backend/src/modules/investments/instruments/stocks/domain/stock-screener-selection.rules.ts

import type { TbankShare } from '#src/integrations/tbank/tbank.api';

export type StockScreenerCatalog = {
  asOf: Date;
  instruments: TbankShare[];
};

export type StockScreenerConditions = {
  countryOfRisk?: string;
  maxLot?: number;
  query?: string;
  realExchange?: string;
  sector?: string;
  shareType?: string;
};

type IdentifiedShare = TbankShare & { uid: string };
const sortBefore = 0;

export function selectStockScreenerInstruments(
  catalog: StockScreenerCatalog,
  conditions: StockScreenerConditions,
): StockScreenerCatalog {
  const representatives = new Map<string, IdentifiedShare>();

  for (const instrument of catalog.instruments) {
    if (!matches(instrument, conditions)) continue;

    const { uid } = instrument;
    const isin = instrument.isin?.trim().toUpperCase();
    const issueKey = isin ? `isin:${isin}` : `uid:${uid}`;
    const existing = representatives.get(issueKey);
    if (!existing || uid.localeCompare(existing.uid) < sortBefore) {
      representatives.set(issueKey, instrument);
    }
  }

  return {
    asOf: catalog.asOf,
    instruments: [...representatives.values()].sort(
      (left, right) =>
        (left.ticker?.trim() ?? '').localeCompare(right.ticker?.trim() ?? '') ||
        left.uid.localeCompare(right.uid),
    ),
  };
}

function matches(
  instrument: TbankShare,
  conditions: StockScreenerConditions,
): instrument is IdentifiedShare {
  if (
    !instrument.uid?.trim() ||
    instrument.buyAvailableFlag !== true ||
    instrument.apiTradeAvailableFlag !== true
  ) {
    return false;
  }

  if (
    conditions.query !== undefined &&
    !`${instrument.name ?? ''}\n${instrument.ticker ?? ''}`
      .toLowerCase()
      .includes(conditions.query.toLowerCase())
  ) {
    return false;
  }

  if (conditions.sector !== undefined && instrument.sector !== conditions.sector) {
    return false;
  }
  if (
    conditions.shareType !== undefined &&
    instrument.shareType !== conditions.shareType
  ) {
    return false;
  }
  if (instrument.currency?.toUpperCase() !== 'RUB') return false;
  if (
    conditions.realExchange !== undefined &&
    instrument.realExchange !== conditions.realExchange
  ) {
    return false;
  }
  if (
    conditions.countryOfRisk !== undefined &&
    instrument.countryOfRisk !== conditions.countryOfRisk
  ) {
    return false;
  }

  const minimumPositiveLot = 0;
  return (
    conditions.maxLot === undefined ||
    (Number.isInteger(instrument.lot) &&
      instrument.lot !== undefined &&
      instrument.lot > minimumPositiveLot &&
      instrument.lot <= conditions.maxLot)
  );
}