better error handlign

lib/customer_service/lead/queries.ex

@@ -13,15 +13,4 @@ defmodule CustomerService.Lead.Queries do
       lead -> {:ok, lead}
     end
   end
-
-  def list_leads(params \\ %{}) do
-    Flop.validate_and_run(QuickLead, params, for: QuickLead)
-  end
-
-  def get_lead(id) do
-    case Repo.get(QuickLead, id) do
-      nil -> {:error, :not_found}
-      lead -> {:ok, lead}
-    end
-  end
 end

lib/customer_service_web/controllers/error_json.ex

@@ -3,15 +3,58 @@ defmodule CustomerServiceWeb.ErrorJSON do
   This module is invoked by your endpoint in case of errors on JSON requests.
   """
 
+  alias Ecto.Changeset
+  alias OpenApiSpex.Error
+
   def render("404.json", _assigns) do
     %{errors: %{detail: "Not Found"}}
   end
 
-  def render("500.json", _assigns) do
-    %{errors: %{detail: "Internal Server Error"}}
+  def render("500.json", assigns) do
+    detail = detailed_message(assigns[:reason], "Internal Server Error")
+    %{errors: %{detail: detail}}
   end
 
-  def render(template, _assigns) do
-    %{errors: %{detail: Phoenix.Controller.status_message_from_template(template)}}
+  def render("400.json", assigns) do
+    detail = detailed_message(assigns[:reason], "Bad Request")
+    %{errors: %{detail: detail}}
+  end
+
+  def render("422.json", assigns) do
+    detail = detailed_message(assigns[:reason], "Unprocessable Entity")
+    %{errors: %{detail: detail}}
+  end
+
+  def render(template, assigns) do
+    detail =
+      detailed_message(
+        assigns[:reason],
+        Phoenix.Controller.status_message_from_template(template)
+      )
+
+    %{errors: %{detail: detail}}
+  end
+
+  defp detailed_message(nil, default), do: default
+
+  defp detailed_message(%Changeset{} = changeset, _default) do
+    format_changeset_errors(changeset)
+    |> inspect()
+  end
+
+  defp detailed_message(%Error{errors: errors}, _default) do
+    Enum.map_join(errors, ", ", fn e -> "#{e.code}: #{e.message}" end)
+  end
+
+  defp detailed_message(reason, _default) do
+    inspect(reason, pretty: true)
+  end
+
+  defp format_changeset_errors(changeset) do
+    Changeset.traverse_errors(changeset, fn {msg, opts} ->
+      Enum.reduce(opts, msg, fn {key, value}, acc ->
+        String.replace(acc, "%{#{key}}", to_string(value))
+      end)
+    end)
   end
 end