XMR native

shared/xmr-pricing.ts

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+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 };
+}