protohackers/main.ts

import { copy } from "https://deno.land/std@0.157.0/streams/conversion.ts?s=copy";
import { Buffer } from "https://deno.land/std@0.157.0/io/buffer.ts";
import { ByteSet } from "https://deno.land/x/bytes@1.0.3/mod.ts";

const QUERY_SIZE = 9;
const PORT = 5588;

const listener = Deno.listen({ port: 5588 });

console.log(`Listening on 0.0.0.0:${PORT}`);

for await (const conn of listener) {
  console.log("Connection established:", conn.remoteAddr);
  try {
    meansToAnEnd(conn);
  } catch (e) {
    console.error(conn.remoteAddr, e);
  }
  console.log("Connection closed:", conn.remoteAddr);
}

// problem 2
async function meansToAnEnd(conn: Deno.Conn) {
  try {
    for await (const query of queries(conn)) {
      console.log("Query:", query);
      conn.write(ByteSet.from(Uint8Array.from([0]), "big").buffer);
    }
    console.log("Done!");
  } catch (err) {
    console.error(err);
  }
}

function queries(conn: Deno.Conn) {
  return {
    async *[Symbol.asyncIterator]() {
      const b = new Uint8Array(1024);
      const q = new Uint8Array();
      let bytesRead = 0;
      console.debug(b.length);
      while (bytesRead < QUERY_SIZE) {
        const n = await conn.read(b);
        bytesRead += n;
        console.debug(n, b.length);
      }
      yield q;
    },
  };
}