Initial Commit

npubCash.ts

@@ -0,0 +1,124 @@
+import {
+  CashuMint,
+  CashuWallet,
+  MintQuoteState,
+  type Proof,
+} from "@cashu/cashu-ts";
+
+import { privateKeyFromSeedWords as nostrPrivateKeyFromSeedWords } from "nostr-tools/nip06";
+import { finalizeEvent, nip98 } from "nostr-tools";
+import type { BodyInit } from "bun";
+
+interface NpubCashQuote {
+  createdAt: number;
+  paidAt?: number;
+  expiresAt: number;
+  mintUrl: string;
+  quoteId: string;
+  request: string;
+  amount: number;
+  state: "PAID" | "ISSUED" | "INFLIGHT";
+  locked: boolean;
+}
+
+interface NpubCashPaginationMetadata {
+  total: number;
+  limit: number;
+}
+
+export default class NpubCash {
+  constructor(private mnemonic: string) {}
+
+  private async fetchWithNip98<T>(
+    { url, method, body }: {
+      url: string;
+      method: string;
+      body?: BodyInit | null;
+    },
+  ): Promise<T> {
+    const nostrPrivateKey = nostrPrivateKeyFromSeedWords(this.mnemonic);
+    const urlWithoutQueryParams = url.split("?")[0] ?? "";
+    const npubCashNip98 = await nip98.getToken(
+      urlWithoutQueryParams,
+      method,
+      (event) => finalizeEvent(event, nostrPrivateKey),
+    );
+    return fetch(url, {
+      method,
+      headers: {
+        "Authorization": `Nostr ${npubCashNip98}`,
+      },
+      body,
+    }).then((data) => data.json() as Promise<T>);
+  }
+
+  private async getQuotes(since: number, limit: number, offset: number) {
+    return this.fetchWithNip98<
+      {
+        error: false;
+        data: { quotes: NpubCashQuote[] };
+        metadata: NpubCashPaginationMetadata;
+      } | {
+        error: true;
+        message: string;
+      }
+    >({
+      url:
+        `https://npubx.cash/api/v2/wallet/quotes?since=${since}&limit=${limit}&offset=${offset}`,
+      method: "GET",
+    });
+  }
+
+  private async getAllPaidQuotes(since: number) {
+    const quotes: NpubCashQuote[] = [];
+    let offset = 0;
+    while (true) {
+      const currentQuotes = await this.getQuotes(since, 50, offset);
+      if (currentQuotes.error === false) {
+        quotes.push(...currentQuotes.data.quotes);
+        if (quotes.length >= currentQuotes.metadata.total) {
+          break;
+        }
+      } else {
+        throw new Error(currentQuotes.message ?? "Unknown error");
+      }
+      offset += 50;
+    }
+    return quotes.sort((a, b) => a.createdAt - b.createdAt).filter(
+      (quote) => quote.state === "PAID",
+    );
+  }
+
+  async *tryRedeemUnredeemedCashuQuotes(
+    latestRedeemedCashuQuoteTimestamp: number,
+  ) {
+    const proofs: Proof[] = [];
+    const quotes: NpubCashQuote[] = await this.getAllPaidQuotes(
+      latestRedeemedCashuQuoteTimestamp,
+    );
+    for (const quote of quotes) {
+      const mint = new CashuMint(quote.mintUrl);
+      const wallet = new CashuWallet(mint);
+      const req = await mint.checkMintQuote(quote.quoteId);
+      if (
+        req.state === MintQuoteState.PAID && typeof quote.paidAt === "number"
+      ) {
+        const newProofs = await wallet.mintProofs(
+          quote.amount,
+          quote.quoteId,
+        );
+        proofs.push(...newProofs);
+        const amountReceived = newProofs.reduce(
+          (sum, p) => sum + p.amount,
+          0,
+        );
+        yield {
+          quoteId: quote.quoteId,
+          amountSat: amountReceived,
+          timestamp: quote.paidAt,
+        };
+      }
+    }
+    return proofs;
+  }
+}