/**
 * Every product on the platform the customer app cannot show, and why.
 *
 *   node scripts/appsweep.mjs
 *   node scripts/appsweep.mjs --json > sweep.json
 *
 * `appgap.mjs` answers this for ONE outlet and is the tool to reach for when
 * somebody reports a specific shop. This is the platform-wide version: it walks
 * every tenant, in every approval state, and reports the products that are
 * unreachable no matter what the app asks for.
 *
 * ── The rule it applies ──────────────────────────────────────────────────────
 *
 * Read off the backend rather than inferred from responses
 * (`controllers/productController.go:431`, `repositories/productRepository.go:858`):
 *
 *   1. `GetProductsBySubcategory` REJECTS `categoryid = 0` with a 400 —
 *      "Valid categoryid is required". It is the first thing the controller
 *      does.
 *   2. The query then filters `WHERE a.categoryid = ?` unconditionally.
 *
 * Together those mean a product stored with `categoryid = 0` is returned for NO
 * request the app can make. Not "usually hidden" — unreachable. It is still
 * listed by `getlocationproducts`, which does not filter on category, so the
 * console shows it and the shop believes it is on sale.
 *
 * Nothing else in that query gates visibility: there is no filter on
 * `approved`, `publishedat`, `productstatus`, or stock level. A product with
 * zero stock still appears. So `categoryid = 0` is the whole defect, and this
 * script looks for exactly it.
 */

const BASE = process.env['FIESTA_URL'] ?? 'https://fiesta.nearle.app';
const WEB = `${BASE}/live/api/v1/web`;

const asJson = process.argv.includes('--json');

/** Fiesta answers under `details` in most places and `data` in a few. */
async function get(path, params = {}) {
  const query = new URLSearchParams(
    Object.entries(params).filter(([, v]) => v !== undefined && v !== ''),
  );
  const response = await fetch(`${WEB}${path}?${query}`, {
    headers: { Accept: 'application/json' },
  });
  if (!response.ok) throw new Error(`HTTP ${response.status} on ${path}`);
  const payload = await response.json().catch(() => null);
  return payload?.details ?? payload?.data ?? null;
}

/** Requests that never succeeded. A non-empty list invalidates the report. */
const failures = [];

/**
 * Bounded concurrency, with retries, and failures that are never swallowed.
 *
 * The first version of this caught every error and substituted `null`. Run
 * across 262 tenants at a concurrency of 8, enough requests were refused that
 * it reported ONE affected tenant out of three known ones — and reported it as
 * a clean result, with no indication anything had gone wrong. A sweep that
 * fails silently is worse than no sweep: it is used to close the investigation.
 *
 * So: three attempts with a widening delay, and anything still failing is
 * recorded and printed at the end as an explicit gap in coverage.
 */
async function mapLimit(items, limit, fn, label = 'request') {
  const out = new Array(items.length);
  let next = 0;
  await Promise.all(
    Array.from({ length: Math.min(limit, items.length) }, async () => {
      for (;;) {
        const i = next++;
        if (i >= items.length) return;
        let lastError;
        for (let attempt = 0; attempt < 3; attempt++) {
          try {
            out[i] = await fn(items[i], i);
            lastError = null;
            break;
          } catch (cause) {
            lastError = cause;
            await new Promise((r) => setTimeout(r, 250 * (attempt + 1)));
          }
        }
        if (lastError) {
          out[i] = null;
          failures.push(`${label}[${i}]: ${lastError?.message ?? lastError}`);
        }
      }
    }),
  );
  return out;
}

/**
 * Every tenant, from two sources because neither is complete on its own.
 *
 * `getalltenants` paginates and its `pageno` is 1-BASED — page 0 returns an
 * empty list rather than the first page, the same off-by-one that
 * `getlocationproducts` has. It carries 262 tenants where the status lists
 * carry 142.
 *
 * `/tenants/search` is still needed alongside it: it branches on the word
 * "pending" and queries `approved = 0` instead of a status
 * (`tenantRepository.go:45-77`), which is the only way to learn that a tenant
 * is unapproved. Suriya Store is one.
 *
 * Building from the status lists ALONE was the first version's other bug: R
 * mart (1147) appears in none of the three, and a sweep that cannot see a
 * tenant reports it as having nothing wrong.
 */
async function allTenants() {
  const seen = new Map();

  for (let page = 1; page <= 20; page++) {
    const rows = (await get('/tenants/getalltenants', { pageno: page, pagesize: 200 })) ?? [];
    const list = Array.isArray(rows) ? rows : [];
    for (const t of list) if (t?.tenantid && !seen.has(t.tenantid)) seen.set(t.tenantid, { ...t });
    if (list.length < 200) break;
  }

  for (const status of ['Active', 'pending', 'InActive']) {
    const rows = (await get('/tenants/search', { status })) ?? [];
    for (const t of Array.isArray(rows) ? rows : []) {
      if (!t?.tenantid) continue;
      const existing = seen.get(t.tenantid) ?? { ...t };
      seen.set(t.tenantid, { ...existing, approvalState: status });
    }
  }

  return [...seen.values()];
}

const tenants = await allTenants();
if (!asJson) console.error(`Scanning ${tenants.length} tenants…`);

/* Pass one — the whole platform, one request per tenant.
   `getallproducts` returns {tenant, products} groups, not a flat list. */
const scanned = await mapLimit(tenants, 8, async (tenant) => {
  const groups = (await get('/products/getallproducts', { tenantid: tenant.tenantid })) ?? [];
  const products = (Array.isArray(groups) ? groups : []).flatMap((g) => g?.products ?? []);
  return { tenant, products, orphans: products.filter((p) => !p.categoryid) };
}, "tenant-products");

const affected = scanned.filter((row) => row && row.orphans.length > 0);

/* Pass two — only the tenants that failed, so the outlet detail costs nothing
   on a clean platform. */
const detailed = await mapLimit(affected, 6, async (row) => {
  const locations = (await get('/tenants/gettenantlocations', { tenantid: row.tenant.tenantid })) ?? [];
  const branches = await mapLimit(Array.isArray(locations) ? locations : [], 4, async (loc) => {
    const shelved = (await get('/products/getlocationproducts', {
      tenantid: row.tenant.tenantid,
      locationid: loc.locationid,
      pageno: 1,
      pagesize: 500,
    })) ?? [];
    const list = Array.isArray(shelved) ? shelved : [];
    const hidden = list.filter((p) => !p.categoryid);
    return {
      locationid: loc.locationid,
      locationname: loc.locationname,
      shelved: list.length,
      hidden: hidden.length,
      // The number that matters to a shopper: an outlet whose entire range is
      // invisible looks like a closed shop, not like a partial catalogue.
      visible: list.length - hidden.length,
    };
  });
  return { ...row, branches: branches.filter(Boolean) };
}, "tenant-branches");

/* Coverage is part of the result, not a footnote. A tenant whose products
   never loaded is UNKNOWN, not clean, and the difference decides whether this
   report can be used to say the platform is fixed. */
const unreached = scanned.filter((row) => !row).length;

if (asJson) {
  console.log(
    JSON.stringify(
      {
        scannedTenants: tenants.length,
        affectedTenants: detailed.length,
        orphanProducts: detailed.reduce((n, r) => n + r.orphans.length, 0),
        tenants: detailed.map((r) => ({
          tenantid: r.tenant.tenantid,
          tenantname: r.tenant.tenantname,
          approvalState: r.tenant.approvalState,
          totalProducts: r.products.length,
          orphans: r.orphans.map((p) => ({
            productid: p.productid,
            productname: p.productname,
            productbrand: p.productbrand,
            catalogueid: p.catalogueid,
            retailprice: p.retailprice,
          })),
          branches: r.branches,
        })),
      },
      null,
      2,
    ),
  );
} else {
  const orphanCount = detailed.reduce((n, r) => n + r.orphans.length, 0);
  const blindOutlets = detailed.flatMap((r) =>
    r.branches.filter((b) => b.shelved > 0 && b.visible === 0),
  );

  console.log(`\n${tenants.length} tenants scanned`);
  console.log(`${detailed.length} affected`);
  console.log(`${orphanCount} products with categoryid 0 — invisible in the app`);
  console.log(`${blindOutlets.length} outlets stocked but showing NOTHING to shoppers\n`);

  if (unreached > 0 || failures.length > 0) {
    console.log(
      `!! ${unreached} tenants could not be read after 3 attempts — this report is INCOMPLETE
`,
    );
    for (const f of failures.slice(0, 10)) console.log(`   ${f}`);
    if (failures.length > 10) console.log(`   … ${failures.length - 10} more
`);
    console.log();
  }

  for (const row of detailed.sort((a, b) => b.orphans.length - a.orphans.length)) {
    const { tenant } = row;
    console.log(
      `${tenant.tenantid}  ${tenant.tenantname}` +
        `  — ${row.orphans.length}/${row.products.length} products hidden` +
        (tenant.approvalState === 'pending' ? '  [unapproved]' : ''),
    );
    for (const p of row.orphans) {
      console.log(`      ${String(p.productid).padEnd(6)} ${p.productname ?? '(unnamed)'}`);
    }
    for (const b of row.branches) {
      if (b.shelved === 0) continue;
      const flag = b.visible === 0 ? '  ← app shows an EMPTY shop' : '';
      console.log(
        `      · ${String(b.locationname ?? b.locationid).padEnd(28)}` +
          ` ${b.visible}/${b.shelved} visible${flag}`,
      );
    }
    console.log();
  }
}