import { TreeIterator, SHOW_ELEMENT } from './TreeIterator';
import { isBlock } from './Category';

// ---

const getBlockWalker = (
    node: Node,
    root: Element | DocumentFragment,
): TreeIterator<HTMLElement> => {
    const walker = new TreeIterator<HTMLElement>(root, SHOW_ELEMENT, isBlock);
    walker.currentNode = node;
    return walker;
};

const getPreviousBlock = (
    node: Node,
    root: Element | DocumentFragment,
): HTMLElement | null => {
    const block = getBlockWalker(node, root).previousNode();
    return block !== root ? block : null;
};

const getNextBlock = (
    node: Node,
    root: Element | DocumentFragment,
): HTMLElement | null => {
    const block = getBlockWalker(node, root).nextNode();
    return block !== root ? block : null;
};

const isEmptyBlock = (block: Element): boolean => {
    return !block.textContent && !block.querySelector('IMG');
};

// ---

export { getBlockWalker, getPreviousBlock, getNextBlock, isEmptyBlock };