feat(stats): Trends dashboard overhaul — title visibility, ranking modes, calendar-accurate windows, tooltips (#140)

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

@@ -1,5 +1,109 @@
 import type { PerAnimeDataPoint } from './StackedTrendChart';
 
+const HIDDEN_TITLES_KEY = 'subminer-stats-trends-hidden-titles';
+const MAX_TITLES_KEY = 'subminer-stats-trends-max-titles';
+const MAX_TITLES_MODE_KEY = 'subminer-stats-trends-max-titles-mode';
+const SHOW_EMPTY_DAYS_KEY = 'subminer-stats-trends-show-empty-days';
+
+export const MAX_TITLES_OPTIONS = [3, 5, 7, 10] as const;
+
+// How the per-chart limit picks which titles survive: 'recent' keeps the most
+// recently active titles, 'total' keeps the highest cumulative totals. 'recent'
+// is listed first so it heads the dropdown.
+export type MaxTitlesMode = 'total' | 'recent';
+export const MAX_TITLES_MODES: readonly MaxTitlesMode[] = ['recent', 'total'];
+
+// First-run defaults: show the 7 most recently active titles per chart.
+const DEFAULT_MAX_TITLES = 7;
+const DEFAULT_MAX_TITLES_MODE: MaxTitlesMode = 'recent';
+const ALL_TITLES_STORED_VALUE = 'all';
+
+function getStorage(): Storage | null {
+  try {
+    return globalThis.localStorage ?? null;
+  } catch {
+    return null;
+  }
+}
+
+export function loadHiddenTitles(): Set<string> {
+  try {
+    const raw = getStorage()?.getItem(HIDDEN_TITLES_KEY);
+    const parsed: unknown = raw ? JSON.parse(raw) : [];
+    if (!Array.isArray(parsed)) return new Set();
+    return new Set(parsed.filter((value): value is string => typeof value === 'string'));
+  } catch {
+    return new Set();
+  }
+}
+
+export function saveHiddenTitles(hidden: ReadonlySet<string>): void {
+  try {
+    getStorage()?.setItem(HIDDEN_TITLES_KEY, JSON.stringify([...hidden]));
+  } catch {
+    // Storage can be blocked in private/restricted contexts; keep the in-memory choice.
+  }
+}
+
+// Returns the persisted per-chart limit: a specific count, or null for "All".
+// Absent/garbage storage falls back to the default count (never null), so a
+// first run shows the default cap rather than every title. "All" is stored
+// explicitly so it round-trips instead of collapsing back to the default.
+export function loadMaxTitles(): number | null {
+  try {
+    const raw = getStorage()?.getItem(MAX_TITLES_KEY);
+    if (raw === ALL_TITLES_STORED_VALUE) return null;
+    const value = Number(raw);
+    return (MAX_TITLES_OPTIONS as readonly number[]).includes(value) ? value : DEFAULT_MAX_TITLES;
+  } catch {
+    return DEFAULT_MAX_TITLES;
+  }
+}
+
+export function saveMaxTitles(value: number | null): void {
+  try {
+    getStorage()?.setItem(MAX_TITLES_KEY, value === null ? ALL_TITLES_STORED_VALUE : String(value));
+  } catch {
+    // Storage can be blocked in private/restricted contexts; keep the in-memory choice.
+  }
+}
+
+export function loadMaxTitlesMode(): MaxTitlesMode {
+  try {
+    const raw = getStorage()?.getItem(MAX_TITLES_MODE_KEY);
+    if (raw === 'recent' || raw === 'total') return raw;
+    return DEFAULT_MAX_TITLES_MODE;
+  } catch {
+    return DEFAULT_MAX_TITLES_MODE;
+  }
+}
+
+export function saveMaxTitlesMode(mode: MaxTitlesMode): void {
+  try {
+    getStorage()?.setItem(MAX_TITLES_MODE_KEY, mode);
+  } catch {
+    // Storage can be blocked in private/restricted contexts; keep the in-memory choice.
+  }
+}
+
+// Whether trend charts zero-fill empty calendar buckets. Defaults to true so a
+// first run shows the calendar-accurate view.
+export function loadShowEmptyDays(): boolean {
+  try {
+    return getStorage()?.getItem(SHOW_EMPTY_DAYS_KEY) !== 'false';
+  } catch {
+    return true;
+  }
+}
+
+export function saveShowEmptyDays(show: boolean): void {
+  try {
+    getStorage()?.setItem(SHOW_EMPTY_DAYS_KEY, show ? 'true' : 'false');
+  } catch {
+    // Storage can be blocked in private/restricted contexts; keep the in-memory choice.
+  }
+}
+
 export function buildAnimeVisibilityOptions(datasets: PerAnimeDataPoint[][]): string[] {
   const totals = new Map<string, number>();
   for (const dataset of datasets) {