import { ADDITIONAL_MARKET_FEE } from './market.ts';
import { assertXmrAmount, xmrCommission } from './xmr-amount.ts';

/** Allocation only, not proof of payment or an instruction to send/retain funds. */
export function allocateXmrSale(gross: bigint, hostingBps: number) {
  assertXmrAmount(gross);
  if (gross === 0n) throw new Error('Sale price must be positive; use a free transfer for gifts');
  if (!Number.isSafeInteger(hostingBps) || hostingBps < 0 || hostingBps > 5000) {
    throw new Error('Hosting commission must be between 0 and 5000 basis points');
  }
  const hosting = xmrCommission(gross, hostingBps);
  const author = xmrCommission(gross, ADDITIONAL_MARKET_FEE.bps);
  return { gross, hosting, author, sellerBeforeNetworkCosts: gross - hosting - author };
}

/**
 * Evaluate an explicitly supplied total seller-funded network-cost budget, including
 * every applicable leg. Does not choose who funds an author leg or approve a quote.
 * The budget is a maximum, not revenue; actual costs/unused budget need accounting.
 */
export function assessXmrSaleBudget(gross: bigint, hostingBps: number, sellerNetworkBudget: bigint) {
  const allocation = allocateXmrSale(gross, hostingBps);
  assertXmrAmount(sellerNetworkBudget);
  const available = allocation.sellerBeforeNetworkCosts;
  const viable = sellerNetworkBudget < available;
  return { ...allocation, sellerNetworkBudget, viable,
    sellerMinimumNet: viable ? available - sellerNetworkBudget : 0n,
    // Additional gross-independent funding required to retain at least one atomic unit.
    fundingShortfall: viable ? 0n : sellerNetworkBudget - available + 1n };
}