Iris/src/js/components/TrackList.js

import React, { useState, useEffect } from 'react';
import { range, uniqBy } from 'lodash';
import Track from './Track';
import { playURIs, changeTrack } from '../services/mopidy/actions';
import { createNotification, showContextMenu } from '../services/ui/actions';
import { isTouchDevice } from '../util/helpers';
import { arrayOf } from '../util/arrays';
import { SmartList } from './SmartList';
import { useSelector } from 'react-redux';
import { useDispatch } from 'react-redux';

const TrackList = ({
  context,
  className = '',
  show_source_icon,
  tracks,
  playTracks,
  removeTracks,
  reorderTracks,
}) => {
  const dispatch = useDispatch();
  const play_state = useSelector((state) => state.mopidy.play_state);
  const { slim_mode } = useSelector((state) => state.ui);
  const [selected, setSelected] = useState([]);

  useEffect(() => {
    setSelected([]);
  }, [tracks.length]);

  useEffect(() => {
    window.addEventListener('keydown', onKeyDown, false);
    return () => {
      window.removeEventListener('keydown', onKeyDown, false);
    };
  }, [selected]);

  const onKeyDown = (e) => {
    const {
      key,
      altKey,
      ctrlKey,
      metaKey,
      shiftKey,
    } = e;

    // When we're focussed on certian elements, don't fire any shortcuts
    // Typically form inputs
    const ignoreNodes = ['INPUT', 'TEXTAREA'];
    if (ignoreNodes.indexOf(e.target.nodeName) > -1) {
      return;
    }

    // Ignore when there are any key modifiers. This enables us to avoid interfering
    // with browser- and OS-default functions.
    if (altKey || ctrlKey || metaKey || shiftKey) {
      return;
    }

    switch (key.toLowerCase()) {
      case 'enter':
        onPlayTracks();
        e.preventDefault();
        break;
      case 'backspace':
      case 'delete':
        onRemoveTracks();
        e.preventDefault();
        break;
      case 'a':
        setSelected(tracks.map((item, index) => ({ item, index })));
        e.preventDefault();
        break;
      default:
        break;
    }
  }

  const events = {
    onDrop: (index) => {
      reorderTracks(arrayOf('index', selected), index);
      setSelected([]);
    },
    onMouseDown: (item, index, e) => {
      if (selectionIndexByItemIndex(index) === -1) {
        e.persist();
        setSelected((prev) => nextSelected(prev, item, index, e));
      }
    },
    onTouchStart: (item, index, e) => { // Only bound to the drag handler
      e.persist();
      setSelected((prev) => nextSelected(prev, item, index, e));
    },
    onDoubleClick: (item, index) => {
      setSelected([{ item, index }]);
      if (context?.type === 'queue') {
        dispatch(changeTrack(item.tlid));
      } else {
        dispatch(playURIs({ uris: [item.uri], from: context }));
      }
    },
    onContextMenu: (item, index, e) => {
      // Do our best to stop any flow-on events
      e.preventDefault();
      e.stopPropagation();
      e.cancelBubble = true;
      const items = getOrUpdateSelected(item, index, e).map(
        ({ index, item }) => ({ index, ...item }),
      );

      dispatch(showContextMenu({
        e,
        context,
        ...(items.length === 1
          ? { type: 'track', item: items[0] }
          : { type: 'tracks', items }
        ),
      }));
    },
  };

  const onPlayTracks = () => {
    if (!selected || !selected.length) return;

    const selectedTracks = arrayOf('item', selected);
    if (playTracks) {
      playTracks(selectedTracks);
    } else {
      dispatch(playURIs({ uris: arrayOf('uri', selectedTracks), from: context }));
    }
  };

  const onRemoveTracks = () => {
    if (!selected || !selected.length) return;

    if (!removeTracks) {
      dispatch(createNotification({
        content: `Cannot delete ${selected.length > 1 ? 'these tracks' : 'this track'}`,
        level: 'error',
      }));
      return;
    }
    removeTracks(selected.map(({ index }) => index));
  };

  const selectionIndexByItemIndex = (index) => (
    selected && selected.length > 0
      ? selected.findIndex(({ index: selectedIndex }) => selectedIndex === index)
      : -1
  );

  // Based on a single track's event, procure the next selected array and update the state
  // Target not selected = select it
  // Target selected = leave as-is and return current selection
  const getOrUpdateSelected = (item, index, e) => {
    const alreadySelected = selectionIndexByItemIndex(index);
    let items = [];
    if (alreadySelected > -1) {
      items = selected;
    } else {
      items = nextSelected(selected, item, index, e);
      setSelected(items);
    }
    return items;
  }

  const nextSelected = (prev, item, index, e = {}, sticky = false) => {
    const alreadySelected = selectionIndexByItemIndex(index);

    if (e.shiftKey) {
      const { index: lastSelectedIndex } = selected[selected.length - 1] || {
        index,
      };
      const from = lastSelectedIndex < index ? lastSelectedIndex : index;
      const to = lastSelectedIndex > index ? lastSelectedIndex : index;

      const newSelection = range(from, to + 1).map((index) => ({
        index,
        item: tracks[index],
      }));

      return uniqBy([...prev, ...newSelection], "index");
    }
    if (e.ctrlKey) {
      if (alreadySelected >= 0 && !sticky) {
        const next = [...prev];
        next.splice(alreadySelected, 1);
        return next;
      }
      return [...prev, { item, index }];
    }
    return [{ item, index }];
  };

  if (!tracks || Object.prototype.toString.call(tracks) !== '[object Array]') {
    return null;
  }

  const is_selected = (index) => selected.find(({ index: i }) => index === i);
  const getDragItem = (item, index) => {
    let selectedForDrag = selected;
    if (selectionIndexByItemIndex(index) === -1) {
      selectedForDrag = nextSelected(selected, item, index);
    }
    return {
      items: selectedForDrag,
      context,
    };
  };

  return (
    <SmartList
      className={`list list--tracks ${className}`}
      items={tracks}
      itemComponent={Track}
      itemProps={{
        play_state,
        show_source_icon,
        context,
        getDragItem,
        can_sort: context?.can_edit,
        is_selected,
        mini_zones: slim_mode || isTouchDevice(),
        events,
      }}
    />
  );
};

export default TrackList;