Replace String.to_integer with safe Integer.parse

Use Integer.parse/1 instead of String.to_integer/1 on user-supplied
and external API input to prevent ArgumentError crashes on non-numeric
values. Adds fallback defaults or nil returns at each call site.

lib/last_fm/artist.ex

@@ -67,10 +67,18 @@ defmodule LastFm.Artist do
   end
 
   defp get_play_count(api_response) do
-    if play_count = get_in(api_response, ["stats", "userplaycount"]) do
-      String.to_integer(play_count)
-    else
-      0
+    case get_in(api_response, ["stats", "userplaycount"]) do
+      nil -> 0
+      value -> parse_play_count(value)
     end
   end
+
+  defp parse_play_count(value) when is_binary(value) do
+    case Integer.parse(value) do
+      {int, ""} -> int
+      _ -> 0
+    end
+  end
+
+  defp parse_play_count(_), do: 0
 end

lib/last_fm/track.ex

@@ -73,8 +73,10 @@ defmodule LastFm.Track do
   end
 
   defp parse_scrobble_at_uts(track) do
-    track["date"]["uts"]
-    |> String.to_integer()
+    case Integer.parse(track["date"]["uts"]) do
+      {int, ""} -> int
+      _ -> nil
+    end
   end
 
   def changeset(track, attrs) do

lib/music_brainz/artist.ex

@@ -53,7 +53,13 @@ defmodule MusicBrainz.Artist do
     end)
   end
 
-  defp parse_discogs_id("https://www.discogs.com/artist/" <> id), do: String.to_integer(id)
+  defp parse_discogs_id("https://www.discogs.com/artist/" <> id) do
+    case Integer.parse(id) do
+      {int, ""} -> int
+      _ -> nil
+    end
+  end
+
   defp parse_discogs_id(_other), do: nil
 
   defp parse_wikidata_id("https://www.wikidata.org/wiki/" <> id), do: id

lib/music_library_web/components/release.ex

@@ -282,7 +282,7 @@ defmodule MusicLibraryWeb.Components.Release do
   def handle_event("scrobble_medium", %{"number" => number}, socket)
       when release_loaded?(socket.assigns) do
     release_with_tracks = socket.assigns.release_with_tracks.result
-    number = String.to_integer(number)
+    {number, ""} = Integer.parse(number)
 
     case ScrobbleActivity.scrobble_medium(number, release_with_tracks,
            finished_at: DateTime.utc_now()
@@ -324,7 +324,7 @@ defmodule MusicLibraryWeb.Components.Release do
   end
 
   def handle_event("toggle_medium", %{"medium-number" => number}, socket) do
-    number = String.to_integer(number)
+    {number, ""} = Integer.parse(number)
     selected_tracks = socket.assigns.selected_tracks
     release_with_tracks = socket.assigns.release_with_tracks.result
 

lib/music_library_web/controllers/collection_controller.ex

@@ -28,15 +28,8 @@ defmodule MusicLibraryWeb.CollectionController do
   end
 
   def index(conn, params) do
-    limit =
-      params
-      |> Map.get("limit", "20")
-      |> String.to_integer()
-
-    offset =
-      params
-      |> Map.get("offset", "0")
-      |> String.to_integer()
+    limit = parse_int(params["limit"], 20)
+    offset = parse_int(params["offset"], 0)
 
     total = Collection.search_records_count("")
 
@@ -44,4 +37,15 @@ defmodule MusicLibraryWeb.CollectionController do
 
     render(conn, :index, total: total, limit: limit, offset: offset, records: records)
   end
+
+  defp parse_int(nil, default), do: default
+
+  defp parse_int(value, default) when is_binary(value) do
+    case Integer.parse(value) do
+      {int, ""} -> int
+      _ -> default
+    end
+  end
+
+  defp parse_int(_, default), do: default
 end

lib/music_library_web/live/scrobble_live/show.ex

@@ -162,7 +162,7 @@ defmodule MusicLibraryWeb.ScrobbleLive.Show do
   end
 
   def handle_event("scrobble_medium", %{"medium_number" => number}, socket) do
-    number = String.to_integer(number)
+    {number, ""} = Integer.parse(number)
 
     case ScrobbleActivity.scrobble_medium(number, socket.assigns.release,
            finished_at: DateTime.utc_now()