fix: A1-5 implement post editor auto-save after 3000ms idle, on tab switch, and on unmount

lib/bds/desktop/shell_live/bridges.ex

@@ -47,6 +47,40 @@ defmodule BDS.Desktop.ShellLive.Bridges do
     {:noreply, assign(socket, :workbench, workbench)}
   end
 
+  @default_auto_save_delay 3000
+
+  def handle_info({:schedule_auto_save, type, id}, socket, _callbacks) do
+    timers = socket.assigns[:auto_save_timers] || %{}
+    key = {type, id}
+
+    case Map.get(timers, key) do
+      nil -> :ok
+      old_ref -> Process.cancel_timer(old_ref)
+    end
+
+    delay = Application.get_env(:bds, :auto_save_delay, @default_auto_save_delay)
+    ref = Process.send_after(self(), {:auto_save_fire, type, id}, delay)
+    {:noreply, assign(socket, :auto_save_timers, Map.put(timers, key, ref))}
+  end
+
+  def handle_info({:cancel_auto_save, type, id}, socket, _callbacks) do
+    timers = socket.assigns[:auto_save_timers] || %{}
+    key = {type, id}
+
+    case Map.get(timers, key) do
+      nil -> :ok
+      old_ref -> Process.cancel_timer(old_ref)
+    end
+
+    {:noreply, assign(socket, :auto_save_timers, Map.delete(timers, key))}
+  end
+
+  def handle_info({:auto_save_fire, :post, post_id}, socket, _callbacks) do
+    timers = socket.assigns[:auto_save_timers] || %{}
+    send_update(PostEditor, id: "post-editor-#{post_id}", action: :save)
+    {:noreply, assign(socket, :auto_save_timers, Map.delete(timers, {:post, post_id}))}
+  end
+
   def handle_info({:editor_command, action, params}, socket, callbacks) do
     {:noreply, callbacks.apply_shell_command.(socket, action, params)}
   end

lib/bds/desktop/shell_live/notify.ex

@@ -62,6 +62,18 @@ defmodule BDS.Desktop.ShellLive.Notify do
     :ok
   end
 
+  @spec schedule_auto_save(atom(), term()) :: :ok
+  def schedule_auto_save(type, id) do
+    send(self(), {:schedule_auto_save, type, id})
+    :ok
+  end
+
+  @spec cancel_auto_save(atom(), term()) :: :ok
+  def cancel_auto_save(type, id) do
+    send(self(), {:cancel_auto_save, type, id})
+    :ok
+  end
+
   @spec parent(term()) :: :ok
   def parent(message) do
     send(self(), message)

lib/bds/desktop/shell_live/post_editor.ex

@@ -185,6 +185,10 @@ defmodule BDS.Desktop.ShellLive.PostEditor do
       Notify.dirty(:post, post_id, dirty?)
     end
 
+    if dirty? do
+      Notify.schedule_auto_save(:post, post_id)
+    end
+
     {:noreply, socket}
   end
 
@@ -471,6 +475,7 @@ defmodule BDS.Desktop.ShellLive.PostEditor do
               Atom.to_string(record_status(record)))
 
             Notify.dirty(:post, post.id, false)
+            Notify.cancel_auto_save(:post, post.id)
             notify_output(socket, dgettext("ui", "Post"), dgettext("ui", "Post saved"))
             socket