/**
 * What this Console is showing, and to whom.
 *
 * One component serves three situations — an admin across every branch, an
 * admin looking at one, and a store user who has exactly one. The differences
 * are almost entirely in the words and in which sections appear, so they are
 * decided here as data rather than scattered through the layout as `isPinned &&`
 * conditions that drift apart.
 *
 * Pure on purpose. The rules about what a store user may see are the kind that
 * get quietly broken by a later refactor, so they are tested rather than
 * inspected.
 */

export type ConsoleRole = 'admin' | 'store-user';

export interface ConsoleScopeInput {
  role: ConsoleRole;
  /** The branch in view. `null` means every branch the user may see. */
  selected: number | null;
  /** Branch name when one is selected. */
  branchName?: string | undefined;
  /** How many branches this user is authorised for. */
  branchCount: number;
}

export interface ConsoleScope {
  /** True only for an admin looking across more than their own single branch. */
  isAggregate: boolean;
  /** Sits beside the "Console" title. */
  countLabel: string;
  /** The sentence under the title. */
  blurb: string;
  /** What Nearle Buddy says it is answering about. */
  buddyContext: string;
  /** Admin-only, and only across branches. */
  showBranchOverview: boolean;
  /** "Your shop" reads as a lie when several are in view. */
  shopSectionTitle: string;
  /** Whether a per-branch column earns its width. */
  showBranchColumn: boolean;
}

export function consoleScope({
  role,
  selected,
  branchName,
  branchCount,
}: ConsoleScopeInput): ConsoleScope {
  // A store user is pinned to one outlet, so "all branches" is not a state they
  // can reach — and if a stray null ever arrives here it must not be read as
  // permission to aggregate.
  const isAggregate = role === 'admin' && selected === null;

  if (isAggregate) {
    return {
      isAggregate: true,
      countLabel: `${branchCount} ${branchCount === 1 ? 'branch' : 'branches'}`,
      blurb: 'Everything trading right now — across your branches, and what needs your attention.',
      buddyContext: 'Across your branches',
      showBranchOverview: true,
      // Naming it "Your shop" while thirteen are in view invites a merchant to
      // read one shop's numbers as the whole business.
      shopSectionTitle: 'Branch performance',
      showBranchColumn: true,
    };
  }

  const name = branchName?.trim() || 'your store';

  return {
    isAggregate: false,
    countLabel: name,
    blurb: `Everything trading right now — for ${name}.`,
    buddyContext: name,
    showBranchOverview: false,
    shopSectionTitle: role === 'store-user' ? 'Your shop' : 'Branch',
    // A store user already knows which branch they are in; an admin who chose
    // one branch does too. Neither needs it repeated in every table row.
    showBranchColumn: false,
  };
}