defmodule ToweropsWeb.ChangelogParserTest do
  use ExUnit.Case, async: true

  alias ToweropsWeb.ChangelogParser

  describe "parse_content/1" do
    test "parses date with title and items" do
      content = """
      2026-03-15 — New Features
      * Added dark mode
      * Improved search
      """

      result = ChangelogParser.parse_content(content)

      assert [{:changelog_entry, "2026-03-15", {:some, "New Features"}, items}] = result
      assert items == ["Added dark mode", "Improved search"]
    end

    test "parses date without title" do
      content = """
      2026-03-15
      * Bug fix one
      * Bug fix two
      """

      result = ChangelogParser.parse_content(content)

      assert [{:changelog_entry, "2026-03-15", :none, items}] = result
      assert items == ["Bug fix one", "Bug fix two"]
    end

    test "parses multiple entries in chronological order" do
      content = """
      2026-03-15 — Latest
      * Item A

      2026-03-10 — Earlier
      * Item B
      * Item C
      """

      result = ChangelogParser.parse_content(content)

      assert [
               {:changelog_entry, "2026-03-15", {:some, "Latest"}, ["Item A"]},
               {:changelog_entry, "2026-03-10", {:some, "Earlier"}, ["Item B", "Item C"]}
             ] = result
    end

    test "ignores non-matching lines" do
      content = """
      Some random text
      2026-03-15 — Release
      * Only item
      More random text
      """

      result = ChangelogParser.parse_content(content)

      assert [{:changelog_entry, "2026-03-15", {:some, "Release"}, ["Only item"]}] = result
    end

    test "handles empty content" do
      assert [] = ChangelogParser.parse_content("")
    end

    test "handles em dash and en dash separators" do
      em_dash = "2026-03-15 — Em Dash Title\n* Item"
      en_dash = "2026-03-15 – En Dash Title\n* Item"

      [{:changelog_entry, _, {:some, "Em Dash Title"}, _}] =
        ChangelogParser.parse_content(em_dash)

      [{:changelog_entry, _, {:some, "En Dash Title"}, _}] =
        ChangelogParser.parse_content(en_dash)
    end

    test "items before any date header are ignored" do
      content = """
      * Orphan item
      2026-03-15 — Release
      * Proper item
      """

      result = ChangelogParser.parse_content(content)

      assert [{:changelog_entry, "2026-03-15", {:some, "Release"}, ["Proper item"]}] = result
    end
  end

  describe "ToweropsWeb.ChangelogParser.parse/0 integration" do
    test "parses the actual changelog file" do
      entries = ChangelogParser.parse()

      assert [_ | _] = entries

      first = List.first(entries)
      assert %{date: %Date{}, items: items} = first
      assert is_list(items) and items != []
    end
  end
end