// ==UserScript==
// @name         Power+ userscript loader
// @namespace    https://powerplus.app/
// @version      1.0
// @description  An alternate, customizable loader for Power+
// @author       jottocraft
// @license      MIT
// @icon         https://powerplus.app/favicon.png
// @grant        none
// @run-at       document-start
// @match        https://*.instructure.com/power+*
// @downloadURL none
// ==/UserScript==

(function () {
    'use strict';

    var s;

    //Check for light or dark theme
    var light = false;
    if (window.localStorage.fluidTheme == "light") {
        light = true;
    } else if (((window.localStorage.fluidTheme == "system") || (window.localStorage.fluidTheme == "auto")) && !window.matchMedia("(prefers-color-scheme: dark)").matches) {
        light = true;
    }

    //Replace canvas 404 page with Power+
    const observer = new MutationObserver(mutations => {
        mutations.forEach(({ addedNodes }) => {
            addedNodes.forEach(node => {
                //Power+ preloader
                if (node.nodeType === 1 && node.tagName === 'BODY') {
                    node.innerHTML = /*html*/`
            <div dtps="true" id="dtpsNativeOverlay" style="background-color: inherit; position: fixed; top: 0px; left: 0px; width: 100%; height: 100vh; z-index: 99;text-align: center;z-index: 999;transition: opacity 0.2s;">
              <img dtps="true" style="height: 100px; margin-top: 132px;" src="${light ? "https://i.imgur.com/0WzWwb1.png" : "https://i.imgur.com/7dDUVh2.png"}" />
			        <br dtps="true" />
              <div dtps="true" class="progress"><div id="dtpsLoadingScreenBar" dtps="true" class="indeterminate"></div></div>
              <style dtps="true">body {background-color: ${light ? "white" : "#151515"}; --crxElements: ${light ? "#ececec" : "#2b2b2b"}; --crxText: ${light ? "#333" : "#efefef"}; overflow: hidden;}*,:after,:before{box-sizing:border-box}.progress{background:var(--crxElements);position:relative;width:600px;height:5px;overflow:hidden;border-radius:12px;backdrop-filter:opacity(.4);display:inline-block;margin-top:75px}.progress .indeterminate{position:absolute;background:#e3ba4b;height:5px;animation:indeterminate 1.4s infinite;animation-timing-function:linear}@keyframes indeterminate{0%{width:5%;left:-15%}to{width:100%;left:110%}}p{font-family:BlinkMacSystemFont,-apple-system,"Segoe UI",Roboto,Oxygen,Ubuntu,Cantarell,"Fira Sans","Droid Sans","Helvetica Neue",Helvetica,Arial,sans-serif;color: var(--crxText);margin-top: 24px;}</style>
            </div>
          `;
                } else if (node.nodeType === 1 && node.tagName === 'HEAD') {
                    node.innerHTML = /*html*/`
            <link dtps="true" rel="shortcut icon" href="https://powerplus.app/favicon.png" type="image/png">
            <meta dtps="true" name="viewport" content="width=device-width, initial-scale=1">
            <meta dtps="true" charset="utf-8">
            <title dtps="true">Power+</title>
            <meta dtps="true" name="description" content="A better UI for Canvas LMS">
            <meta dtps="true" name="author" content="jottocraft">
          `;
                } else if (node.nodeType === 1 && node.tagName === 'SCRIPT' && (node.textContent && node.textContent.includes('"current_user"'))) {
                    //Do nothing for node containing enviornment data for faster load times
                } else if (node.nodeType === 1 && node.getAttribute("dtps") != "true") {
                    //Node is not added by dtps
                    node.remove();
                }
            })
        })
    })

    //Start MutationObserver
    observer.observe(document.documentElement, {
        childList: true,
        subtree: true
    });

    //Get Power+ base URL
    var baseURL = "https://powerplus.app";
    if (window.localStorage.dtpsLoaderPref == "dev") {
        baseURL = "https://dev.dtps.jottocraft.com";
    } else if (window.localStorage.githubRepo && (window.localStorage.dtpsLoaderPref == "github")) {
        baseURL = "https://jottocraft.github.io/" + window.localStorage.githubRepo;
    } else if (window.localStorage.externalReleaseURL && (window.localStorage.dtpsLoaderPref == "external")) {
        baseURL = window.localStorage.externalReleaseURL;
    } else if (window.localStorage.dtpsLoaderPref == "local") {
        baseURL = "http://localhost:2750";
    }

    //Set DTPS loader parameters
    s = document.createElement("script");
    s.textContent = "window.dtpsPreLoader = true;window.dtpsBaseURL = '" + baseURL + "'";
    s.async = false;
    s.setAttribute("dtps", "true");
    document.documentElement.appendChild(s);

    //Load jQuery
    s = document.createElement("script");
    s.src = "https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js";
    s.async = false;
    s.setAttribute("dtps", "true");
    document.documentElement.appendChild(s);

    //Wait for page to load
    window.onload = function () {
        //Stop observer
        observer.disconnect();

        //Determine LMS script to load
        var lmsScript = null;
        if (window.location.hostname.startsWith("dtechhs")) {
            lmsScript = "dtech";
        } else {
            lmsScript = "canvas";
        }

        //Check for debugging LMS overrides
        if (window.localStorage.dtpsLMSOverride) lmsScript = window.localStorage.dtpsLMSOverride;

        //Add script to DOM
        s = document.createElement("script");
        s.src = baseURL + "/scripts/lms/" + lmsScript + ".js";
        s.async = false;
        s.setAttribute("dtps", "true");
        document.documentElement.appendChild(s);
        s.onerror = function () {
            //Couldn't load debugging script, fallback to production
            if (window.localStorage.dtpsLoaderPref && (window.localStorage.dtpsLoaderPref !== "prod")) {
                console.log("[DTPS CHROME] Failed to load debugging script. Falling back to production.");
                window.localStorage.dtpsLoaderPref = "prod";
                window.location.reload();
            } else {
                document.getElementById("dtpsLoadingScreenBar").style.animationPlayState = "paused";
                document.getElementById("dtpsLoadingScreenStatus").innerText = "Could not load Power+. Please try again later.";
            }
        };
    }
})();