/***
    This file is part of snapcast
    Copyright (C) 2014-2019  Johannes Pohl

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    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
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
***/

#ifndef ENCODER_H
#define ENCODER_H

#include <memory>
#include <string>

#include "common/sample_format.hpp"
#include "message/codecHeader.h"
#include "message/pcmChunk.h"


class Encoder;

/// Callback interface for users of Encoder
/**
 * Users of Encoder should implement this to get the encoded PCM data
 */
class EncoderListener
{
public:
    virtual void onChunkEncoded(const Encoder* encoder, msg::PcmChunk* chunk, double duration) = 0;
};



/// Abstract Encoder class
/**
 * Stream encoder. PCM chunks are fed into the encoder.
 * As soon as a frame is encoded, the encoded data is passed to the EncoderListener
 */
class Encoder
{
public:
    /// ctor. Codec options (E.g. compression level) are passed as string and are codec dependend
    Encoder(const std::string& codecOptions = "") : headerChunk_(nullptr), codecOptions_(codecOptions)
    {
    }

    virtual ~Encoder() = default;

    /// The listener will receive the encoded stream
    virtual void init(EncoderListener* listener, const SampleFormat& format)
    {
        if (codecOptions_ == "")
            codecOptions_ = getDefaultOptions();
        listener_ = listener;
        sampleFormat_ = format;
        initEncoder();
    }

    /// Here the work is done. Encoded data is passed to the EncoderListener.
    virtual void encode(const msg::PcmChunk* chunk) = 0;

    virtual std::string name() const = 0;

    virtual std::string getAvailableOptions() const
    {
        return "No codec options supported";
    }

    virtual std::string getDefaultOptions() const
    {
        return "";
    }

    /// Header information needed to decode the data
    virtual std::shared_ptr<msg::CodecHeader> getHeader() const
    {
        return headerChunk_;
    }

protected:
    virtual void initEncoder() = 0;

    SampleFormat sampleFormat_;
    std::shared_ptr<msg::CodecHeader> headerChunk_;
    EncoderListener* listener_;
    std::string codecOptions_;
};


#endif