/***
    This file is part of snapcast
    Copyright (C) 2014-2024  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/>.
***/

#pragma once

// local headers
#include "common/message/codec_header.hpp"
#include "common/message/pcm_chunk.hpp"
#include "common/sample_format.hpp"

// standard headers
#include <functional>
#include <memory>
#include <string>


namespace encoder
{

/// 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:
    /// Callback type to return encoded chunks, along with the encoder itself and the duration in ms of the chunk
    using OnEncodedCallback = std::function<void(const Encoder&, std::shared_ptr<msg::PcmChunk>, double)>;

    /// c'tor
    /// Codec options (E.g. compression level) are passed as string and are codec dependend
    Encoder(const std::string& codecOptions = "") : headerChunk_(nullptr), codecOptions_(codecOptions)
    {
    }

    /// d'tor
    virtual ~Encoder() = default;

    /// The listener will receive the encoded stream
    virtual void init(OnEncodedCallback callback, const SampleFormat& format)
    {
        if (codecOptions_.empty())
            codecOptions_ = getDefaultOptions();
        encoded_callback_ = std::move(callback);
        sampleFormat_ = format;
        initEncoder();
    }

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

    /// @return the name of the encoder
    virtual std::string name() const = 0;

    /// @return configuration options of the encoder
    virtual std::string getAvailableOptions() const
    {
        return "No codec options supported";
    }

    /// @return default configuration option of the encoder
    virtual std::string getDefaultOptions() const
    {
        return "";
    }

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

protected:
    /// Initialize the encoder
    virtual void initEncoder() = 0;

    /// The sampleformat
    SampleFormat sampleFormat_;
    /// The codec header, sent to each newly connected streaming client
    std::shared_ptr<msg::CodecHeader> headerChunk_;
    /// The configured codec options
    std::string codecOptions_;
    /// Callback to return encoded chunks
    OnEncodedCallback encoded_callback_;
};

} // namespace encoder