/*!
 * Jodit Editor (https://xdsoft.net/jodit/)
 * License GNU General Public License version 2 or later;
 * Copyright 2013-2019 Valeriy Chupurnov https://xdsoft.net
 */

export const inView = (elm: HTMLElement, root: HTMLElement, doc: Document) => {
    let rect: ClientRect = elm.getBoundingClientRect(),
        el: HTMLElement | null = elm as HTMLElement | null;
    const top: number = rect.top,
        height: number = rect.height;

    do {
        if (el && el.parentNode) {
            el = el.parentNode as HTMLElement;
            rect = el.getBoundingClientRect();
            if (!(top <= rect.bottom)) {
                return false;
            }

            // Check if the element is out of view due to a container scrolling
            if (top + height <= rect.top) {
                return false;
            }
        }
    } while (el && el !== root && el.parentNode);

    // Check its within the document viewport
    return (
        top <= ((doc.documentElement && doc.documentElement.clientHeight) || 0)
    );
};

export const scrollIntoView = (
    elm: HTMLElement,
    root: HTMLElement,
    doc: Document
) => {
    if (!inView(elm, root, doc)) {
        if (root.clientHeight !== root.scrollHeight) {
            root.scrollTop = elm.offsetTop;
        }
        if (!inView(elm, root, doc)) {
            elm.scrollIntoView();
        }
    }
};