App architecture modifications.

Now GUI and the app itself is divided into two different binaries.
The app also provides system tray icon.
Whereas the GUI can be used to configure the app.

app/src/main.rs

@@ -0,0 +1,114 @@
+use std::env;
+use std::error::Error;
+use std::path::PathBuf;
+
+use once_cell::sync::{Lazy, OnceCell};
+use platform_dirs::{AppDirs};
+
+// expose the config
+mod config;
+
+// include log
+#[macro_use]
+extern crate simple_log;
+mod log;
+
+// include app
+mod app;
+
+// include db
+mod db;
+
+// include tray
+// @TODO. macOS currently not supported for tray functionality.
+#[cfg(not(target_os = "macos"))]
+mod tray;
+
+// include recorder
+mod recorder;
+
+// include speech-to-text
+mod stt;
+
+// include text-to-speech
+// empty
+
+// include commands
+mod commands;
+use commands::AssistantCommand;
+use crate::commands::list;
+
+// include audio
+mod audio;
+
+// include listener
+mod listener;
+
+// some global data
+static APP_DIR: Lazy<PathBuf> = Lazy::new(|| {env::current_dir().unwrap()});
+static SOUND_DIR: Lazy<PathBuf> = Lazy::new(|| {APP_DIR.clone().join("sound")});
+static APP_DIRS: OnceCell<AppDirs> = OnceCell::new();
+static APP_CONFIG_DIR: OnceCell<PathBuf> = OnceCell::new();
+static APP_LOG_DIR: OnceCell<PathBuf> = OnceCell::new();
+static DB: OnceCell<db::structs::Settings> = OnceCell::new();
+static COMMANDS_LIST: OnceCell<Vec<AssistantCommand>> = OnceCell::new();
+
+fn main() -> Result<(), String> {
+    // initialize directories
+    config::init_dirs()?;
+
+    // initialize logging
+    log::init_logging()?;
+
+    // log some base info
+    info!("Starting Jarvis v{} ...", config::APP_VERSION.unwrap());
+    info!("Config directory is: {}", APP_CONFIG_DIR.get().unwrap().display());
+    info!("Log directory is: {}", APP_LOG_DIR.get().unwrap().display());
+
+    // initialize database (settings)
+    DB.set(db::init_settings());
+
+    // initialize tray
+    // @TODO. macOS currently not supported for tray functionality,
+    // due to the separate thread in which tray processing works,
+    // but macOS requires it to be processed in the main thread only
+    // The solution may be to include wake-word detection etc. in the winit event loop. (only for MacOS, though?)
+    #[cfg(not(target_os = "macos"))]
+    tray::init();
+
+    // init recorder
+    if recorder::init().is_err() {
+        app::close(1); // cannot continue without recorder
+    }
+
+    // init stt engine
+    if stt::init().is_err() {
+        // @TODO. Allow continuing even without STT, if commands is using keywords or smthng?
+        app::close(1); // cannot continue without stt
+    }
+
+    // init tts engine
+    // none for now (Silero-rs coming)
+
+    // init commands
+    info!("Initializing commands.");
+    let commands = commands::parse_commands().unwrap();
+    info!("Commands initialized.\nOverall commands parsed: {}\nParsed commands: {:?}", commands.len(), commands::list(&commands));
+    COMMANDS_LIST.set(commands).unwrap();
+
+    // init audio
+    if audio::init().is_err() {
+        // @TODO. Allow continuing even without audio?
+        app::close(1); // cannot continue without audio
+    }
+
+    // init wake-word engine
+    if listener::init().is_err() {
+        app::close(1); // cannot continue without wake-word engine
+    }
+
+    // start the app
+    app::start();
+
+    Ok(())
+}