defmodule VavPipeline.MannaShabbatTest do
  @moduledoc "Shemot 16:22–26: Friday's double portion is the Shabbat's too; nothing else crosses the day boundary."
  use ExUnit.Case, async: false
  alias VavPipeline.Manna

  @friday ~D[2026-10-16]
  @saturday ~D[2026-10-17]
  @sunday ~D[2026-10-18]

  defp write(date, type, expires) do
    path = Manna.provision_file()
    File.mkdir_p!(Path.dirname(path))
    File.write!(path, Jason.encode!(%{"date" => Date.to_iso8601(date), "provision" => %{"compute_units" => 2000, "memory_mb" => 1, "api_calls_external" => 1, "storage_delta_mb" => 1, "sanhedrin_panels_max" => 1}, "type" => type, "expires_at" => expires, "written_by" => "test", "written_at" => "2026-10-16T00:01:00Z"}))
    on_exit(fn -> File.rm(path) end)
  end

  defp at(date, h), do: DateTime.new!(date, Time.new!(h, 0, 0), "Etc/UTC")

  test "Friday's double stands on Saturday" do
    write(@friday, "double", "2026-10-18T00:30:00Z")
    assert {:ok, %{type: :double}} = Manna.check_at(at(@friday, 12))
    assert {:ok, %{type: :double}} = Manna.check_at(at(@saturday, 12))
  end

  test "a regular provision does not cross the boundary; a double does not reach Sunday" do
    write(@friday, "regular", "2026-10-18T00:30:00Z")
    assert {:error, "MANNA_STALE" <> _} = Manna.check_at(at(@saturday, 12))
    write(@friday, "double", "2026-10-19T00:30:00Z")
    assert {:error, "MANNA_STALE" <> _} = Manna.check_at(at(@sunday, 12))
  end

  test "a double written on a Thursday does not carry to Friday — only Shabbat receives it" do
    write(~D[2026-10-15], "double", "2026-10-17T00:30:00Z")
    assert {:error, "MANNA_STALE" <> _} = Manna.check_at(at(@friday, 12))
  end
end