import * as cheerio from 'cheerio';

// The public ARBA show-search listing. The page is a WordPress "Ninja Tables"
// table whose ~2,000 rows are server-rendered into the HTML as plain positional
// <td> cells (the cells themselves carry no column classes — only the <thead>
// does). So we fetch the page and read each row's cells by index.
//
// IMPORTANT: arba.net sits behind Cloudflare. A bare request (no/!browser
// User-Agent) gets a "Sorry, you have been blocked" challenge page instead of
// the listing. Sending a normal browser User-Agent + Accept header is enough to
// pass, so those headers are mandatory here — do not remove them. (We
// deliberately do NOT set Accept-Encoding: undici/global-fetch negotiates and
// transparently decompresses gzip/br only when it owns that header.)
const ARBA_URL = 'https://arba.net/show-search/';

const BROWSER_HEADERS = {
  'User-Agent':
    'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36',
  Accept: 'text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8',
  'Accept-Language': 'en-US,en;q=0.9',
};

// US states + DC. Rows whose state isn't one of these are international (blank,
// or a Canadian province like QC/ON) and are excluded per the design doc.
const US_STATES = new Set([
  'AL', 'AK', 'AZ', 'AR', 'CA', 'CO', 'CT', 'DE', 'FL', 'GA',
  'HI', 'ID', 'IL', 'IN', 'IA', 'KS', 'KY', 'LA', 'ME', 'MD',
  'MA', 'MI', 'MN', 'MS', 'MO', 'MT', 'NE', 'NV', 'NH', 'NJ',
  'NM', 'NY', 'NC', 'ND', 'OH', 'OK', 'OR', 'PA', 'RI', 'SC',
  'SD', 'TN', 'TX', 'UT', 'VT', 'VA', 'WA', 'WV', 'WI', 'WY',
  'DC',
]);

// The five show-type buckets the browser filter exposes. `FAIR SHOW` wins over
// the open/youth × all-breed/specialty split when a show is a fair show.
export type ShowType =
  | 'ALL BREED OPEN'
  | 'ALL BREED YOUTH'
  | 'SPECIALTY OPEN'
  | 'SPECIALTY YOUTH'
  | 'FAIR SHOW'
  | 'OTHER';

export interface ArbaShow {
  sanctionNumber: string;
  date: string | null; // ISO YYYY-MM-DD, or null if unparseable
  rawDate: string; // original MM/DD/YYYY as shown on ARBA
  state: string;
  district: string;
  city: string;
  clubName: string;
  showType: ShowType;
  showTypeFull: string; // e.g. "OPEN ALL BREED SHOW"
  specialBreed: string | null;
  address: string;
  mapsUrl: string | null;
  secretary: string;
  email: string;
  catalogUrl: string | null;
}

// "CLUB NAME, (OPEN|YOUTH) (ALL BREED|SPECIALTY) [BREED] [FAIR] SHOW[, BREED]".
// Club names can themselves contain commas, so we anchor on the show-type phrase
// rather than naively splitting on the first comma.
const SHOW_INFO_RE =
  /^(.*?),\s*((OPEN|YOUTH)\s+(ALL BREED|SPECIALTY)(?:\s+BREED)?(\s+FAIR)?\s+SHOW)(?:,\s*(.*))?$/i;

interface ParsedShowInfo {
  clubName: string;
  showType: ShowType;
  showTypeFull: string;
  specialBreed: string | null;
}

export function parseShowInformation(raw: string): ParsedShowInfo {
  const text = raw.trim();
  const m = text.match(SHOW_INFO_RE);
  if (!m) {
    // Unexpected format — keep the whole string as the club name so the show
    // isn't dropped; it just won't match a specific show-type filter.
    return { clubName: text, showType: 'OTHER', showTypeFull: '', specialBreed: null };
  }

  const clubName = m[1].trim();
  const showTypeFull = m[2].replace(/\s+/g, ' ').trim();
  const isYouth = /YOUTH/i.test(m[3]);
  const isSpecialty = /SPECIALTY/i.test(m[4]);
  const isFair = Boolean(m[5]);
  const breed = m[6] ? m[6].trim() : '';

  let showType: ShowType;
  if (isFair) showType = 'FAIR SHOW';
  else if (isSpecialty) showType = isYouth ? 'SPECIALTY YOUTH' : 'SPECIALTY OPEN';
  else showType = isYouth ? 'ALL BREED YOUTH' : 'ALL BREED OPEN';

  // A breed segment is only meaningful for specialty shows; all-breed/fair shows
  // shouldn't carry one even if a stray trailing comma produced text.
  const specialBreed = isSpecialty && breed ? breed : null;

  return { clubName, showType, showTypeFull, specialBreed };
}

// MM/DD/YYYY or M/D/YYYY → ISO. Returns null for anything else so the caller can
// still keep the original via rawDate.
function toIsoDate(raw: string): string | null {
  const m = raw.trim().match(/^(\d{1,2})\/(\d{1,2})\/(\d{4})$/);
  if (!m) return null;
  const [, mm, dd, yyyy] = m;
  return `${yyyy}-${mm.padStart(2, '0')}-${dd.padStart(2, '0')}`;
}

function cellHref($cell: cheerio.Cheerio<any>): string | null {
  const href = $cell.find('a').first().attr('href');
  return href ? href.trim() : null;
}

/**
 * Fetch the ARBA listing and return the normalized, US-only, cavy-excluded set.
 * Throws on a Cloudflare block, a non-OK response, or a missing/empty table so
 * the caller can surface an error state and keep serving the previous cache.
 */
export async function fetchArbaShows(): Promise<ArbaShow[]> {
  let html: string;
  try {
    const res = await fetch(ARBA_URL, { headers: BROWSER_HEADERS });
    if (!res.ok) {
      throw new Error(`ARBA responded with HTTP ${res.status}`);
    }
    html = await res.text();
  } catch (err) {
    throw new Error(`Failed to reach ARBA: ${(err as Error).message}`);
  }

  if (/you have been blocked|cf-error-details|Attention Required/i.test(html)) {
    throw new Error('ARBA request was blocked by Cloudflare');
  }

  const $ = cheerio.load(html);
  // The data table is the one whose header row defines the sanction-number
  // column. Anchoring on that class avoids picking up unrelated page tables.
  const table = $('th.ninja_clmn_nm_sanctionnumber').first().closest('table');
  const rows = table.find('tbody tr');
  if (rows.length === 0) {
    throw new Error('ARBA listing table was empty or not found (page layout may have changed)');
  }

  const shows: ArbaShow[] = [];
  rows.each((_, tr) => {
    const cells = $(tr).find('td');
    if (cells.length < 10) return; // malformed/placeholder row

    const sanctionNumber = cells.eq(0).text().trim();
    const rawDate = cells.eq(1).text().trim();
    const state = cells.eq(2).text().trim().toUpperCase();
    const district = cells.eq(3).text().trim();
    const city = cells.eq(4).text().trim();
    const showInformation = cells.eq(5).text().trim();
    const address = cells.eq(6).text().trim();
    const mapsUrl = cellHref(cells.eq(7));
    const secretary = cells.eq(8).text().trim();
    const email = cells.eq(9).text().trim();
    const catalogUrl = cells.length > 10 ? cellHref(cells.eq(10)) : null;

    // Cavy shows are excluded at normalization (CAVY appears as the breed
    // segment, e.g. "..., OPEN SPECIALTY BREED SHOW, CAVY").
    if (/\bCAVY\b/i.test(showInformation)) return;
    // US-only.
    if (!US_STATES.has(state)) return;

    const { clubName, showType, showTypeFull, specialBreed } =
      parseShowInformation(showInformation);

    shows.push({
      sanctionNumber,
      date: toIsoDate(rawDate),
      rawDate,
      state,
      district,
      city,
      clubName,
      showType,
      showTypeFull,
      specialBreed,
      address,
      mapsUrl,
      secretary,
      email,
      catalogUrl,
    });
  });

  // Default sort: date ascending, then state.
  shows.sort((a, b) => {
    const da = a.date ?? '9999-99-99';
    const db = b.date ?? '9999-99-99';
    if (da !== db) return da < db ? -1 : 1;
    return a.state.localeCompare(b.state);
  });

  return shows;
}