const parseUrl = process.env.PARSE_URL || 'http://127.0.0.1:3000/parse';
const appId = process.env.PARSE_APP_ID;
const masterKey = process.env.PARSE_MASTER_KEY;
const fallbackShopId = process.env.FALLBACK_SHOP_ID;

if (!appId || !masterKey || !fallbackShopId) {
  throw new Error('Missing PARSE_APP_ID, PARSE_MASTER_KEY, or FALLBACK_SHOP_ID');
}

const headers = {
  'Content-Type': 'application/json',
  'X-Parse-Application-Id': appId,
  'X-Parse-Master-Key': masterKey,
};
const shopPointer = objectId => ({ __type: 'Pointer', className: 'Shop', objectId });

async function request(path, method = 'GET', body) {
  const response = await fetch(`${parseUrl}${path}`, {
    method,
    headers,
    body: body === undefined ? undefined : JSON.stringify(body),
  });
  const text = await response.text();
  let result = {};
  try { result = JSON.parse(text); } catch {}
  if (!response.ok || result.error) {
    throw new Error(`${method} ${path}: ${result.error?.message || result.error || text.slice(0, 300) || response.status}`);
  }
  return result;
}

async function allRows(className, keys = '') {
  const rows = [];
  let skip = 0;
  while (true) {
    const page = await request(`/classes/${className}?limit=1000&skip=${skip}${keys ? `&keys=${keys}` : ''}`);
    rows.push(...(page.results || []));
    const length = page.results?.length || 0;
    if (length < 1000) return rows;
    skip += length;
  }
}

async function batch(requests) {
  for (let start = 0; start < requests.length; start += 25) {
    const result = await request('/batch', 'POST', { requests: requests.slice(start, start + 25) });
    const error = result.find?.(item => item.error)?.error;
    if (error) throw new Error(error.error || error.code || 'Parse batch failed');
  }
}

function returnKey(row) {
  const date = row.return_date?.iso || row.returnDate?.iso || row.return_date || row.returnDate || '';
  const orderId = row.order_id || row.orderId || row.amazon_order_id || '';
  const sku = row.sku || row.seller_sku || '';
  return [date, orderId, sku, row.asin || '', row.license_plate_number || ''].join('|');
}

const [returns, orders] = await Promise.all([
  allRows('ReturnRecord'),
  allRows('Order', 'platformOrderId,orderId,shop'),
]);

const orderShop = new Map();
for (const order of orders) {
  for (const id of [order.platformOrderId, order.orderId]) {
    if (id && order.shop?.objectId) orderShop.set(id, order.shop.objectId);
  }
}

const groups = new Map();
for (const row of returns) {
  const key = returnKey(row);
  if (!groups.has(key)) groups.set(key, []);
  groups.get(key).push(row);
}

const updates = [];
const deletes = [];
let matchedOrders = 0;

for (const rows of groups.values()) {
  const orderId = rows[0].order_id || rows[0].orderId || rows[0].amazon_order_id || '';
  const targetShopId = orderShop.get(orderId) || fallbackShopId;
  if (orderShop.has(orderId)) matchedOrders++;
  const keep = rows.find(row => row.shop?.objectId === targetShopId) || rows[0];

  updates.push({
    method: 'PUT',
    path: `/parse/classes/ReturnRecord/${keep.objectId}`,
    body: {
      shop: shopPointer(targetShopId),
      orderId,
      returnDate: keep.returnDate || keep.return_date,
      asin: keep.asin || '',
      sku: keep.sku || keep.seller_sku || '',
      reason: keep.reason || '',
      quantity: Number(keep.quantity || 0),
      comment: keep.customer_comments || keep.comment || '',
      disposition: keep.detailed_disposition || keep.disposition || '',
      fulfillmentCenterId: keep.fulfillment_center_id || keep.fulfillmentCenterId || '',
      licensePlateNumber: keep.license_plate_number || keep.licensePlateNumber || '',
    },
  });

  for (const row of rows) {
    if (row.objectId === keep.objectId) continue;
    deletes.push({ method: 'DELETE', path: `/parse/classes/ReturnRecord/${row.objectId}` });
  }
}

await batch(updates);
await batch(deletes);

const after = await allRows('ReturnRecord', 'objectId,shop,orderId');
console.log(JSON.stringify({
  before: returns.length,
  uniqueBusinessKeys: groups.size,
  matchedOrders,
  fallbackAssignments: groups.size - matchedOrders,
  updated: updates.length,
  deleted: deletes.length,
  after: after.length,
}, null, 2));