随机计算

1. 随机 1-9 的计算公式， 不得重复，例如 1+2 仅能出现一次， 但是可以出现2+1
2. 答对了自动进入下一题，答错了不继续下一题，依然保持这一题
3. 重复N次后，统计总耗时，并且算出耗时最久的前5道题目

const express = require("express");
const bodyParser = require("body-parser");
const app = express();
let count = 0;

app.use(bodyParser.urlencoded({ extended: false }));

app.get("/", (req, res) => {
  if (isMaxrecordEnd()) {
    res.send("<h1>您的机会已用完</h1>");
    return;
  }
  const oldId = req.query.id;
  let record;
  if (oldId) {
    record = getRecord(oldId);
  } else {
    record = addRecord();
  }

  console.log("CURRENT==>", JSON.stringify(record));

  const { id, calc } = record;
  totalLog();

  res.send(`
    <div style=" width:500px;margin:0 auto;">
        <h1>随机计算</h1>
        <form action="/submit" method="post">
            <span style="font-size: 20px;">${calc} =</span>
            <span>
                <input type="number" name="sum" id="sum">
            </span>
            <span>
                <button type="submit">提交</button>
            </span>
            <input type="hidden" name="id" value="${id}">
        </form>
        <br>
        <a href="/restart">重新开始</a>
    </div>
    <script>
       document.querySelector('#sum').focus()
    </script>
    `);
});

app.post("/submit", (req, res) => {
  const { id, sum } = req.body;
  if (isNaN(sum)) {
    res.redirect(`/?id=${id}`);
    return;
  }
  const record = getRecord(id);

  if (+sum === +record.sum) {
    ediRecord(+id);
    if (++count >= 10) res.redirect("/history");
    else res.redirect("/");
  } else {
    res.redirect(`/?id=${id}`);
  }
});

app.get("/history", (req, res) => {
  const top5 = getTop5();
  res.send(`
    <div style=" width:500px;margin:0 auto;">
        <div>总耗时：${sumTime()}秒</div>
        <div>答题耗时最多Top5</div>
        <ul>
        ${top5
          .map((item) => {
            return `<li>题目：${item.calc} = ${item.sum} 耗时：${item.timeTaken} 秒</li>`;
          })
          .join(" ")}
            
        </ul>
        <a href="/restart">重新开始</a>
    </div>
    `);
});

app.get("/restart", (req, res) => {
  count = 0;
  init();
  res.redirect("/");
});

app.listen(3000, () => {
  console.log("server runing on http://127.0.0.1:3000");
});

const examedPool = [];
let uuid = 1;

const getRandom = () => Math.floor(Math.random() * 10);

function generateExam() {
  const f = getRandom() || 1;
  const s = getRandom() || 1;
  const sum = f + s;
  const execH = `${f} + ${s}`;
  if (hasExam(execH)) return generateExam();
  return {
    execH,
    sum,
  };
}
function hasExam(e) {
  return examedPool.findIndex((item) => item.calc === e) > -1;
}

function getRecord(id) {
  return examedPool.find((item) => item.id === +id);
}

function addRecord() {
  const { execH, sum } = generateExam();
  const record = {
    calc: execH,
    id: uuid++,
    sum,
    timeStart: Date.now(),
    timeTaken: 0,
  };
  examedPool.push(record);
  return record;
}

function ediRecord(id) {
  const record = getRecord(id);
  if (!record) return;
  record.timeEnd = Date.now();
  record.timeTaken = Math.round((record.timeEnd - record.timeStart) / 1000);
}

function getTop5() {
  const records = examedPool.sort((a, b) => b.timeTaken - a.timeTaken);
  return records.slice(0, 5);
}

function sumTime() {
  return examedPool.reduce((acc, record) => acc + (record.timeTaken || 0), 0);
}

function isMaxrecordEnd() {
  return examedPool.length >= 81;
}
function init() {
  examedPool.length = 0;
  uuid = 1;
}

function totalLog() {
  console.log("ALL===>", JSON.stringify(examedPool));
}