/**
 *    Copyright (C) 2018-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the Server Side Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */

#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kStorage

#include "mongo/platform/basic.h"

#include "mongo/db/storage/remove_saver.h"

#include <boost/filesystem/operations.hpp>
#include <fstream>

#include "mongo/db/service_context.h"
#include "mongo/db/storage/encryption_hooks.h"
#include "mongo/db/storage/storage_options.h"
#include "mongo/util/errno_util.h"
#include "mongo/util/log.h"


using std::ios_base;
using std::ofstream;
using std::stringstream;
using std::string;

namespace mongo {

RemoveSaver::RemoveSaver(const string& a, const string& b, const string& why) {
    static int NUM = 0;

    _root = storageGlobalParams.dbpath;
    if (a.size())
        _root /= a;
    if (b.size())
        _root /= b;
    verify(a.size() || b.size());

    _file = _root;

    stringstream ss;
    ss << why << "." << terseCurrentTime(false) << "." << NUM++ << ".bson";
    _file /= ss.str();

    auto encryptionHooks = EncryptionHooks::get(getGlobalServiceContext());
    if (encryptionHooks->enabled()) {
        _protector = encryptionHooks->getDataProtector();
        _file += encryptionHooks->getProtectedPathSuffix();
    }
}

RemoveSaver::~RemoveSaver() {
    if (_protector && _out) {
        auto encryptionHooks = EncryptionHooks::get(getGlobalServiceContext());
        invariant(encryptionHooks->enabled());

        size_t protectedSizeMax = encryptionHooks->additionalBytesForProtectedBuffer();
        std::unique_ptr<uint8_t[]> protectedBuffer(new uint8_t[protectedSizeMax]);

        size_t resultLen;
        Status status = _protector->finalize(protectedBuffer.get(), protectedSizeMax, &resultLen);
        if (!status.isOK()) {
            severe() << "Unable to finalize DataProtector while closing RemoveSaver: "
                     << redact(status);
            fassertFailed(34350);
        }

        _out->write(reinterpret_cast<const char*>(protectedBuffer.get()), resultLen);
        if (_out->fail()) {
            severe() << "Couldn't write finalized DataProtector data to: " << _file.string()
                     << " for remove saving: " << redact(errnoWithDescription());
            fassertFailed(34351);
        }

        protectedBuffer.reset(new uint8_t[protectedSizeMax]);
        status = _protector->finalizeTag(protectedBuffer.get(), protectedSizeMax, &resultLen);
        if (!status.isOK()) {
            severe() << "Unable to get finalizeTag from DataProtector while closing RemoveSaver: "
                     << redact(status);
            fassertFailed(34352);
        }

        if (resultLen != _protector->getNumberOfBytesReservedForTag()) {
            severe() << "Attempted to write tag of size " << resultLen
                     << " when DataProtector only reserved "
                     << _protector->getNumberOfBytesReservedForTag() << " bytes";
            fassertFailed(34353);
        }

        _out->seekp(0);
        _out->write(reinterpret_cast<const char*>(protectedBuffer.get()), resultLen);

        if (_out->fail()) {
            severe() << "Couldn't write finalizeTag from DataProtector to: " << _file.string()
                     << " for remove saving: " << redact(errnoWithDescription());
            fassertFailed(34354);
        }
    }
}

Status RemoveSaver::goingToDelete(const BSONObj& o) {
    if (!_out) {
        // We don't expect to ever pass "" to create_directories below, but catch
        // this anyway as per SERVER-26412.
        invariant(!_root.empty());
        boost::filesystem::create_directories(_root);
        _out.reset(new ofstream(_file.string().c_str(), ios_base::out | ios_base::binary));

        if (_out->fail()) {
            string msg = str::stream() << "couldn't create file: " << _file.string()
                                       << " for remove saving: " << redact(errnoWithDescription());
            error() << msg;
            _out.reset();
            _out = 0;
            return Status(ErrorCodes::FileNotOpen, msg);
        }
    }

    const uint8_t* data = reinterpret_cast<const uint8_t*>(o.objdata());
    size_t dataSize = o.objsize();

    std::unique_ptr<uint8_t[]> protectedBuffer;
    if (_protector) {
        auto encryptionHooks = EncryptionHooks::get(getGlobalServiceContext());
        invariant(encryptionHooks->enabled());

        size_t protectedSizeMax = dataSize + encryptionHooks->additionalBytesForProtectedBuffer();
        protectedBuffer.reset(new uint8_t[protectedSizeMax]);

        size_t resultLen;
        Status status = _protector->protect(
            data, dataSize, protectedBuffer.get(), protectedSizeMax, &resultLen);

        if (!status.isOK()) {
            return status;
        }

        data = protectedBuffer.get();
        dataSize = resultLen;
    }

    _out->write(reinterpret_cast<const char*>(data), dataSize);

    if (_out->fail()) {
        string msg = str::stream() << "couldn't write document to file: " << _file.string()
                                   << " for remove saving: " << redact(errnoWithDescription());
        error() << msg;
        return Status(ErrorCodes::OperationFailed, msg);
    }

    return Status::OK();
}

}  // namespace mongo