// ==UserScript==
// @name        CCNA Autofill
// @namespace   Violentmonkey Scripts
// @match       *://assessment.netacad.net/*
// @match       *://www.assessment.netacad.net/*
// @grant       GM_setValue
// @grant       GM_getValue
// @grant       GM_xmlhttpRequest
// @grant       GM_log
// @version     0.0.1
// @author      Dominik Säume
// ==/UserScript==

const URL_STORAGE_KEY = "itexamanswers.net URL";
let awnserData;

console.log = console.__proto__.log;

window.addEventListener("keydown", event => {
  switch(event.key){
    case "p":
        const oldAwnsersURL = GM_getValue(URL_STORAGE_KEY);
        let newAwnsersURL = prompt("Please input the answer url (itexamanswers.net)", oldAwnsersURL);
        GM_setValue(URL_STORAGE_KEY, newAwnsersURL);
        fetchData(newAwnsersURL);
        break;

    case "n":
        document.getElementById("next").click();
        break;

    case "a":
        awnserQuestion();
        break;
  }
})

function awnserQuestion(){
    const question = document.querySelector(".question:not(.hidden)");
    if (!question) {
        return;
    }

    const questionTextDom = question.querySelector(".questionText .mattext");
    if (!questionTextDom) return;
    const questionText = questionTextDom.textContent.trim();

    const answersDom = question.querySelector("ul.coreContent");
    if (!answersDom) return;
    const answers = answersDom.children;

    for (let answer of answers) {
        const input = answer.querySelector("input");
        if (!input) continue;
        input.checked = false;
    }

    const correctAnswers = findAnswers(questionText, answers);
    if (correctAnswers.length === 0) {
        GM_log("no awnser")
        return;
    }

    for (const answer of correctAnswers) {
        const input = answer.querySelector("input");
        if (!input) continue;
        input.checked = true;
    }
}

function findAnswers(questionText, answers) {
    if (awnserData === null) {
        alert("No chapter data loaded. Maybe the fetch failed?!");
        return [];
    }

    const correctAnswers = [];
    for (let entry of awnserData) {
        if (matchAwnser(questionText.trim(), entry.question.trim())) {
            for (let availableAnswer of answers) {
                for (let possibleAnswer of entry.answers) {
                    if (matchAwnser(availableAnswer.textContent.trim(), possibleAnswer)) {
                        correctAnswers.push(availableAnswer);
                    }
                }
            }
        }
    }

    return correctAnswers;
}

function matchAwnser(textA, textB) {
    const replaceRegex = /[^\w]/gi;
    textA = textA.replace(replaceRegex, "");
    textB = textB.replace(replaceRegex, "");
    return (textA === textB);
}

function fetchData(awnserURL = ""){
    GM_xmlhttpRequest({
      method: "GET",
      url: awnserURL,
      headers: {
        "Content-Type": "text/html"
      },
      onload: function(response) {
        awnserImgs = new Map();
        const results = [];
        const parser = new DOMParser();
        const virtDom = parser.parseFromString(response.responseText, "text/html");

        let answersDom = virtDom.querySelector(".pf-content");
        if (!answersDom) {
          answersDom = virtDom.querySelector(".thecontent");
        }

        let index = -1;
        for (let childDom of answersDom.children) {
            index++;

            if (childDom.tagName === "P" || childDom.tagName === "STRONG" ) {

                // maybe a question question
                let innerDom = childDom.querySelector("strong");
                if (innerDom === null) {
                  if(!childDom.textContent){
                    continue;
                  }
                  innerDom = childDom;
                };

                const textContent = innerDom.textContent.trim();
                const matches = textContent.match(/^[0-9]+\. (.*)$/);
                if (matches !== null) {
                    const questionText = matches[1];

                    // most likely a question
                    let nextChild = answersDom.children[index + 1];

                    if (nextChild.tagName === "P"){
                      nextChild = answersDom.children[index + 2];
                    };

                    if (nextChild === null) continue;

                    if (nextChild.tagName === "UL") {
                        // most likely the awnser
                        const answers = [];
                        for (let answerDom of nextChild.querySelectorAll("strong")) {
                            let answerText = answerDom.textContent.trim();
                            if (answerText.endsWith("*")) {
                                answerText = answerText.substring(0, answerText.length - 1);
                            }
                            answers.push(answerText);
                        }

                        results.push({
                            question: questionText,
                            answers: answers
                        });
                    }
                }

            }
        }
        awnserData = results;
        GM_log(results);
        GM_log(awnserImgs);
      }
    });
}