/** Site-wide constants (URL, name) used by metadata, sitemap and OG images. */
export const SITE_URL = (process.env.NEXT_PUBLIC_SITE_URL ?? 'https://www.countryatlas.co').replace(/\/$/, '');
export const SITE_NAME = 'CountryAtlas';
export const SITE_DOMAIN = 'countryatlas.co';
export const TAGLINE = 'Explore the world through data.';
export const OG_SIZE = { width: 1200, height: 630 } as const;
/** Public API version shown in docs and the footer (path stays /api/v1; the minor tracks additive endpoints). */
export const API_VERSION = '1.1';

type Q = Record<string, string | number | boolean | null | undefined>;
function query(q?: Q): string {
  if (!q) return '';
  const p = new URLSearchParams();
  for (const [k, v] of Object.entries(q)) if (v !== undefined && v !== null && v !== '' && v !== false) p.set(k, String(v));
  const s = p.toString();
  return s ? `?${s}` : '';
}

/** Route helpers — keep every internal href in one place so the next agent can add pages consistently. */
export const routes = {
  home: () => '/',
  countries: () => '/countries',
  country: (slug: string) => `/countries/${slug}`,
  countryTopic: (slug: string, topic: string) => `/countries/${slug}/${topic}`,
  countryIndicator: (slug: string, topic: string, indicator: string) => `/countries/${slug}/${topic}#${indicator}`,
  countryDownload: (id: string, fmt: 'csv' | 'json' = 'csv') => `/api/v1/countries/${id}/download.${fmt}`,
  compare: (...slugs: string[]) => (slugs.length ? `/compare/${slugs.join('/')}` : '/compare'),
  compareOg: (slugs: string[]) => `/compare/og?slugs=${slugs.join(',')}`,
  compareDownload: (ids: string[], indicators: string[], q: { from?: number | null; to?: number | null } = {}, fmt: 'csv' | 'json' = 'csv') =>
    `/api/v1/compare/download.${fmt}?countries=${ids.join(',')}&indicators=${indicators.join(',')}${q.from != null ? `&from=${q.from}` : ''}${q.to != null ? `&to=${q.to}` : ''}`,
  rankings: () => '/rankings',
  ranking: (indicator: string, q?: { year?: number | null; group?: string | null }) => {
    const p = new URLSearchParams();
    if (q?.year != null) p.set('year', String(q.year));
    if (q?.group && q.group !== 'world') p.set('group', q.group);
    const s = p.toString();
    return `/rankings/${indicator}${s ? `?${s}` : ''}`;
  },
  indicators: (topic?: string) => (topic ? `/indicators?topic=${encodeURIComponent(topic)}` : '/indicators'),
  indicator: (slug: string) => `/indicators/${slug}`,
  indicatorDownload: (slug: string, fmt: 'csv' | 'json' = 'csv') => `/api/v1/indicators/${slug}/download.${fmt}`,
  regions: () => '/regions',
  region: (slug: string) => `/regions/${slug}`,
  regionCompare: (a: string, b: string) => `/regions/compare?a=${a}&b=${b}`,
  sources: () => '/sources',
  source: (id: string) => `/sources/${id}`,
  methodology: () => '/methodology',
  data: () => '/data',
  download: (q?: Q) => `/download${query(q)}`,
  api: () => '/api',
  changes: () => '/changes',
  /** World Explorer — full-viewport map + time slider. */
  explore: (q?: { indicator?: string; year?: number | null; view?: 'map' | 'rank' | 'trend' | 'distribution'; country?: string | null }) => `/explore${query(q)}`,
  trajectories: (q?: { x?: string; y?: string; size?: string; year?: number | null; group?: string | null }) => `/trajectories${query(q)}`,
  scatter: (q?: { x?: string; y?: string; size?: string; year?: number | null; group?: string | null; log?: string }) => `/scatter${query(q)}`,
  finder: (q?: Q) => `/finder${query(q)}`,
  extremes: (q?: { window?: string; topic?: string }) => `/extremes${query(q)}`,
  stories: () => '/stories',
  story: (slug: string) => `/stories/${slug}`,
  updates: () => '/updates',
  peers: (q?: { y?: string; x?: string; year?: number | null }) => `/peers${query(q)}`,
  search: (q: string) => `/search?q=${encodeURIComponent(q)}`,
  apiSwagger: () => '/api/v1/docs',
  apiOpenapi: () => '/api/v1/openapi.json',
  admin: (section?: 'coverage' | 'runs' | 'issues' | 'raw') => (section ? `/admin/${section}` : '/admin'),
  adminLogin: () => '/admin/login',
} as const;