From dd2d28bf39eb6c0a37e0f8d525529be83fa5585a Mon Sep 17 00:00:00 2001
From: Dan Connolly <connolly@agoric.com>
Date: Tue, 21 Jan 2025 14:28:51 -0600
Subject: [PATCH] fixup! feat(multichain/tools): executeOfferTx does not wait
 for completion

---
 multichain-testing/tools/block-iter.js | 59 ++++++++++++++++++++++++++
 multichain-testing/tools/query.ts      | 11 +++++
 2 files changed, 70 insertions(+)
 create mode 100644 multichain-testing/tools/block-iter.js

diff --git a/multichain-testing/tools/block-iter.js b/multichain-testing/tools/block-iter.js
new file mode 100644
index 00000000000..191baac7bdc
--- /dev/null
+++ b/multichain-testing/tools/block-iter.js
@@ -0,0 +1,59 @@
+import { makeIntervalIterable } from '@agoric/client-utils/src/clock-timer.js';
+
+const { freeze } = Object;
+
+/**
+ * @import {IntervalIO} from '@agoric/client-utils/src/clock-timer.js';
+ * @import {makeQueryClient} from './query.js';
+ */
+
+/**
+ * @param {ReturnType<typeof makeQueryClient>} api
+ * @param {number} [delta]
+ */
+const recentBlockRate = async (api, delta = 2) => {
+  /** @param {{ height: number, time: string }} header */
+  const relevant = ({ height, time }) => ({ height, time });
+  const { block: latest } = await api.queryBlock();
+  const heightRecent = Number(latest.header.height) - delta;
+  const { block: recent } = await api.queryBlock(heightRecent);
+  const t0 = Date.parse(recent.header.time);
+  const t1 = Date.parse(latest.header.time);
+  return {
+    delta,
+    latest: { ...relevant(latest.header) },
+    recent: { ...relevant(recent.header) },
+    elapsed: t1 - t0,
+    period: (t1 - t0) / delta,
+  };
+};
+
+/**
+ * Make an iterator for observing each block.
+ *
+ * We measure the block rate by observing the latest block
+ * and one earlier (by `delta`) block.
+ *
+ * Then we poll at 2x that rate (Nyquist frequency) and
+ * fire the iterator when the height changes.
+ *
+ * @param {IntervalIO & { api: ReturnType<typeof makeQueryClient>, delta?: number }} io
+ */
+export const makeBlocksIterable = ({ api, delta = 2, ...io }) => {
+  return freeze({
+    async *[Symbol.asyncIterator]() {
+      const { period } = await recentBlockRate(api, delta);
+      const nyquist = period / 2;
+      let prev;
+      const ticks = makeIntervalIterable(nyquist, io);
+      for await (const tick of ticks) {
+        const { block } = await api.queryBlock();
+        const current = Number(block.header.height);
+        if (current === prev) continue;
+        prev = current;
+        const { time } = block.header;
+        yield freeze({ tick, height: current, time });
+      }
+    },
+  });
+};
diff --git a/multichain-testing/tools/query.ts b/multichain-testing/tools/query.ts
index 1e4c10b13f4..b8633825ba4 100644
--- a/multichain-testing/tools/query.ts
+++ b/multichain-testing/tools/query.ts
@@ -10,8 +10,15 @@ import type { QueryDenomHashResponseSDKType } from '@agoric/cosmic-proto/ibc/app
 import type { QueryChannelResponseSDKType } from '@agoric/cosmic-proto/ibc/core/channel/v1/query.js';
 import type { QueryChannelsResponseSDKType } from '@agoric/cosmic-proto/ibc/core/channel/v1/query.js';
 
+// TODO: export tendermint Block from @agoric/cosmic-proto
+type BlockHeaderPartial = {
+  height: number;
+  time: string;
+};
+
 // TODO use telescope generated query client from @agoric/cosmic-proto
 // https://github.com/Agoric/agoric-sdk/issues/9200
+// TODO: inject fetch
 export function makeQueryClient(apiUrl: string) {
   const query = async <T>(path: string): Promise<T> => {
     try {
@@ -26,6 +33,10 @@ export function makeQueryClient(apiUrl: string) {
 
   return {
     query,
+    queryBlock: (height?: number) =>
+      query<{ block: { header: BlockHeaderPartial } }>(
+        `/cosmos/base/tendermint/v1beta1/blocks/${height || 'latest'}`,
+      ),
     queryBalances: (address: string) =>
       query<QueryAllBalancesResponseSDKType>(
         `/cosmos/bank/v1beta1/balances/${address}`,