persisting in postgres

lib/elixir_ai/data/conversation.ex

@@ -0,0 +1,26 @@
+defmodule ElixirAi.Conversation do
+  import Ecto.Query
+  alias ElixirAi.Repo
+
+  def all_names do
+    Repo.all(from c in "conversations", select: c.name)
+  end
+
+  def create(name) do
+    case Repo.insert_all("conversations", [[id: Ecto.UUID.generate(), name: name, inserted_at: now(), updated_at: now()]]) do
+      {1, _} -> :ok
+      _ -> {:error, :db_error}
+    end
+  rescue
+    e in Ecto.ConstraintError -> if e.constraint == "conversations_name_index", do: {:error, :already_exists}, else: {:error, :db_error}
+  end
+
+  def find_id(name) do
+    case Repo.one(from c in "conversations", where: c.name == ^name, select: c.id) do
+      nil -> {:error, :not_found}
+      id -> {:ok, id}
+    end
+  end
+
+  defp now, do: DateTime.truncate(DateTime.utc_now(), :second)
+end

lib/elixir_ai/data/message.ex

@@ -0,0 +1,49 @@
+defmodule ElixirAi.Message do
+  import Ecto.Query
+  alias ElixirAi.Repo
+
+  def load_for_conversation(conversation_id) do
+    Repo.all(
+      from m in "messages",
+        where: m.conversation_id == ^conversation_id,
+        order_by: m.position,
+        select: %{
+          role: m.role,
+          content: m.content,
+          reasoning_content: m.reasoning_content,
+          tool_calls: m.tool_calls,
+          tool_call_id: m.tool_call_id
+        }
+    )
+    |> Enum.map(&decode_message/1)
+  end
+
+  def insert(conversation_id, message, position) do
+    Repo.insert_all("messages", [
+      [
+        id: Ecto.UUID.generate(),
+        conversation_id: conversation_id,
+        role: to_string(message.role),
+        content: message[:content],
+        reasoning_content: message[:reasoning_content],
+        tool_calls: encode_tool_calls(message[:tool_calls]),
+        tool_call_id: message[:tool_call_id],
+        position: position,
+        inserted_at: DateTime.truncate(DateTime.utc_now(), :second)
+      ]
+    ])
+  end
+
+  defp encode_tool_calls(nil), do: nil
+  defp encode_tool_calls(calls), do: Jason.encode!(calls)
+
+  defp decode_message(row) do
+    row
+    |> Map.update!(:role, &String.to_existing_atom/1)
+    |> drop_nil_fields()
+  end
+
+  defp drop_nil_fields(map) do
+    Map.reject(map, fn {_k, v} -> is_nil(v) end)
+  end
+end

lib/elixir_ai/data/repo.ex

@@ -0,0 +1,5 @@
+defmodule ElixirAi.Repo do
+  use Ecto.Repo,
+    otp_app: :elixir_ai,
+    adapter: Ecto.Adapters.Postgres
+end