From e2530762859924a4ef21b8301ca197a0287bd018 Mon Sep 17 00:00:00 2001
From: Nathan Chapman <nathan@windmillapps.org>
Date: Fri, 22 Nov 2024 09:34:43 -0700
Subject: [PATCH] Add contact infinite pagination

---
 lib/send_it/marketing.ex                      |  8 +++-
 lib/send_it_web/components/core_components.ex |  3 +-
 lib/send_it_web/live/contact_live/index.ex    | 45 ++++++++++++++++++-
 .../live/contact_live/index.html.heex         |  5 +++
 4 files changed, 57 insertions(+), 4 deletions(-)

diff --git a/lib/send_it/marketing.ex b/lib/send_it/marketing.ex
index 1f80e0e..81e0c86 100644
--- a/lib/send_it/marketing.ex
+++ b/lib/send_it/marketing.ex
@@ -17,8 +17,12 @@ defmodule SendIt.Marketing do
       [%Contact{}, ...]
 
   """
-  def list_contacts do
-    Repo.all(Contact)
+  def list_contacts(opts \\ [offset: 0, limit: 20]) do
+    Repo.all(
+      from c in Contact,
+        offset: ^opts[:offset],
+        limit: ^opts[:limit]
+    )
   end
 
   def list_subscribed_contacts do
diff --git a/lib/send_it_web/components/core_components.ex b/lib/send_it_web/components/core_components.ex
index c172692..d0dd614 100644
--- a/lib/send_it_web/components/core_components.ex
+++ b/lib/send_it_web/components/core_components.ex
@@ -436,6 +436,7 @@ defmodule SendItWeb.CoreComponents do
   end
 
   slot :action, doc: "the slot for showing user actions in the last table column"
+  attr :rest, :global, doc: "the arbitrary HTML attributes to add to a table"
 
   def table(assigns) do
     assigns =
@@ -453,7 +454,7 @@ defmodule SendItWeb.CoreComponents do
           </th>
         </tr>
       </thead>
-      <tbody id={@id} phx-update={match?(%Phoenix.LiveView.LiveStream{}, @rows) && "stream"}>
+      <tbody id={@id} phx-update={match?(%Phoenix.LiveView.LiveStream{}, @rows) && "stream"} {@rest}>
         <tr :for={row <- @rows} id={@row_id && @row_id.(row)}>
           <td
             :for={{col, i} <- Enum.with_index(@col)}
diff --git a/lib/send_it_web/live/contact_live/index.ex b/lib/send_it_web/live/contact_live/index.ex
index da757b7..01d7696 100644
--- a/lib/send_it_web/live/contact_live/index.ex
+++ b/lib/send_it_web/live/contact_live/index.ex
@@ -6,7 +6,10 @@ defmodule SendItWeb.ContactLive.Index do
 
   @impl true
   def mount(_params, _session, socket) do
-    {:ok, stream(socket, :contacts, Marketing.list_contacts())}
+    {:ok,
+     socket
+     |> assign(page: 1, per_page: 20)
+     |> paginate_contacts(1)}
   end
 
   @impl true
@@ -38,4 +41,44 @@ defmodule SendItWeb.ContactLive.Index do
 
     {:noreply, stream_delete(socket, :contacts, contact)}
   end
+
+  def handle_event("next-page", _, socket) do
+    IO.puts("NEXT Pageee")
+    {:noreply, paginate_contacts(socket, socket.assigns.page + 1)}
+  end
+
+  def handle_event("prev-page", %{"_overran" => true}, socket) do
+    {:noreply, paginate_contacts(socket, 1)}
+  end
+
+  def handle_event("prev-page", _, socket) do
+    if socket.assigns.page > 1 do
+      {:noreply, paginate_contacts(socket, socket.assigns.page - 1)}
+    else
+      {:noreply, socket}
+    end
+  end
+
+  defp paginate_contacts(socket, new_page) when new_page >= 1 do
+    %{per_page: per_page, page: cur_page} = socket.assigns
+    contacts = Marketing.list_contacts(offset: (new_page - 1) * per_page, limit: per_page)
+
+    {contacts, at, limit} =
+      if new_page >= cur_page do
+        {contacts, -1, per_page * 3 * -1}
+      else
+        {Enum.reverse(contacts), 0, per_page * 3}
+      end
+
+    case contacts do
+      [] ->
+        assign(socket, end_of_timeline?: at == -1)
+
+      [_ | _] = contacts ->
+        socket
+        |> assign(end_of_timeline?: false)
+        |> assign(:page, new_page)
+        |> stream(:contacts, contacts, at: at, limit: limit)
+    end
+  end
 end
diff --git a/lib/send_it_web/live/contact_live/index.html.heex b/lib/send_it_web/live/contact_live/index.html.heex
index 9d5bdff..71c4869 100644
--- a/lib/send_it_web/live/contact_live/index.html.heex
+++ b/lib/send_it_web/live/contact_live/index.html.heex
@@ -11,6 +11,9 @@
   id="contacts"
   rows={@streams.contacts}
   row_click={fn {_id, contact} -> JS.navigate(~p"/contacts/#{contact}") end}
+  phx-viewport-top={@page > 1 && "prev-page"}
+  phx-viewport-bottom={!@end_of_timeline? && "next-page"}
+  phx-page-loading
 >
   <:col :let={{_id, contact}} label="Name"><%= contact.name %></:col>
   <:col :let={{_id, contact}} label="Email"><%= contact.email %></:col>
@@ -25,6 +28,8 @@
   </:action>
 </.table>
 
+<h3 :if={@end_of_timeline?}>No more contacts!</h3>
+
 <.modal :if={@live_action in [:new]} id="contact-modal" show on_cancel={JS.patch(~p"/contacts")}>
   <.live_component
     module={SendItWeb.ContactLive.FormComponent}