feat: add private help and feedback reports (#43)

Issue: #43
User-Visible: yes

src/support-feedback.ts

@@ -0,0 +1,150 @@
+/** Pure state/validation helpers for the lazy Help & Feedback dialog (#43). */
+
+export const SUPPORT_MESSAGE_LIMIT = 10_000;
+export const SUPPORT_CONTACT_LIMIT = 320;
+
+export interface SupportPreview {
+  token: string;
+  expiresAt: number;
+  size: number;
+  sha256: string;
+  spaces: number;
+  format: string;
+  version: number;
+  text: string;
+  preparedAt: number;
+}
+
+export type SupportDialogStatus =
+  | 'idle'
+  | 'building'
+  | 'ready'
+  | 'sending'
+  | 'success'
+  | 'error';
+
+export interface SupportDialogState {
+  draftId: string;
+  idempotencyKey: string;
+  contact: string;
+  message: string;
+  attach: boolean;
+  status: SupportDialogStatus;
+  preview: SupportPreview | null;
+  rawOpen: boolean;
+  errorCode: string;
+  reportId: string;
+}
+
+export interface SupportRuntimeFacts {
+  browser_family: 'chromium' | 'firefox' | 'webkit' | 'unknown';
+  browser_major: number;
+  language: 'en' | 'ru' | 'de' | 'fr';
+  coarse_pointer: boolean;
+  hover_capable: boolean;
+  registry_access: 'full' | 'partial' | 'unavailable';
+  registry_age_bucket: 'fresh' | 'stale' | 'unknown';
+}
+
+function randomId(prefix: string): string {
+  const id = globalThis.crypto?.randomUUID?.()
+    ?? `${Date.now().toString(36)}-${Math.random().toString(36).slice(2)}`;
+  return `${prefix}-${id}`;
+}
+
+export function newSupportDialogState(): SupportDialogState {
+  return {
+    draftId: randomId('draft'),
+    idempotencyKey: randomId('report'),
+    contact: '',
+    message: '',
+    attach: false,
+    status: 'idle',
+    preview: null,
+    rawOpen: false,
+    errorCode: '',
+    reportId: '',
+  };
+}
+
+export function codePointLength(value: string): number {
+  return [...value].length;
+}
+
+export type SupportDraftError =
+  | 'message_required'
+  | 'message_too_long'
+  | 'contact_too_long'
+  | 'preview_missing'
+  | 'preview_expired'
+  | null;
+
+export function supportDraftError(state: SupportDialogState, now = Date.now()): SupportDraftError {
+  const message = state.message.trim();
+  if (!message) return 'message_required';
+  if (codePointLength(message) > SUPPORT_MESSAGE_LIMIT) return 'message_too_long';
+  if (codePointLength(state.contact.trim()) > SUPPORT_CONTACT_LIMIT) return 'contact_too_long';
+  if (state.attach && !state.preview) return 'preview_missing';
+  if (state.attach && state.preview!.expiresAt <= now) return 'preview_expired';
+  return null;
+}
+
+export function supportCanSubmit(state: SupportDialogState, now = Date.now()): boolean {
+  return state.status !== 'building'
+    && state.status !== 'sending'
+    && state.status !== 'success'
+    && supportDraftError(state, now) === null;
+}
+
+function browserOf(userAgent: string): { family: SupportRuntimeFacts['browser_family']; major: number } {
+  const firefox = /Firefox\/(\d+)/i.exec(userAgent);
+  if (firefox) return { family: 'firefox', major: Number(firefox[1]) || 0 };
+  const chromium = /(?:Chrome|Chromium|Edg)\/(\d+)/i.exec(userAgent);
+  if (chromium) return { family: 'chromium', major: Number(chromium[1]) || 0 };
+  const webkit = /Version\/(\d+).+Safari\//i.exec(userAgent);
+  if (webkit) return { family: 'webkit', major: Number(webkit[1]) || 0 };
+  return { family: 'unknown', major: 0 };
+}
+
+export function supportRuntimeFacts(
+  options: {
+    userAgent?: string;
+    language: string;
+    coarsePointer?: boolean;
+    hoverCapable?: boolean;
+    registryAccess: 'pending' | 'full' | 'limited';
+    registryLastSuccess?: number;
+    now?: number;
+  },
+): SupportRuntimeFacts {
+  const browser = browserOf(options.userAgent ?? globalThis.navigator?.userAgent ?? '');
+  const now = options.now ?? Date.now();
+  const last = Number(options.registryLastSuccess || 0);
+  const age = last <= 0 ? 'unknown' : now - last <= 10 * 60_000 ? 'fresh' : 'stale';
+  const language = (['en', 'ru', 'de', 'fr'] as const).includes(options.language as any)
+    ? options.language as SupportRuntimeFacts['language'] : 'en';
+  const media = globalThis.matchMedia?.bind(globalThis);
+  return {
+    browser_family: browser.family,
+    browser_major: Math.max(0, Math.min(999, browser.major)),
+    language,
+    coarse_pointer: options.coarsePointer ?? !!media?.('(pointer: coarse)').matches,
+    hover_capable: options.hoverCapable ?? !!media?.('(hover: hover)').matches,
+    registry_access: options.registryAccess === 'full'
+      ? 'full' : options.registryAccess === 'limited' ? 'partial' : 'unavailable',
+    registry_age_bucket: age,
+  };
+}
+
+export function supportErrorCode(value: unknown): string {
+  const code = value && typeof value === 'object'
+    ? String((value as any).code || '') : '';
+  return new Set([
+    'support_invalid_message', 'support_preview_expired', 'support_package_too_large',
+    'support_rate_limited', 'support_unavailable', 'support_rejected', 'unauthorized',
+  ]).has(code) ? code : 'support_unavailable';
+}
+
+export function supportSizeKiB(size: number): string {
+  return (Math.max(0, size) / 1024).toFixed(size < 10 * 1024 ? 1 : 0);
+}