#include <xrpl/nodestore/detail/DatabaseNodeImp.h>

namespace ripple {
namespace NodeStore {

void
DatabaseNodeImp::store(
    NodeObjectType type,
    Blob&& data,
    uint256 const& hash,
    std::uint32_t)
{
    storeStats(1, data.size());

    auto obj = NodeObject::createObject(type, std::move(data), hash);
    backend_->store(obj);
    if (cache_)
    {
        // After the store, replace a negative cache entry if there is one
        cache_->canonicalize(
            hash, obj, [](std::shared_ptr<NodeObject> const& n) {
                return n->getType() == hotDUMMY;
            });
    }
}

void
DatabaseNodeImp::asyncFetch(
    uint256 const& hash,
    std::uint32_t ledgerSeq,
    std::function<void(std::shared_ptr<NodeObject> const&)>&& callback)
{
    if (cache_)
    {
        std::shared_ptr<NodeObject> obj = cache_->fetch(hash);
        if (obj)
        {
            callback(obj->getType() == hotDUMMY ? nullptr : obj);
            return;
        }
    }
    Database::asyncFetch(hash, ledgerSeq, std::move(callback));
}

void
DatabaseNodeImp::sweep()
{
    if (cache_)
        cache_->sweep();
}

std::shared_ptr<NodeObject>
DatabaseNodeImp::fetchNodeObject(
    uint256 const& hash,
    std::uint32_t,
    FetchReport& fetchReport,
    bool duplicate)
{
    std::shared_ptr<NodeObject> nodeObject =
        cache_ ? cache_->fetch(hash) : nullptr;

    if (!nodeObject)
    {
        JLOG(j_.trace()) << "fetchNodeObject " << hash << ": record not "
                         << (cache_ ? "cached" : "found");

        Status status;

        try
        {
            status = backend_->fetch(hash.data(), &nodeObject);
        }
        catch (std::exception const& e)
        {
            JLOG(j_.fatal())
                << "fetchNodeObject " << hash
                << ": Exception fetching from backend: " << e.what();
            Rethrow();
        }

        switch (status)
        {
            case ok:
                if (cache_)
                {
                    if (nodeObject)
                        cache_->canonicalize_replace_client(hash, nodeObject);
                    else
                    {
                        auto notFound =
                            NodeObject::createObject(hotDUMMY, {}, hash);
                        cache_->canonicalize_replace_client(hash, notFound);
                        if (notFound->getType() != hotDUMMY)
                            nodeObject = notFound;
                    }
                }
                break;
            case notFound:
                break;
            case dataCorrupt:
                JLOG(j_.fatal()) << "fetchNodeObject " << hash
                                 << ": nodestore data is corrupted";
                break;
            default:
                JLOG(j_.warn())
                    << "fetchNodeObject " << hash
                    << ": backend returns unknown result " << status;
                break;
        }
    }
    else
    {
        JLOG(j_.trace()) << "fetchNodeObject " << hash
                         << ": record found in cache";
        if (nodeObject->getType() == hotDUMMY)
            nodeObject.reset();
    }

    if (nodeObject)
        fetchReport.wasFound = true;

    return nodeObject;
}

std::vector<std::shared_ptr<NodeObject>>
DatabaseNodeImp::fetchBatch(std::vector<uint256> const& hashes)
{
    std::vector<std::shared_ptr<NodeObject>> results{hashes.size()};
    using namespace std::chrono;
    auto const before = steady_clock::now();
    std::unordered_map<uint256 const*, size_t> indexMap;
    std::vector<uint256 const*> cacheMisses;
    uint64_t hits = 0;
    uint64_t fetches = 0;
    for (size_t i = 0; i < hashes.size(); ++i)
    {
        auto const& hash = hashes[i];
        // See if the object already exists in the cache
        auto nObj = cache_ ? cache_->fetch(hash) : nullptr;
        ++fetches;
        if (!nObj)
        {
            // Try the database
            indexMap[&hash] = i;
            cacheMisses.push_back(&hash);
        }
        else
        {
            results[i] = nObj->getType() == hotDUMMY ? nullptr : nObj;
            // It was in the cache.
            ++hits;
        }
    }

    JLOG(j_.debug()) << "fetchBatch - cache hits = "
                     << (hashes.size() - cacheMisses.size())
                     << " - cache misses = " << cacheMisses.size();
    auto dbResults = backend_->fetchBatch(cacheMisses).first;

    for (size_t i = 0; i < dbResults.size(); ++i)
    {
        auto nObj = std::move(dbResults[i]);
        size_t index = indexMap[cacheMisses[i]];
        auto const& hash = hashes[index];

        if (nObj)
        {
            // Ensure all threads get the same object
            if (cache_)
                cache_->canonicalize_replace_client(hash, nObj);
        }
        else
        {
            JLOG(j_.error())
                << "fetchBatch - "
                << "record not found in db or cache. hash = " << strHex(hash);
            if (cache_)
            {
                auto notFound = NodeObject::createObject(hotDUMMY, {}, hash);
                cache_->canonicalize_replace_client(hash, notFound);
                if (notFound->getType() != hotDUMMY)
                    nObj = std::move(notFound);
            }
        }
        results[index] = std::move(nObj);
    }

    auto fetchDurationUs =
        std::chrono::duration_cast<std::chrono::microseconds>(
            steady_clock::now() - before)
            .count();
    updateFetchMetrics(fetches, hits, fetchDurationUs);
    return results;
}

}  // namespace NodeStore
}  // namespace ripple