//jsloader.js

(function() {
    if(typeof XMLHttpRequest!="function") {
        if(typeof loadfail=="function") {
            loadfail("1-jsloader.js: XMLHttpRequest(type of "+(typeof XMLHttpRequest)+") is not a function");
        } else {
            window.alert("1-jsloader.js: XMLHttpRequest(type of "+(typeof XMLHttpRequest)+") is not a function");
        }
        return;
    }

    var ScriptManager= {};
    ScriptManager.loading_count=0;

    ScriptManager.loadjs=async function(pth) {
        var resolve;
        var reject;
        var ret=new Promise(function(s, r) {
            resolve=s;
            reject=r;
        });
        var xhr=new XMLHttpRequest();

        var onreadystatechange=async function() {
            if(xhr.readyState!=XMLHttpRequest.DONE) {
                return;
            }
            removelisteners();
            ScriptManager.loading_count--;
            if(xhr.status!=200) {
                onfail();
                return;
            }
            console.debug("script "+pth+" fetched successfully.");
            try {
                var fn=new Function(xhr.responseText);
                Object.defineProperty(fn, "name", {"value":pth});
                var re=await fn();
                if(typeof re=="function") {
                    await re();
                } else {
                    await re;
                }
            } catch(e) {
                console.error(e);
                onfail();
                return;
            }
            console.debug("script "+pth+" loaded.");
            resolve();
            return;
        };

        var onfail=function() {
            removelisteners();
            xhr.abort();
            window.loadfail("script "+pth+" load failed");
            reject("script "+pth+" load failed");
        };

        var removelisteners=function() {
            xhr.removeEventListener("readystatechange", onreadystatechange);
            xhr.removeEventListener("error", onfail);
            xhr.removeEventListener("abort", onfail);
        };

        xhr.addEventListener("readystatechange", onreadystatechange);
        xhr.addEventListener("error", onfail);
        xhr.addEventListener("abort", onfail);

        xhr.open("GET", pth, true);
        xhr.send();

        ScriptManager.loading_count++;
        return ret;
    };

    ScriptManager.isDone=function() {
        return ScriptManager.loading_count==0;
    };

    ScriptManager.waitAll=async function() {
        return new Promise(function(resolve, reject) {
            var i;
            i=setInterval(function() {
                if(ScriptManager.loading_count==0) {
                    clearInterval(i);
                    resolve();
                }
            }, 100);
        });
    };

    window.ScriptManager=ScriptManager;
})();