import { Deferred } from "evt/tools/Deferred";

export function appendHead(
    params: {
        type: "css";
        href: string;
    } | {
        type: "javascript";
        src: string;
    }
) {

    const htmlElement = document.createElement(
        (() => {
            switch (params.type) {
                case "css": return "link";
                case "javascript": return "script";
            }
        })()
    );

    const dLoaded = new Deferred<void>();

    htmlElement.addEventListener("load", () => dLoaded.resolve());

    Object.assign(
        htmlElement,
        (() => {
            switch (params.type) {
                case "css": return {
                    "href": params.href,
                    "type": "text/css",
                    "rel": "stylesheet",
                    "media": "screen,print"
                };
                case "javascript": return {
                    "src": params.src,
                    "type": "text/javascript",
                };
            }
        })()
    );

    document.getElementsByTagName("head")[0].appendChild(htmlElement);

    return dLoaded.pr;

}