import { ANCHOR_PREFIX } from "#configuration/constants/document.constants";
import { LINE_INFIX } from "#configuration/constants/anatomy.constants";
import type { NodeTarget } from "#types/folder.types";

export const targetOf = function targetOf(href: string): NodeTarget | null {
    const cut = href.lastIndexOf(ANCHOR_PREFIX);
    if (cut === -1) {
        return null;
    }
    const fragment = href.slice(cut + ANCHOR_PREFIX.length);
    const mark = fragment.indexOf(LINE_INFIX);
    if (mark === -1) {
        return { id: fragment, line: null, text: null };
    }
    const tail = fragment.slice(mark + LINE_INFIX.length);
    const line = Number(tail);
    return Number.isInteger(line)
        ? { id: fragment.slice(0, mark), line, text: null }
        : { id: fragment.slice(0, mark), line: null, text: tail };
};