proxmox/packages/economics-toolkit/src/path-gate.ts

import { evaluateEconomics, impliedGrossPct, type EconomicsInput } from './economics-engine.js';
import { pmmQuoteAmountOutFromChain } from './chain138-pmm-quote.js';

export interface PathGateParams {
  rpcUrl: string;
  poolAddress: string;
  tokenIn: string;
  amountIn: bigint;
  traderForView: string;
  /** Token decimals for both legs (typical: 6 for cUSDT/cUSDC). */
  decimals: number;
  economics: Omit<EconomicsInput, 'grossPct'>;
}

export interface PathGateResult {
  amountOut: bigint | null;
  impliedGrossPct: number;
  economics: ReturnType<typeof evaluateEconomics>;
  passesEconomicsGate: boolean;
  error?: string;
}

export async function evaluatePathGate(params: PathGateParams): Promise<PathGateResult> {
  const amountOut = await pmmQuoteAmountOutFromChain({
    rpcUrl: params.rpcUrl,
    poolAddress: params.poolAddress,
    tokenInLookup: params.tokenIn,
    amountIn: params.amountIn,
    traderForView: params.traderForView,
  });

  if (amountOut === null) {
    return {
      amountOut: null,
      impliedGrossPct: 0,
      economics: evaluateEconomics({ grossPct: 0, flashFeePct: params.economics.flashFeePct }),
      passesEconomicsGate: false,
      error: 'quote_failed_or_invalid_token_pair',
    };
  }

  const gross = impliedGrossPct(params.amountIn, amountOut, params.decimals);
  const economics = evaluateEconomics({
    grossPct: gross,
    ...params.economics,
  });

  return {
    amountOut,
    impliedGrossPct: gross,
    economics,
    passesEconomicsGate: economics.passesResidual,
  };
}