defmodule MicrowavepropWeb.MetricsLogSuppressionTest do
  @moduledoc """
  Regression test for the `/metrics` log-suppression bug.

  `Plug.forward/4` rewrites `conn.path_info` to the remainder after the
  matched prefix before dispatching to the forwarded plug. For the
  `forward "/metrics", MetricsPlug` route this means `path_info` is `[]`
  (and `script_name` is `["metrics"]`) by the time the response is being
  sent. Since `send_resp/2` runs inside the forwarded plug, the
  `register_before_send` callback installed by `Plug.Telemetry` sees the
  rewritten conn and the endpoint's `log_level/1` pattern on
  `path_info: ["metrics" | _]` never matches — so a `Sent 200 in Xms`
  line is logged on every Prometheus scrape.
  """

  use MicrowavepropWeb.ConnCase, async: false

  import ExUnit.CaptureLog

  setup do
    # The project config sets :logger level to :warning in test, which
    # would drop the :info-level "Sent 200" line before capture_log ever
    # saw it. Bump to :info for this test so the suppression behaviour
    # is actually observable, then restore afterwards.
    prev_level = Logger.level()
    Logger.configure(level: :info)
    on_exit(fn -> Logger.configure(level: prev_level) end)
    :ok
  end

  test "GET /metrics does not emit a Phoenix endpoint Sent log line", %{conn: conn} do
    log =
      capture_log([level: :info], fn ->
        conn = get(conn, "/metrics")
        assert conn.status == 200
      end)

    refute log =~ "Sent 200"
  end

  test "GET /live does not emit a Phoenix endpoint Sent log line", %{conn: conn} do
    log =
      capture_log([level: :info], fn ->
        conn = get(conn, "/live")
        assert conn.status == 200
      end)

    refute log =~ "Sent 200"
    refute log =~ "GET /live"
  end

  test "log_level/1 returns false for /live", %{conn: _conn} do
    assert MicrowavepropWeb.Endpoint.log_level(%{
             request_path: "/live",
             method: "GET"
           }) == false
  end

  test "log_level/1 returns false for the rewritten conn shape produced by forward", %{
    conn: _conn
  } do
    # When Plug.forward dispatches to the MetricsPlug, the conn it passes
    # has path_info stripped (empty) and script_name holding the prefix.
    # Plug.Telemetry's before_send sees this exact shape.
    rewritten = %{
      path_info: [],
      script_name: ["metrics"],
      request_path: "/metrics",
      method: "GET"
    }

    assert MicrowavepropWeb.Endpoint.log_level(rewritten) == false
  end

  test "log_level/1 returns false when the original method stashed before Plug.Head was HEAD" do
    # Plug.Head runs BEFORE Plug.Telemetry's register_before_send fires
    # and rewrites HEAD→GET, so matching `method: \"HEAD\"` at log time
    # never hits. Endpoint now stashes the original method in private
    # before Plug.Head runs; assert the filter keys off it.
    conn = %{
      request_path: "/some/page",
      method: "GET",
      private: %{original_method: "HEAD"}
    }

    assert MicrowavepropWeb.Endpoint.log_level(conn) == false
  end

  test "HEAD request to a real route does not emit a Phoenix endpoint Sent log line", %{
    conn: conn
  } do
    log =
      capture_log([level: :info], fn ->
        conn = dispatch(conn, MicrowavepropWeb.Endpoint, "HEAD", "/")
        assert conn.status in [200, 302]
      end)

    refute log =~ "Sent 200"
    refute log =~ "Sent 302"
    refute log =~ "HEAD /"
  end
end