Files
familienarchiv/frontend/src/lib/hooks/useBlockDragDrop.svelte.ts

89 lines
2.4 KiB
TypeScript

import type { TranscriptionBlockData } from '$lib/types';
type Options = {
getSortedBlocks: () => TranscriptionBlockData[];
onReorder: (blockIds: string[]) => void;
};
export function createBlockDragDrop({ getSortedBlocks, onReorder }: Options) {
let draggedBlockId = $state<string | null>(null);
let dropTargetIdx = $state<number | null>(null);
let dragOffsetY = $state(0);
// Internal mutable refs — not reactive
let dragStartY = 0;
let capturedEl: HTMLElement | null = null;
let listEl: HTMLElement | null = null;
function setListElement(el: HTMLElement | null): void {
listEl = el;
}
function handleGripDown(e: PointerEvent, blockId: string): void {
if (!(e.target as HTMLElement).closest('[data-drag-handle]')) return;
e.preventDefault();
draggedBlockId = blockId;
dragStartY = e.clientY;
dragOffsetY = 0;
capturedEl = (e.target as HTMLElement).closest('[data-block-wrapper]') as HTMLElement;
capturedEl?.setPointerCapture(e.pointerId);
}
function handlePointerMove(e: PointerEvent): void {
if (!draggedBlockId || !listEl) return;
dragOffsetY = e.clientY - dragStartY;
const sortedBlocks = getSortedBlocks();
const wrappers = Array.from(listEl.querySelectorAll('[data-block-wrapper]'));
const dragIdx = sortedBlocks.findIndex((b) => b.id === draggedBlockId);
let target: number | null = null;
for (let i = 0; i < wrappers.length; i++) {
const rect = wrappers[i].getBoundingClientRect();
if (e.clientY < rect.top + rect.height / 2) {
target = i;
break;
}
}
if (target === null) target = wrappers.length;
if (target === dragIdx || target === dragIdx + 1) target = null;
dropTargetIdx = target;
}
function handlePointerUp(): void {
if (!draggedBlockId) return;
if (dropTargetIdx !== null) {
const sorted = [...getSortedBlocks()];
const fromIdx = sorted.findIndex((b) => b.id === draggedBlockId);
if (fromIdx >= 0) {
const [moved] = sorted.splice(fromIdx, 1);
const insertAt = dropTargetIdx > fromIdx ? dropTargetIdx - 1 : dropTargetIdx;
sorted.splice(insertAt, 0, moved);
onReorder(sorted.map((b) => b.id));
}
}
draggedBlockId = null;
dropTargetIdx = null;
dragOffsetY = 0;
capturedEl = null;
}
return {
get draggedBlockId() {
return draggedBlockId;
},
get dropTargetIdx() {
return dropTargetIdx;
},
get dragOffsetY() {
return dragOffsetY;
},
setListElement,
handleGripDown,
handlePointerMove,
handlePointerUp
};
}