feat(stats): add v1 immersion stats dashboard (#19)

stats/src/components/trends/anime-visibility.ts

@@ -0,0 +1,32 @@
+import type { PerAnimeDataPoint } from './StackedTrendChart';
+
+export function buildAnimeVisibilityOptions(datasets: PerAnimeDataPoint[][]): string[] {
+  const totals = new Map<string, number>();
+  for (const dataset of datasets) {
+    for (const point of dataset) {
+      totals.set(point.animeTitle, (totals.get(point.animeTitle) ?? 0) + point.value);
+    }
+  }
+
+  return [...totals.entries()]
+    .sort((a, b) => b[1] - a[1] || a[0].localeCompare(b[0]))
+    .map(([title]) => title);
+}
+
+export function filterHiddenAnimeData(
+  data: PerAnimeDataPoint[],
+  hiddenAnime: ReadonlySet<string>,
+): PerAnimeDataPoint[] {
+  if (hiddenAnime.size === 0) {
+    return data;
+  }
+  return data.filter((point) => !hiddenAnime.has(point.animeTitle));
+}
+
+export function pruneHiddenAnime(
+  hiddenAnime: ReadonlySet<string>,
+  availableAnime: readonly string[],
+): Set<string> {
+  const availableSet = new Set(availableAnime);
+  return new Set([...hiddenAnime].filter((title) => availableSet.has(title)));
+}