Mailspring/internal_packages/thread-list/lib/selected-items-stack.jsx

import _ from 'underscore'
import React, {Component, PropTypes} from 'react'
import {ListensToObservable} from 'nylas-component-kit'
import ThreadListStore from './thread-list-store'


function getObservable() {
  return (
    ThreadListStore.selectionObservable()
    .map(items => items.length)
  )
}

function getStateFromObservable(selectionCount) {
  if (!selectionCount) {
    return {selectionCount: 0}
  }
  return {selectionCount}
}

class SelectedItemsStack extends Component {
  static displayName = "SelectedItemsStack";

  static propTypes = {
    selectionCount: PropTypes.number,
  };

  static containerRequired = false;

  onClearSelection = () => {
    ThreadListStore.dataSource().selection.clear()
  };

  render() {
    const {selectionCount} = this.props
    if (selectionCount <= 1) {
      return <span />
    }
    const cardCount = Math.min(5, selectionCount)

    return (
      <div className="selected-items-stack">
        <div className="selected-items-stack-content">
          <div className="stack">
            {_.times(cardCount, (idx) => {
              let deg = idx * 0.9;

              if (idx === 1) {
                deg += 0.5
              }
              let transform = `rotate(${deg}deg)`
              if (idx === cardCount - 1) {
                transform += ' translate3d(2px, 3px, 0)'
              }
              const style = {
                transform,
                zIndex: 5 - idx,
              }
              return <div key={`card-${idx}`} style={style} className="card" />
            })}
          </div>
          <div className="count-info">
            <div className="count">{selectionCount}</div>
            <div className="count-message">messages selected</div>
            <div className="clear btn" onClick={this.onClearSelection}>Clear Selection</div>
          </div>
        </div>
      </div>
    )
  }
}

export default ListensToObservable(SelectedItemsStack, {getObservable, getStateFromObservable})