/*
 *  Copyright (C) 2004-2026 Savoir-faire Linux Inc.
 *
 *  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 <https://www.gnu.org/licenses/>.
 */
#pragma once

#include "audio/audiolayer.h"
#include "noncopyable.h"

#include <alsa/asoundlib.h>

#include <memory>
#include <thread>

#define PCM_DMIX "plug:dmix" /** Alsa plugin for software mixing */

// Error codes for error handling
#define ALSA_CAPTURE_DEVICE  0x0001 /** Error while opening capture device */
#define ALSA_PLAYBACK_DEVICE 0x0010 /** Error while opening playback device */

/**
 * @file  AlsaLayer.h
 * @brief Main sound class. Manages the data transfers between the application and the hardware.
 */

namespace jami {

class AlsaThread;
class RingBuffer;
class AudioPreference;

/** Associate a sound card index to its string description */
typedef std::pair<int, std::string> HwIDPair;

class AlsaLayer : public AudioLayer
{
public:
    /**
     * Constructor
     */
    AlsaLayer(const AudioPreference& pref);

    /**
     * Destructor
     */
    ~AlsaLayer();

    /**
     * Start the capture stream and prepare the playback stream.
     * The playback starts accordingly to its threshold
     * ALSA Library API
     */
    virtual void startStream(AudioDeviceType stream);

    /**
     * Stop the playback and capture streams.
     * Drops the pending frames and put the capture and playback handles to PREPARED state
     * ALSA Library API
     */
    virtual void stopStream(AudioDeviceType stream = AudioDeviceType::ALL);

    /**
     * Concatenate two strings. Used to build a valid pcm device name.
     * @param plugin the alsa PCM name
     * @param card the sound card number
     * @return std::string the concatenated string
     */
    std::string buildDeviceTopo(const std::string& plugin, int card);

    /**
     * Scan the sound card available on the system
     * @return std::vector<std::string> The vector containing the string description of the card
     */
    virtual std::vector<std::string> getCaptureDeviceList() const;
    virtual std::vector<std::string> getPlaybackDeviceList() const;

    /**
     * Check if the given index corresponds to an existing sound card and supports the specified
     *streaming mode
     * @param card   An index
     * @param stream  The stream mode
     *		  AudioDeviceType::CAPTURE
     *		  AudioDeviceType::PLAYBACK
     *		  AudioDeviceType::RINGTONE
     * @return bool True if it exists and supports the mode
     *		    false otherwise
     */
    static bool soundCardIndexExists(int card, AudioDeviceType stream);

    /**
     * An index is associated with its string description
     * @param description The string description
     * @return	int	  Its index
     */
    int getAudioDeviceIndex(const std::string& description, AudioDeviceType type) const;
    std::string getAudioDeviceName(int index, AudioDeviceType type) const;

    void playback();
    void ringtone();
    void capture();

    /**
     * Get the index of the audio card for capture
     * @return int The index of the card used for capture
     *                     0 for the first available card on the system, 1 ...
     */
    virtual int getIndexCapture() const;

    /**
     * Get the index of the audio card for playback
     * @return int The index of the card used for playback
     *                     0 for the first available card on the system, 1 ...
     */
    virtual int getIndexPlayback() const;

    /**
     * Get the index of the audio card for ringtone (could be differnet from playback)
     * @return int The index of the card used for ringtone
     *                 0 for the first available card on the system, 1 ...
     */
    virtual int getIndexRingtone() const;

    void run();

private:
    /**
     * Returns a map of audio device hardware description and index
     */
    std::vector<HwIDPair> getAudioDeviceIndexMap(bool getCapture) const;

    /**
     * Calls snd_pcm_open and retries if device is busy, since dmix plugin
     * will often hold on to a device temporarily after it has been opened
     * and closed.
     */
    bool openDevice(snd_pcm_t** pcm, const std::string& dev, snd_pcm_stream_t stream, AudioFormat& format);

    /**
     * Number of audio cards on which capture stream has been opened
     */
    int indexIn_;

    /**
     * Number of audio cards on which playback stream has been opened
     */
    int indexOut_;

    /**
     * Number of audio cards on which ringtone stream has been opened
     */
    int indexRing_;

    NON_COPYABLE(AlsaLayer);

    /**
     * Drop the pending frames and close the capture device
     * ALSA Library API
     */
    void closeCaptureStream();
    void stopCaptureStream();
    void startCaptureStream();
    void prepareCaptureStream();

    void closePlaybackStream();
    void stopPlaybackStream();
    void startPlaybackStream();
    void closeRingtoneStream();

    bool alsa_set_params(snd_pcm_t* pcm_handle, AudioFormat& format);

    void startThread();
    void stopThread();

    /**
     * Copy a data buffer in the internal ring buffer
     * ALSA Library API
     * @param buffer The non-interleaved data to be copied
     * @param frames Frames in the buffer
     */
    void write(const AudioFrame& buffer, snd_pcm_t* handle);

    /**
     * Read data from the internal ring buffer
     * ALSA Library API
     * @param buffer  The buffer to stock the read data
     * @param frames  The number of frames to get
     * @return int The number of frames actually read
     */
    std::unique_ptr<AudioFrame> read(unsigned frames);

    virtual void updatePreference(AudioPreference& pref, int index, AudioDeviceType type);

    /**
     * Handles to manipulate playback stream
     * ALSA Library API
     */
    snd_pcm_t* playbackHandle_ {nullptr};

    /**
     * Handles to manipulate ringtone stream
     *
     */
    snd_pcm_t* ringtoneHandle_ {nullptr};

    /**
     * Handles to manipulate capture stream
     * ALSA Library API
     */
    snd_pcm_t* captureHandle_ {nullptr};

    /**
     * name of the alsa audio plugin used
     */
    std::string audioPlugin_;

    bool is_capture_prepared_ {false};
    bool is_playback_running_ {false};
    bool is_capture_running_ {false};
    bool is_playback_open_ {false};
    bool is_capture_open_ {false};

    std::atomic_bool running_ {false};
    std::thread audioThread_;
};

} // namespace jami
