Use rates

src/hooks/rates.ts

@@ -0,0 +1,32 @@
+import { bech32ToHex } from "@snort/shared";
+import { EventKind, ReplaceableNoteStore, RequestBuilder } from "@snort/system";
+import { useRequestBuilder } from "@snort/system-react";
+import { useMemo } from "react";
+
+// Snort backend publishes rates
+const SnortPubkey = "npub1sn0rtcjcf543gj4wsg7fa59s700d5ztys5ctj0g69g2x6802npjqhjjtws";
+
+export function useRates(symbol: string, leaveOpen = true) {
+  const sub = useMemo(() => {
+    const rb = new RequestBuilder(`rates:${symbol}`);
+    rb.withOptions({
+      leaveOpen,
+    });
+    rb.withFilter()
+      .kinds([1009 as EventKind])
+      .authors([bech32ToHex(SnortPubkey)])
+      .tag("d", [symbol]);
+    return rb;
+  }, [symbol]);
+
+  const data = useRequestBuilder(ReplaceableNoteStore, sub);
+
+  const tag = data?.data?.tags.find(a => a[0] === "d" && a[1] === symbol);
+  return {
+    time: data.data?.created_at,
+    ask: Number(tag?.[2]),
+    bid: Number(tag?.[3]),
+    low: Number(tag?.[4]),
+    hight: Number(tag?.[5]),
+  };
+}