import _ from 'underscore';
import { scaleLinear, scaleThreshold } from 'd3-scale';
import { select } from 'd3-selection';
import { getDayName, getDayDifference } from '~/lib/utils/datetime_utility';
import axios from '~/lib/utils/axios_utils';
import flash from '~/flash';
import { __ } from '~/locale';

const d3 = { select, scaleLinear, scaleThreshold };

const LOADING_HTML = `
  <div class="text-center">
    <i class="fa fa-spinner fa-spin user-calendar-activities-loading"></i>
  </div>
`;

function getSystemDate(systemUtcOffsetSeconds) {
  const date = new Date();
  const localUtcOffsetMinutes = 0 - date.getTimezoneOffset();
  const systemUtcOffsetMinutes = systemUtcOffsetSeconds / 60;
  date.setMinutes((date.getMinutes() - localUtcOffsetMinutes) + systemUtcOffsetMinutes);
  return date;
}

function formatTooltipText({ date, count }) {
  const dateObject = new Date(date);
  const dateDayName = getDayName(dateObject);
  const dateText = dateObject.format('mmm d, yyyy');

  let contribText = 'No contributions';
  if (count > 0) {
    contribText = `${count} contribution${count > 1 ? 's' : ''}`;
  }
  return `${contribText}<br />${dateDayName} ${dateText}`;
}

const initColorKey = () => d3.scaleLinear().range(['#acd5f2', '#254e77']).domain([0, 3]);

export default class ActivityCalendar {
  constructor(container, timestamps, calendarActivitiesPath, utcOffset = 0) {
    this.calendarActivitiesPath = calendarActivitiesPath;
    this.clickDay = this.clickDay.bind(this);
    this.currentSelectedDate = '';
    this.daySpace = 1;
    this.daySize = 15;
    this.daySizeWithSpace = this.daySize + (this.daySpace * 2);
    this.monthNames = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
    this.months = [];

    // Loop through the timestamps to create a group of objects
    // The group of objects will be grouped based on the day of the week they are
    this.timestampsTmp = [];
    let group = 0;

    const today = getSystemDate(utcOffset);
    today.setHours(0, 0, 0, 0, 0);

    const oneYearAgo = new Date(today);
    oneYearAgo.setFullYear(today.getFullYear() - 1);

    const days = getDayDifference(oneYearAgo, today);

    for (let i = 0; i <= days; i += 1) {
      const date = new Date(oneYearAgo);
      date.setDate(date.getDate() + i);

      const day = date.getDay();
      const count = timestamps[date.format('yyyy-mm-dd')] || 0;

      // Create a new group array if this is the first day of the week
      // or if is first object
      if ((day === 0 && i !== 0) || i === 0) {
        this.timestampsTmp.push([]);
        group += 1;
      }

      // Push to the inner array the values that will be used to render map
      const innerArray = this.timestampsTmp[group - 1];
      innerArray.push({ count, date, day });
    }

    // Init color functions
    this.colorKey = initColorKey();
    this.color = this.initColor();

    // Init the svg element
    this.svg = this.renderSvg(container, group);
    this.renderDays();
    this.renderMonths();
    this.renderDayTitles();
    this.renderKey();

    // Init tooltips
    $(`${container} .js-tooltip`).tooltip({ html: true });
  }

  // Add extra padding for the last month label if it is also the last column
  getExtraWidthPadding(group) {
    let extraWidthPadding = 0;
    const lastColMonth = this.timestampsTmp[group - 1][0].date.getMonth();
    const secondLastColMonth = this.timestampsTmp[group - 2][0].date.getMonth();

    if (lastColMonth !== secondLastColMonth) {
      extraWidthPadding = 6;
    }

    return extraWidthPadding;
  }

  renderSvg(container, group) {
    const width = ((group + 1) * this.daySizeWithSpace) + this.getExtraWidthPadding(group);
    return d3.select(container)
      .append('svg')
        .attr('width', width)
        .attr('height', 167)
        .attr('class', 'contrib-calendar');
  }

  renderDays() {
    this.svg.selectAll('g').data(this.timestampsTmp).enter().append('g')
      .attr('transform', (group, i) => {
        _.each(group, (stamp, a) => {
          if (a === 0 && stamp.day === 0) {
            const month = stamp.date.getMonth();
            const x = (this.daySizeWithSpace * i) + 1 + this.daySizeWithSpace;
            const lastMonth = _.last(this.months);
            if (
              lastMonth == null ||
              (month !== lastMonth.month && x - this.daySizeWithSpace !== lastMonth.x)
            ) {
              this.months.push({ month, x });
            }
          }
        });
        return `translate(${(this.daySizeWithSpace * i) + 1 + this.daySizeWithSpace}, 18)`;
      })
      .selectAll('rect')
        .data(stamp => stamp)
        .enter()
        .append('rect')
          .attr('x', '0')
          .attr('y', stamp => this.daySizeWithSpace * stamp.day)
          .attr('width', this.daySize)
          .attr('height', this.daySize)
          .attr('fill', stamp => (
            stamp.count !== 0 ? this.color(Math.min(stamp.count, 40)) : '#ededed'
          ))
          .attr('title', stamp => formatTooltipText(stamp))
          .attr('class', 'user-contrib-cell js-tooltip')
          .attr('data-container', 'body')
          .on('click', this.clickDay);
  }

  renderDayTitles() {
    const days = [
      {
        text: 'M',
        y: 29 + (this.daySizeWithSpace * 1),
      }, {
        text: 'W',
        y: 29 + (this.daySizeWithSpace * 3),
      }, {
        text: 'F',
        y: 29 + (this.daySizeWithSpace * 5),
      },
    ];
    this.svg.append('g')
      .selectAll('text')
        .data(days)
        .enter()
        .append('text')
          .attr('text-anchor', 'middle')
          .attr('x', 8)
          .attr('y', day => day.y)
          .text(day => day.text)
          .attr('class', 'user-contrib-text');
  }

  renderMonths() {
    this.svg.append('g')
      .attr('direction', 'ltr')
      .selectAll('text')
        .data(this.months)
        .enter()
        .append('text')
          .attr('x', date => date.x)
          .attr('y', 10)
          .attr('class', 'user-contrib-text')
          .text(date => this.monthNames[date.month]);
  }

  renderKey() {
    const keyValues = ['no contributions', '1-9 contributions', '10-19 contributions', '20-29 contributions', '30+ contributions'];
    const keyColors = ['#ededed', this.colorKey(0), this.colorKey(1), this.colorKey(2), this.colorKey(3)];

    this.svg.append('g')
      .attr('transform', `translate(18, ${(this.daySizeWithSpace * 8) + 16})`)
      .selectAll('rect')
        .data(keyColors)
        .enter()
        .append('rect')
          .attr('width', this.daySize)
          .attr('height', this.daySize)
          .attr('x', (color, i) => this.daySizeWithSpace * i)
          .attr('y', 0)
          .attr('fill', color => color)
          .attr('class', 'js-tooltip')
          .attr('title', (color, i) => keyValues[i])
          .attr('data-container', 'body');
  }

  initColor() {
    const colorRange = ['#ededed', this.colorKey(0), this.colorKey(1), this.colorKey(2), this.colorKey(3)];
    return d3.scaleThreshold().domain([0, 10, 20, 30]).range(colorRange);
  }

  clickDay(stamp) {
    if (this.currentSelectedDate !== stamp.date) {
      this.currentSelectedDate = stamp.date;

      const date = [
        this.currentSelectedDate.getFullYear(),
        this.currentSelectedDate.getMonth() + 1,
        this.currentSelectedDate.getDate(),
      ].join('-');

      $('.user-calendar-activities').html(LOADING_HTML);

      axios.get(this.calendarActivitiesPath, {
        params: {
          date,
        },
        responseType: 'text',
      })
      .then(({ data }) => $('.user-calendar-activities').html(data))
      .catch(() => flash(__('An error occurred while retrieving calendar activity')));
    } else {
      this.currentSelectedDate = '';
      $('.user-calendar-activities').html('');
    }
  }
}