add query helpers

lib/workload_service_web/query_helpers.ex

@@ -0,0 +1,28 @@
+defmodule WorkloadServiceWeb.QueryHelpers do
+  @moduledoc false
+
+  alias OpenApiSpex.Schema
+
+  @filter_count 3
+
+  def flop(filter_fields, order_fields, other \\ []) do
+    filter_params = build_filter_params(filter_fields, @filter_count)
+
+    [
+      page: [in: :query, schema: %Schema{type: :number, default: 1}],
+      page_size: [in: :query, schema: %Schema{type: :number, default: 20}],
+      "order_by[]": [in: :query, schema: %Schema{type: :array, items: %Schema{type: :string, enum: order_fields}}],
+      "order_directions[]": [in: :query, schema: %Schema{type: :array, items: %Schema{type: :string, enum: ["asc", "desc"]}}]
+    ] ++ filter_params ++ other
+  end
+
+  defp build_filter_params(fields, count) do
+    for i <- 0..(count - 1) do
+      [
+        {"filters[#{i}][field]", [in: :query, schema: %Schema{type: :string, enum: fields}]},
+        {"filters[#{i}][op]", [in: :query, schema: %Schema{type: :string, enum: Flop.Filter.allowed_operators(:all)}]},
+        {"filters[#{i}][value]", [in: :query, schema: %Schema{type: :string}]}
+      ]
+    end |> List.flatten()
+  end
+end