session-desktop/ts/components/LightboxGallery.tsx

/**
 * @prettier
 */
import React, { useEffect, useState } from 'react';

import * as MIME from '../types/MIME';
import { Lightbox } from './Lightbox';
import { Message } from './conversation/media-gallery/types/Message';

import { AttachmentType } from '../types/Attachment';
// tslint:disable-next-line: no-submodule-imports
import useKey from 'react-use/lib/useKey';

export interface MediaItemType {
  objectURL?: string;
  thumbnailObjectUrl?: string;
  contentType: MIME.MIMEType;
  index: number;
  attachment: AttachmentType;
  message: Message;
}

type Props = {
  close: () => void;
  media: Array<MediaItemType>;
  onSave?: (options: { attachment: AttachmentType; message: Message; index: number }) => void;
  selectedIndex: number;
};

export const LightboxGallery = (props: Props) => {
  const { close, media, onSave } = props;
  const [currentIndex, setCurrentIndex] = useState(0);

  // just run once, when the component is mounted. It's to show the lightbox on the specified index at start.
  useEffect(() => {
    setCurrentIndex(props.selectedIndex);
  }, []);

  const selectedMedia = media[currentIndex];
  const firstIndex = 0;
  const lastIndex = media.length - 1;
  const onPrevious =
    currentIndex > firstIndex
      ? () => {
          setCurrentIndex(Math.max(currentIndex - 1, 0));
        }
      : undefined;
  const onNext =
    currentIndex < lastIndex
      ? () => {
          setCurrentIndex(Math.min(currentIndex + 1, lastIndex));
        }
      : undefined;

  const handleSave = () => {
    if (!onSave) {
      return;
    }

    const mediaItem = media[currentIndex];

    onSave({
      attachment: mediaItem.attachment,
      message: mediaItem.message,
      index: mediaItem.index,
    });
  };

  const objectURL = selectedMedia.objectURL || 'images/alert-outline.svg';
  const { attachment } = selectedMedia;

  const saveCallback = onSave ? handleSave : undefined;
  const captionCallback = attachment ? attachment.caption : undefined;

  useKey(
    'ArrowRight',
    () => {
      onNext?.();
    },
    undefined,
    [currentIndex]
  );
  useKey(
    'ArrowLeft',
    () => {
      onPrevious?.();
    },
    undefined,
    [currentIndex]
  );

  useKey('Escape', () => {
    props.close?.();
  });

  return (
    <Lightbox
      close={close}
      onPrevious={onPrevious}
      onNext={onNext}
      onSave={saveCallback}
      objectURL={objectURL}
      caption={captionCallback}
      contentType={selectedMedia.contentType}
    />
  );
};