rust_voice_chat_room/protocol/src/protocol.rs

use std::sync::Arc;

use bincode::{Decode, Encode};
use tokio::sync::broadcast;

use crate::Error;

const SIGNAL_DATA_LENGTH: usize = 4;
pub const NETWORK_DATA_LENGTH: usize = 6;
pub const SPEAKER_ACTION_CHANNEL_LENGTH: usize = 128;
pub const AUDIO_DATA_SENDER_CHANNEL_LENGTH: usize = 1024 * 4;
pub const DEFAULT_SAMPLE_RATE: u32 = 44100;

pub type SpeakerWithDataAndAction = (SpeakerWithData, SpeakerAction);
type SignalBufferReturn = [u8; SIGNAL_DATA_LENGTH];
type NetworkBufferReturn = [u8; NETWORK_DATA_LENGTH];

static BINCODE_CONFIG: bincode::config::Configuration<bincode::config::BigEndian> =
    bincode::config::standard().with_big_endian();

#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Encode, Decode)]
pub struct Speaker {
    id: u8,
}

impl Speaker {
    pub fn new(id: u8) -> Self {
        Self { id }
    }

    pub fn get_id(&self) -> u8 {
        self.id
    }
}

#[derive(Debug, Clone, Copy)]
pub enum SpeakerAction {
    Join,
    Left,
}

#[derive(Debug, Clone)]
pub struct SpeakerWithData {
    speaker: Speaker,
    speaker_action_sender: Arc<broadcast::Sender<(SpeakerWithData, SpeakerAction)>>,
    audio_data_sender: Arc<broadcast::Sender<f32>>,
}

impl SpeakerWithData {
    pub fn new(speaker: Speaker) -> Self {
        let speaker_action_sender = broadcast::channel(SPEAKER_ACTION_CHANNEL_LENGTH).0.into();
        let audio_data_sender = broadcast::channel(AUDIO_DATA_SENDER_CHANNEL_LENGTH)
            .0
            .into();

        Self {
            speaker,
            speaker_action_sender,
            audio_data_sender,
        }
    }

    pub fn get_speaker_id(&self) -> u8 {
        self.speaker.get_id()
    }

    pub fn get_speaker(&self) -> Speaker {
        self.speaker
    }

    pub fn send_speaker_action(&self, speaker_with_data_and_action: SpeakerWithDataAndAction) {
        let _ = self
            .speaker_action_sender
            .send(speaker_with_data_and_action);
    }

    pub fn clone_audio_data_sender(&self) -> Arc<broadcast::Sender<f32>> {
        self.audio_data_sender.clone()
    }

    pub fn subscribe_speaker_action_channel(
        &self,
    ) -> broadcast::Receiver<(SpeakerWithData, SpeakerAction)> {
        self.speaker_action_sender.subscribe()
    }

    pub fn subscribe_audio_data_channel(&self) -> broadcast::Receiver<f32> {
        self.audio_data_sender.subscribe()
    }
}

#[derive(Debug, Clone, Copy, Encode, Decode)]
pub enum SignalType {
    AudioDatum,
    SpeakerLeft,
}

#[derive(Debug, Clone, Copy, Encode, Decode)]
pub struct Signal {
    signal_type: SignalType,
    speaker: Speaker,
    data: SignalBufferReturn,
}

impl Signal {
    pub fn get_signal_type(&self) -> SignalType {
        self.signal_type
    }

    pub fn get_speaker_id(&self) -> u8 {
        self.speaker.get_id()
    }

    pub fn get_audio_datum(&self) -> f32 {
        f32::from_be_bytes(self.data)
    }

    pub fn unpack(data: NetworkBufferReturn) -> Result<Self, Error> {
        Ok(bincode::decode_from_slice::<Self, _>(&data, BINCODE_CONFIG)
            .map_err(|inner| Error::Deserialization(inner.to_string()))?
            .0)
    }

    fn pack(self) -> NetworkBufferReturn {
        let encoded = serialize(self);

        assert_eq!(encoded.len(), NETWORK_DATA_LENGTH);

        let mut buffer = NetworkBufferReturn::default();
        buffer.copy_from_slice(&encoded);

        buffer
    }

    pub fn pack_audio_datum(speaker: Speaker, audio_datum: f32) -> NetworkBufferReturn {
        let signal = Self {
            signal_type: SignalType::AudioDatum,
            speaker,
            data: audio_datum.to_be_bytes(),
        };

        Self::pack(signal)
    }

    pub fn pack_speaker_left(speaker: Speaker) -> NetworkBufferReturn {
        let signal = Self {
            signal_type: SignalType::SpeakerLeft,
            speaker,
            data: SignalBufferReturn::default(),
        };

        signal.pack()
    }
}

fn serialize<E>(value: E) -> Vec<u8>
where
    E: bincode::enc::Encode,
{
    bincode::encode_to_vec(value, BINCODE_CONFIG)
        .map_err(|inner| Error::Serialization(inner.to_string()))
        .unwrap()
}