import type { AnyNode, Element } from "domhandler";
import { findAll, findOne } from "domutils";
import { parseDocument } from "htmlparser2";

/** Parse an HTML fragment / document and return the DOM root list. */
export function parse(html: string): AnyNode[] {
    return parseDocument(html).children;
}

/** Find the first element matching a predicate (deep search). */
export function findFirst(
    html: string,
    predicate: (el: Element) => boolean
): Element | null {
    const roots = parse(html);
    return findOne(predicate, roots, true);
}

/** Find every element matching a predicate (deep search). */
export function findEvery(
    html: string,
    predicate: (el: Element) => boolean
): Element[] {
    const roots = parse(html);
    return findAll(predicate, roots);
}

/** Extract text content from an element (recursive). */
export function textOf(el: Element | AnyNode | null | undefined): string {
    if (el === null || el === undefined) return "";
    if ("data" in el && typeof el.data === "string" && el.type === "text") {
        return el.data;
    }
    if ("children" in el && Array.isArray(el.children)) {
        return el.children.map((c) => textOf(c as AnyNode)).join("");
    }
    return "";
}