1 files changed, 52 insertions, 0 deletions
diff --git a/src/file_registry.rs b/src/file_registry.rs
new file mode 100644
index 0000000..25aba3f
--- /dev/null
+++ b/src/file_registry.rs
@@ -0,0 +1,52 @@
+//! Manages tracking of open files and window controllers.
+//!
+//! GTK is single-threaded, so thread-local storage is safe here.
+
+use std::cell::RefCell;
+use std::path::PathBuf;
+
+use relm4::component::Controller;
+use relm4::gtk;
+
+use crate::AppModel;
+
+thread_local! {
+    /// Keeps window controllers alive for the lifetime of each window.
+    static WINDOW_CONTROLLERS: RefCell<Vec<Controller<AppModel>>> = const { RefCell::new(Vec::new()) };
+
+    /// Tracks which files are currently open to prevent duplicate windows.
+    static OPEN_FILES: RefCell<Vec<(PathBuf, gtk::Window)>> = const { RefCell::new(Vec::new()) };
+}
+
+/// Stores a window controller to keep it alive.
+pub fn store_controller(controller: Controller<AppModel>) {
+    WINDOW_CONTROLLERS.with_borrow_mut(|controllers| {
+        controllers.push(controller);
+    });
+}
+
+/// Returns the window that has the given file open, if any.
+pub fn find_window_for_file(path: &PathBuf) -> Option<gtk::Window> {
+    OPEN_FILES.with_borrow(|files| {
+        files
+            .iter()
+            .find(|(file_path, _)| file_path == path)
+            .map(|(_, window)| window.clone())
+    })
+}
+
+/// Registers a file as being open in the given window.
+pub fn register_file(path: &PathBuf, window: &gtk::Window) {
+    OPEN_FILES.with_borrow_mut(|files| {
+        if !files.iter().any(|(file_path, _)| file_path == path) {
+            files.push((path.clone(), window.clone()));
+        }
+    });
+}
+
+/// Unregisters a file when its window is closed.
+pub fn unregister_file(path: &PathBuf) {
+    OPEN_FILES.with_borrow_mut(|files| {
+        files.retain(|(file_path, _)| file_path != path);
+    });
+}