defmodule BDS.UI.TaskGroupingTest do
  use ExUnit.Case, async: true

  alias BDS.UI.TaskGrouping

  defp task(id, status, opts \\ %{}) do
    %{
      id: id,
      name: Map.get(opts, :name, "Task #{id}"),
      status: status,
      progress: Map.get(opts, :progress),
      message: nil,
      group_id: Map.get(opts, :group_id),
      group_name: Map.get(opts, :group_name)
    }
  end

  describe "build_task_entries/1" do
    test "tasks without a group stay single entries in order" do
      entries = TaskGrouping.build_task_entries([task("a", :running), task("b", :completed)])

      assert [{:single, %{id: "a"}}, {:single, %{id: "b"}}] = entries
    end

    test "tasks with a group_id are grouped by first-seen order" do
      entries =
        TaskGrouping.build_task_entries([
          task("a", :running, %{group_id: "g1", group_name: "Import"}),
          task("b", :running),
          task("c", :pending, %{group_id: "g1", group_name: "Import"}),
          task("d", :completed, %{group_id: "g2", group_name: "Upload"})
        ])

      assert [
               {:group, "g1", "Import", [%{id: "a"}, %{id: "c"}]},
               {:single, %{id: "b"}},
               {:group, "g2", "Upload", [%{id: "d"}]}
             ] = entries
    end

    test "group label falls back to the group_id when no group_name is set" do
      assert [{:group, "g1", "g1", [_]}] =
               TaskGrouping.build_task_entries([task("a", :running, %{group_id: "g1"})])
    end
  end

  describe "summarize_task_group/1" do
    test "counts statuses and averages progress contributions" do
      summary =
        TaskGrouping.summarize_task_group([
          task("a", :running, %{progress: 0.5}),
          task("b", :pending),
          task("c", :completed)
        ])

      assert summary.total == 3
      assert summary.running == 1
      assert summary.pending == 1
      assert summary.completed == 1
      assert summary.failed == 0
      assert summary.cancelled == 0
      # contributions: 0.5 (running) + 0 (pending) + 1.0 (completed)
      assert_in_delta summary.progress, 0.5, 0.001
    end

    test "finished failures and cancellations count as full progress" do
      summary = TaskGrouping.summarize_task_group([task("a", :failed), task("b", :cancelled)])

      assert summary.progress == 1.0
      assert summary.failed == 1
      assert summary.cancelled == 1
    end

    test "empty group summarizes to zero" do
      assert %{total: 0, progress: +0.0} = TaskGrouping.summarize_task_group([])
    end
  end
end