feat(nvim): implement auto-spawning headless instance and interactive preemption

nvim-core/src/headless.rs

@@ -0,0 +1,42 @@
+use std::sync::Arc;
+use std::sync::LazyLock;
+
+pub static ACTIVE_SOCKET: LazyLock<Arc<std::sync::Mutex<Option<String>>>> =
+    LazyLock::new(|| Arc::new(std::sync::Mutex::new(None)));
+
+pub static HEADLESS_PROC: LazyLock<Arc<std::sync::Mutex<Option<tokio::process::Child>>>> =
+    LazyLock::new(|| Arc::new(std::sync::Mutex::new(None)));
+
+pub async fn spawn_headless_nvim() -> Result<String, String> {
+    if std::process::Command::new("nvim").arg("--version").output().is_err() {
+        return Err("Error: Neovim is not installed or not in PATH. Cannot execute nvim tool. Fallback to basic terminal tools.".to_string());
+    }
+
+    #[cfg(windows)]
+    let socket_name = format!(r"\\.\pipe\agy-headless-nvim-{}", std::process::id());
+    #[cfg(unix)]
+    let socket_name = format!("/tmp/agy-headless-nvim-{}.sock", std::process::id());
+
+    let child = tokio::process::Command::new("nvim")
+        .arg("--headless")
+        .arg("--listen")
+        .arg(&socket_name)
+        .kill_on_drop(true)
+        .spawn()
+        .map_err(|e| format!("Failed to spawn headless Neovim: {}", e))?;
+
+    tokio::time::sleep(tokio::time::Duration::from_millis(1000)).await;
+
+    let mut old_child = {
+        let mut lock = HEADLESS_PROC.lock().unwrap_or_else(|e| e.into_inner());
+        let old = lock.take();
+        *lock = Some(child);
+        old
+    };
+
+    if let Some(mut old) = old_child {
+        let _ = old.kill().await;
+    }
+
+    Ok(socket_name)
+}