3 files changed, 217 insertions, 1 deletions

diff --git a/mumd/src/audio/fallback_sfx.wav b/mumd/src/audio/fallback_sfx.wav
new file mode 100644
index 0000000..82ee4d4
--- /dev/null
+++ b/mumd/src/audio/fallback_sfx.wav
diff --git a/mumd/src/audio/output.rs b/mumd/src/audio/output.rs
index b945710..6aa67dd 100644
--- a/mumd/src/audio/output.rs
+++ b/mumd/src/audio/output.rs
@@ -180,7 +180,7 @@ impl DefaultAudioOutputDevice {
             .supported_output_configs()
             .map_err(|e| AudioError::NoConfigs(AudioStream::Output, e))?
             .find_map(|c| {
-                if c.min_sample_rate() <= sample_rate && c.max_sample_rate() >= sample_rate {
+                if c.min_sample_rate() <= sample_rate && c.max_sample_rate() >= sample_rate && c.channels() == 2 {
                     Some(c)
                 } else {
                     None
diff --git a/mumd/src/audio/sound_effects.rs b/mumd/src/audio/sound_effects.rs
new file mode 100644
index 0000000..205b3f7
--- /dev/null
+++ b/mumd/src/audio/sound_effects.rs
@@ -0,0 +1,216 @@
+use dasp_interpolate::linear::Linear;
+use dasp_signal::{self as signal, Signal};
+use log::warn;
+use mumlib::config::SoundEffect;
+use std::borrow::Cow;
+use std::collections::HashMap;
+use std::convert::TryFrom;
+use std::fs::File;
+#[cfg(feature = "ogg")]
+use std::io::Cursor;
+use std::io::Read;
+use std::path::Path;
+use strum::IntoEnumIterator;
+use strum_macros::EnumIter;
+
+use crate::audio::SAMPLE_RATE;
+
+/// The different kinds of files we can open.
+enum AudioFileKind {
+    Ogg,
+    Wav,
+}
+
+impl TryFrom<&str> for AudioFileKind {
+    type Error = ();
+
+    fn try_from(s: &str) -> Result<Self, Self::Error> {
+        match s {
+            "ogg" => Ok(AudioFileKind::Ogg),
+            "wav" => Ok(AudioFileKind::Wav),
+            _ => Err(()),
+        }
+    }
+}
+
+/// A specification accompanying some audio data.
+struct AudioSpec {
+    channels: u32,
+    sample_rate: u32,
+}
+
+/// An event where a notification is shown and a sound effect is played.
+#[derive(Debug, Eq, PartialEq, Clone, Copy, Hash, EnumIter)]
+pub enum NotificationEvents {
+    ServerConnect,
+    ServerDisconnect,
+    UserConnected,
+    UserDisconnected,
+    UserJoinedChannel,
+    UserLeftChannel,
+    Mute,
+    Unmute,
+    Deafen,
+    Undeafen,
+}
+
+impl TryFrom<&str> for NotificationEvents {
+    type Error = ();
+
+    fn try_from(s: &str) -> Result<Self, Self::Error> {
+        match s {
+            "server_connect" => Ok(NotificationEvents::ServerConnect),
+            "server_disconnect" => Ok(NotificationEvents::ServerDisconnect),
+            "user_connected" => Ok(NotificationEvents::UserConnected),
+            "user_disconnected" => Ok(NotificationEvents::UserDisconnected),
+            "user_joined_channel" => Ok(NotificationEvents::UserJoinedChannel),
+            "user_left_channel" => Ok(NotificationEvents::UserLeftChannel),
+            "mute" => Ok(NotificationEvents::Mute),
+            "unmute" => Ok(NotificationEvents::Unmute),
+            "deafen" => Ok(NotificationEvents::Deafen),
+            "undeafen" => Ok(NotificationEvents::Undeafen),
+            _ => {
+                warn!("Unknown notification event '{}' in config", s);
+                Err(())
+            }
+        }
+    }
+}
+
+/// Loads files into an "event -> data"-map, with support for overriding
+/// specific events with another sound file.
+pub fn load_sound_effects(overrides: &[SoundEffect], num_channels: usize) -> HashMap<NotificationEvents, Vec<f32>> {
+    let overrides: HashMap<_, _> = overrides
+        .iter()
+        .filter_map(|sound_effect| {
+            let (event, file) = (&sound_effect.event, &sound_effect.file);
+            if let Ok(event) = NotificationEvents::try_from(event.as_str()) {
+                Some((event, file))
+            } else {
+                None
+            }
+        })
+        .collect();
+
+    // Construct a hashmap that maps every [NotificationEvent] to a vector of
+    // plain floating point audio data with the global sample rate as a
+    // Vec<f32>. We do this by iterating over all [NotificationEvent]-variants
+    // and opening either the file passed as an override or the fallback sound
+    // effect (if omitted). We then use dasp to convert to the correct sample rate.
+    NotificationEvents::iter()
+        .map(|event| {
+            let file = overrides.get(&event);
+            // Try to open the file if overriden, otherwise use the default sound effect.
+            let (data, kind) = file
+                .and_then(|file| {
+                    // Try to get the file kind from the extension.
+                    let kind = file
+                        .split('.')
+                        .last()
+                        .and_then(|ext| AudioFileKind::try_from(ext).ok())?;
+                    Some((get_sfx(file), kind))
+                })
+                .unwrap_or_else(|| (get_default_sfx(), AudioFileKind::Wav));
+            // Unpack the samples.
+            let (samples, spec) = unpack_audio(data, kind);
+            // If the audio is mono (single channel), pad every sample with
+            // itself, since we later assume that audio is stored interleaved as
+            // LRLRLR (or RLRLRL). Without this, mono audio would be played in
+            // double speed.
+            let iter: Box<dyn Iterator<Item = f32>> = match spec.channels {
+                1 => Box::new(samples.into_iter().flat_map(|e| vec![e, e])),
+                2 => Box::new(samples.into_iter()),
+                _ => unimplemented!("Only mono and stereo sound is supported. See #80."),
+            };
+            // Create a dasp signal containing stereo sound.
+            let mut signal = signal::from_interleaved_samples_iter::<_, [f32; 2]>(iter);
+            // Create a linear interpolator, in case we need to convert the sample rate.
+            let interp = Linear::new(Signal::next(&mut signal), Signal::next(&mut signal));
+            // Create our resulting samples.
+            let samples = signal
+                .from_hz_to_hz(interp, spec.sample_rate as f64, SAMPLE_RATE as f64)
+                .until_exhausted()
+                // If the source audio is stereo and is being played as mono, discard the first channel.
+                .flat_map(|e| {
+                    if num_channels == 1 {
+                        vec![e[0]]
+                    } else {
+                        e.to_vec()
+                    }
+                })
+                .collect::<Vec<f32>>();
+            (event, samples)
+        })
+        .collect()
+}
+
+/// Unpack audio data. The required audio spec is read from the file and returned as well.
+fn unpack_audio(data: Cow<'_, [u8]>, kind: AudioFileKind) -> (Vec<f32>, AudioSpec) {
+    match kind {
+        AudioFileKind::Ogg => unpack_ogg(data),
+        AudioFileKind::Wav => unpack_wav(data),
+    }
+}
+
+#[cfg(feature = "ogg")]
+/// Unpack ogg data.
+fn unpack_ogg(data: Cow<'_, [u8]>) -> (Vec<f32>, AudioSpec) {
+    let mut reader = lewton::inside_ogg::OggStreamReader::new(Cursor::new(data.as_ref())).unwrap();
+    let mut samples = Vec::new();
+    while let Ok(Some(mut frame)) = reader.read_dec_packet_itl() {
+        samples.append(&mut frame);
+    }
+    let samples = samples.iter().map(|s| cpal::Sample::to_f32(s)).collect();
+    let spec = AudioSpec {
+        channels: reader.ident_hdr.audio_channels as u32,
+        sample_rate: reader.ident_hdr.audio_sample_rate,
+    };
+    (samples, spec)
+}
+
+#[cfg(not(feature = "ogg"))]
+/// Fallback to default sound effect since ogg is disabled.
+fn unpack_ogg(_: Cow<'_, [u8]>) -> (Vec<f32>, AudioSpec) {
+    warn!("Can't open .ogg without the ogg-feature enabled.");
+    unpack_wav(get_default_sfx())
+}
+
+/// Unpack wav data.
+fn unpack_wav(data: Cow<'_, [u8]>) -> (Vec<f32>, AudioSpec) {
+    let reader = hound::WavReader::new(data.as_ref()).unwrap();
+    let spec = reader.spec();
+    let samples = match spec.sample_format {
+        hound::SampleFormat::Float => reader
+            .into_samples::<f32>()
+            .map(|e| e.unwrap())
+            .collect::<Vec<_>>(),
+        hound::SampleFormat::Int => reader
+            .into_samples::<i16>()
+            .map(|e| cpal::Sample::to_f32(&e.unwrap()))
+            .collect::<Vec<_>>(),
+    };
+    let spec = AudioSpec {
+        channels: spec.channels as u32,
+        sample_rate: spec.sample_rate,
+    };
+    (samples, spec)
+}
+
+/// Open and return the data contained in a file, or the default sound effect if
+/// the file couldn't be found.
+// moo
+fn get_sfx<P: AsRef<Path>>(file: P) -> Cow<'static, [u8]> {
+    let mut buf: Vec<u8> = Vec::new();
+    if let Ok(mut file) = File::open(file.as_ref()) {
+        file.read_to_end(&mut buf).unwrap();
+        Cow::from(buf)
+    } else {
+        warn!("File not found: '{}'", file.as_ref().display());
+        get_default_sfx()
+    }
+}
+
+/// Get the default sound effect.
+fn get_default_sfx() -> Cow<'static, [u8]> {
+    Cow::from(include_bytes!("fallback_sfx.wav").as_ref())
+}