refactor(settings): unify JSONB single-field update between member-field changes

lib/membership/setting/changes/jsonb_result.ex

@@ -0,0 +1,98 @@
+defmodule Mv.Membership.Setting.Changes.JsonbResult do
+  @moduledoc """
+  Shared normalization for the JSONB column values returned by the atomic
+  single-member-field settings updates.
+
+  PostgreSQL may return a JSONB column as an already-decoded map (atom or string
+  keys) or as a raw JSON string depending on the driver path. This helper
+  normalizes either form to a string-keyed map, returning `%{}` for unexpected
+  or undecodable input.
+  """
+
+  alias Ash.Error.Invalid
+  alias Ecto.Adapters.SQL
+  require Logger
+
+  @doc """
+  Runs an atomic single-statement JSONB settings UPDATE inside an after_action
+  and maps the RETURNING row back onto the settings struct.
+
+  Shared by the single-member-field change modules, which differ only in the
+  SQL statement, its parameters, the row-to-settings mapping, and the error
+  labels. The three-branch result handling (row found / not found / SQL error)
+  is identical and lives here.
+
+  Options:
+    - `:sql` - The UPDATE statement with a RETURNING clause (required).
+    - `:params` - The full parameter list for the statement (required).
+    - `:on_row` - 1-arity function mapping the RETURNING row (a list of column
+      values) to the updated settings struct (required).
+    - `:error_field` - Ash error field for the not-found / failure errors.
+    - `:not_found_message` - Error message when no row matched.
+    - `:error_message` - Error message when the SQL statement failed.
+    - `:log_message` - Log prefix written on SQL failure.
+  """
+  @spec run_update(keyword()) ::
+          {:ok, map()} | {:error, Exception.t()}
+  def run_update(opts) do
+    sql = Keyword.fetch!(opts, :sql)
+    params = Keyword.fetch!(opts, :params)
+    on_row = Keyword.fetch!(opts, :on_row)
+    error_field = Keyword.fetch!(opts, :error_field)
+    not_found_message = Keyword.fetch!(opts, :not_found_message)
+    error_message = Keyword.fetch!(opts, :error_message)
+    log_message = Keyword.fetch!(opts, :log_message)
+
+    case SQL.query(Mv.Repo, sql, params) do
+      {:ok, %{rows: [row | _]}} ->
+        {:ok, on_row.(row)}
+
+      {:ok, %{rows: []}} ->
+        {:error,
+         Invalid.exception(
+           field: error_field,
+           message: not_found_message
+         )}
+
+      {:error, error} ->
+        Logger.error("#{log_message}: #{inspect(error)}")
+
+        {:error,
+         Invalid.exception(
+           field: error_field,
+           message: error_message
+         )}
+    end
+  end
+
+  @doc """
+  Normalizes a JSONB column value to a string-keyed map.
+  """
+  @spec normalize(map() | binary() | any()) :: map()
+  def normalize(updated_jsonb) do
+    case updated_jsonb do
+      map when is_map(map) ->
+        Enum.reduce(map, %{}, fn
+          {k, v}, acc when is_atom(k) -> Map.put(acc, Atom.to_string(k), v)
+          {k, v}, acc -> Map.put(acc, k, v)
+        end)
+
+      binary when is_binary(binary) ->
+        case Jason.decode(binary) do
+          {:ok, decoded} when is_map(decoded) ->
+            decoded
+
+          {:ok, _} ->
+            %{}
+
+          {:error, reason} ->
+            Logger.warning("Failed to decode JSONB: #{inspect(reason)}")
+            %{}
+        end
+
+      _ ->
+        Logger.warning("Unexpected JSONB format: #{inspect(updated_jsonb)}")
+        %{}
+    end
+  end
+end