defmodule MicrowavepropWeb.Api.RateLimiterTest do
  use ExUnit.Case, async: false

  import Plug.Conn
  import Plug.Test

  alias MicrowavepropWeb.Api.RateLimiter

  setup do
    RateLimiter.reset()
    :ok
  end

  describe "init/1" do
    test "passes options through unchanged" do
      assert RateLimiter.init(anon_limit: 5) == [anon_limit: 5]
    end
  end

  describe "call/2 anonymous" do
    test "annotates RateLimit headers and lets requests through under the limit" do
      conn = RateLimiter.call(conn(:get, "/"), anon_limit: 3)

      refute conn.halted
      assert ["3"] = get_resp_header(conn, "ratelimit-limit")
      assert ["2"] = get_resp_header(conn, "ratelimit-remaining")
      assert [reset] = get_resp_header(conn, "ratelimit-reset")
      assert String.to_integer(reset) >= 1
    end

    test "halts with 429 when the bucket is exhausted" do
      opts = [anon_limit: 2, window_ms: 60_000]

      _ = RateLimiter.call(conn(:get, "/"), opts)
      _ = RateLimiter.call(conn(:get, "/"), opts)
      conn = RateLimiter.call(conn(:get, "/"), opts)

      assert conn.halted
      assert conn.status == 429
      assert get_resp_header(conn, "retry-after") != []
      assert ["0"] = get_resp_header(conn, "ratelimit-remaining")
    end
  end

  describe "call/2 authenticated" do
    test "uses the auth_limit when current_api_token is assigned" do
      conn =
        :get
        |> conn("/")
        |> assign(:current_api_token, %{id: "tok-1"})
        |> RateLimiter.call(auth_limit: 5, anon_limit: 1)

      refute conn.halted
      assert ["5"] = get_resp_header(conn, "ratelimit-limit")
    end

    test "different tokens occupy different buckets" do
      opts = [auth_limit: 1]

      conn_a =
        :get
        |> conn("/")
        |> assign(:current_api_token, %{id: "A"})
        |> RateLimiter.call(opts)

      conn_b =
        :get
        |> conn("/")
        |> assign(:current_api_token, %{id: "B"})
        |> RateLimiter.call(opts)

      refute conn_a.halted
      refute conn_b.halted
    end
  end

  describe "reset/0" do
    test "clears the table even before any call" do
      assert RateLimiter.reset() == :ok
    end
  end
end