Nomad changes

packages/elixir/lib/kreuzberg/embedding_backend_bridge.ex

@@ -0,0 +1,74 @@
+defmodule KreuzbergEmbeddingBackendBridge do
+  @moduledoc """
+  GenServer bridge for EmbeddingBackend implementation in kreuzberg.
+
+  Handles incoming trait method calls from Rust and dispatches them to an implementation module.
+  """
+
+  use GenServer
+
+  require Logger
+
+  @doc """
+  Start a GenServer linked to the current process.
+
+  impl_module should be a module that implements the EmbeddingBackend trait methods.
+  """
+  def start_link(impl_module) do
+    GenServer.start_link(__MODULE__, impl_module, name: __MODULE__)
+  end
+
+  @impl GenServer
+  def init(impl_module) do
+    {:ok, impl_module}
+  end
+
+  @doc """
+  Handle an incoming trait call message.
+
+  Message format: {:trait_call, method_atom, args_json, reply_id}
+  """
+  @impl GenServer
+  def handle_info({:trait_call, method, args_json, reply_id}, impl_module) do
+    try do
+      args = Jason.decode!(args_json)
+      method_name = to_string(method)
+      ordered_args = ordered_args(impl_module, method_name, args)
+
+      # Dispatch to the implementation module
+      result = apply(impl_module, String.to_existing_atom(method_name), ordered_args)
+
+      # Send result back to Rust
+      Kreuzberg.Native.complete_trait_call(reply_id, Jason.encode!(result))
+    rescue
+      e ->
+        Logger.error("Error calling {impl_module}.{method}: {Exception.message(e)}")
+        Kreuzberg.Native.fail_trait_call(reply_id, Exception.message(e))
+    end
+
+    {:noreply, impl_module}
+  end
+
+  defp ordered_args(impl_module, method_name, args) when is_map(args) do
+    if function_exported?(impl_module, :__alef_arg_order__, 1) do
+      impl_module.__alef_arg_order__(method_name)
+      |> Enum.map(&Map.fetch!(args, &1))
+    else
+      args
+      |> Map.keys()
+      |> Enum.sort()
+      |> Enum.map(&Map.fetch!(args, &1))
+    end
+  end
+
+  defp ordered_args(_impl_module, _method_name, args) when is_list(args), do: args
+
+  @doc """
+  Register an implementation module, starting a GenServer to handle trait calls.
+  """
+  def register(impl_module) do
+    plugin_name = impl_module.name()
+    {:ok, pid} = start_link(impl_module)
+    Kreuzberg.Native.register_embedding_backend(pid, plugin_name)
+  end
+end