// routes/pwoSourceAudit.js
// "PWO Source Report" — for each Production Order, shows whether each of its
// four lifecycle actions (Create / Release / Issue / Receipt) was done
// through this portal or directly in SAP B1. Pulled entirely from SAP B1
// Service Layer + this portal's own local tracking table.
//
// How each stage is told apart:
//  - CREATE:  SAP UDF U_ERP_SO_NO on the Production Order itself — stamped
//             with this portal's own local record ID whenever it creates
//             one (see routes/productionOrders.js). Blank = created
//             directly in SAP.
//  - RELEASE: no UDF exists for this — instead, compares SAP's live
//             ProductionOrderStatus against this portal's own local
//             tracking record's workflow log. A "Release" / "completed"
//             entry only ever gets written by the portal's own Release
//             route, so its presence (or absence, with SAP nonetheless
//             showing Released) is what's checked here.
//  - ISSUE / RECEIPT: no UDF exists on InventoryGenExits/InventoryGenEntries
//             either, and DI API (needed to add one) isn't available on
//             this SAP install — so the portal instead tags the Comments
//             field of every Issue/Receipt document it posts with
//             "[Portal PWO#<id>]" (see routes/sap.js). A document without
//             that tag was posted directly in SAP.
//
// NOTE — this only works going forward from when each tagging mechanism was
// added: historical orders/documents posted before that have no tag either
// way and will show as "Direct (SAP)" even if they went through the portal.
'use strict';
const express = require('express');
const router  = express.Router();
const { verifyToken } = require('../middleware/auth');
const poStore = () => require('../services/productionOrderStore');

let _sapSvc = null;
function getSap(){
  if(!_sapSvc) _sapSvc = require('../services/sapServiceLayer');
  return _sapSvc;
}
const cq = (req) => req.query?.company || req.body?.company || null;

// Follows SAP's nextLink until exhausted or MAX_PAGES hit — no $top on the
// initial request (confirmed elsewhere in this app: SAP treats an explicit
// $top as a TOTAL cap across the whole nextLink chain here, not a per-page
// size, silently truncating a large result set otherwise).
async function fetchAllPaged(sap, co, entity, filter, select, orderByField = 'DocDate') {
  const out = [];
  let url = `${entity}?$filter=${encodeURIComponent(filter)}&$select=${select}&$orderby=${orderByField} desc`;
  const MAX_PAGES = 300;
  for (let p = 0; p < MAX_PAGES && url; p++) {
    const r = await sap.sapRequest('GET', url, null, co);
    out.push(...(r?.value || []));
    url = r?.['odata.nextLink'] || r?.['@odata.nextLink'] || null;
    if (!r?.value?.length) break;
  }
  return out;
}

router.get('/report', verifyToken, async (req, res) => {
  const co = cq(req);
  const { from, to } = req.query;
  if (!from || !to) return res.status(400).json({ success: false, message: 'from and to dates are required' });

  try {
    const sap = getSap();

    // ProductionOrders has no "DocDate" field (confirmed live — filtering on
    // it 502s instead of a clean error) — PostingDate is its equivalent
    // "when created" field.
    const orders = await fetchAllPaged(
      sap, co, 'ProductionOrders',
      `PostingDate ge '${from}' and PostingDate le '${to}'`,
      'AbsoluteEntry,DocumentNumber,ItemNo,ProductDescription,ProductionOrderStatus,PostingDate,U_ERP_SO_NO',
      'PostingDate'
    );
    if (!orders.length) return res.json({ success: true, data: [] });

    // Issue/Receipt can, in principle, happen any time after an order is
    // created — but scanning with no upper bound turned out to be far too
    // heavy in practice (2000+ Goods Issue documents for a single month on
    // this install, ~100+ SAP pages, occasionally 502-ing SAP's own gateway
    // under the load). Scoped to the SAME [from,to] window as the orders
    // themselves instead — the known trade-off: an order created near the
    // END of the selected range whose Issue/Receipt happens AFTER `to` will
    // show that stage as "not reached yet" here even though it has been.
    // Widen `to` (or re-run with a later range) to see those.
    const genFilter = `DocDate ge '${from}' and DocDate le '${to}'`;
    const [genExits, genEntries] = await Promise.all([
      fetchAllPaged(sap, co, 'InventoryGenExits', genFilter, 'DocEntry,DocNum,DocumentLines'),
      fetchAllPaged(sap, co, 'InventoryGenEntries', genFilter, 'DocEntry,DocNum,DocumentLines'),
    ]);

    const localRecs = await poStore().listProductionOrders({ company: co });
    const localByEntry = {};
    localRecs.forEach(p => { if (p.sapAbsEntry != null) localByEntry[p.sapAbsEntry] = p; });

    // Portal-origin marker is now a genuine per-LINE UDF (IGE1/IGN1's own
    // U_ERP_SO_NO — set directly in routes/sap.js's creation payload, holding
    // the same local Production Order tracking ID as OWOR.U_ERP_SO_NO).
    // Checked per matching LINE, not per whole document, since one document
    // could in principle carry lines for more than one Production Order.
    function groupByBaseEntry(docs) {
      const map = {};
      docs.forEach(d => {
        (d.DocumentLines || []).forEach(l => {
          if (l.BaseType === 202 && l.BaseEntry != null) (map[l.BaseEntry] = map[l.BaseEntry] || []).push(l);
        });
      });
      return map;
    }
    const issueByEntry = groupByBaseEntry(genExits);
    const receiptByEntry = groupByBaseEntry(genEntries);
    function sourceLabel(lines) {
      if (!lines || !lines.length) return null;   // stage not reached yet
      const tagged = lines.filter(l => !!l.U_ERP_SO_NO).length;
      if (tagged === lines.length) return 'Portal';
      if (tagged === 0) return 'Direct (SAP)';
      return 'Mixed';
    }

    const rows = orders.map(o => {
      const local = localByEntry[o.AbsoluteEntry];
      const released = o.ProductionOrderStatus === 'boposReleased' || o.ProductionOrderStatus === 'boposClosed';
      let releaseSource = null;
      if (released) {
        const hasPortalRelease = !!(local && Array.isArray(local.workflowLog) && local.workflowLog.some(l => l.step === 'Release' && l.action === 'completed'));
        releaseSource = hasPortalRelease ? 'Portal' : 'Direct (SAP)';
      }
      return {
        absoluteEntry: o.AbsoluteEntry,
        docNum: o.DocumentNumber,
        itemCode: o.ItemNo,
        itemName: o.ProductDescription,
        status: (o.ProductionOrderStatus || '').replace('bopos', ''),
        creationSource: o.U_ERP_SO_NO ? 'Portal' : 'Direct (SAP)',
        releaseSource,
        issueSource: sourceLabel(issueByEntry[o.AbsoluteEntry]),
        receiptSource: sourceLabel(receiptByEntry[o.AbsoluteEntry]),
      };
    });
    res.json({ success: true, data: rows });
  } catch (err) {
    res.status(400).json({ success: false, message: err.message });
  }
});

module.exports = router;