Add beacon monitor registration and fix prod SMTP

Users can now register beacon monitors on the settings page. Each
monitor gets a unique random token the remote program will use to
authenticate its reports. Name is the only user-supplied field for
now; more will be added as the monitor protocol is defined.

Also adds :gen_smtp to deps. Swoosh's SMTP adapter depends on
:mimemail which lives in that package, and production was 500'ing
when trying to send confirmation emails without it.

lib/microwaveprop/beacon_monitors.ex

@@ -0,0 +1,74 @@
+defmodule Microwaveprop.BeaconMonitors do
+  @moduledoc """
+  The BeaconMonitors context: manages the monitor stations a user
+  has registered. Each monitor has a unique random token the remote
+  program uses to authenticate its reports.
+  """
+
+  import Ecto.Query
+
+  alias Microwaveprop.Accounts.User
+  alias Microwaveprop.BeaconMonitors.BeaconMonitor
+  alias Microwaveprop.Repo
+
+  @token_bytes 32
+
+  @doc """
+  Returns all monitors for the given user, newest first.
+  """
+  def list_monitors_for_user(%User{id: user_id}) do
+    Repo.all(
+      from m in BeaconMonitor,
+        where: m.user_id == ^user_id,
+        order_by: [desc: m.inserted_at]
+    )
+  end
+
+  @doc """
+  Creates a new monitor for the given user with a freshly generated token.
+  """
+  def create_monitor(%User{} = user, attrs) do
+    %BeaconMonitor{user_id: user.id, token: generate_token()}
+    |> BeaconMonitor.changeset(attrs)
+    |> Repo.insert()
+  end
+
+  @doc """
+  Deletes a monitor owned by the given user.
+
+  Returns `{:error, :not_found}` if the monitor does not exist or
+  belongs to another user.
+  """
+  def delete_monitor(%User{id: user_id}, monitor_id) do
+    query =
+      from m in BeaconMonitor,
+        where: m.id == ^monitor_id and m.user_id == ^user_id
+
+    case Repo.one(query) do
+      nil -> {:error, :not_found}
+      monitor -> Repo.delete(monitor)
+    end
+  rescue
+    Ecto.Query.CastError -> {:error, :not_found}
+  end
+
+  @doc """
+  Looks up a monitor by its token. Returns nil if not found.
+  """
+  def get_monitor_by_token(token) when is_binary(token) do
+    Repo.get_by(BeaconMonitor, token: token)
+  end
+
+  @doc """
+  Returns a blank changeset for rendering the new-monitor form.
+  """
+  def change_monitor(attrs \\ %{}) do
+    BeaconMonitor.changeset(%BeaconMonitor{}, attrs)
+  end
+
+  defp generate_token do
+    @token_bytes
+    |> :crypto.strong_rand_bytes()
+    |> Base.url_encode64(padding: false)
+  end
+end

lib/microwaveprop/beacon_monitors/beacon_monitor.ex

@@ -0,0 +1,36 @@
+defmodule Microwaveprop.BeaconMonitors.BeaconMonitor do
+  @moduledoc """
+  A beacon monitor is a remote station running the monitor program
+  that reports beacon reception data. Each monitor is owned by a user
+  and identified by a random token the program uses to authenticate.
+  """
+
+  use Ecto.Schema
+
+  import Ecto.Changeset
+
+  alias Microwaveprop.Accounts.User
+
+  @primary_key {:id, :binary_id, autogenerate: true}
+  @foreign_key_type :binary_id
+  schema "beacon_monitors" do
+    field :name, :string
+    field :token, :string
+    field :last_seen_at, :utc_datetime
+
+    belongs_to :user, User
+
+    timestamps(type: :utc_datetime)
+  end
+
+  @doc """
+  Changeset for user-controlled fields (name only for now).
+  Token and user_id are assigned by the context, not cast from user input.
+  """
+  def changeset(monitor, attrs) do
+    monitor
+    |> cast(attrs, [:name])
+    |> validate_required([:name])
+    |> validate_length(:name, min: 1, max: 100)
+  end
+end

lib/microwaveprop_web/controllers/beacon_monitor_controller.ex

@@ -0,0 +1,38 @@
+defmodule MicrowavepropWeb.BeaconMonitorController do
+  use MicrowavepropWeb, :controller
+
+  alias Microwaveprop.BeaconMonitors
+
+  def create(conn, %{"beacon_monitor" => params}) do
+    user = conn.assigns.current_scope.user
+
+    case BeaconMonitors.create_monitor(user, params) do
+      {:ok, monitor} ->
+        conn
+        |> put_flash(:info, "Monitor '#{monitor.name}' created. Copy its token below.")
+        |> redirect(to: ~p"/users/settings")
+
+      {:error, changeset} ->
+        message =
+          changeset
+          |> Ecto.Changeset.traverse_errors(fn {msg, _} -> msg end)
+          |> Enum.map_join("; ", fn {k, v} -> "#{k}: #{Enum.join(v, ", ")}" end)
+
+        conn
+        |> put_flash(:error, "Could not create monitor (#{message}).")
+        |> redirect(to: ~p"/users/settings")
+    end
+  end
+
+  def delete(conn, %{"id" => id}) do
+    user = conn.assigns.current_scope.user
+
+    conn =
+      case BeaconMonitors.delete_monitor(user, id) do
+        {:ok, _monitor} -> put_flash(conn, :info, "Monitor deleted.")
+        {:error, :not_found} -> put_flash(conn, :error, "Monitor not found.")
+      end
+
+    redirect(conn, to: ~p"/users/settings")
+  end
+end

lib/microwaveprop_web/controllers/user_settings_controller.ex

@@ -4,10 +4,12 @@ defmodule MicrowavepropWeb.UserSettingsController do
   import MicrowavepropWeb.UserAuth, only: [require_sudo_mode: 2]
 
   alias Microwaveprop.Accounts
+  alias Microwaveprop.BeaconMonitors
   alias MicrowavepropWeb.UserAuth
 
   plug :require_sudo_mode
   plug :assign_email_and_password_changesets
+  plug :assign_beacon_monitors
 
   def edit(conn, _params) do
     render(conn, :edit)
@@ -74,4 +76,12 @@ defmodule MicrowavepropWeb.UserSettingsController do
     |> assign(:email_changeset, Accounts.change_user_email(user))
     |> assign(:password_changeset, Accounts.change_user_password(user))
   end
+
+  defp assign_beacon_monitors(conn, _opts) do
+    user = conn.assigns.current_scope.user
+
+    conn
+    |> assign(:beacon_monitors, BeaconMonitors.list_monitors_for_user(user))
+    |> assign(:beacon_monitor_changeset, BeaconMonitors.change_monitor())
+  end
 end

lib/microwaveprop_web/controllers/user_settings_html/edit.html.heex

@@ -46,4 +46,80 @@
       Save Password
     </.button>
   </.form>
+
+  <div class="divider" />
+
+  <section id="beacon-monitors" class="space-y-4">
+    <.header>
+      Beacon monitors
+      <:subtitle>
+        Register remote monitor stations. Each monitor gets a unique token the
+        monitor program uses to authenticate its reports.
+      </:subtitle>
+    </.header>
+
+    <.form
+      :let={f}
+      for={@beacon_monitor_changeset}
+      as={:beacon_monitor}
+      action={~p"/users/beacon-monitors"}
+      id="create_beacon_monitor"
+      class="flex items-end gap-2"
+    >
+      <div class="flex-1">
+        <.input
+          field={f[:name]}
+          type="text"
+          label="Monitor name"
+          placeholder="e.g. Shack Pi"
+          required
+        />
+      </div>
+      <.button variant="primary" phx-disable-with="Adding...">Add monitor</.button>
+    </.form>
+
+    <%= if @beacon_monitors == [] do %>
+      <p class="text-sm opacity-70">No monitors registered yet.</p>
+    <% else %>
+      <div class="overflow-x-auto">
+        <table class="table table-sm">
+          <thead>
+            <tr>
+              <th>Name</th>
+              <th>Token</th>
+              <th>Last seen</th>
+              <th class="w-1"></th>
+            </tr>
+          </thead>
+          <tbody>
+            <%= for monitor <- @beacon_monitors do %>
+              <tr>
+                <td class="font-semibold">{monitor.name}</td>
+                <td>
+                  <code class="text-xs break-all select-all">{monitor.token}</code>
+                </td>
+                <td class="text-sm opacity-70">
+                  <%= if monitor.last_seen_at do %>
+                    {Calendar.strftime(monitor.last_seen_at, "%Y-%m-%d %H:%M UTC")}
+                  <% else %>
+                    never
+                  <% end %>
+                </td>
+                <td>
+                  <.link
+                    href={~p"/users/beacon-monitors/#{monitor.id}"}
+                    method="delete"
+                    class="btn btn-ghost btn-xs text-error"
+                    data-confirm={"Delete monitor '#{monitor.name}'? Its token will stop working immediately."}
+                  >
+                    Delete
+                  </.link>
+                </td>
+              </tr>
+            <% end %>
+          </tbody>
+        </table>
+      </div>
+    <% end %>
+  </section>
 </Layouts.app>

lib/microwaveprop_web/router.ex

@@ -86,6 +86,9 @@ defmodule MicrowavepropWeb.Router do
     get "/users/settings", UserSettingsController, :edit
     put "/users/settings", UserSettingsController, :update
     get "/users/settings/confirm-email/:token", UserSettingsController, :confirm_email
+
+    post "/users/beacon-monitors", BeaconMonitorController, :create
+    delete "/users/beacon-monitors/:id", BeaconMonitorController, :delete
   end
 
   scope "/", MicrowavepropWeb do

mix.exs

@@ -58,6 +58,7 @@ defmodule Microwaveprop.MixProject do
       {:heroicons,
        github: "tailwindlabs/heroicons", tag: "v2.2.0", sparse: "optimized", app: false, compile: false, depth: 1},
       {:swoosh, "~> 1.16"},
+      {:gen_smtp, "~> 1.2"},
       {:req, "~> 0.5"},
       {:telemetry_metrics, "~> 1.0"},
       {:telemetry_poller, "~> 1.0"},

mix.lock

@@ -20,6 +20,7 @@
   "file_system": {:hex, :file_system, "1.1.1", "31864f4685b0148f25bd3fbef2b1228457c0c89024ad67f7a81a3ffbc0bbad3a", [:mix], [], "hexpm", "7a15ff97dfe526aeefb090a7a9d3d03aa907e100e262a0f8f7746b78f8f87a5d"},
   "finch": {:hex, :finch, "0.21.0", "b1c3b2d48af02d0c66d2a9ebfb5622be5c5ecd62937cf79a88a7f98d48a8290c", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.6.2 or ~> 1.7", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "87dc6e169794cb2570f75841a19da99cfde834249568f2a5b121b809588a4377"},
   "fine": {:hex, :fine, "0.1.4", "b19a89c1476c7c57afb5f9314aed5960b5bc95d5277de4cb5ee8e1d1616ce379", [:mix], [], "hexpm", "be3324cc454a42d80951cf6023b9954e9ff27c6daa255483b3e8d608670303f5"},
+  "gen_smtp": {:hex, :gen_smtp, "1.3.0", "62c3d91f0dcf6ce9db71bcb6881d7ad0d1d834c7f38c13fa8e952f4104a8442e", [:rebar3], [{:ranch, ">= 1.8.0", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm", "0b73fbf069864ecbce02fe653b16d3f35fd889d0fdd4e14527675565c39d84e6"},
   "gettext": {:hex, :gettext, "0.26.2", "5978aa7b21fada6deabf1f6341ddba50bc69c999e812211903b169799208f2a8", [:mix], [{:expo, "~> 0.5.1 or ~> 1.0", [hex: :expo, repo: "hexpm", optional: false]}], "hexpm", "aa978504bcf76511efdc22d580ba08e2279caab1066b76bb9aa81c4a1e0a32a5"},
   "heroicons": {:git, "https://github.com/tailwindlabs/heroicons.git", "0435d4ca364a608cc75e2f8683d374e55abbae26", [tag: "v2.2.0", sparse: "optimized", depth: 1]},
   "hpax": {:hex, :hpax, "1.0.3", "ed67ef51ad4df91e75cc6a1494f851850c0bd98ebc0be6e81b026e765ee535aa", [:mix], [], "hexpm", "8eab6e1cfa8d5918c2ce4ba43588e894af35dbd8e91e6e55c817bca5847df34a"},
@@ -46,6 +47,7 @@
   "plug_crypto": {:hex, :plug_crypto, "2.1.1", "19bda8184399cb24afa10be734f84a16ea0a2bc65054e23a62bb10f06bc89491", [:mix], [], "hexpm", "6470bce6ffe41c8bd497612ffde1a7e4af67f36a15eea5f921af71cf3e11247c"},
   "polaris": {:hex, :polaris, "0.1.0", "dca61b18e3e801ecdae6ac9f0eca5f19792b44a5cb4b8d63db50fc40fc038d22", [:mix], [{:nx, "~> 0.5", [hex: :nx, repo: "hexpm", optional: false]}], "hexpm", "13ef2b166650e533cb24b10e2f3b8ab4f2f449ba4d63156e8c569527f206e2c2"},
   "postgrex": {:hex, :postgrex, "0.22.0", "fb027b58b6eab1f6de5396a2abcdaaeb168f9ed4eccbb594e6ac393b02078cbd", [:mix], [{:db_connection, "~> 2.9", [hex: :db_connection, repo: "hexpm", optional: false]}, {:decimal, "~> 1.5 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:table, "~> 0.1.0", [hex: :table, repo: "hexpm", optional: true]}], "hexpm", "a68c4261e299597909e03e6f8ff5a13876f5caadaddd0d23af0d0a61afcc5d84"},
+  "ranch": {:hex, :ranch, "2.2.0", "25528f82bc8d7c6152c57666ca99ec716510fe0925cb188172f41ce93117b1b0", [:make, :rebar3], [], "hexpm", "fa0b99a1780c80218a4197a59ea8d3bdae32fbff7e88527d7d8a4787eff4f8e7"},
   "req": {:hex, :req, "0.5.17", "0096ddd5b0ed6f576a03dde4b158a0c727215b15d2795e59e0916c6971066ede", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:ezstd, "~> 1.0", [hex: :ezstd, repo: "hexpm", optional: true]}, {:finch, "~> 0.17", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "0b8bc6ffdfebbc07968e59d3ff96d52f2202d0536f10fef4dc11dc02a2a43e39"},
   "stream_data": {:hex, :stream_data, "1.3.0", "bde37905530aff386dea1ddd86ecbf00e6642dc074ceffc10b7d4e41dfd6aac9", [:mix], [], "hexpm", "3cc552e286e817dca43c98044c706eec9318083a1480c52ae2688b08e2936e3c"},
   "styler": {:hex, :styler, "1.11.0", "35010d970689a23c2bcc8e97bd8bf7d20e3561d60c49be84654df5c37d051a9c", [:mix], [], "hexpm", "70f36165d0cf238a32b7a456fdef6a9c72e77e657d7ac4a0ace33aeba3f2b8c0"},

priv/repo/migrations/20260408154735_create_beacon_monitors.exs

@@ -0,0 +1,18 @@
+defmodule Microwaveprop.Repo.Migrations.CreateBeaconMonitors do
+  use Ecto.Migration
+
+  def change do
+    create table(:beacon_monitors, primary_key: false) do
+      add :id, :binary_id, primary_key: true
+      add :user_id, references(:users, type: :binary_id, on_delete: :delete_all), null: false
+      add :name, :string, null: false
+      add :token, :string, null: false
+      add :last_seen_at, :utc_datetime
+
+      timestamps(type: :utc_datetime)
+    end
+
+    create index(:beacon_monitors, [:user_id])
+    create unique_index(:beacon_monitors, [:token])
+  end
+end

test/microwaveprop/beacon_monitors_test.exs

@@ -0,0 +1,99 @@
+defmodule Microwaveprop.BeaconMonitorsTest do
+  use Microwaveprop.DataCase
+
+  import Microwaveprop.AccountsFixtures
+
+  alias Microwaveprop.BeaconMonitors
+  alias Microwaveprop.BeaconMonitors.BeaconMonitor
+
+  describe "create_monitor/2" do
+    test "creates a monitor with a generated token" do
+      user = user_fixture()
+
+      assert {:ok, %BeaconMonitor{} = monitor} =
+               BeaconMonitors.create_monitor(user, %{"name" => "Shack Pi"})
+
+      assert monitor.user_id == user.id
+      assert monitor.name == "Shack Pi"
+      assert is_binary(monitor.token)
+      # strong_rand_bytes(32) |> url_encode64(padding: false) is 43 chars
+      assert String.length(monitor.token) == 43
+    end
+
+    test "generates a unique token per monitor" do
+      user = user_fixture()
+      {:ok, m1} = BeaconMonitors.create_monitor(user, %{"name" => "One"})
+      {:ok, m2} = BeaconMonitors.create_monitor(user, %{"name" => "Two"})
+
+      refute m1.token == m2.token
+    end
+
+    test "requires a name" do
+      user = user_fixture()
+
+      assert {:error, changeset} = BeaconMonitors.create_monitor(user, %{"name" => ""})
+      assert %{name: ["can't be blank"]} = errors_on(changeset)
+    end
+  end
+
+  describe "list_monitors_for_user/1" do
+    test "returns monitors belonging to the user, newest first" do
+      user = user_fixture()
+      other = user_fixture()
+
+      {:ok, first} = BeaconMonitors.create_monitor(user, %{"name" => "First"})
+      Process.sleep(1100)
+      {:ok, second} = BeaconMonitors.create_monitor(user, %{"name" => "Second"})
+      {:ok, _other} = BeaconMonitors.create_monitor(other, %{"name" => "Nope"})
+
+      assert [second_result, first_result] = BeaconMonitors.list_monitors_for_user(user)
+      assert second_result.id == second.id
+      assert first_result.id == first.id
+    end
+
+    test "returns empty list when user has no monitors" do
+      user = user_fixture()
+      assert BeaconMonitors.list_monitors_for_user(user) == []
+    end
+  end
+
+  describe "delete_monitor/2" do
+    test "deletes a monitor owned by the user" do
+      user = user_fixture()
+      {:ok, monitor} = BeaconMonitors.create_monitor(user, %{"name" => "Bye"})
+
+      assert {:ok, %BeaconMonitor{}} = BeaconMonitors.delete_monitor(user, monitor.id)
+      assert BeaconMonitors.list_monitors_for_user(user) == []
+    end
+
+    test "does not delete a monitor owned by another user" do
+      user = user_fixture()
+      other = user_fixture()
+      {:ok, monitor} = BeaconMonitors.create_monitor(other, %{"name" => "Theirs"})
+
+      assert {:error, :not_found} = BeaconMonitors.delete_monitor(user, monitor.id)
+      assert [_] = BeaconMonitors.list_monitors_for_user(other)
+    end
+
+    test "returns :not_found for nonexistent id" do
+      user = user_fixture()
+
+      assert {:error, :not_found} =
+               BeaconMonitors.delete_monitor(user, "11111111-1111-1111-1111-111111111111")
+    end
+  end
+
+  describe "get_monitor_by_token/1" do
+    test "returns the monitor matching the token" do
+      user = user_fixture()
+      {:ok, monitor} = BeaconMonitors.create_monitor(user, %{"name" => "Find Me"})
+
+      found = BeaconMonitors.get_monitor_by_token(monitor.token)
+      assert found.id == monitor.id
+    end
+
+    test "returns nil for unknown token" do
+      refute BeaconMonitors.get_monitor_by_token("not-a-real-token")
+    end
+  end
+end

test/microwaveprop_web/controllers/beacon_monitor_controller_test.exs

@@ -0,0 +1,65 @@
+defmodule MicrowavepropWeb.BeaconMonitorControllerTest do
+  use MicrowavepropWeb.ConnCase, async: true
+
+  import Microwaveprop.AccountsFixtures
+
+  alias Microwaveprop.BeaconMonitors
+
+  setup :register_and_log_in_user
+
+  describe "POST /users/beacon-monitors" do
+    test "creates a monitor for the current user", %{conn: conn, user: user} do
+      conn =
+        post(conn, ~p"/users/beacon-monitors", %{
+          "beacon_monitor" => %{"name" => "Shack Pi"}
+        })
+
+      assert redirected_to(conn) == ~p"/users/settings"
+      assert Phoenix.Flash.get(conn.assigns.flash, :info) =~ "Shack Pi"
+
+      assert [monitor] = BeaconMonitors.list_monitors_for_user(user)
+      assert monitor.name == "Shack Pi"
+      assert is_binary(monitor.token)
+    end
+
+    test "shows an error when name is blank", %{conn: conn, user: user} do
+      conn =
+        post(conn, ~p"/users/beacon-monitors", %{
+          "beacon_monitor" => %{"name" => ""}
+        })
+
+      assert redirected_to(conn) == ~p"/users/settings"
+      assert Phoenix.Flash.get(conn.assigns.flash, :error) =~ "name"
+      assert BeaconMonitors.list_monitors_for_user(user) == []
+    end
+
+    test "redirects unauthenticated users to login" do
+      conn = post(build_conn(), ~p"/users/beacon-monitors", %{"beacon_monitor" => %{"name" => "Nope"}})
+
+      assert redirected_to(conn) == ~p"/users/log-in"
+    end
+  end
+
+  describe "DELETE /users/beacon-monitors/:id" do
+    test "deletes a monitor owned by the current user", %{conn: conn, user: user} do
+      {:ok, monitor} = BeaconMonitors.create_monitor(user, %{"name" => "Bye"})
+
+      conn = delete(conn, ~p"/users/beacon-monitors/#{monitor.id}")
+
+      assert redirected_to(conn) == ~p"/users/settings"
+      assert Phoenix.Flash.get(conn.assigns.flash, :info) =~ "deleted"
+      assert BeaconMonitors.list_monitors_for_user(user) == []
+    end
+
+    test "does not delete a monitor owned by another user", %{conn: conn} do
+      other = user_fixture()
+      {:ok, monitor} = BeaconMonitors.create_monitor(other, %{"name" => "Theirs"})
+
+      conn = delete(conn, ~p"/users/beacon-monitors/#{monitor.id}")
+
+      assert redirected_to(conn) == ~p"/users/settings"
+      assert Phoenix.Flash.get(conn.assigns.flash, :error) =~ "not found"
+      assert [_] = BeaconMonitors.list_monitors_for_user(other)
+    end
+  end
+end