From 533574d0cc3103a3475dcecfb794102a8ea75337 Mon Sep 17 00:00:00 2001
From: Max Marcon <maxmarcon@gmx.net>
Date: Fri, 1 Dec 2023 12:31:18 +0100
Subject: [PATCH] allow selection to be updated from the form

---
 lib/live_select.ex             |  5 ++--
 lib/live_select/component.ex   | 47 +++++++++++++++++++++++++++++++---
 test/live_select_tags_test.exs | 26 +++++++++++++++++++
 test/live_select_test.exs      | 22 ++++++++++++++++
 4 files changed, 94 insertions(+), 6 deletions(-)

diff --git a/lib/live_select.ex b/lib/live_select.ex
index 5f6b626..08953c0 100644
--- a/lib/live_select.ex
+++ b/lib/live_select.ex
@@ -37,7 +37,8 @@ defmodule LiveSelect do
 
   ## Options
 
-  You can pass or update the list of options the user can choose from with the `options` assign.
+  You can set the initial list of options the user can choose from with the `options` assign.
+  Afterwards, you can update the options at any time using `Phoenix.LiveView.send_update/3`.
   Each option will be assigned a label, which will be shown in the dropdown, and a value, which will be the value of the
   LiveSelect input when the option is selected.
 
@@ -280,7 +281,7 @@ defmodule LiveSelect do
 
   attr :options, :list,
     doc:
-      ~s(initial available options to select from. See the "Options" section for details on what you can pass here)
+      ~s(initial available options to select from. Note that, after the initial rendering of the component, options can only be updated using `Phoenix.LiveView.send_update/3` - See the "Options" section for details)
 
   attr :value, :any, doc: "used to manually set a selection - overrides any values from the form. 
   Must be a single element in `:single` mode, or a list of elements in `:tags` mode."
diff --git a/lib/live_select/component.ex b/lib/live_select/component.ex
index 6f0678e..0ae288f 100644
--- a/lib/live_select/component.ex
+++ b/lib/live_select/component.ex
@@ -108,6 +108,17 @@ defmodule LiveSelect.Component do
   def update(assigns, socket) do
     validate_assigns!(assigns)
 
+    initial_render = !socket.assigns[:field]
+
+    assigns =
+      if !initial_render && Map.has_key?(assigns, :field) do
+        # do not reset option when rerendering
+        # TODO: missing test
+        Map.delete(assigns, :options)
+      else
+        assigns
+      end
+
     socket =
       socket
       |> assign(assigns)
@@ -131,10 +142,21 @@ defmodule LiveSelect.Component do
       end)
       |> update(:options, &normalize_options/1)
       |> assign(:text_input_field, String.to_atom("#{socket.assigns.field.field}_text_input"))
-      |> assign_new(:selection, fn
-        %{field: field, options: options, mode: mode} ->
-          set_selection(field.value, options, mode)
-      end)
+
+    socket =
+      if assigns[:field] do
+        assign(
+          socket,
+          :selection,
+          set_selection(
+            decode(socket.assigns.field.value, socket.assigns.mode),
+            socket.assigns.options,
+            socket.assigns.mode
+          )
+        )
+      else
+        socket
+      end
 
     socket =
       if Map.has_key?(assigns, :value) do
@@ -586,6 +608,23 @@ defmodule LiveSelect.Component do
 
   defp encode(value), do: Jason.encode!(value)
 
+  defp decode(nil, _), do: nil
+
+  defp decode(value, :tags) do
+    value
+    |> List.wrap()
+    |> Enum.map(&decode(&1, :single))
+  end
+
+  defp decode(value, :single) when is_binary(value) do
+    case Jason.decode(value) do
+      {:ok, decoded} -> decoded
+      {:error, _} -> value
+    end
+  end
+
+  defp decode(value, :single), do: value
+
   defp already_selected?(option, selection) do
     option.label in Enum.map(selection, & &1.label)
   end
diff --git a/test/live_select_tags_test.exs b/test/live_select_tags_test.exs
index 35c0a93..fd2d7f7 100644
--- a/test/live_select_tags_test.exs
+++ b/test/live_select_tags_test.exs
@@ -444,4 +444,30 @@ defmodule LiveSelectTagsTest do
       })
     end
   end
+
+  test "selection can be updated from the form", %{conn: conn} do
+    stub_options([
+      %{value: 1, label: "A"},
+      %{value: 2, label: "B"},
+      %{value: 3, label: "C"}
+    ])
+
+    {:ok, live, _html} = live(conn, "/?mode=tags")
+
+    type(live, "ABC")
+
+    select_nth_option(live, 1)
+
+    type(live, "ABC")
+
+    select_nth_option(live, 2, method: :click)
+
+    assert_selected_multiple(live, [%{value: 1, label: "A"}, %{value: 2, label: "B"}])
+
+    send_update(live,
+      field: Phoenix.Component.to_form(%{"city_search" => [2, 3]}, as: :my_form)[:city_search]
+    )
+
+    assert_selected_multiple_static(live, [%{value: 2, label: "B"}, %{value: 3, label: "C"}])
+  end
 end
diff --git a/test/live_select_test.exs b/test/live_select_test.exs
index dbcbebc..b6ae798 100644
--- a/test/live_select_test.exs
+++ b/test/live_select_test.exs
@@ -639,6 +639,28 @@ defmodule LiveSelectTest do
     assert tag =~ "with custom slot"
   end
 
+  test "selection can be updated from the form", %{conn: conn} do
+    stub_options(
+      A: 1,
+      B: 2,
+      C: 3
+    )
+
+    {:ok, live, _html} = live(conn, "/")
+
+    type(live, "ABC")
+
+    select_nth_option(live, 2)
+
+    assert_selected(live, :B, 2)
+
+    send_update(live,
+      field: Phoenix.Component.to_form(%{"city_search" => 1}, as: :my_form)[:city_search]
+    )
+
+    assert_selected_static(live, :A, 1)
+  end
+
   for style <- [:daisyui, :tailwind, :none, nil] do
     @style style