Improve available_selectors in getMetric's metadata

If a metric is available in multiple modules, combine the available
metrics when reporting in the API.

lib/sanbase/available_metrics/available_metrics.ex

@@ -68,6 +68,7 @@ defmodule Sanbase.AvailableMetrics do
     metrics
     |> Enum.map(fn metric ->
       {:ok, m} = Sanbase.Metric.metadata(metric)
+      {:ok, available_selectors} = Sanbase.Metric.available_selectors(metric)
 
       %{
         metric: m.metric,
@@ -79,7 +80,7 @@ defmodule Sanbase.AvailableMetrics do
         frequency_seconds: Sanbase.DateTimeUtils.str_to_sec(m.min_interval),
         sanbase_access: "free",
         sanapi_access: "free",
-        available_selectors: m.available_selectors,
+        available_selectors: available_selectors,
         required_selectors: m.required_selectors,
         access: Map.get(access_map, metric)
       }

lib/sanbase/metric/behaviour.ex

@@ -121,6 +121,8 @@ defmodule Sanbase.Metric.Behaviour do
 
   @type available_label_fqns_result :: {:ok, list(String.t())} | {:error, String.t()}
 
+  @type available_selectors_result :: {:ok, list(atom())} | {:error, String.t()}
+
   @type has_incomplete_data_result :: boolean()
 
   @type complexity_weight_result :: number()

lib/sanbase/metric/metric.ex

@@ -430,6 +430,33 @@ defmodule Sanbase.Metric do
     end
   end
 
+  @doc ~s"""
+  Get the list of available selectors for a metric.
+  This is a separate function as it combines the available selectors from multiple
+  modules that implement the metric.
+  Most notably, social metrics from CH are precomptued only for slugs, while the
+  SocialData.MetricAdapter implements it for text, founders, etc.
+  """
+  @spec available_selectors(metric) :: Type.available_selectors_result()
+  def available_selectors(metric) do
+    case get_module(metric, return_all_modules: true) do
+      nil ->
+        metric_not_available_error(metric)
+
+      module_or_modules ->
+        available_selectors =
+          module_or_modules
+          |> List.wrap()
+          |> Enum.flat_map(fn module ->
+            {:ok, metadata} = apply(module, :metadata, [metric])
+            metadata.available_selectors
+          end)
+          |> Enum.uniq()
+
+        {:ok, available_selectors}
+    end
+  end
+
   @doc ~s"""
   Get the first datetime for which a given metric is available for a given slug
   """
@@ -851,7 +878,10 @@ defmodule Sanbase.Metric do
         end
 
       true ->
-        metric_to_single_module(metric, opts)
+        case Keyword.get(opts, :return_all_modules, false) do
+          false -> metric_to_single_module(metric, opts)
+          true -> Map.get(Helper.metric_to_modules_map(), metric)
+        end
     end
   end
 

lib/sanbase_web/graphql/resolvers/metric/metric_resolver.ex

@@ -131,6 +131,16 @@ defmodule SanbaseWeb.Graphql.Resolvers.MetricResolver do
     end
   end
 
+  def get_available_selectors(_root, _args, %{source: %{metric: metric}}) do
+    case Metric.available_selectors(metric) do
+      {:ok, selectors} ->
+        {:ok, selectors}
+
+      {:error, error} ->
+        {:error, handle_graphql_error("available_selectors", %{metric: metric}, error)}
+    end
+  end
+
   def timeseries_data_complexity(_root, args, resolution) do
     # Explicitly set `child_complexity` to 2 as this would be the
     # value if both `datetime` and `value` fields are queried.

lib/sanbase_web/graphql/schema/types/metric_types.ex

@@ -407,7 +407,9 @@ defmodule SanbaseWeb.Graphql.MetricTypes do
     Every metric has `availableSelectors` in its metadata, showing exactly
     which of the selectors can be used.
     """
-    field(:available_selectors, list_of(:selector_name))
+    field :available_selectors, list_of(:selector_name) do
+      resolve(&MetricResolver.get_available_selectors/3)
+    end
 
     @desc ~s"""
     The list of required selectors for the metric. It is used to show the list