import Chart from 'chart.js';

function resetActive(activeButton) {
  const buttons = document.getElementsByClassName('timerange-button');
  for (let i = 0; i < buttons.length; i += 1) {
    const button = buttons[i];
    button.classList.remove('selected');
  }

  activeButton.classList.add('selected');
}

function sumAnalytics(data, key) {
  return Object.entries(data).reduce((sum, day) => sum + day[1][key].total, 0);
}

function cardHTML(stat, header) {
  return `
    <h4>${header}</h4>
    <div class="featured-stat">${stat}</div>
  `;
}

function writeCards(data, timeRangeLabel) {
  const readers = sumAnalytics(data, 'page_views');
  const reactions = sumAnalytics(data, 'reactions');
  const comments = sumAnalytics(data, 'comments');
  const follows = sumAnalytics(data, 'follows');

  const reactionCard = document.getElementById('reactions-card');
  const commentCard = document.getElementById('comments-card');
  const followerCard = document.getElementById('followers-card');
  const readerCard = document.getElementById('readers-card');

  readerCard.innerHTML = cardHTML(readers, `Readers ${timeRangeLabel}`);
  commentCard.innerHTML = cardHTML(comments, `Comments ${timeRangeLabel}`);
  reactionCard.innerHTML = cardHTML(reactions, `Reactions ${timeRangeLabel}`);
  followerCard.innerHTML = cardHTML(follows, `Followers ${timeRangeLabel}`);
}

function drawChart({ canvas, title, labels, datasets }) {
  const options = {
    legend: {
      position: 'bottom',
    },
    responsive: true,
    title: {
      display: true,
      text: title,
    },
    scales: {
      yAxes: [
        {
          ticks: {
            suggestedMin: 0,
            precision: 0,
          },
        },
      ],
    },
  };

  // eslint-disable-next-line no-new
  new Chart(canvas, {
    type: 'line',
    data: {
      labels,
      datasets,
      options,
    },
  });
}

function drawCharts(data, timeRangeLabel) {
  const labels = Object.keys(data);
  const parsedData = Object.entries(data).map(date => date[1]);
  const comments = parsedData.map(date => date.comments.total);
  const reactions = parsedData.map(date => date.reactions.total);
  const likes = parsedData.map(date => date.reactions.like);
  const readingList = parsedData.map(date => date.reactions.readinglist);
  const unicorns = parsedData.map(date => date.reactions.unicorn);
  const followers = parsedData.map(date => date.follows.total);
  const readers = parsedData.map(date => date.page_views.total);

  drawChart({
    canvas: document.getElementById('reactionsChart'),
    title: `Reactions ${timeRangeLabel}`,
    labels,
    datasets: [
      {
        label: 'Total',
        data: reactions,
        fill: false,
        borderColor: 'rgb(75, 192, 192)',
        lineTension: 0.1,
      },
      {
        label: 'Likes',
        data: likes,
        fill: false,
        borderColor: 'rgb(229, 100, 100)',
        lineTension: 0.1,
      },
      {
        label: 'Unicorns',
        data: unicorns,
        fill: false,
        borderColor: 'rgb(157, 57, 233)',
        lineTension: 0.1,
      },
      {
        label: 'Bookmarks',
        data: readingList,
        fill: false,
        borderColor: 'rgb(10, 133, 255)',
        lineTension: 0.1,
      },
    ],
  });

  drawChart({
    canvas: document.getElementById('commentsChart'),
    title: `Comments ${timeRangeLabel}`,
    labels,
    datasets: [
      {
        label: 'Comments',
        data: comments,
        fill: false,
        borderColor: 'rgb(75, 192, 192)',
        lineTension: 0.1,
      },
    ],
  });

  drawChart({
    canvas: document.getElementById('followersChart'),
    title: `New Followers ${timeRangeLabel}`,
    labels,
    datasets: [
      {
        label: 'Followers',
        data: followers,
        fill: false,
        borderColor: 'rgb(10, 133, 255)',
        lineTension: 0.1,
      },
    ],
  });

  drawChart({
    canvas: document.getElementById('readersChart'),
    title: `Reads ${timeRangeLabel}`,
    labels,
    datasets: [
      {
        label: 'Reads',
        data: readers,
        fill: false,
        borderColor: 'rgb(157, 57, 233)',
        lineTension: 0.1,
      },
    ],
  });
}

function callAnalyticsApi(date, timeRangeLabel, organizationId) {
  let url = `/api/analytics/historical?start=${
    date.toISOString().split('T')[0]
  }`;

  if (organizationId) {
    url = `${url}&organization_id=${organizationId}`;
  }

  fetch(url)
    .then(data => data.json())
    .then(data => {
      drawCharts(data, timeRangeLabel);
      writeCards(data, timeRangeLabel);
    });
}

function drawWeekCharts(organizationId) {
  resetActive(document.getElementById('week-button'));
  const oneWeekAgo = new Date();
  oneWeekAgo.setDate(oneWeekAgo.getDate() - 7);
  callAnalyticsApi(oneWeekAgo, 'this Week', organizationId);
}

function drawMonthCharts(organizationId) {
  resetActive(document.getElementById('month-button'));
  const oneMonthAgo = new Date();
  oneMonthAgo.setMonth(oneMonthAgo.getMonth() - 1);
  callAnalyticsApi(oneMonthAgo, 'this Month', organizationId);
}

function drawInfinityCharts(organizationId) {
  resetActive(document.getElementById('infinity-button'));
  // April 1st is when the DEV analytics feature went into place
  const beginningOfTime = new Date('2019-4-1');
  callAnalyticsApi(beginningOfTime, '', organizationId);
}

export default function initCharts({ organizationId }) {
  const weekButton = document.getElementById('week-button');
  weekButton.addEventListener(
    'click',
    drawWeekCharts.bind(null, organizationId),
  );

  const monthButton = document.getElementById('month-button');
  monthButton.addEventListener(
    'click',
    drawMonthCharts.bind(null, organizationId),
  );

  const infinityButton = document.getElementById('infinity-button');
  infinityButton.addEventListener(
    'click',
    drawInfinityCharts.bind(null, organizationId),
  );

  // draw week charts by default
  drawWeekCharts(organizationId);
}