/**
 * The sentences the school page and the compare page print about where an
 * Ofsted grade came from and what the latest visit was. One wording, two pages.
 * Rule: docs/superpowers/specs/2026-10-05-ofsted-current-status-design.md
 */

import type { OfstedCurrentGrade, OfstedInspection, OfstedLatestVisit } from './types';

export function formatOfstedDate(iso: string | null | undefined): string {
  if (!iso) return '';
  const d = new Date(iso);
  if (Number.isNaN(d.getTime())) return '';
  return d.toLocaleDateString('en-GB', { day: 'numeric', month: 'long', year: 'numeric' });
}

const VISIT_KIND: Record<OfstedLatestVisit['kind'], string> = {
  report_card: 'Report card inspection',
  graded: 'Graded inspection',
  ungraded: 'Ungraded inspection',
};

/** "Graded inspection, 6 July 2016" or "Confirmed at an ungraded inspection, 14 March 2023". */
export function gradeSourceLine(current: OfstedCurrentGrade): string {
  const when = formatOfstedDate(current.date);
  const what = current.basis === 'confirmed' ? 'Confirmed at an ungraded inspection' : 'Graded inspection';
  return when ? `${what}, ${when}` : what;
}

/** "Ungraded inspection, 13 November 2024: Standards maintained". */
export function latestVisitLine(visit: OfstedLatestVisit): string {
  const head = `${VISIT_KIND[visit.kind]}, ${formatOfstedDate(visit.date)}`;
  return visit.outcome ? `${head}: ${visit.outcome}` : head;
}

/**
 * Whether the latest visit needs its own line: when it is not where the grade
 * came from, or when there is no grade but an ungraded outcome to report. A
 * graded visit without a grade is already dated by the section title.
 */
export function showLatestVisitLine(
  ofsted: Pick<OfstedInspection, 'current_grade' | 'latest_visit'>,
): boolean {
  const visit = ofsted.latest_visit;
  if (!visit || visit.kind === 'report_card') return false;
  const current = ofsted.current_grade;
  if (current) return current.date !== visit.date;
  return visit.kind === 'ungraded';
}