From 12554b2f6cd89ad3cd3721bbc790d7772a21c3ae Mon Sep 17 00:00:00 2001
From: Rubens Brandao <git@rubens.io>
Date: Wed, 7 Apr 2021 09:29:23 -0300
Subject: Create a trait and default implementation for device audio input

---
 mumd/src/audio/input.rs | 110 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 109 insertions(+), 1 deletion(-)

(limited to 'mumd/src/audio/input.rs')

diff --git a/mumd/src/audio/input.rs b/mumd/src/audio/input.rs
index 176747d..f4e9c4c 100644
--- a/mumd/src/audio/input.rs
+++ b/mumd/src/audio/input.rs
@@ -1,8 +1,11 @@
-use cpal::{InputCallbackInfo, Sample};
+use cpal::{InputCallbackInfo, Sample, SampleFormat, SampleRate, StreamConfig};
+use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
 use tokio::sync::watch;
 use log::*;
 
 use crate::state::StatePhase;
+use crate::audio::SAMPLE_RATE;
+use crate::error::{AudioError, AudioStream};
 
 pub fn callback<T: Sample>(
     mut input_sender: futures_channel::mpsc::Sender<f32>,
@@ -24,3 +27,108 @@ pub fn callback<T: Sample>(
         }
     }
 }
+
+pub trait AudioInputDevice {
+    fn play(&self) -> Result<(), AudioError>;
+    fn pause(&self) -> Result<(), AudioError>;
+    fn set_volume(&self, volume: f32);
+    fn sample_receiver(&mut self) -> futures_channel::mpsc::Receiver<f32>;
+    fn get_num_channels(&self) -> usize;
+}
+
+pub struct DefaultAudioInputDevice {
+    _stream: cpal::Stream,
+    sample_receiver: Option<futures_channel::mpsc::Receiver<f32>>,
+    volume_sender: watch::Sender<f32>,
+    channels: u16,
+}
+
+impl DefaultAudioInputDevice {
+    pub fn new(input_volume: f32, phase_watcher: watch::Receiver<StatePhase>) -> Result<Self, AudioError> {
+        let sample_rate = SampleRate(SAMPLE_RATE);
+
+        let host = cpal::default_host();
+
+        let input_device = host
+            .default_input_device()
+            .ok_or(AudioError::NoDevice(AudioStream::Input))?;
+        let input_supported_config = input_device
+            .supported_input_configs()
+            .map_err(|e| AudioError::NoConfigs(AudioStream::Input, e))?
+            .find_map(|c| {
+                if c.min_sample_rate() <= sample_rate && c.max_sample_rate() >= sample_rate {
+                    Some(c)
+                } else {
+                    None
+                }
+            })
+            .ok_or(AudioError::NoSupportedConfig(AudioStream::Input))?
+            .with_sample_rate(sample_rate);
+        let input_supported_sample_format = input_supported_config.sample_format();
+        let input_config: StreamConfig = input_supported_config.into();
+
+        let err_fn = |err| error!("An error occurred on the output audio stream: {}", err);
+
+        let (sample_sender, sample_receiver) = futures_channel::mpsc::channel(1_000_000);
+
+        let (volume_sender, input_volume_receiver) = watch::channel::<f32>(input_volume);
+
+        let input_stream = match input_supported_sample_format {
+            SampleFormat::F32 => input_device.build_input_stream(
+                &input_config,
+                callback::<f32>(
+                    sample_sender,
+                    input_volume_receiver,
+                    phase_watcher,
+                ),
+                err_fn,
+            ),
+            SampleFormat::I16 => input_device.build_input_stream(
+                &input_config,
+                callback::<i16>(
+                    sample_sender,
+                    input_volume_receiver,
+                    phase_watcher,
+                ),
+                err_fn,
+            ),
+            SampleFormat::U16 => input_device.build_input_stream(
+                &input_config,
+                callback::<u16>(
+                    sample_sender,
+                    input_volume_receiver,
+                    phase_watcher,
+                ),
+                err_fn,
+            ),
+        }
+        .map_err(|e| AudioError::InvalidStream(AudioStream::Input, e))?;
+
+        let res = Self {
+            _stream: input_stream,
+            sample_receiver: Some(sample_receiver),
+            volume_sender,
+            channels: input_config.channels,
+        };
+        Ok(res)
+    }
+}
+
+impl AudioInputDevice for DefaultAudioInputDevice {
+    fn play(&self) -> Result<(), AudioError> {
+        self._stream.play().map_err(|e| AudioError::InputPlayError(e))
+    }
+    fn pause(&self) -> Result<(), AudioError> {
+        self._stream.pause().map_err(|e| AudioError::InputPauseError(e))
+    }
+    fn set_volume(&self, volume: f32) {
+        self.volume_sender.send(volume).unwrap();
+    }
+    fn sample_receiver(&mut self) -> futures_channel::mpsc::Receiver<f32> {
+        let ret = self.sample_receiver.take();
+        ret.unwrap()
+    }
+    fn get_num_channels(&self) -> usize {
+        self.channels as usize
+    }
+}
-- 
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