const _ = require('lodash');
const readline = require('readline');
const fs = require('fs');
const dayjs = require('dayjs');

let stat = fs.statSync('/Users/chenfeng/Downloads/buyers.csv');
let totalSize = stat.size;
let passedLength = 0;
let lastSize = 0;
let startTime = Date.now();


setTimeout(function show() {
  let percent = Math.ceil((passedLength / totalSize) * 100);
  let size = Math.ceil(passedLength / 1000000);
  let diff = size - lastSize;

  lastSize = size;
  console.log('已完成' + size + 'MB, ' + percent + '%, 速度：' + diff * 2 + 'MB/s');
  if (passedLength < totalSize) {
    setTimeout(show, 500);
  } else {
    let endTime = Date.now();

    console.log();
    console.log('共用时：' + (endTime - startTime) / 1000 + '秒。');
  }
}, 500);


function queryData() {
  const dataItems = [];

  return new Promise(r => {
    const fr = fs.createReadStream('/Users/chenfeng/Downloads/buyers.csv', {encoding: 'utf-8'});
    const rl = readline.createInterface({
      input: fr
    });

    rl.on('line', line => {
      passedLength += line.length;
      const splits = line.split(',');

      dataItems.push({
        productId: +splits[0],
        nickName: splits[1],
        icon: splits[2],
        time: splits[3],
      });
    });
    rl.on('close', () => {
      r(dataItems);
    });
  });
}

const buyereds = {};

async function excute() {
  const result = await queryData();

  console.log('result: ', result.length)
  const dataByUser = {};
  const dataByDate = {};

  _.forEach(result, (item, index) => {
    const userKey = `${item.nickName}${item.icon}`;
    const dateKey = dayjs(item.time).format('YYYY-MM-DD');

    if (!dataByUser[userKey]) {
      dataByUser[userKey] = [item.time];
    } else {
      dataByUser[userKey].push(item.time);
    }
    if (dayjs(item.time).diff(dayjs('2018-11-01'), 'day') >= 0) {
      if (!dataByDate[dateKey]) {
        dataByDate[dateKey] = [userKey];
      } else {
        dataByDate[dateKey].push(userKey);
      }
    }
    !(index % 10000) && console.log('process:', index)
  });
  console.log('process over');
  const start = dayjs('2018-11-01');
  const end = dayjs(Date.now());
  const diff = end.diff(start, 'day');

  for (let i = 0; i <= diff; i++) {
    const date = start.add(i, 'day');
    const dateKey = date.format('YYYY-MM-DD');

    console.log('calc:', i);

    if (dataByDate[dateKey]) {
      const allBuyers = dataByDate[dateKey].length;
      const oldBuyers = dataByDate[dateKey].filter(key => {
        if (buyereds[key]) {
          return true;
        }
        if (dataByUser[key]) {
          const isBuy = _.some(dataByUser[key], item => {
            return dayjs(item).diff(date, 'day') < 0;
          });

          if (isBuy) {
            buyereds[key] = true;
            dataByUser[key].length = 0;
          }

          return isBuy;
        }
        return false;
      });

      dataByDate[dateKey].length = 0;

      console.log(`data:${dateKey},${allBuyers - oldBuyers.length},${oldBuyers.length}`);
    }
  }
}

excute();