Fix settings save validation and desync poster picks across instances.

classes/core/posterMetadataDb.js

@@ -1,4 +1,6 @@
 const fs = require("fs");
+const os = require("os");
+const crypto = require("crypto");
 const path = require("path");
 const Cache = require("./cache");
 const MediaCard = require("../cards/MediaCard");
@@ -22,6 +24,15 @@ const MAX_ENTRIES = 100000;
 const MIN_FILE_BYTES = 256;
 const DEFAULT_FALLBACK_COUNT = 24;
 
+const POSTER_PICK_INSTANCE_OFFSET = (() => {
+  const host = String(os.hostname() || "");
+  let h = 0;
+  for (let i = 0; i < host.length; i++) {
+    h = (Math.imul(31, h) + host.charCodeAt(i)) >>> 0;
+  }
+  return (h + crypto.randomInt(0, 1000000)) >>> 0;
+})();
+
 const SCHEMA_SQL = `
 CREATE TABLE IF NOT EXISTS poster_entries (
   cache_file TEXT PRIMARY KEY NOT NULL,
@@ -1067,6 +1078,10 @@ function pickRandomEntries(count, serverKindOpt, hideContentRatings, serverIdsOp
     const j = Math.floor(Math.random() * (i + 1));
     [shuffled[i], shuffled[j]] = [shuffled[j], shuffled[i]];
   }
+  const rotateBy = POSTER_PICK_INSTANCE_OFFSET % shuffled.length;
+  if (rotateBy > 0) {
+    return shuffled.slice(rotateBy).concat(shuffled.slice(0, rotateBy)).slice(0, Math.min(count, shuffled.length));
+  }
   return shuffled.slice(0, Math.min(count, shuffled.length));
 }