Add Platform trait.

I did some more thinking about the whole trait/boundary stuff and reallized that we don't need the GUI to handle the generic-ness of a trait object since only 1 platform will ever be used in a binary. What do you think of the following:

1. Define a platform trait
2. Each platform defines a zero-sized struct implementing the trait (ex `WebPlatform`).
3. Create an ifdef'd type alias on those structs:

```
     // gui/src/platform/mod.rs
     #[cfg(feature = "web")]
     pub type CurrentPlatform = web::WebPlatform;
     #[cfg(feature = "desktop")]
     pub type CurrentPlatform = desktop::DesktopPlatform;
     #[cfg(feature = "mobile")]
     pub type CurrentPlatform = mobile::MobilePlatform;
```

4. Add a compile time assertion that `CurrentPlatform` implements `Platform`.

Pros:

- We don't end up working around async trait objects
- We define what functions are needed for a platform
- We save a little on binary size by avoiding a fully generic solution.

Cons:

- The trait does not really do much other than being a collection of functions.
- In some ways it seems like what we're currently doing but with extra steps.

gui/src/effects.rs

@@ -7,7 +7,10 @@ use std::cell::RefCell;
 use std::sync::Arc;
 use tracing::{error, info};
 
-use crate::imp;
+use crate::imp::{CurrentPlatform, PlatformRuntime, SpawnHandleTrait};
+
+/// The spawn handle type for the current platform.
+type SpawnHandle = <CurrentPlatform as PlatformRuntime>::SpawnHandle;
 
 static DF_MODEL: Asset = asset!("/assets/DeepFilterNet3_ll_onnx.tar.gz");
 // TODO: make this user configurable.
@@ -33,7 +36,7 @@ enum DenoisingModelState {
 }
 
 fn with_denoising_model<O>(
-    spawn: &imp::SpawnHandle,
+    spawn: &SpawnHandle,
     func: impl FnOnce(&mut DfTract) -> O,
 ) -> Option<O> {
     // Using a thread local is super gross, but DfTract is not Send (so it can never leave the current
@@ -89,7 +92,7 @@ fn with_denoising_model<O>(
 
 pub struct AudioProcessor {
     denoise: bool,
-    spawn: imp::SpawnHandle,
+    spawn: SpawnHandle,
     buffer: Vec<f32>,
     noise_floor: f32,
     /// Whether we were transmitting in the previous frame
@@ -102,7 +105,7 @@ impl AudioProcessor {
     pub fn new_plain() -> Self {
         AudioProcessor {
             denoise: false,
-            spawn: imp::SpawnHandle::current(),
+            spawn: SpawnHandle::current(),
             buffer: Vec::new(),
             noise_floor: DEFAULT_NOISE_FLOOR,
             was_transmitting: false,
@@ -113,7 +116,7 @@ impl AudioProcessor {
     pub fn new_denoising() -> Self {
         AudioProcessor {
             denoise: true,
-            spawn: imp::SpawnHandle::current(),
+            spawn: SpawnHandle::current(),
             buffer: Vec::new(),
             noise_floor: DEFAULT_NOISE_FLOOR,
             was_transmitting: false,

gui/src/imp/desktop.rs

@@ -1,13 +1,114 @@
+use crate::app::Command;
+use color_eyre::eyre::Error;
+use dioxus::hooks::UnboundedReceiver;
 use etcetera::{choose_app_strategy, AppStrategy, AppStrategyArgs};
-use mumble_web2_common::ClientConfig;
+use mumble_web2_common::{ClientConfig, ServerStatus};
 use std::collections::HashMap;
-pub use tokio::runtime::Handle as SpawnHandle;
-pub use tokio::task::spawn;
-pub use tokio::time::sleep;
+use std::future::Future;
+use std::time::Duration;
+
+use super::{Platform, PlatformConfig, PlatformInit, PlatformNetwork, PlatformRuntime, SpawnHandleTrait};
 
 pub use super::connect::*;
 pub use super::native_audio::*;
 
+pub use tokio::task::spawn;
+pub use tokio::time::sleep;
+
+// ============================================================================
+// Platform Struct
+// ============================================================================
+
+/// Desktop platform implementation using Tokio and native audio.
+pub struct DesktopPlatform;
+
+// ============================================================================
+// SpawnHandle
+// ============================================================================
+
+pub type SpawnHandle = tokio::runtime::Handle;
+
+impl SpawnHandleTrait for SpawnHandle {
+    fn spawn<F>(&self, future: F)
+    where
+        F: Future<Output = ()> + Send + 'static,
+    {
+        let _ = tokio::runtime::Handle::spawn(self, future);
+    }
+
+    fn current() -> Self {
+        tokio::runtime::Handle::current()
+    }
+}
+
+// ============================================================================
+// Trait Implementations
+// ============================================================================
+
+impl PlatformRuntime for DesktopPlatform {
+    type SpawnHandle = SpawnHandle;
+
+    fn spawn<F>(future: F)
+    where
+        F: Future<Output = ()> + Send + 'static,
+    {
+        let _ = tokio::task::spawn(future);
+    }
+
+    async fn sleep(duration: Duration) {
+        tokio::time::sleep(duration).await;
+    }
+}
+
+impl PlatformConfig for DesktopPlatform {
+    async fn load_config() -> color_eyre::Result<ClientConfig> {
+        load_config().await
+    }
+
+    fn load_username() -> Option<String> {
+        load_username()
+    }
+
+    fn load_server_url() -> Option<String> {
+        load_server_url()
+    }
+
+    fn set_default_username(username: &str) -> Option<()> {
+        set_default_username(username)
+    }
+
+    fn set_default_server(server: &str) -> Option<()> {
+        set_default_server(server)
+    }
+}
+
+impl PlatformNetwork for DesktopPlatform {
+    async fn network_connect(
+        address: String,
+        username: String,
+        event_rx: &mut UnboundedReceiver<Command>,
+        gui_config: &ClientConfig,
+    ) -> Result<(), Error> {
+        network_connect(address, username, event_rx, gui_config).await
+    }
+
+    async fn get_status(client: &reqwest::Client) -> color_eyre::Result<ServerStatus> {
+        get_status(client).await
+    }
+}
+
+impl PlatformInit for DesktopPlatform {
+    fn init_logging() {
+        init_logging();
+    }
+
+    fn request_permissions() {
+        // No-op on desktop
+    }
+}
+
+impl Platform for DesktopPlatform {}
+
 fn get_config_path() -> std::path::PathBuf {
     let strategy = choose_app_strategy(AppStrategyArgs {
         top_level_domain: "com".to_string(),

gui/src/imp/mobile.rs

@@ -1,16 +1,115 @@
 use android_permissions::{PermissionManager, RECORD_AUDIO};
+use crate::app::Command;
+use color_eyre::eyre::Error;
+use dioxus::hooks::UnboundedReceiver;
 use jni::{objects::JObject, JavaVM};
-use mumble_web2_common::ClientConfig;
+use mumble_web2_common::{ClientConfig, ServerStatus};
+use std::future::Future;
+use std::time::Duration;
 
-use std::collections::HashMap;
-pub use tokio::runtime::Handle as SpawnHandle;
-pub use tokio::task::spawn;
-pub use tokio::time::sleep;
+use super::{Platform, PlatformConfig, PlatformInit, PlatformNetwork, PlatformRuntime, SpawnHandleTrait};
 
 pub use super::connect::*;
 pub use super::native_audio::*;
 
-pub fn set_default_username(username: &str) -> Option<()> {
+pub use tokio::task::spawn;
+pub use tokio::time::sleep;
+
+// ============================================================================
+// Platform Struct
+// ============================================================================
+
+/// Mobile platform implementation using Tokio, native audio, and Android permissions.
+pub struct MobilePlatform;
+
+// ============================================================================
+// SpawnHandle
+// ============================================================================
+
+pub type SpawnHandle = tokio::runtime::Handle;
+
+impl SpawnHandleTrait for SpawnHandle {
+    fn spawn<F>(&self, future: F)
+    where
+        F: Future<Output = ()> + Send + 'static,
+    {
+        let _ = tokio::runtime::Handle::spawn(self, future);
+    }
+
+    fn current() -> Self {
+        tokio::runtime::Handle::current()
+    }
+}
+
+// ============================================================================
+// Trait Implementations
+// ============================================================================
+
+impl PlatformRuntime for MobilePlatform {
+    type SpawnHandle = SpawnHandle;
+
+    fn spawn<F>(future: F)
+    where
+        F: Future<Output = ()> + Send + 'static,
+    {
+        let _ = tokio::task::spawn(future);
+    }
+
+    async fn sleep(duration: Duration) {
+        tokio::time::sleep(duration).await;
+    }
+}
+
+impl PlatformConfig for MobilePlatform {
+    async fn load_config() -> color_eyre::Result<ClientConfig> {
+        load_config().await
+    }
+
+    fn load_username() -> Option<String> {
+        load_username()
+    }
+
+    fn load_server_url() -> Option<String> {
+        load_server_url()
+    }
+
+    fn set_default_username(username: &str) -> Option<()> {
+        set_default_username(username)
+    }
+
+    fn set_default_server(server: &str) -> Option<()> {
+        set_default_server(server)
+    }
+}
+
+impl PlatformNetwork for MobilePlatform {
+    async fn network_connect(
+        address: String,
+        username: String,
+        event_rx: &mut UnboundedReceiver<Command>,
+        gui_config: &ClientConfig,
+    ) -> Result<(), Error> {
+        network_connect(address, username, event_rx, gui_config).await
+    }
+
+    async fn get_status(client: &reqwest::Client) -> color_eyre::Result<ServerStatus> {
+        get_status(client).await
+    }
+}
+
+impl PlatformInit for MobilePlatform {
+    fn init_logging() {
+        init_logging();
+    }
+
+    fn request_permissions() {
+        request_recording_permission();
+    }
+}
+
+impl Platform for MobilePlatform {}
+
+pub fn set_default_username(_username: &str) -> Option<()> {
     None
 }
 

gui/src/imp/mod.rs

@@ -1,3 +1,126 @@
+//! Platform abstraction layer
+//!
+//! This module defines traits that each platform (web, desktop, mobile) must implement.
+//! The traits make the platform boundary explicit and provide compile-time verification.
+
+use crate::app::Command;
+use color_eyre::eyre::Error;
+use dioxus::hooks::UnboundedReceiver;
+use mumble_web2_common::{ClientConfig, ServerStatus};
+use std::future::Future;
+use std::time::Duration;
+
+// ============================================================================
+// Trait Definitions
+// ============================================================================
+
+/// Trait for spawn handles that can be stored and used to spawn tasks later.
+#[cfg(feature = "web")]
+pub trait SpawnHandleTrait: Clone + 'static {
+    /// Spawn an async task using this handle.
+    fn spawn<F>(&self, future: F)
+    where
+        F: Future<Output = ()> + 'static;
+
+    /// Get a spawn handle for the current context.
+    fn current() -> Self;
+}
+
+/// Trait for spawn handles that can be stored and used to spawn tasks later.
+#[cfg(any(feature = "desktop", feature = "mobile"))]
+pub trait SpawnHandleTrait: Clone + 'static {
+    /// Spawn an async task using this handle.
+    fn spawn<F>(&self, future: F)
+    where
+        F: Future<Output = ()> + Send + 'static;
+
+    /// Get a spawn handle for the current context.
+    fn current() -> Self;
+}
+
+/// Runtime primitives: task spawning and async sleep.
+#[cfg(feature = "web")]
+pub trait PlatformRuntime {
+    /// The spawn handle type for this platform.
+    type SpawnHandle: SpawnHandleTrait;
+
+    /// Spawn an async task.
+    fn spawn<F>(future: F)
+    where
+        F: Future<Output = ()> + 'static;
+
+    /// Async sleep for the given duration.
+    fn sleep(duration: Duration) -> impl Future<Output = ()>;
+}
+
+/// Runtime primitives: task spawning and async sleep.
+#[cfg(any(feature = "desktop", feature = "mobile"))]
+pub trait PlatformRuntime {
+    /// The spawn handle type for this platform.
+    type SpawnHandle: SpawnHandleTrait;
+
+    /// Spawn an async task.
+    fn spawn<F>(future: F)
+    where
+        F: Future<Output = ()> + Send + 'static;
+
+    /// Async sleep for the given duration.
+    fn sleep(duration: Duration) -> impl Future<Output = ()>;
+}
+
+/// Configuration persistence: loading and saving user preferences.
+pub trait PlatformConfig {
+    /// Load the client configuration (proxy URL, cert hash, etc.).
+    fn load_config() -> impl Future<Output = color_eyre::Result<ClientConfig>>;
+
+    /// Load saved username.
+    fn load_username() -> Option<String>;
+
+    /// Load saved server URL.
+    fn load_server_url() -> Option<String>;
+
+    /// Save the default username.
+    fn set_default_username(username: &str) -> Option<()>;
+
+    /// Save the default server URL.
+    fn set_default_server(server: &str) -> Option<()>;
+}
+
+/// Network operations: connecting to servers.
+pub trait PlatformNetwork {
+    /// Establish a connection to the Mumble server and run the network loop.
+    fn network_connect(
+        address: String,
+        username: String,
+        event_rx: &mut UnboundedReceiver<Command>,
+        gui_config: &ClientConfig,
+    ) -> impl Future<Output = Result<(), Error>>;
+
+    /// Get server status (user count, version, etc.).
+    fn get_status(client: &reqwest::Client)
+        -> impl Future<Output = color_eyre::Result<ServerStatus>>;
+}
+
+/// Platform initialization.
+pub trait PlatformInit {
+    /// Initialize logging for the platform.
+    fn init_logging();
+
+    /// Request runtime permissions (Android audio recording, etc.).
+    fn request_permissions();
+}
+
+/// Combined platform trait.
+///
+/// This is the main trait that each platform must implement. It combines all
+/// platform-specific functionality into a single interface, providing compile-time
+/// verification that all platforms implement the required functionality.
+pub trait Platform: PlatformRuntime + PlatformConfig + PlatformNetwork + PlatformInit {}
+
+// ============================================================================
+// Platform Modules
+// ============================================================================
+
 #[cfg(feature = "web")]
 mod web;
 
@@ -11,6 +134,30 @@ mod desktop;
 #[cfg(feature = "mobile")]
 mod mobile;
 
+// ============================================================================
+// Platform Type Alias
+// ============================================================================
+
+/// The current platform type, selected at compile time based on features.
+#[cfg(feature = "web")]
+pub type CurrentPlatform = web::WebPlatform;
+
+#[cfg(feature = "desktop")]
+pub type CurrentPlatform = desktop::DesktopPlatform;
+
+#[cfg(feature = "mobile")]
+pub type CurrentPlatform = mobile::MobilePlatform;
+
+/// Compile-time assertion that CurrentPlatform implements Platform.
+const _: () = {
+    fn assert_platform<T: Platform>() {}
+    let _ = assert_platform::<CurrentPlatform>;
+};
+
+// ============================================================================
+// Platform Re-exports
+// ============================================================================
+
 #[cfg(feature = "desktop")]
 pub use desktop::*;
 #[cfg(feature = "mobile")]
@@ -24,6 +171,3 @@ pub fn request_permissions() {}
 
 #[cfg(all(feature = "web", not(any(feature = "desktop", feature = "mobile"))))]
 pub use web::*;
-
-#[cfg(any(feature = "desktop"))]
-pub use desktop::*;

gui/src/imp/web.rs

@@ -29,7 +29,6 @@ use web_sys::AudioWorkletNode;
 use web_sys::EncodedAudioChunk;
 use web_sys::EncodedAudioChunkInit;
 use web_sys::EncodedAudioChunkType;
-use web_sys::MediaStream;
 use web_sys::MediaStreamConstraints;
 use web_sys::MessageEvent;
 use web_sys::WebTransport;
@@ -39,6 +38,8 @@ use web_sys::WorkletOptions;
 use web_sys::{console, window};
 use web_sys::{AudioContext, AudioDataCopyToOptions};
 
+use super::{Platform, PlatformConfig, PlatformInit, PlatformNetwork, PlatformRuntime, SpawnHandleTrait};
+
 pub use wasm_bindgen_futures::spawn_local as spawn;
 
 pub trait ImpRead: AsyncRead + Unpin + 'static {}
@@ -47,10 +48,98 @@ impl<T: AsyncRead + Unpin + 'static> ImpRead for T {}
 pub trait ImpWrite: AsyncWrite + Unpin + 'static {}
 impl<T: AsyncWrite + Unpin + 'static> ImpWrite for T {}
 
+// ============================================================================
+// Platform Struct
+// ============================================================================
+
+/// Web platform implementation using WebTransport and Web Audio API.
+pub struct WebPlatform;
+
 pub async fn sleep(d: Duration) {
     TimeoutFuture::new(d.as_millis() as u32).await
 }
 
+// ============================================================================
+// Trait Implementations
+// ============================================================================
+
+impl SpawnHandleTrait for SpawnHandle {
+    fn spawn<F>(&self, future: F)
+    where
+        F: Future<Output = ()> + 'static,
+    {
+        wasm_bindgen_futures::spawn_local(future);
+    }
+
+    fn current() -> Self {
+        SpawnHandle
+    }
+}
+
+impl PlatformRuntime for WebPlatform {
+    type SpawnHandle = SpawnHandle;
+
+    fn spawn<F>(future: F)
+    where
+        F: Future<Output = ()> + 'static,
+    {
+        wasm_bindgen_futures::spawn_local(future);
+    }
+
+    async fn sleep(duration: Duration) {
+        TimeoutFuture::new(duration.as_millis() as u32).await;
+    }
+}
+
+impl PlatformConfig for WebPlatform {
+    async fn load_config() -> color_eyre::Result<ClientConfig> {
+        load_config().await
+    }
+
+    fn load_username() -> Option<String> {
+        load_username()
+    }
+
+    fn load_server_url() -> Option<String> {
+        load_server_url()
+    }
+
+    fn set_default_username(username: &str) -> Option<()> {
+        set_default_username(username)
+    }
+
+    fn set_default_server(server: &str) -> Option<()> {
+        set_default_server(server)
+    }
+}
+
+impl PlatformNetwork for WebPlatform {
+    async fn network_connect(
+        address: String,
+        username: String,
+        event_rx: &mut UnboundedReceiver<Command>,
+        gui_config: &ClientConfig,
+    ) -> Result<(), Error> {
+        network_connect(address, username, event_rx, gui_config).await
+    }
+
+    async fn get_status(client: &reqwest::Client) -> color_eyre::Result<ServerStatus> {
+        get_status(client).await
+    }
+}
+
+impl PlatformInit for WebPlatform {
+    fn init_logging() {
+        init_logging();
+    }
+
+    fn request_permissions() {
+        // No-op on web
+    }
+}
+
+impl Platform for WebPlatform {}
+
 trait ResultExt<T> {
     fn ey(self) -> Result<T, Error>;
 }
@@ -495,6 +584,7 @@ pub fn init_logging() {
     info!("logging initiated");
 }
 
+#[derive(Clone)]
 pub struct SpawnHandle;
 
 impl SpawnHandle {

gui/src/lib.rs

@@ -27,7 +27,7 @@ use tracing::error;
 use tracing::info;
 
 use crate::effects::AudioProcessor;
-use crate::imp::AudioSystem;
+use crate::imp::{AudioSystem, CurrentPlatform, Platform, PlatformNetwork, PlatformRuntime};
 
 pub mod app;
 mod effects;
@@ -47,7 +47,7 @@ pub async fn network_entrypoint(mut event_rx: UnboundedReceiver<Command>) {
 
         *STATE.server.write() = Default::default();
         *STATE.status.write() = ConnectionState::Connecting;
-        if let Err(error) = imp::network_connect(address, username, &mut event_rx, &config).await {
+        if let Err(error) = CurrentPlatform::network_connect(address, username, &mut event_rx, &config).await {
             error!("could not connect {:?}", error);
             *STATE.status.write() = ConnectionState::Failed(error.to_string());
         } else {
@@ -105,7 +105,7 @@ pub async fn network_loop<R: imp::ImpRead, W: imp::ImpWrite>(
                     break;
                 }
 
-                imp::sleep(Duration::from_millis(3000)).await;
+                CurrentPlatform::sleep(Duration::from_millis(3000)).await;
             }
         });
     }