <<
        "activated " << peer->getRemoteAddress() <<
        " (" << peer->id() <<
        ":" << toBase58 (
            TokenType::NodePublic,
            peer->getNodePublic()) << ")";

    // We just accepted this peer so we have non-zero active peers
    assert(size() != 0);
}

void
OverlayImpl::onPeerDeactivate (Peer::id_t id)
{
    std::lock_guard <decltype(mutex_)> lock (mutex_);
    ids_.erase(id);
}

void
OverlayImpl::onManifests (
    std::shared_ptr<protocol::TMManifests> const& m,
        std::shared_ptr<PeerImp> const& from)
{
    auto& hashRouter = app_.getHashRouter();
    auto const n = m->list_size();
    auto const& journal = from->pjournal();

    JLOG(journal.debug()) << "TMManifest, " << n << (n == 1 ? " item" : " items");

    for (std::size_t i = 0; i < n; ++i)
    {
        auto& s = m->list ().Get (i).stobject ();

        if (auto mo = Manifest::make_Manifest (s))
        {
            uint256 const hash = mo->hash ();
            if (!hashRouter.addSuppressionPeer (hash, from->id ())) {
                JLOG(journal.info()) << "Duplicate manifest #" << i + 1;
                continue;
            }

            if (! app_.validators().listed (mo->masterKey))
            {
                JLOG(journal.info()) << "Untrusted manifest #" << i + 1;
                app_.getOPs().pubManifest (*mo);
                continue;
            }

            auto const serialized = mo->serialized;

            auto const result = app_.validatorManifests ().applyManifest (
                std::move(*mo));

            if (result == ManifestDisposition::accepted)
            {
                app_.getOPs().pubManifest (
                    *Manifest::make_Manifest(serialized));
            }

            if (result == ManifestDisposition::accepted)
            {
                auto db = app_.getWalletDB ().checkoutDb ();

                soci::transaction tr(*db);
                static const char* const sql =
                        "INSERT INTO ValidatorManifests (RawData) VALUES (:rawData);";
                soci::blob rawData(*db);
                convert (serialized, rawData);
                *db << sql, soci::use (rawData);
                tr.commit ();

                protocol::TMManifests o;
                o.add_list ()->set_stobject (s);

                auto const toSkip = hashRouter.shouldRelay (hash);
                if(toSkip)
                    foreach (send_if_not (
                        std::make_shared<Message>(o, protocol::mtMANIFESTS),
                            peer_in_set (*toSkip)));
            }
            else
            {
                JLOG(journal.info()) << "Bad manifest #" << i + 1 <<
                    ": " << to_string(result);
            }
        }
        else
        {
            JLOG(journal.warn()) << "Malformed manifest #" << i + 1;
            continue;
        }
    }
}

void
OverlayImpl::reportTraffic (
    TrafficCount::category cat,
    bool isInbound,
    int number)
{
    m_traffic.addCount (cat, isInbound, number);
}

Json::Value
OverlayImpl::crawlShards(bool pubKey, std::uint32_t hops)
{
    using namespace std::chrono;
    using namespace std::chrono_literals;

    Json::Value jv(Json::objectValue);
    auto const numPeers {size()};
    if (numPeers == 0)
        return jv;

    // If greater than a hop away, we may need to gather or freshen data
    if (hops > 0)
    {
        // Prevent crawl spamming
        clock_type::time_point const last(csLast_.load());
        if ((clock_type::now() - last) > 60s)
        {
            auto const timeout(seconds((hops * hops) * 10));
            std::unique_lock<std::mutex> l {csMutex_};

            // Check if already requested
            if (csIDs_.empty())
            {
                {
                    std::lock_guard <decltype(mutex_)> lock {mutex_};
                    for (auto& id : ids_)
                        csIDs_.emplace(id.first);
                }

                // Relay request to active peers
                protocol::TMGetShardInfo tmGS;
                tmGS.set_hops(hops);
                foreach(send_always(std::make_shared<Message>(
                    tmGS, protocol::mtGET_SHARD_INFO)));

                if (csCV_.wait_for(l, timeout) == std::cv_status::timeout)
                {
                    csIDs_.clear();
                    csCV_.notify_all();
                }
                csLast_ = duration_cast<seconds>(
                    clock_type::now().time_since_epoch());
            }
            else
                csCV_.wait_for(l, timeout);
        }
    }

    // Combine the shard info from peers and their sub peers
    hash_map<PublicKey, PeerImp::ShardInfo> peerShardInfo;
    for_each([&](std::shared_ptr<PeerImp> const& peer)
    {
        if (auto psi = peer->getPeerShardInfo())
        {
            for (auto const& e : *psi)
            {
                auto it {peerShardInfo.find(e.first)};
                if (it != peerShardInfo.end())
                    // The key exists so join the shard indexes.
                    it->second.shardIndexes += e.second.shardIndexes;
                else
                    peerShardInfo.emplace(std::move(e));
            }
        }
    });

    // Prepare json reply
    auto& av = jv[jss::peers] = Json::Value(Json::arrayValue);
    for (auto const& e : peerShardInfo)
    {
        auto& pv {av.append(Json::Value(Json::objectValue))};
        if (pubKey)
            pv[jss::public_key] = toBase58(TokenType::NodePublic, e.first);

        auto const& address {e.second.endpoint.address()};
        if (!address.is_unspecified())
            pv[jss::ip] = address.to_string();

        pv[jss::complete_shards] = to_string(e.second.shardIndexes);
    }

    return jv;
}

void
OverlayImpl::lastLink(std::uint32_t id)
{
    // Notify threads when every peer has received a last link.
    // This doesn't account for every node that might reply but
    // it is adequate.
    std::lock_guard<std::mutex> l {csMutex_};
    if (csIDs_.erase(id) && csIDs_.empty())
        csCV_.notify_all();
}

std::size_t
OverlayImpl::selectPeers (PeerSet& set, std::size_t limit,
    std::function<bool(std::shared_ptr<Peer> const&)> score)
{
    using item = std::pair<int, std::shared_ptr<PeerImp>>;

    std::vector<item> v;
    v.reserve(size());

    for_each ([&](std::shared_ptr<PeerImp>&& e)
    {
        auto const s = e->getScore(score(e));
        v.emplace_back(s, std::move(e));
    });

    std::sort(v.begin(), v.end(),
        [](item const& lhs, item const&rhs)
        {
            return lhs.first > rhs.first;
        });

    std::size_t accepted = 0;
    for (auto const& e : v)
    {
        if (set.insert(e.second) && ++accepted >= limit)
            break;
    }
    return accepted;
}

/** The number of active peers on the network
    Active peers are only those peers that have completed the handshake
    and are running the Ripple protocol.
*/
std::size_t
OverlayImpl::size()
{
    std::lock_guard <decltype(mutex_)> lock (mutex_);
    return ids_.size ();
}

int
OverlayImpl::limit()
{
    return m_peerFinder->config().maxPeers;
}

Json::Value
OverlayImpl::crawl()
{
    using namespace std::chrono;
    Json::Value jv;
    auto& av = jv["active"] = Json::Value(Json::arrayValue);

    for_each ([&](std::shared_ptr<PeerImp>&& sp)
    {
        auto& pv = av.append(Json::Value(Json::objectValue));
        pv[jss::public_key] = base64_encode(
            sp->getNodePublic().data(),
                sp->getNodePublic().size());
        pv[jss::type] = sp->slot()->inbound() ?
            "in" : "out";
        pv[jss::uptime] =
            static_cast<std::uint32_t>(duration_cast<seconds>(
                sp->uptime()).count());
        if (sp->crawl())
        {
            pv[jss::ip] = sp->getRemoteAddress().address().to_string();
            if (sp->slot()->inbound())
            {
                if (auto port = sp->slot()->listening_port())
                    pv[jss::port] = *port;
            }
            else
            {
                pv[jss::port] = std::to_string(
                    sp->getRemoteAddress().port());
            }
        }

        {
            auto version {sp->getVersion()};
            if (!version.empty())
                pv[jss::version] = std::move(version);
        }

        std::uint32_t minSeq, maxSeq;
        sp->ledgerRange(minSeq, maxSeq);
        if (minSeq != 0 || maxSeq != 0)
            pv[jss::complete_ledgers] =
                std::to_string(minSeq) + "-" +
                    std::to_string(maxSeq);

        if (auto shardIndexes = sp->getShardIndexes())
            pv[jss::complete_shards] = to_string(*shardIndexes);
    });

    return jv;
}

// Returns information on verified peers.
Json::Value
OverlayImpl::json ()
{
    return foreach (get_peer_json());
}

bool
OverlayImpl::processRequest (http_request_type const& req,
    Handoff& handoff)
{
    if (req.target() != "/crawl")
        return false;

    boost::beast::http::response<json_body> msg;
    msg.version(req.version());
    msg.result(boost::beast::http::status::ok);
    msg.insert("Server", BuildInfo::getFullVersionString());
    msg.insert("Content-Type", "application/json");
    msg.insert("Connection", "close");
    msg.body()["overlay"] = crawl();
    msg.prepare_payload();
    handoff.response = std::make_shared<SimpleWriter>(msg);
    return true;
}

Overlay::PeerSequence
OverlayImpl::getActivePeers()
{
    Overlay::PeerSequence ret;
    ret.reserve(size());

    for_each ([&ret](std::shared_ptr<PeerImp>&& sp)
    {
        ret.emplace_back(std::move(sp));
    });

    return ret;
}

void
OverlayImpl::checkSanity (std::uint32_t index)
{
    for_each ([index](std::shared_ptr<PeerImp>&& sp)
    {
        sp->checkSanity (index);
    });
}

void
OverlayImpl::check ()
{
    for_each ([](std::shared_ptr<PeerImp>&& sp)
    {
        sp->check ();
    });
}

std::shared_ptr<Peer>
OverlayImpl::findPeerByShortID (Peer::id_t const& id)
{
    std::lock_guard <decltype(mutex_)> lock (mutex_);
    auto const iter = ids_.find (id);
    if (iter != ids_.end ())
        return iter->second.lock();
    return {};
}

void
OverlayImpl::send (protocol::TMProposeSet& m)
{
    if (setup_.expire)
        m.set_hops(0);
    auto const sm = std::make_shared<Message>(
        m, protocol::mtPROPOSE_LEDGER);
    for_each([&](std::shared_ptr<PeerImp>&& p)
    {
        if (! m.has_hops() || p->hopsAware())
            p->send(sm);
    });
}
void
OverlayImpl::send (protocol::TMValidation& m)
{
    if (setup_.expire)
        m.set_hops(0);
    auto const sm = std::make_shared<Message>(
        m, protocol::mtVALIDATION);
    for_each([&](std::shared_ptr<PeerImp>&& p)
    {
        if (! m.has_hops() || p->hopsAware())
            p->send(sm);
    });

    SerialIter sit (m.validation().data(), m.validation().size());
    auto val = std::make_shared<STValidation>(
        std::ref(sit),
        [this](PublicKey const& pk) {
            return calcNodeID(app_.validatorManifests().getMasterKey(pk));
        },
        false);
    app_.getOPs().pubValidation (val);
}

void
OverlayImpl::relay (protocol::TMProposeSet& m,
    uint256 const& uid)
{
    if (m.has_hops() && m.hops() >= maxTTL)
        return;
    auto const toSkip = app_.getHashRouter().shouldRelay(uid);
    if (!toSkip)
        return;
    auto const sm = std::make_shared<Message>(
        m, protocol::mtPROPOSE_LEDGER);
    for_each([&](std::shared_ptr<PeerImp>&& p)
    {
        if (toSkip->find(p->id()) != toSkip->end())
            return;
        if (! m.has_hops() || p->hopsAware())
            p->send(sm);
    });
}

void
OverlayImpl::relay (protocol::TMValidation& m,
    uint256 const& uid)
{
    if (m.has_hops() && m.hops() >= maxTTL)
        return;
    auto const toSkip = app_.getHashRouter().shouldRelay(uid);
    if (! toSkip)
        return;
    auto const sm = std::make_shared<Message>(
        m, protocol::mtVALIDATION);
    for_each([&](std::shared_ptr<PeerImp>&& p)
    {
        if (toSkip->find(p->id()) != toSkip->end())
            return;
        if (! m.has_hops() || p->hopsAware())
            p->send(sm);
    });
}

//------------------------------------------------------------------------------

void
OverlayImpl::remove (Child& child)
{
    std::lock_guard<decltype(mutex_)> lock(mutex_);
    list_.erase(&child);
    if (list_.empty())
        checkStopped();
}

void
OverlayImpl::stop()
{
    // Calling list_[].second->stop() may cause list_ to be modified
    // (OverlayImpl::remove() may be called on this same thread).  So
    // iterating directly over list_ to call child->stop() could lead to
    // undefined behavior.
    //
    // Therefore we copy all of the weak/shared ptrs out of list_ before we
    // start calling stop() on them.  That guarantees OverlayImpl::remove()
    // won't be called until vector<> children leaves scope.
    std::vector<std::shared_ptr<Child>> children;
    {
        std::lock_guard<decltype(mutex_)> lock(mutex_);
        if (!work_)
            return;
        work_ = boost::none;

        children.reserve (list_.size());
        for (auto const& element : list_)
        {
            children.emplace_back (element.second.lock());
        }
    } // lock released

    for (auto const& child : children)
    {
        if (child != nullptr)
            child->stop();
    }
}

void
OverlayImpl::autoConnect()
{
    auto const result = m_peerFinder->autoconnect();
    for (auto addr : result)
        connect (addr);
}

void
OverlayImpl::sendEndpoints()
{
    auto const result = m_peerFinder->buildEndpointsForPeers();
    for (auto const& e : result)
    {
        std::shared_ptr<PeerImp> peer;
        {
            std::lock_guard <decltype(mutex_)> lock (mutex_);
            auto const iter = m_peers.find (e.first);
            if (iter != m_peers.end())
                peer = iter->second.lock();
        }
        if (peer)
            peer->sendEndpoints (e.second.begin(), e.second.end());
    }
}

//------------------------------------------------------------------------------

bool ScoreHasLedger::operator()(std::shared_ptr<Peer> const& bp) const
{
    auto const& p = std::dynamic_pointer_cast<PeerImp>(bp);
    return p->hasLedger (hash_, seq_);
}

bool ScoreHasTxSet::operator()(std::shared_ptr<Peer> const& bp) const
{
    auto const& p = std::dynamic_pointer_cast<PeerImp>(bp);
    return p->hasTxSet (hash_);
}

//------------------------------------------------------------------------------

Overlay::Setup
setup_Overlay (BasicConfig const& config)
{
    Overlay::Setup setup;
    auto const& section = config.section("overlay");
    setup.context = make_SSLContext("");
    setup.expire = get<bool>(section, "expire", false);

    set (setup.ipLimit, "ip_limit", section);
    if (setup.ipLimit < 0)
        Throw<std::runtime_error> ("Configured IP limit is invalid");

    std::string ip;
    set (ip, "public_ip", section);
    if (! ip.empty ())
    {
        boost::system::error_code ec;
        setup.public_ip = beast::IP::Address::from_string (ip, ec);
        if (ec || beast::IP::is_private (setup.public_ip))
            Throw<std::runtime_error> ("Configured public IP is invalid");
    }
    return setup;
}

std::unique_ptr <Overlay>
make_Overlay (
    Application& app,
    Overlay::Setup const& setup,
    Stoppable& parent,
    ServerHandler& serverHandler,
    Resource::Manager& resourceManager,
    Resolver& resolver,
    boost::asio::io_service& io_service,
    BasicConfig const& config)
{
    return std::make_unique<OverlayImpl>(app, setup, parent, serverHandler,
        resourceManager, resolver, io_service, config);
}

}