import fetch from 'node-fetch';

const ageMap = {
  "10000": "all",
  "41700": "0-65",
  "53950": "65-80",
  "21700": "80+"
};

const sexMap = {
  "1100": "all"
};

const residents = {
  "2015": (16992010 + 17072044) / 2,
  "2016": (16992010 + 17072044) / 2,
  "2017": (17091456 + 17172903) / 2,
  "2018": (17192306 + 17271231) / 2,
  "2019": (17299343 + 17399364) / 2,
  "2020": (17422992 + 17469635) / 2,
  "2021": (17422992 + 17469635) / 2
};

function range(start, stop, step) {
  var a = [start], b = start;
  while (b < stop) {
    a.push(b += step || 1);
  }
  return a;
}

const selectSex = (sex = 1100) => `(Geslacht eq '${sex}')`;
const selectAge = (age = 10000) => `(LeeftijdOp31December eq '${age}')`;
const selectWeek = (year, week) => `(Perioden eq '${year}W${100 + week}')`;
const selectYear = (year, startWeek = 2, endWeek = 51) => range(startWeek, endWeek).map((week) => selectWeek(year, week));

function buildUrl(year, startWeek = 2, endWeek = 51) {
  const filterSexes = [1100].map(selectSex);
  const filterAges = [10000, 41700, 53950, 21700].map(selectAge);
  const filterPeriods = selectYear(year, startWeek, endWeek);
  const select = `Geslacht, LeeftijdOp31December, Perioden, Overledenen_1`;
  const filter = `(${filterSexes.join(' or ')}) and (${filterAges.join(' or ')}) and (${filterPeriods.join(' or ')})`;
  return `https://opendata.cbs.nl/ODataApi/odata/70895ned/UntypedDataSet?$filter=${filter}&$select=${select}`
}

async function main() {
  const data = [];

  const getYearTasks = range(2015, 2021).map((year) => ({year, get: new Promise((resolve, reject) => {
    (async () => {
      try {
        const response = await fetch(buildUrl(year, 29, 39));
        const json = await response.json();
        resolve(json);
      } catch(e) {
        reject(e);
      }
    })();
  })}));

  for(const getYearTask of getYearTasks) {
    const deathsWeekMap = {};
    const yearData = await getYearTask.get;
    const yearValues = yearData.value;

    for(const value of yearValues) {
      const sex = sexMap[value['Geslacht']];
      const age = ageMap[value['LeeftijdOp31December']];
      const year = Number(value['Perioden'].substring(0, 4));
      const week = Number(value['Perioden'].substring(6, 8));
      const deaths = Number(value['Overledenen_1']);
      if(!deathsWeekMap[week]) {
        deathsWeekMap[week] = {};
      }
      deathsWeekMap[week]['Week'] = `${year} week ${week}`;
      deathsWeekMap[week][age] = deaths;
    }

    data.push(Object.values(deathsWeekMap));
  }

  const [during_2021, during_2020, ...before_2020_rest] = data.reverse();

  {
    console.log("all:");
    const during_2020_total = during_2020.reduce((r, week) => week['all'] + r, 0);
    const during_2021_total = during_2021.reduce((r, week) => week['all'] + r, 0);
    const before_2020_average = before_2020_rest.reduce((r, year) => year.reduce((r, week) => week['all'] + r, 0) + r, 0) / before_2020_rest.length;

    console.log("deaths during 2020 week 29-39:\n", during_2020_total);
    console.log("deaths during 2021 week 29-39:\n", during_2021_total);
    console.log("average between 2015 until 2019 week 29-39:\n", before_2020_average);
    console.log("difference before 2020 vs during 2020 week 29-39:\n", during_2020_total - before_2020_average);
    console.log("difference before 2020 vs during 2021 week 29-39:\n", during_2021_total - before_2020_average);
  }
  console.log();
  {
    console.log("0-65:");
    const during_2020_total = during_2020.reduce((r, week) => week['0-65'] + r, 0);
    const during_2021_total = during_2021.reduce((r, week) => week['0-65'] + r, 0);
    const before_2020_average = before_2020_rest.reduce((r, year) => year.reduce((r, week) => week['0-65'] + r, 0) + r, 0) / before_2020_rest.length;

    console.log("deaths during 2020 week 29-39:\n", during_2020_total);
    console.log("deaths during 2021 week 29-39:\n", during_2021_total);
    console.log("average between 2015 until 2019 week 29-39:\n", before_2020_average);
    console.log("difference before 2020 vs during 2020 week 29-39:\n", during_2020_total - before_2020_average);
    console.log("difference before 2020 vs during 2021 week 29-39:\n", during_2021_total - before_2020_average);
  }
  console.log();
  {
    console.log("65-80:");
    const during_2020_total = during_2020.reduce((r, week) => week['65-80'] + r, 0);
    const during_2021_total = during_2021.reduce((r, week) => week['65-80'] + r, 0);
    const before_2020_average = before_2020_rest.reduce((r, year) => year.reduce((r, week) => week['65-80'] + r, 0) + r, 0) / before_2020_rest.length;

    console.log("deaths during 2020 week 29-39:\n", during_2020_total);
    console.log("deaths during 2021 week 29-39:\n", during_2021_total);
    console.log("average between 2015 until 2019 week 29-39:\n", before_2020_average);
    console.log("difference before 2020 vs during 2020 week 29-39:\n", during_2020_total - before_2020_average);
    console.log("difference before 2020 vs during 2021 week 29-39:\n", during_2021_total - before_2020_average);
  }
  console.log();
  {
    console.log("80+:");
    const during_2020_total = during_2020.reduce((r, week) => week['80+'] + r, 0);
    const during_2021_total = during_2021.reduce((r, week) => week['80+'] + r, 0);
    const before_2020_average = before_2020_rest.reduce((r, year) => year.reduce((r, week) => week['80+'] + r, 0) + r, 0) / before_2020_rest.length;

    console.log("deaths during 2020 week 29-39:\n", during_2020_total);
    console.log("deaths during 2021 week 29-39:\n", during_2021_total);
    console.log("average between 2015 until 2019 week 29-39:\n", before_2020_average);
    console.log("difference before 2020 vs during 2020 week 29-39:\n", during_2020_total - before_2020_average);
    console.log("difference before 2020 vs during 2021 week 29-39:\n", during_2021_total - before_2020_average);
  }
}

main().catch(x => console.error(x));