import type { Role } from '../core/store/AuthStore';

/**
 * Who sits at the editor (#428): somebody signed in, with their role, or a guest trying a demo
 * copy without an account.
 */
export interface Session {
  guest: boolean;
  role: Role;
}

/**
 * Everything the editor does that writes to the server or manages it. A guest's project lives in
 * the tab alone, so a guest does none of these; an account does all of them but the
 * administrators' own.
 */
export type SessionAction =
  | 'save'
  | 'upload'
  | 'deleteFile'
  | 'projects'
  | 'snapshots'
  | 'release'
  | 'password'
  | 'users'
  | 'demoCopy'
  | 'offerDemo';

const ADMINISTRATORS_ONLY: ReadonlySet<SessionAction> = new Set(['users', 'demoCopy', 'offerDemo']);

/** Whether `session` may do `action`. The server decides again; this is what the editor offers. */
export function sessionAllows(session: Session, action: SessionAction): boolean {
  if (session.guest) return false;
  return !ADMINISTRATORS_ONLY.has(action) || session.role === 'admin';
}

/** What a guest is told when something would need the server. */
export const GUEST_REFUSAL = 'Guests keep nothing on the server – sign in to keep your work';

let current: Session = { guest: false, role: 'user' };

/**
 * The session of this page, for the places that are not handed the account: the pickers, a file
 * dropped on the editor, a finished recording. One page holds one session at a time.
 */
export function setSession(session: Session): void {
  current = session;
}

export function allows(action: SessionAction): boolean {
  return sessionAllows(current, action);
}