@medalsocial/meda/dist/kanban/kanban-drop-handler.js

Shared Meda UI shell and runtime package.

import { isKanbanCardDropAllowed } from './kanban-collision.js';
/** Returns true if the drag was handled as a kanban column drop (column-to-column
 * move or reorder); false if `over` was null or did not resolve to a kanban column/
 * item, so the consumer can handle it (e.g. an external drop slot). */
export function handleKanbanColumnDrop(args) {
    const { event, items, columns, onCardMove, onReorder, canDropCard } = args;
    const { active, over } = event;
    if (!over)
        return false;
    const activeItemId = active.id;
    const overId = over.id;
    const draggedItem = items.find((item) => item.id === activeItemId);
    if (!draggedItem)
        return false;
    // Build itemsByStatus map for position resolution
    const itemsByStatus = new Map();
    for (const column of columns) {
        itemsByStatus.set(column.id, []);
    }
    for (const item of items) {
        const status = item.status;
        const columnItems = itemsByStatus.get(status);
        if (columnItems) {
            columnItems.push(item);
        }
    }
    for (const [status, columnItems] of itemsByStatus) {
        columnItems.sort((a, b) => (a.position ?? 0) - (b.position ?? 0));
        itemsByStatus.set(status, columnItems);
    }
    // Resolve drop target: check if over.id is a column id
    const targetColumn = columns.find((col) => col.id === overId);
    if (targetColumn) {
        const targetStatus = targetColumn.id;
        const columnItems = itemsByStatus.get(targetStatus) ?? [];
        if (!isKanbanCardDropAllowed({
            itemId: activeItemId,
            sourceStatus: draggedItem.status,
            targetStatus,
            canDropCard,
        })) {
            return true; // handled (rejected) — don't fall through to external handler
        }
        if (draggedItem.status !== targetStatus || draggedItem.position !== columnItems.length) {
            if (onReorder) {
                onReorder(activeItemId, targetStatus, columnItems.length);
            }
            if (onCardMove && draggedItem.status !== targetStatus) {
                void Promise.resolve(onCardMove(activeItemId, targetStatus)).catch(() => {
                    // Mutation handlers handle toast + rollback on failure.
                });
            }
        }
        return true;
    }
    // Check if over.id is an item id in one of the kanban columns
    const targetItem = items.find((item) => item.id === overId);
    if (!targetItem)
        return false;
    const targetStatus = targetItem.status;
    const columnItems = itemsByStatus.get(targetStatus) ?? [];
    const targetIndex = columnItems.findIndex((item) => item.id === overId);
    if (targetIndex === -1)
        return false;
    if (!isKanbanCardDropAllowed({
        itemId: activeItemId,
        sourceStatus: draggedItem.status,
        targetStatus,
        canDropCard,
    })) {
        return true; // handled (rejected)
    }
    if (draggedItem.status !== targetStatus || draggedItem.position !== targetIndex) {
        if (onReorder) {
            onReorder(activeItemId, targetStatus, targetIndex);
        }
        if (onCardMove && draggedItem.status !== targetStatus) {
            void Promise.resolve(onCardMove(activeItemId, targetStatus)).catch(() => {
                // Mutation handlers handle toast + rollback on failure.
            });
        }
    }
    return true;
}