ML-162: enable /api/v1/errors endpoint

lib/music_library_web/controllers/error_json.ex

@@ -1,21 +1,85 @@
 defmodule MusicLibraryWeb.ErrorJSON do
   @moduledoc """
-  This module is invoked by your endpoint in case of errors on JSON requests.
+  JSON rendering for production errors via the API and for Phoenix error responses.
 
-  See config/config.exs.
+  This module serves dual purpose:
+  - Renders error/occurrence data for the /api/v1/errors endpoints
+  - Renders generic error responses (404, 500, etc.) for the Phoenix endpoint
+    when the request accepts JSON (configured in config/config.exs render_errors)
   """
+  use MusicLibraryWeb, :json
 
-  # If you want to customize a particular status code,
-  # you may add your own clauses, such as:
-  #
-  # def render("500.json", _assigns) do
-  #   %{errors: %{detail: "Internal Server Error"}}
-  # end
-
-  # By default, Phoenix returns the status message from
-  # the template name. For example, "404.json" becomes
-  # "Not Found".
+  # Catch-all for Phoenix error template rendering (404, 500, etc.)
   def render(template, _assigns) do
-    %{errors: %{detail: Phoenix.Controller.status_message_from_template(template)}}
+    %{error: Phoenix.Controller.status_message_from_template(template)}
   end
+
+  def index(%{errors: errors, total: total, limit: limit, offset: offset}) do
+    %{
+      errors: Enum.map(errors, &error/1),
+      total: total,
+      limit: limit,
+      offset: offset
+    }
+  end
+
+  def show(%{error: error}) do
+    %{
+      error: error_with_occurrences(error)
+    }
+  end
+
+  defp error(e) do
+    %{
+      id: e.id,
+      kind: e.kind,
+      reason: e.reason,
+      source_line: e.source_line,
+      source_function: e.source_function,
+      status: atom_to_string(e.status),
+      fingerprint: e.fingerprint,
+      last_occurrence_at: datetime_to_iso8601(e.last_occurrence_at),
+      muted: e.muted,
+      inserted_at: datetime_to_iso8601(e.inserted_at),
+      updated_at: datetime_to_iso8601(e.updated_at)
+    }
+  end
+
+  defp error_with_occurrences(e) do
+    error(e)
+    |> Map.put(:occurrence_count, Map.get(e, :occurrence_count, 0))
+    |> Map.put(:first_occurrence_at, datetime_to_iso8601(Map.get(e, :first_occurrence_at)))
+    |> Map.put(:occurrences, Enum.map(Map.get(e, :occurrences, []), &occurrence/1))
+  end
+
+  defp occurrence(o) do
+    %{
+      id: o.id,
+      reason: o.reason,
+      context: o.context,
+      breadcrumbs: o.breadcrumbs,
+      stacktrace: %{
+        lines: Enum.map(o.stacktrace.lines, &stacktrace_line/1)
+      },
+      error_id: o.error_id,
+      inserted_at: datetime_to_iso8601(o.inserted_at)
+    }
+  end
+
+  defp stacktrace_line(line) do
+    %{
+      application: line.application,
+      module: line.module,
+      function: line.function,
+      arity: line.arity,
+      file: line.file,
+      line: line.line
+    }
+  end
+
+  defp datetime_to_iso8601(nil), do: nil
+  defp datetime_to_iso8601(dt), do: DateTime.to_iso8601(dt)
+
+  defp atom_to_string(nil), do: nil
+  defp atom_to_string(atom), do: Atom.to_string(atom)
 end