feat: prevent join requests with equal mail

lib/membership/join_request.ex

@@ -77,6 +77,17 @@ defmodule Mv.Membership.JoinRequest do
 
       change Mv.Membership.JoinRequest.Changes.RejectRequest
     end
+
+    # Internal: resend confirmation (new token) when user submits form again with same email.
+    # Called from domain with authorize?: false; not exposed to public.
+    update :regenerate_confirmation_token do
+      description "Set new confirmation token and expiry (resend flow)"
+      require_atomic? false
+
+      argument :confirmation_token, :string, allow_nil?: false
+
+      change Mv.Membership.JoinRequest.Changes.RegenerateConfirmationToken
+    end
   end
 
   policies do
@@ -175,6 +186,11 @@ defmodule Mv.Membership.JoinRequest do
     attribute :approved_at, :utc_datetime_usec
     attribute :rejected_at, :utc_datetime_usec
     attribute :reviewed_by_user_id, :uuid
+
+    attribute :reviewed_by_display, :string do
+      description "Denormalized reviewer display (e.g. email) for UI without loading User"
+    end
+
     attribute :source, :string
 
     create_timestamp :inserted_at

lib/membership/join_request/changes/approve_request.ex

@@ -16,11 +16,13 @@ defmodule Mv.Membership.JoinRequest.Changes.ApproveRequest do
 
     if current_status == :submitted do
       reviewed_by_id = Helpers.actor_id(context.actor)
+      reviewed_by_display = Helpers.actor_email(context.actor)
 
       changeset
       |> Ash.Changeset.force_change_attribute(:status, :approved)
       |> Ash.Changeset.force_change_attribute(:approved_at, DateTime.utc_now())
       |> Ash.Changeset.force_change_attribute(:reviewed_by_user_id, reviewed_by_id)
+      |> Ash.Changeset.force_change_attribute(:reviewed_by_display, reviewed_by_display)
     else
       Ash.Changeset.add_error(changeset,
         field: :status,

lib/membership/join_request/changes/helpers.ex

@@ -16,4 +16,24 @@ defmodule Mv.Membership.JoinRequest.Changes.Helpers do
   end
 
   def actor_id(_), do: nil
+
+  @doc """
+  Extracts the actor's email for display (e.g. reviewed_by_display).
+
+  Supports both atom and string keys for compatibility with different actor representations.
+  """
+  @spec actor_email(term()) :: String.t() | nil
+  def actor_email(nil), do: nil
+
+  def actor_email(actor) when is_map(actor) do
+    raw = Map.get(actor, :email) || Map.get(actor, "email")
+    if is_nil(raw), do: nil, else: actor_email_string(raw)
+  end
+
+  def actor_email(_), do: nil
+
+  defp actor_email_string(raw) do
+    s = raw |> to_string() |> String.trim()
+    if s == "", do: nil, else: s
+  end
 end

lib/membership/join_request/changes/regenerate_confirmation_token.ex

@@ -0,0 +1,30 @@
+defmodule Mv.Membership.JoinRequest.Changes.RegenerateConfirmationToken do
+  @moduledoc """
+  Sets a new confirmation token hash and expiry on an existing join request (resend flow).
+
+  Used when the user submits the join form again with the same email while a request
+  is still pending_confirmation. Internal use only (domain calls with authorize?: false).
+  """
+  use Ash.Resource.Change
+
+  alias Mv.Membership.JoinRequest
+
+  @confirmation_validity_hours 24
+
+  @spec change(Ash.Changeset.t(), keyword(), Ash.Resource.Change.context()) :: Ash.Changeset.t()
+  def change(changeset, _opts, _context) do
+    token = Ash.Changeset.get_argument(changeset, :confirmation_token)
+
+    if is_binary(token) and token != "" do
+      hash = JoinRequest.hash_confirmation_token(token)
+      expires_at = DateTime.utc_now() |> DateTime.add(@confirmation_validity_hours, :hour)
+
+      changeset
+      |> Ash.Changeset.force_change_attribute(:confirmation_token_hash, hash)
+      |> Ash.Changeset.force_change_attribute(:confirmation_token_expires_at, expires_at)
+      |> Ash.Changeset.force_change_attribute(:confirmation_sent_at, DateTime.utc_now())
+    else
+      changeset
+    end
+  end
+end

lib/membership/join_request/changes/reject_request.ex

@@ -15,11 +15,13 @@ defmodule Mv.Membership.JoinRequest.Changes.RejectRequest do
 
     if current_status == :submitted do
       reviewed_by_id = Helpers.actor_id(context.actor)
+      reviewed_by_display = Helpers.actor_email(context.actor)
 
       changeset
       |> Ash.Changeset.force_change_attribute(:status, :rejected)
       |> Ash.Changeset.force_change_attribute(:rejected_at, DateTime.utc_now())
       |> Ash.Changeset.force_change_attribute(:reviewed_by_user_id, reviewed_by_id)
+      |> Ash.Changeset.force_change_attribute(:reviewed_by_display, reviewed_by_display)
     else
       Ash.Changeset.add_error(changeset,
         field: :status,

lib/membership/membership.ex

@@ -29,7 +29,11 @@ defmodule Mv.Membership do
   require Ash.Query
   import Ash.Expr
   alias Ash.Error.Query.NotFound, as: NotFoundError
+  alias Mv.Helpers.SystemActor
   alias Mv.Membership.JoinRequest
+  alias Mv.Membership.Member
+  alias MvWeb.Emails.JoinAlreadyMemberEmail
+  alias MvWeb.Emails.JoinAlreadyPendingEmail
   alias MvWeb.Emails.JoinConfirmationEmail
   require Logger
 
@@ -365,15 +369,130 @@ defmodule Mv.Membership do
 
   ## Returns
     - `{:ok, request}` - Created JoinRequest in status pending_confirmation, email sent
+    - `{:ok, :notified_already_member}` - Email already a member; notice sent by email only (no request created)
+    - `{:ok, :notified_already_pending}` - Email already has pending/submitted request; notice or resend sent by email only
     - `{:error, :email_delivery_failed}` - Request created but confirmation email could not be sent (logged)
     - `{:error, error}` - Validation or authorization error
   """
   def submit_join_request(attrs, opts \\ []) do
     actor = Keyword.get(opts, :actor)
-    token = Map.get(attrs, :confirmation_token) || generate_confirmation_token()
+    email = normalize_submit_email(attrs)
 
-    # Raw token is passed to the submit action; JoinRequest.Changes.SetConfirmationToken
-    # hashes it before persist. Only the hash is stored; the raw token is sent in the email link.
+    pending =
+      if email != nil and email != "", do: pending_join_request_with_email(email), else: nil
+
+    cond do
+      email != nil and email != "" and member_exists_with_email?(email) ->
+        send_already_member_and_return(email)
+
+      pending != nil ->
+        handle_already_pending(email, pending)
+
+      true ->
+        do_create_join_request(attrs, actor)
+    end
+  end
+
+  defp normalize_submit_email(attrs) do
+    raw = attrs["email"] || attrs[:email]
+    if is_binary(raw), do: String.trim(raw), else: nil
+  end
+
+  defp member_exists_with_email?(email) when is_binary(email) do
+    system_actor = SystemActor.get_system_actor()
+    opts = [actor: system_actor, domain: __MODULE__]
+
+    case Ash.get(Member, %{email: email}, opts) do
+      {:ok, _member} -> true
+      _ -> false
+    end
+  end
+
+  defp member_exists_with_email?(_), do: false
+
+  defp pending_join_request_with_email(email) when is_binary(email) do
+    system_actor = SystemActor.get_system_actor()
+
+    query =
+      JoinRequest
+      |> Ash.Query.filter(expr(email == ^email and status in [:pending_confirmation, :submitted]))
+      |> Ash.Query.sort(inserted_at: :desc)
+      |> Ash.Query.limit(1)
+
+    case Ash.read_one(query, actor: system_actor, domain: __MODULE__) do
+      {:ok, request} -> request
+      _ -> nil
+    end
+  end
+
+  defp pending_join_request_with_email(_), do: nil
+
+  defp apply_anti_enumeration_delay do
+    Process.sleep(100 + :rand.uniform(200))
+  end
+
+  defp send_already_member_and_return(email) do
+    case JoinAlreadyMemberEmail.send(email) do
+      {:ok, _} ->
+        :ok
+
+      {:error, reason} ->
+        Logger.error("Join already-member email failed for #{email}: #{inspect(reason)}")
+    end
+
+    apply_anti_enumeration_delay()
+    {:ok, :notified_already_member}
+  end
+
+  defp handle_already_pending(email, existing) do
+    if existing.status == :pending_confirmation do
+      resend_confirmation_to_pending(email, existing)
+    else
+      send_already_pending_and_return(email)
+    end
+  end
+
+  defp resend_confirmation_to_pending(email, request) do
+    new_token = generate_confirmation_token()
+
+    case request
+         |> Ash.Changeset.for_update(:regenerate_confirmation_token, %{
+           confirmation_token: new_token
+         })
+         |> Ash.update(domain: __MODULE__, authorize?: false) do
+      {:ok, _updated} ->
+        case JoinConfirmationEmail.send(email, new_token, resend: true) do
+          {:ok, _} ->
+            :ok
+
+          {:error, reason} ->
+            Logger.error("Join resend confirmation email failed for #{email}: #{inspect(reason)}")
+        end
+
+        apply_anti_enumeration_delay()
+        {:ok, :notified_already_pending}
+
+      {:error, _} ->
+        # Fallback: do not create duplicate; send generic pending email
+        send_already_pending_and_return(email)
+    end
+  end
+
+  defp send_already_pending_and_return(email) do
+    case JoinAlreadyPendingEmail.send(email) do
+      {:ok, _} ->
+        :ok
+
+      {:error, reason} ->
+        Logger.error("Join already-pending email failed for #{email}: #{inspect(reason)}")
+    end
+
+    apply_anti_enumeration_delay()
+    {:ok, :notified_already_pending}
+  end
+
+  defp do_create_join_request(attrs, actor) do
+    token = Map.get(attrs, :confirmation_token) || generate_confirmation_token()
     attrs_with_token = Map.put(attrs, :confirmation_token, token)
 
     case Ash.create(JoinRequest, attrs_with_token,
@@ -384,6 +503,7 @@ defmodule Mv.Membership do
       {:ok, request} ->
         case JoinConfirmationEmail.send(request.email, token) do
           {:ok, _email} ->
+            apply_anti_enumeration_delay()
             {:ok, request}
 
           {:error, reason} ->

lib/mv_web/emails/join_already_member_email.ex

@@ -0,0 +1,42 @@
+defmodule MvWeb.Emails.JoinAlreadyMemberEmail do
+  @moduledoc """
+  Sends an email when someone submits the join form with an address that is already a member.
+
+  Used for anti-enumeration: the UI shows the same success message; only the email
+  informs the recipient. Uses the unified email layout.
+  """
+  use Phoenix.Swoosh,
+    view: MvWeb.EmailsView,
+    layout: {MvWeb.EmailLayoutView, "layout.html"}
+
+  use MvWeb, :verified_routes
+  import Swoosh.Email
+  use Gettext, backend: MvWeb.Gettext, otp_app: :mv
+
+  alias Mv.Mailer
+
+  @doc """
+  Sends the "already a member" notice to the given address.
+
+  Returns `{:ok, email}` on success, `{:error, reason}` on delivery failure.
+  """
+  def send(email_address) when is_binary(email_address) do
+    subject = gettext("Membership application – already a member")
+
+    assigns = %{
+      subject: subject,
+      app_name: Mailer.mail_from() |> elem(0),
+      locale: Gettext.get_locale(MvWeb.Gettext)
+    }
+
+    email =
+      new()
+      |> from(Mailer.mail_from())
+      |> to(email_address)
+      |> subject(subject)
+      |> put_view(MvWeb.EmailsView)
+      |> render_body("join_already_member.html", assigns)
+
+    Mailer.deliver(email, Mailer.smtp_config())
+  end
+end

lib/mv_web/emails/join_already_pending_email.ex

@@ -0,0 +1,43 @@
+defmodule MvWeb.Emails.JoinAlreadyPendingEmail do
+  @moduledoc """
+  Sends an email when someone submits the join form with an address that already
+  has a submitted (confirmed) application under review.
+
+  Used for anti-enumeration: the UI shows the same success message; only the email
+  informs the recipient. Uses the unified email layout.
+  """
+  use Phoenix.Swoosh,
+    view: MvWeb.EmailsView,
+    layout: {MvWeb.EmailLayoutView, "layout.html"}
+
+  use MvWeb, :verified_routes
+  import Swoosh.Email
+  use Gettext, backend: MvWeb.Gettext, otp_app: :mv
+
+  alias Mv.Mailer
+
+  @doc """
+  Sends the "application already under review" notice to the given address.
+
+  Returns `{:ok, email}` on success, `{:error, reason}` on delivery failure.
+  """
+  def send(email_address) when is_binary(email_address) do
+    subject = gettext("Membership application – already under review")
+
+    assigns = %{
+      subject: subject,
+      app_name: Mailer.mail_from() |> elem(0),
+      locale: Gettext.get_locale(MvWeb.Gettext)
+    }
+
+    email =
+      new()
+      |> from(Mailer.mail_from())
+      |> to(email_address)
+      |> subject(subject)
+      |> put_view(MvWeb.EmailsView)
+      |> render_body("join_already_pending.html", assigns)
+
+    Mailer.deliver(email, Mailer.smtp_config())
+  end
+end

lib/mv_web/emails/join_confirmation_email.ex

@@ -18,10 +18,16 @@ defmodule MvWeb.Emails.JoinConfirmationEmail do
   Uses the same SMTP configuration as the test mail (Settings or boot ENV) via
   `Mailer.deliver/2` with `Mailer.smtp_config/0` for consistency.
 
-  Called from the domain after a JoinRequest is created (submit flow).
+  Called from the domain after a JoinRequest is created (submit flow) or when
+  resending to an existing pending request.
+
+  ## Options
+    - `:resend` - If true, adds a short note that the link is being sent again for an existing request.
+
   Returns `{:ok, email}` on success, `{:error, reason}` on delivery failure.
   """
-  def send(email_address, token) when is_binary(email_address) and is_binary(token) do
+  def send(email_address, token, opts \\ [])
+      when is_binary(email_address) and is_binary(token) do
     confirm_url = url(~p"/confirm_join/#{token}")
     subject = gettext("Confirm your membership request")
 
@@ -29,7 +35,8 @@ defmodule MvWeb.Emails.JoinConfirmationEmail do
       confirm_url: confirm_url,
       subject: subject,
       app_name: Mailer.mail_from() |> elem(0),
-      locale: Gettext.get_locale(MvWeb.Gettext)
+      locale: Gettext.get_locale(MvWeb.Gettext),
+      resend: Keyword.get(opts, :resend, false)
     }
 
     email =

lib/mv_web/live/join_request_live/helpers.ex

@@ -21,9 +21,24 @@ defmodule MvWeb.JoinRequestLive.Helpers do
   @doc """
   Returns the reviewer display string (e.g. email) for a join request, or nil if none.
 
-  Accepts a join request struct or map with optional :reviewed_by_user (loaded User struct).
+  Prefers the denormalized :reviewed_by_display (set on approve/reject) so the UI
+  works for all roles without loading the User resource. Falls back to
+  :reviewed_by_user when loaded (e.g. admin or legacy data before backfill).
   """
   def reviewer_display(req) when is_map(req) do
+    case Map.get(req, :reviewed_by_display) do
+      s when is_binary(s) ->
+        trimmed = String.trim(s)
+        if trimmed == "", do: reviewer_display_from_user(req), else: trimmed
+
+      _ ->
+        reviewer_display_from_user(req)
+    end
+  end
+
+  def reviewer_display(_), do: nil
+
+  defp reviewer_display_from_user(req) do
     user = Map.get(req, :reviewed_by_user)
 
     case user do
@@ -42,6 +57,4 @@ defmodule MvWeb.JoinRequestLive.Helpers do
         nil
     end
   end
-
-  def reviewer_display(_), do: nil
 end

lib/mv_web/live/join_request_live/show.ex

@@ -264,11 +264,16 @@ defmodule MvWeb.JoinRequestLive.Show do
   defp format_applicant_value(nil), do: nil
   defp format_applicant_value(""), do: nil
   defp format_applicant_value(%Date{} = date), do: DateFormatter.format_date(date)
-  defp format_applicant_value(value) when is_map(value), do: format_applicant_value_from_map(value)
+
+  defp format_applicant_value(value) when is_map(value),
+    do: format_applicant_value_from_map(value)
+
   defp format_applicant_value(value) when is_boolean(value),
     do: if(value, do: gettext("Yes"), else: gettext("No"))
+
   defp format_applicant_value(value) when is_binary(value) or is_number(value),
     do: to_string(value)
+
   defp format_applicant_value(value), do: to_string(value)
 
   defp format_applicant_value_from_map(value) do
@@ -283,8 +288,10 @@ defmodule MvWeb.JoinRequestLive.Show do
   end
 
   defp format_applicant_value_simple(raw, _value) when is_binary(raw), do: raw
+
   defp format_applicant_value_simple(raw, _value) when is_boolean(raw),
     do: if(raw, do: gettext("Yes"), else: gettext("No"))
+
   defp format_applicant_value_simple(raw, _value) when is_integer(raw), do: to_string(raw)
   defp format_applicant_value_simple(_raw, value), do: to_string(value)
 

lib/mv_web/templates/emails/join_already_member.html.heex

@@ -0,0 +1,10 @@
+<div style="color: #111827;">
+  <p style="margin: 0 0 16px; font-size: 16px; line-height: 1.5;">
+    {gettext(
+      "We have received your request. The email address you entered is already registered as a member."
+    )}
+  </p>
+  <p style="margin: 0; font-size: 14px; color: #6b7280;">
+    {gettext("If you have any questions, please contact us.")}
+  </p>
+</div>

lib/mv_web/templates/emails/join_already_pending.html.heex

@@ -0,0 +1,10 @@
+<div style="color: #111827;">
+  <p style="margin: 0 0 16px; font-size: 16px; line-height: 1.5;">
+    {gettext(
+      "We have received your request. You already have a membership application that is being reviewed."
+    )}
+  </p>
+  <p style="margin: 0; font-size: 14px; color: #6b7280;">
+    {gettext("If you have any questions, please contact us.")}
+  </p>
+</div>

lib/mv_web/templates/emails/join_confirmation.html.heex

@@ -1,4 +1,9 @@
 <div style="color: #111827;">
+  <%= if @resend do %>
+    <p style="margin: 0 0 16px; font-size: 16px; line-height: 1.5;">
+      {gettext("You already had a pending request. Here is a new confirmation link.")}
+    </p>
+  <% end %>
   <p style="margin: 0 0 16px; font-size: 16px; line-height: 1.5;">
     {gettext(
       "We have received your membership request. To complete it, please click the link below."