defmodule Farmbot.CeleryScript.AST.HeapTest do
  use ExUnit.Case
  alias Farmbot.CeleryScript.AST
  alias AST.Heap

  test "Heap access with address" do
    heap =
      Heap.new()
      |> Heap.alot("abc")
      |> Heap.alot("def")
      |> Heap.alot("ghi")

    assert is_null?(heap.entries[Address.new(0)])
    assert match?(%{:__kind => "abc"}, heap.entries[Address.new(1)])
    assert match?(%{:__kind => "def"}, heap.entries[Address.new(2)])
    assert match?(%{:__kind => "ghi"}, heap.entries[Address.new(3)])
  end

  test "puts a key value pair on an existing aloted slot" do
    heap =
      Heap.new()
      |> Heap.alot("abc")
      |> Heap.put("key", "value")

    assert match?(
             %{:__kind => "abc", key: "value"},
             heap.entries[Address.new(1)]
           )
  end

  test "Puts key/value pairs at arbitrary addresses" do
    heap =
      Heap.new()
      |> Heap.alot("abc")
      |> Heap.alot("def")
      |> Heap.alot("ghi")

    mutated = Heap.put(heap, Address.new(2), "abc_key", "value")

    assert match?(
             %{:__kind => "def", abc_key: "value"},
             mutated.entries[Address.new(2)]
           )
  end

  test "Can't update on bad a address" do
    heap =
      Heap.new()
      |> Heap.alot("abc")
      |> Heap.alot("def")
      |> Heap.alot("ghi")

    assert_raise RuntimeError, fn ->
      Heap.put(heap, Address.new(200), "abc_key", "value")
    end
  end

  defp is_null?(%Address{value: 0}), do: true
  defp is_null?(%Address{value: _}), do: false

  defp is_null?(%{
         __body: %Address{value: 0},
         __kind: :nothing,
         __next: %Address{value: 0},
         __parent: %Address{value: 0}
       }),
       do: true

  defp is_null?(_), do: false
end