feishin/src/renderer/components/item-list/helpers/get-dragged-items.ts

import {
    ItemListStateActions,
    ItemListStateItemWithRequiredProperties,
} from '/@/renderer/components/item-list/helpers/item-list-state';
import {
    Album,
    AlbumArtist,
    Artist,
    Folder,
    Genre,
    Playlist,
    Song,
} from '/@/shared/types/domain-types';

/**
 * Type guard to assert that an item has the required properties for dragging
 */
const hasRequiredDragProperties = (
    item: unknown,
): item is ItemListStateItemWithRequiredProperties => {
    return (
        typeof item === 'object' &&
        item !== null &&
        'id' in item &&
        typeof (item as any).id === 'string' &&
        '_itemType' in item &&
        typeof (item as any)._itemType === 'string' &&
        '_serverId' in item &&
        typeof (item as any)._serverId === 'string'
    );
};

/**
 * Gets the items that should be dragged based on the current data and selection state.
 * If the current item is already selected, drag all selected items.
 * Otherwise, select and drag only the current item.
 * If internalState is not provided, returns the single item wrapped in an array.
 *
 * @param data - The item data to drag (Album, AlbumArtist, Artist, Folder, Playlist, or Song)
 * @param internalState - The item list state actions (optional)
 * @param updateSelection - Whether to update the selection state (default: true)
 * @returns Array of items that should be dragged (with original values, asserting id, itemType, and _serverId)
 */
export const getDraggedItems = (
    data: Album | AlbumArtist | Artist | Folder | Genre | Playlist | Song | undefined,
    internalState?: ItemListStateActions,
    updateSelection: boolean = true,
): ItemListStateItemWithRequiredProperties[] => {
    if (!data) {
        return [];
    }

    if (!hasRequiredDragProperties(data)) {
        return [];
    }

    const draggedItem = data as ItemListStateItemWithRequiredProperties;

    if (!internalState) {
        return [draggedItem];
    }

    const rowId = internalState.extractRowId(data);

    if (!rowId) {
        return [draggedItem];
    }

    const previouslySelected = internalState.getSelected();
    const isDraggingSelectedItem = previouslySelected.some((selected) => {
        if (hasRequiredDragProperties(selected)) {
            return internalState.extractRowId(selected) === rowId;
        }
        return false;
    });

    const draggedItems: ItemListStateItemWithRequiredProperties[] = [];

    if (isDraggingSelectedItem) {
        const selectedItems = previouslySelected.filter(
            (item): item is ItemListStateItemWithRequiredProperties =>
                hasRequiredDragProperties(item),
        );
        draggedItems.push(...selectedItems);
    } else {
        if (updateSelection) {
            internalState.setSelected([draggedItem]);
        }
        draggedItems.push(draggedItem);
    }

    return draggedItems;
};