content: import React from 'react';
  import PropTypes from 'prop-types';
  import api from 'mastodon/api';
  import { FormattedNumber } from 'react-intl';
  import { Sparklines, SparklinesCurve } from 'react-sparklines';
  import classNames from 'classnames';
  import Skeleton from 'mastodon/components/skeleton';
  
  const percIncrease = (a, b) => {
    let percent;
  
    if (b !== 0) {
      if (a !== 0) {
        percent = (b - a) / a;
      } else {
        percent = 1;
      }
    } else if (b === 0 && a === 0) {
      percent = 0;
    } else {
      percent = - 1;
    }
  
    return percent;
  };
  
  export default class Counter extends React.PureComponent {
  
    static propTypes = {
      measure: PropTypes.string.isRequired,
      start_at: PropTypes.string.isRequired,
      end_at: PropTypes.string.isRequired,
      label: PropTypes.string.isRequired,
      href: PropTypes.string,
      params: PropTypes.object,
      target: PropTypes.string,
    };
  
    state = {
      loading: true,
      data: null,
    };
  
    componentDidMount () {
      const { measure, start_at, end_at, params } = this.props;
  
      api().post('/api/v1/admin/measures', { keys: [measure], start_at, end_at, [measure]: params }).then(res => {
        this.setState({
          loading: false,
          data: res.data,
        });
      }).catch(err => {
        console.error(err);
      });
    }
  
    render () {
      const { label, href, target } = this.props;
      const { loading, data } = this.state;
  
      let content;
  
      if (loading) {
        content = (
          <React.Fragment>
            <span className='sparkline__value__total'><Skeleton width={43} /></span>
            <span className='sparkline__value__change'><Skeleton width={43} /></span>
          </React.Fragment>
        );
      } else {
        const measure = data[0];
        const percentChange = measure.previous_total && percIncrease(measure.previous_total * 1, measure.total * 1);
  
        content = (
          <React.Fragment>
            <span className='sparkline__value__total'>{measure.human_value || <FormattedNumber value={measure.total} />}</span>
            {measure.previous_total && (<span className={classNames('sparkline__value__change', { positive: percentChange > 0, negative: percentChange < 0 })}>{percentChange > 0 && '+'}<FormattedNumber value={percentChange} style='percent' /></span>)}
          </React.Fragment>
        );
      }
  
      const inner = (
        <React.Fragment>
          <div className='sparkline__value'>
            {content}
          </div>
  
          <div className='sparkline__label'>
            {label}
          </div>
  
          <div className='sparkline__graph'>
            {!loading && (
              <Sparklines width={259} height={55} data={data[0].data.map(x => x.value * 1)}>
                <SparklinesCurve />
              </Sparklines>
            )}
          </div>
        </React.Fragment>
      );
  
      if (href) {
        return (
          <a href={href} className='sparkline' target={target}>
            {inner}
          </a>
        );
      } else {
        return (
          <div className='sparkline'>
            {inner}
          </div>
        );
      }
    }
  
  }
  