feat: POW miner

packages/system/src/pow.ts

@@ -0,0 +1,56 @@
+import { v4 as uuid } from "uuid";
+import { NostrEvent } from "./nostr";
+import { PowWorkerMessage } from "./pow-worker";
+
+export interface PowMiner {
+  minePow(ev: NostrEvent, target: number): Promise<NostrEvent>;
+}
+
+interface PowQueue {
+  resolve: (ev: NostrEvent) => void;
+  reject: () => void;
+  timeout: ReturnType<typeof setTimeout>;
+}
+
+export class PowWorker implements PowMiner {
+  #worker: Worker;
+  #queue: Map<string, PowQueue> = new Map();
+
+  constructor(script: string) {
+    this.#worker = new Worker(script, {
+      name: "POW",
+    });
+    this.#worker.onerror = ev => {
+      console.error(ev);
+    };
+    this.#worker.onmessage = ev => {
+      const data = ev.data as PowWorkerMessage;
+      const job = this.#queue.get(data.id);
+      if (job) {
+        clearTimeout(job.timeout);
+        this.#queue.delete(data.id);
+        job.resolve(data.event);
+      }
+    };
+  }
+
+  minePow(ev: NostrEvent, target: number) {
+    return new Promise<NostrEvent>((resolve, reject) => {
+      const req = {
+        id: uuid(),
+        cmd: "req",
+        event: ev,
+        target,
+      } as PowWorkerMessage;
+      this.#queue.set(req.id, {
+        resolve: ex => resolve(ex),
+        reject,
+        timeout: setTimeout(() => {
+          this.#queue.delete(req.id);
+          reject();
+        }, 600_000),
+      });
+      this.#worker.postMessage(req);
+    });
+  }
+}