Add post visibility and days_until_live helpers

blogex/lib/blogex/post.ex

@@ -44,6 +44,23 @@ defmodule Blogex.Post do
           published: boolean()
         }
 
+  @type visibility :: :draft | :scheduled | :live
+
+  @doc "Returns the visibility of a post: :draft, :scheduled, or :live."
+  def visibility(%__MODULE__{published: false}), do: :draft
+
+  def visibility(%__MODULE__{published: true, date: date}) do
+    if Date.after?(date, Date.utc_today()), do: :scheduled, else: :live
+  end
+
+  @doc "Returns days until a scheduled post goes live, or nil."
+  def days_until_live(%__MODULE__{} = post) do
+    case visibility(post) do
+      :scheduled -> Date.diff(post.date, Date.utc_today())
+      _ -> nil
+    end
+  end
+
   @doc """
   Build callback for NimblePublisher.
 

blogex/test/blogex/post_visibility_test.exs

@@ -0,0 +1,45 @@
+defmodule Blogex.Post.VisibilityTest do
+  use ExUnit.Case
+
+  import Blogex.Test.PostBuilder
+
+  describe "visibility/1" do
+    test "returns :draft when post is not published" do
+      post = build(published: false, date: ~D[2026-01-01])
+      assert Blogex.Post.visibility(post) == :draft
+    end
+
+    test "returns :scheduled when post is published with future date" do
+      post = build(published: true, date: ~D[2099-01-01])
+      assert Blogex.Post.visibility(post) == :scheduled
+    end
+
+    test "returns :live when post is published with past date" do
+      post = build(published: true, date: ~D[2020-01-01])
+      assert Blogex.Post.visibility(post) == :live
+    end
+
+    test "returns :live when post is published with today's date" do
+      post = build(published: true, date: Date.utc_today())
+      assert Blogex.Post.visibility(post) == :live
+    end
+  end
+
+  describe "days_until_live/1" do
+    test "returns positive integer for scheduled post" do
+      future = Date.add(Date.utc_today(), 10)
+      post = build(published: true, date: future)
+      assert Blogex.Post.days_until_live(post) == 10
+    end
+
+    test "returns nil for draft post" do
+      post = build(published: false, date: ~D[2099-01-01])
+      assert Blogex.Post.days_until_live(post) == nil
+    end
+
+    test "returns nil for live post" do
+      post = build(published: true, date: ~D[2020-01-01])
+      assert Blogex.Post.days_until_live(post) == nil
+    end
+  end
+end