/*

 * Copyright 2013-2022 Step Function I/O, LLC

 *

 * Licensed to Green Energy Corp (www.greenenergycorp.com) and Step Function I/O

 * LLC (https://stepfunc.io) under one or more contributor license agreements.

 * See the NOTICE file distributed with this work for additional information

 * regarding copyright ownership. Green Energy Corp and Step Function I/O LLC license

 * this file to you under the Apache License, Version 2.0 (the "License"); you

 * may not use this file except in compliance with the License. You may obtain

 * a copy of the License at:

 *

 * http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#ifndef OPENDNP3_LINKLAYERPARSER_H

#define OPENDNP3_LINKLAYERPARSER_H

#include "link/IFrameSink.h"

#include "link/LinkFrame.h"

#include "link/LinkHeader.h"

#include "link/ShiftableBuffer.h"

#include "opendnp3/link/LinkStatistics.h"

#include "opendnp3/logging/Logger.h"

#include <ser4cpp/container/SequenceTypes.h>

namespace opendnp3

{

/// Parses FT3 frames

class LinkLayerParser

{

    enum class State

    {

        FindSync,

        ReadHeader,

        ReadBody,

        Complete

    };

public:

    /// @param logger_ Logger that the receiver is to use.

    /// @param pSink_ Completely parsed frames are sent to this interface

    LinkLayerParser(const Logger& logger);

    /// Called when valid data has been written to the current buffer write position

    /// Parses the new data and calls the specified frame sink

    /// @param numBytes Number of bytes written

    void OnRead(size_t numBytes, IFrameSink& sink);

    /// @return Buffer that can currently be used for writing

    ser4cpp::wseq_t WriteBuff() const;

    /// Resets the state of parser

    void Reset();

    const LinkStatistics::Parser& Statistics() const

    {

        return this->statistics;

    }

private:

    State ParseUntilComplete();

    State ParseOneStep();

    State ParseSync();

    State ParseHeader();

    State ParseBody();

    void PushFrame(IFrameSink& sink);

    bool ReadHeader();

    bool ValidateBody();

    bool ValidateHeaderParameters();

    bool ValidateFunctionCode();

    void FailFrame();

    void TransferUserData();

    Logger logger;

    LinkStatistics::Parser statistics;

    LinkHeader header;

    State state;

    size_t frameSize;

    ser4cpp::rseq_t userData;

    // buffer where received data is written

    uint8_t rxBuffer[LPDU_MAX_FRAME_SIZE];

    // facade over the rxBuffer that provides ability to "shift" as data is read

    ShiftableBuffer buffer;

};

} // namespace opendnp3

#endif