Fix: discord activity sanitizer (#4119)

Co-authored-by: Angelos Bouklis <me@arjix.dev>

src/plugins/discord/discord-service.ts

@@ -9,7 +9,7 @@ import { TimerManager } from './timer-manager';
 import {
   buildDiscordButtons,
   padHangulFields,
-  truncateString,
+  sanitizeActivityText,
   isSeek,
 } from './utils';
 
@@ -114,13 +114,17 @@ export class DiscordService {
     const activityInfo: SetActivity = {
       type: ActivityType.Listening,
       statusDisplayType: config.statusDisplayType,
-      details: truncateString(songInfo.alternativeTitle ?? songInfo.title, 128), // Song title
+      details: sanitizeActivityText(
+        songInfo.alternativeTitle ?? songInfo.title
+      ), // Song title
       detailsUrl: songInfo.url ?? undefined,
-      state: truncateString(songInfo.tags?.at(0) ?? songInfo.artist, 128), // Artist name
+      state: sanitizeActivityText(
+        songInfo.tags?.at(0) ?? songInfo.artist
+      ), // Artist name
       stateUrl: songInfo.artistUrl,
       largeImageKey: songInfo.imageSrc ?? undefined,
       largeImageText: songInfo.album
-        ? truncateString(songInfo.album, 128)
+        ? sanitizeActivityText(songInfo.album)
         : undefined,
       buttons: buildDiscordButtons(config, songInfo),
     };

src/plugins/discord/utils.ts

@@ -19,6 +19,27 @@ export const truncateString = (str: string, length: number): string => {
   return str;
 };
 
+/**
+ * Sanitizes a string for Discord Rich Presence activity, ensuring it meets length requirements.
+ * @param input - The string to sanitize.
+ * @param fallback - A fallback string to use if the input is empty or whitespace. Defaults to 'undefined'.
+ * @returns The sanitized string, compliant with Discord's requirements.
+ */
+export function sanitizeActivityText(input: string | undefined, fallback: string = 'undefined'): string {
+  const text = (input && input.trim()) ? input.trim() : fallback.trim();
+  let safeString = truncateString(text, 128);
+
+  if (safeString.length === 0) {
+    return fallback;
+  }
+
+  if (safeString.length < 2) {
+    safeString = safeString.padEnd(2, '⠀'); // change if necessary
+  }
+
+  return safeString;
+}
+
 /**
  * Builds the array of buttons for the Discord Rich Presence activity.
  * @param config - The plugin configuration.