/**
 *    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.
 */

#pragma once

#include <atomic>
#include <map>

#include "mongo/db/concurrency/d_concurrency.h"
#include "mongo/db/storage/biggie/biggie_visibility_manager.h"
#include "mongo/db/storage/biggie/store.h"
#include "mongo/db/storage/capped_callback.h"
#include "mongo/db/storage/record_store.h"
#include "mongo/platform/atomic_word.h"
#include "mongo/stdx/mutex.h"

namespace mongo {
namespace biggie {

/**
 * A RecordStore that stores all data in-memory.
 */
class RecordStore final : public ::mongo::RecordStore {
public:
    explicit RecordStore(StringData ns,
                         StringData ident,
                         bool isCapped = false,
                         int64_t cappedMaxSize = -1,
                         int64_t cappedMaxDocs = -1,
                         CappedCallback* cappedCallback = nullptr,
                         VisibilityManager* visibilityManager = nullptr);
    ~RecordStore() = default;

    virtual const char* name() const;
    virtual const std::string& getIdent() const;
    virtual long long dataSize(OperationContext* opCtx) const;
    virtual long long numRecords(OperationContext* opCtx) const;
    virtual bool isCapped() const;
    virtual void setCappedCallback(CappedCallback*);
    virtual int64_t storageSize(OperationContext* opCtx,
                                BSONObjBuilder* extraInfo = NULL,
                                int infoLevel = 0) const;

    virtual bool findRecord(OperationContext* opCtx, const RecordId& loc, RecordData* rd) const;

    virtual void deleteRecord(OperationContext* opCtx, const RecordId& dl);

    virtual Status insertRecords(OperationContext* opCtx,
                                 std::vector<Record>* inOutRecords,
                                 const std::vector<Timestamp>& timestamps);

    virtual Status insertRecordsWithDocWriter(OperationContext* opCtx,
                                              const DocWriter* const* docs,
                                              const Timestamp*,
                                              size_t nDocs,
                                              RecordId* idsOut);

    virtual Status updateRecord(OperationContext* opCtx,
                                const RecordId& oldLocation,
                                const char* data,
                                int len);

    virtual bool updateWithDamagesSupported() const;

    virtual StatusWith<RecordData> updateWithDamages(OperationContext* opCtx,
                                                     const RecordId& loc,
                                                     const RecordData& oldRec,
                                                     const char* damageSource,
                                                     const mutablebson::DamageVector& damages);

    std::unique_ptr<SeekableRecordCursor> getCursor(OperationContext* opCtx,
                                                    bool forward) const final;

    virtual Status truncate(OperationContext* opCtx);
    StatusWith<int64_t> truncateWithoutUpdatingCount(OperationContext* opCtx);

    virtual void cappedTruncateAfter(OperationContext* opCtx, RecordId end, bool inclusive);

    virtual Status validate(OperationContext* opCtx,
                            ValidateCmdLevel level,
                            ValidateAdaptor* adaptor,
                            ValidateResults* results,
                            BSONObjBuilder* output);

    virtual void appendCustomStats(OperationContext* opCtx,
                                   BSONObjBuilder* result,
                                   double scale) const;

    virtual Status touch(OperationContext* opCtx, BSONObjBuilder* output) const;

    virtual boost::optional<RecordId> oplogStartHack(OperationContext* opCtx,
                                                     const RecordId& startingPosition) const;

    void waitForAllEarlierOplogWritesToBeVisible(OperationContext* opCtx) const override;

    virtual void updateStatsAfterRepair(OperationContext* opCtx,
                                        long long numRecords,
                                        long long dataSize);

private:
    friend class VisibilityManagerChange;

    /**
     * This gets the next (guaranteed) unique record id.
     */
    inline int64_t _nextRecordId() {
        return _highestRecordId.fetchAndAdd(1);
    }

    /**
     *  Two helper functions for deleting excess records in capped record stores.
     *  The caller should not have an active SizeAdjuster.
     */
    bool _cappedAndNeedDelete(OperationContext* opCtx, StringStore* workingCopy);
    void _cappedDeleteAsNeeded(OperationContext* opCtx, StringStore* workingCopy);

    const bool _isCapped;
    const int64_t _cappedMaxSize;
    const int64_t _cappedMaxDocs;

    std::string _identStr;
    StringData _ident;

    std::string _prefix;
    std::string _postfix;

    mutable stdx::mutex _cappedCallbackMutex;  // Guards _cappedCallback
    CappedCallback* _cappedCallback;

    mutable stdx::mutex _cappedDeleterMutex;

    AtomicWord<long long> _highestRecordId{1};
    AtomicWord<long long> _numRecords{0};
    AtomicWord<long long> _dataSize{0};

    std::string generateKey(const uint8_t* key, size_t key_len) const;

    bool _isOplog;
    VisibilityManager* _visibilityManager;

    /**
     * Automatically adjust the record count and data size based on the size in change of the
     * underlying radix store during the life time of the SizeAdjuster.
     */
    friend class SizeAdjuster;
    class SizeAdjuster {
    public:
        SizeAdjuster(OperationContext* opCtx, RecordStore* rs);
        ~SizeAdjuster();

    private:
        OperationContext* const _opCtx;
        RecordStore* const _rs;
        const StringStore* _workingCopy;
        const int64_t _origNumRecords;
        const int64_t _origDataSize;
    };

    class Cursor final : public SeekableRecordCursor {
        OperationContext* opCtx;
        StringData _ident;
        std::string _prefix;
        std::string _postfix;
        StringStore::const_iterator it;
        boost::optional<std::string> _savedPosition;
        bool _needFirstSeek = true;
        bool _lastMoveWasRestore = false;
        bool _isCapped;
        bool _isOplog;
        VisibilityManager* _visibilityManager;

    public:
        Cursor(OperationContext* opCtx,
               const RecordStore& rs,
               VisibilityManager* visibilityManager);
        boost::optional<Record> next() final;
        boost::optional<Record> seekExact(const RecordId& id) final override;
        void save() final;
        void saveUnpositioned() final override;
        bool restore() final;
        void detachFromOperationContext() final;
        void reattachToOperationContext(OperationContext* opCtx) final;

    private:
        bool inPrefix(const std::string& key_string);
    };

    class ReverseCursor final : public SeekableRecordCursor {
        OperationContext* opCtx;
        StringData _ident;
        std::string _prefix;
        std::string _postfix;
        StringStore::const_reverse_iterator it;
        boost::optional<std::string> _savedPosition;
        bool _needFirstSeek = true;
        bool _lastMoveWasRestore = false;
        bool _isCapped;
        bool _isOplog;
        VisibilityManager* _visibilityManager;

    public:
        ReverseCursor(OperationContext* opCtx,
                      const RecordStore& rs,
                      VisibilityManager* visibilityManager);
        boost::optional<Record> next() final;
        boost::optional<Record> seekExact(const RecordId& id) final override;
        void save() final;
        void saveUnpositioned() final override;
        bool restore() final;
        void detachFromOperationContext() final;
        void reattachToOperationContext(OperationContext* opCtx) final;

    private:
        bool inPrefix(const std::string& key_string);
    };
};

}  // namespace biggie
}  // namespace mongo