content: import React from 'react';
  import ImmutablePropTypes from 'react-immutable-proptypes';
  import PropTypes from 'prop-types';
  import { is } from 'immutable';
  import IconButton from './icon_button';
  import { defineMessages, injectIntl, FormattedMessage } from 'react-intl';
  import { isIOS } from '../is_mobile';
  import classNames from 'classnames';
  import { autoPlayGif, displayMedia } from '../initial_state';
  import { decode } from 'blurhash';
  
  const messages = defineMessages({
    toggle_visible: { id: 'media_gallery.toggle_visible', defaultMessage: 'Toggle visibility' },
  });
  
  class Item extends React.PureComponent {
  
    static propTypes = {
      attachment: ImmutablePropTypes.map.isRequired,
      standalone: PropTypes.bool,
      index: PropTypes.number.isRequired,
      size: PropTypes.number.isRequired,
      onClick: PropTypes.func.isRequired,
      displayWidth: PropTypes.number,
      visible: PropTypes.bool.isRequired,
    };
  
    static defaultProps = {
      standalone: false,
      index: 0,
      size: 1,
    };
  
    state = {
      loaded: false,
    };
  
    handleMouseEnter = (e) => {
      if (this.hoverToPlay()) {
        e.target.play();
      }
    }
  
    handleMouseLeave = (e) => {
      if (this.hoverToPlay()) {
        e.target.pause();
        e.target.currentTime = 0;
      }
    }
  
    hoverToPlay () {
      const { attachment } = this.props;
      return !autoPlayGif && attachment.get('type') === 'gifv';
    }
  
    handleClick = (e) => {
      const { index, onClick } = this.props;
  
      if (e.button === 0 && !(e.ctrlKey || e.metaKey)) {
        if (this.hoverToPlay()) {
          e.target.pause();
          e.target.currentTime = 0;
        }
        e.preventDefault();
        onClick(index);
      }
  
      e.stopPropagation();
    }
  
    componentDidMount () {
      if (this.props.attachment.get('blurhash')) {
        this._decode();
      }
    }
  
    componentDidUpdate (prevProps) {
      if (prevProps.attachment.get('blurhash') !== this.props.attachment.get('blurhash') && this.props.attachment.get('blurhash')) {
        this._decode();
      }
    }
  
    _decode () {
      const hash   = this.props.attachment.get('blurhash');
      const pixels = decode(hash, 32, 32);
  
      if (pixels) {
        const ctx       = this.canvas.getContext('2d');
        const imageData = new ImageData(pixels, 32, 32);
  
        ctx.putImageData(imageData, 0, 0);
      }
    }
  
    setCanvasRef = c => {
      this.canvas = c;
    }
  
    handleImageLoad = () => {
      this.setState({ loaded: true });
    }
  
    render () {
      const { attachment, index, size, standalone, displayWidth, visible } = this.props;
  
      let width  = 50;
      let height = 100;
      let top    = 'auto';
      let left   = 'auto';
      let bottom = 'auto';
      let right  = 'auto';
  
      if (size === 1) {
        width = 100;
      }
  
      if (size === 4 || (size === 3 && index > 0)) {
        height = 50;
      }
  
      if (size === 2) {
        if (index === 0) {
          right = '2px';
        } else {
          left = '2px';
        }
      } else if (size === 3) {
        if (index === 0) {
          right = '2px';
        } else if (index > 0) {
          left = '2px';
        }
  
        if (index === 1) {
          bottom = '2px';
        } else if (index > 1) {
          top = '2px';
        }
      } else if (size === 4) {
        if (index === 0 || index === 2) {
          right = '2px';
        }
  
        if (index === 1 || index === 3) {
          left = '2px';
        }
  
        if (index < 2) {
          bottom = '2px';
        } else {
          top = '2px';
        }
      }
  
      let thumbnail = '';
  
      if (attachment.get('type') === 'unknown') {
        return (
          <div className={classNames('media-gallery__item', { standalone })} key={attachment.get('id')} style={{ left: left, top: top, right: right, bottom: bottom, width: `${width}%`, height: `${height}%` }}>
            <a className='media-gallery__item-thumbnail' href={attachment.get('remote_url')} target='_blank' style={{ cursor: 'pointer' }} title={attachment.get('description')}>
              <canvas width={32} height={32} ref={this.setCanvasRef} className='media-gallery__preview' />
            </a>
          </div>
        );
      } else if (attachment.get('type') === 'image') {
        const previewUrl   = attachment.get('preview_url');
        const previewWidth = attachment.getIn(['meta', 'small', 'width']);
  
        const originalUrl   = attachment.get('url');
        const originalWidth = attachment.getIn(['meta', 'original', 'width']);
  
        const hasSize = typeof originalWidth === 'number' && typeof previewWidth === 'number';
  
        const srcSet = hasSize ? `${originalUrl} ${originalWidth}w, ${previewUrl} ${previewWidth}w` : null;
        const sizes  = hasSize && (displayWidth > 0) ? `${displayWidth * (width / 100)}px` : null;
  
        const focusX = attachment.getIn(['meta', 'focus', 'x']) || 0;
        const focusY = attachment.getIn(['meta', 'focus', 'y']) || 0;
        const x      = ((focusX /  2) + .5) * 100;
        const y      = ((focusY / -2) + .5) * 100;
  
        thumbnail = (
          <a
            className='media-gallery__item-thumbnail'
            href={attachment.get('remote_url') || originalUrl}
            onClick={this.handleClick}
            target='_blank'
          >
            <img
              src={previewUrl}
              srcSet={srcSet}
              sizes={sizes}
              alt={attachment.get('description')}
              title={attachment.get('description')}
              style={{ objectPosition: `${x}% ${y}%` }}
              onLoad={this.handleImageLoad}
            />
          </a>
        );
      } else if (attachment.get('type') === 'gifv') {
        const autoPlay = !isIOS() && autoPlayGif;
  
        thumbnail = (
          <div className={classNames('media-gallery__gifv', { autoplay: autoPlay })}>
            <video
              className='media-gallery__item-gifv-thumbnail'
              aria-label={attachment.get('description')}
              title={attachment.get('description')}
              role='application'
              src={attachment.get('url')}
              onClick={this.handleClick}
              onMouseEnter={this.handleMouseEnter}
              onMouseLeave={this.handleMouseLeave}
              autoPlay={autoPlay}
              loop
              muted
            />
  
            <span className='media-gallery__gifv__label'>GIF</span>
          </div>
        );
      }
  
      return (
        <div className={classNames('media-gallery__item', { standalone })} key={attachment.get('id')} style={{ left: left, top: top, right: right, bottom: bottom, width: `${width}%`, height: `${height}%` }}>
          <canvas width={32} height={32} ref={this.setCanvasRef} className={classNames('media-gallery__preview', { 'media-gallery__preview--hidden': visible && this.state.loaded })} />
          {visible && thumbnail}
        </div>
      );
    }
  
  }
  
  export default @injectIntl
  class MediaGallery extends React.PureComponent {
  
    static propTypes = {
      sensitive: PropTypes.bool,
      standalone: PropTypes.bool,
      media: ImmutablePropTypes.list.isRequired,
      size: PropTypes.object,
      height: PropTypes.number.isRequired,
      onOpenMedia: PropTypes.func.isRequired,
      intl: PropTypes.object.isRequired,
      defaultWidth: PropTypes.number,
      cacheWidth: PropTypes.func,
      visible: PropTypes.bool,
      onToggleVisibility: PropTypes.func,
    };
  
    static defaultProps = {
      standalone: false,
    };
  
    state = {
      visible: this.props.visible !== undefined ? this.props.visible : (displayMedia !== 'hide_all' && !this.props.sensitive || displayMedia === 'show_all'),
      width: this.props.defaultWidth,
    };
  
    componentWillReceiveProps (nextProps) {
      if (!is(nextProps.media, this.props.media) && nextProps.visible === undefined) {
        this.setState({ visible: displayMedia !== 'hide_all' && !nextProps.sensitive || displayMedia === 'show_all' });
      } else if (!is(nextProps.visible, this.props.visible) && nextProps.visible !== undefined) {
        this.setState({ visible: nextProps.visible });
      }
    }
  
    handleOpen = () => {
      if (this.props.onToggleVisibility) {
        this.props.onToggleVisibility();
      } else {
        this.setState({ visible: !this.state.visible });
      }
    }
  
    handleClick = (index) => {
      this.props.onOpenMedia(this.props.media, index);
    }
  
    handleRef = (node) => {
      if (node /*&& this.isStandaloneEligible()*/) {
        // offsetWidth triggers a layout, so only calculate when we need to
        if (this.props.cacheWidth) this.props.cacheWidth(node.offsetWidth);
  
        this.setState({
          width: node.offsetWidth,
        });
      }
    }
  
    isStandaloneEligible() {
      const { media, standalone } = this.props;
      return standalone && media.size === 1 && media.getIn([0, 'meta', 'small', 'aspect']);
    }
  
    render () {
      const { media, intl, sensitive, height, defaultWidth } = this.props;
      const { visible } = this.state;
  
      const width = this.state.width || defaultWidth;
  
      let children, spoilerButton;
  
      const style = {};
  
      if (this.isStandaloneEligible()) {
        if (width) {
          style.height = width / this.props.media.getIn([0, 'meta', 'small', 'aspect']);
        }
      } else if (width) {
        style.height = width / (16/9);
      } else {
        style.height = height;
      }
  
      const size = media.take(4).size;
  
      if (this.isStandaloneEligible()) {
        children = <Item standalone onClick={this.handleClick} attachment={media.get(0)} displayWidth={width} visible={visible} />;
      } else {
        children = media.take(4).map((attachment, i) => <Item key={attachment.get('id')} onClick={this.handleClick} attachment={attachment} index={i} size={size} displayWidth={width} visible={visible} />);
      }
  
      if (visible) {
        spoilerButton = <IconButton title={intl.formatMessage(messages.toggle_visible)} icon='eye-slash' overlay onClick={this.handleOpen} />;
      } else {
        spoilerButton = (
          <button type='button' onClick={this.handleOpen} className='spoiler-button__overlay'>
            <span className='spoiler-button__overlay__label'>{sensitive ? <FormattedMessage id='status.sensitive_warning' defaultMessage='Sensitive content' /> : <FormattedMessage id='status.media_hidden' defaultMessage='Media hidden' />}</span>
          </button>
        );
      }
  
      return (
        <div className='media-gallery' style={style} ref={this.handleRef}>
          <div className={classNames('spoiler-button', { 'spoiler-button--minified': visible })}>
            {spoilerButton}
          </div>
  
          {children}
        </div>
      );
    }
  
  }
  