feat: add server process control panel to Tauri app

tauri-app/src-tauri/src/lib.rs

@@ -1,9 +1,79 @@
-use tauri::Manager;
+use std::process::{Child, Command};
+use std::sync::Mutex;
+use tauri::{Manager, State};
+
+pub struct ServerState(pub Mutex<Option<Child>>);
+
+#[tauri::command]
+fn start_server(
+    state: State<ServerState>,
+    model_path: String,
+    addr: String,
+    gpu_layers: i32,
+) -> Result<String, String> {
+    let mut guard = state.0.lock().map_err(|e| e.to_string())?;
+
+    if guard.is_some() {
+        return Err("Server is already running".into());
+    }
+
+    // Resolve binary path relative to the app's resource dir or PATH
+    let binary = if cfg!(target_os = "windows") {
+        "localllm.exe"
+    } else {
+        "localllm"
+    };
+
+    let child = Command::new(binary)
+        .env("LOCALLLM_MODEL", &model_path)
+        .env("LOCALLLM_ADDR", &addr)
+        .env("LOCALLLM_GPU_LAYERS", gpu_layers.to_string())
+        .spawn()
+        .map_err(|e| format!("Failed to start server: {e}"))?;
+
+    let pid = child.id();
+    *guard = Some(child);
+
+    Ok(format!("Server started (pid={pid}) on {addr}"))
+}
+
+#[tauri::command]
+fn stop_server(state: State<ServerState>) -> Result<String, String> {
+    let mut guard = state.0.lock().map_err(|e| e.to_string())?;
+
+    match guard.as_mut() {
+        None => Err("Server is not running".into()),
+        Some(child) => {
+            child
+                .kill()
+                .map_err(|e| format!("Failed to kill server: {e}"))?;
+            let _ = child.wait();
+            *guard = None;
+            Ok("Server stopped".into())
+        }
+    }
+}
+
+#[tauri::command]
+fn server_status(state: State<ServerState>) -> String {
+    let guard = state.0.lock().unwrap();
+    if guard.is_some() {
+        "running".into()
+    } else {
+        "stopped".into()
+    }
+}
 
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
     tauri::Builder::default()
         .plugin(tauri_plugin_shell::init())
+        .manage(ServerState(Mutex::new(None)))
+        .invoke_handler(tauri::generate_handler![
+            start_server,
+            stop_server,
+            server_status
+        ])
         .setup(|app| {
             #[cfg(debug_assertions)]
             {