Implement Soroban Transfer Confirmation Poller

src/polling/stellar/confirmation-poller.service.ts

@@ -0,0 +1,81 @@
+export interface ConfirmationStatus {
+  transactionHash: string;
+  confirmed: boolean;
+  ledger: number | null;
+  confirmations: number;
+  checkedAt: Date;
+}
+
+export interface PollerConfig {
+  horizonUrl: string;
+  intervalMs: number;
+  requiredConfirmations: number;
+}
+
+const DEFAULT_CONFIG: PollerConfig = {
+  horizonUrl: 'https://horizon-testnet.stellar.org',
+  intervalMs: 5000,
+  requiredConfirmations: 1,
+};
+
+type StatusCallback = (status: ConfirmationStatus) => void;
+
+export class StellarTransferConfirmationPoller {
+  private readonly config: PollerConfig;
+  private timers = new Map<string, ReturnType<typeof setInterval>>();
+
+  constructor(config: Partial<PollerConfig> = {}) {
+    this.config = { ...DEFAULT_CONFIG, ...config };
+  }
+
+  /**
+   * Starts polling for a transaction until confirmed, then calls onConfirmed.
+   */
+  poll(txHash: string, onUpdate: StatusCallback): void {
+    if (this.timers.has(txHash)) return;
+
+    const timer = setInterval(async () => {
+      const status = await this.check(txHash);
+      onUpdate(status);
+      if (status.confirmed) this.stop(txHash);
+    }, this.config.intervalMs);
+
+    this.timers.set(txHash, timer);
+  }
+
+  stop(txHash: string): void {
+    const t = this.timers.get(txHash);
+    if (t) { clearInterval(t); this.timers.delete(txHash); }
+  }
+
+  stopAll(): void {
+    for (const txHash of this.timers.keys()) this.stop(txHash);
+  }
+
+  async check(txHash: string): Promise<ConfirmationStatus> {
+    try {
+      const [txRes, rootRes] = await Promise.all([
+        fetch(`${this.config.horizonUrl}/transactions/${txHash}`),
+        fetch(this.config.horizonUrl),
+      ]);
+
+      if (!txRes.ok) {
+        return { transactionHash: txHash, confirmed: false, ledger: null, confirmations: 0, checkedAt: new Date() };
+      }
+
+      const tx = (await txRes.json()) as { ledger: number };
+      const root = (await rootRes.json()) as { core_latest_ledger: number };
+      const confirmations = Math.max(0, root.core_latest_ledger - tx.ledger);
+
+      return {
+        transactionHash: txHash,
+        confirmed: confirmations >= this.config.requiredConfirmations,
+        ledger: tx.ledger,
+        confirmations,
+        checkedAt: new Date(),
+      };
+    } catch {
+      return { transactionHash: txHash, confirmed: false, ledger: null, confirmations: 0, checkedAt: new Date() };
+    }
+  }
+}