package com.github.dtschust.zork.parser.dom;

import com.github.dtschust.zork.parser.DOMUtils;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import java.util.AbstractList;
import java.util.List;
import java.util.RandomAccess;
import java.util.stream.Collectors;

public class Elements extends AbstractList<Element> implements RandomAccess {
    private final NodeList list;

    public static Elements byTagName(final Element parent, final String name) {
        return new Elements(parent.getElementsByTagName(name));
    }

    public static List<String> innerTextByTagName(final Element parent, final String name) {
        return Elements.byTagName(parent, name).stream()
                .map(DOMUtils::getInnerText)
                .collect(Collectors.toList());
    }

    private Elements(final NodeList l) {
        list = l;
    }

    @Override
    public Element get(int index) {
        final Node e = list.item(index);
        if (!(e instanceof Element)) {
            // the contract of getElementsByTagName states that it returns a list of Element objects
            throw new IllegalStateException("unreachable");
        }
        return (Element) e;
    }

    @Override
    public int size() {
        return list.getLength();
    }
}