fix: issue #15 calendar index not properly created, also some smaller bugs

lib/bds/generation/outputs.ex

@@ -375,7 +375,7 @@ defmodule BDS.Generation.Outputs do
     main_static_outputs =
       [
         {"404.html", render_not_found_output(plan, language)},
-        {"feed.xml", render_feed(plan, language, published_posts)},
+        {"rss.xml", render_feed(plan, language, published_posts)},
         {"atom.xml", render_atom(plan, language, published_posts)},
         {"calendar.json", render_calendar(published_posts)}
       ]
@@ -399,7 +399,7 @@ defmodule BDS.Generation.Outputs do
            [
              {Path.join(localized_language, "404.html"),
               render_not_found_output(plan, localized_language)},
-             {Path.join(localized_language, "feed.xml"),
+             {Path.join(localized_language, "rss.xml"),
               render_feed(plan, localized_language, localized_source_posts)},
              {Path.join(localized_language, "atom.xml"),
               render_atom(plan, localized_language, localized_source_posts)}

lib/bds/generation/paths.ex

@@ -237,7 +237,7 @@ defmodule BDS.Generation.Paths do
 
   @spec sitemap_route_output?(String.t()) :: boolean()
   def sitemap_route_output?("404.html"), do: false
-  def sitemap_route_output?("feed.xml"), do: false
+  def sitemap_route_output?("rss.xml"), do: false
   def sitemap_route_output?("atom.xml"), do: false
   def sitemap_route_output?("calendar.json"), do: false
   def sitemap_route_output?(relative_path), do: String.ends_with?(relative_path, ".html")

lib/bds/generation/sitemap.ex

@@ -212,13 +212,19 @@ defmodule BDS.Generation.Sitemap do
     "<feed><title>#{xml_escape(plan.project_name)} (#{xml_escape(language || "default")})</title>#{entries}</feed>"
   end
 
-  @doc "Render a JSON calendar of all published posts."
+  @doc """
+  Render the JSON calendar archive consumed by the calendar runtime:
+  post counts keyed by year ("2024"), month ("2024-05"), and day ("2024-05-17").
+  """
   @spec render_calendar([map()]) :: String.t()
   def render_calendar(published_posts) do
-    published_posts
-    |> Enum.map(fn post ->
-      %{date: Paths.local_date_iso8601!(post.created_at), slug: post.slug, title: post.title}
-    end)
+    day_keys = Enum.map(published_posts, &Paths.local_date_iso8601!(&1.created_at))
+
+    %{
+      years: Enum.frequencies_by(day_keys, &binary_part(&1, 0, 4)),
+      months: Enum.frequencies_by(day_keys, &binary_part(&1, 0, 7)),
+      days: Enum.frequencies(day_keys)
+    }
     |> Jason.encode!()
   end