Duolingo Course Progress Script 2.5d by Martin (https://github.com/kane77/userscripts/tree/new) Mods by Dessamator (added gold skill count and next lesson)

Duolingo Course Progress.user.js

// ==UserScript==
// @name        Duolingo Course Progress
// @namespace   https://github.com/kane77/userscripts
// @include     https://www.duolingo.com/*
// @author      Martin Harvan
// @version     2.5d
// @grant GM_getValue
// ==/UserScript==
//Mods by Dessamator
// Added golden skill count
// Added next skill
function inject(f) { //Inject the script into the document
    var script;
    script = document.createElement('script');
    script.type = 'text/javascript';
    script.setAttribute('name', 'lesson_stats');
    script.textContent = '(' + f.toString() + ')(jQuery)';
    document.head.appendChild(script);
}
inject(f);
function f($) {
    function duolingoStats() {
        try {
            var language = window.duo.user.attributes.learning_language;
            var langData = window.duo.user.attributes.language_data[language];
            var totalSkills = langData.skills.models.length;
            var doneSkills = 0;
            var totalActivities = 0;
            var doneActivities = 0;
            var iGoldenSkills=0;
            var iStartedSkills=0;
            for (var i = 0; i < langData.skills.models.length; i++) {
                var skill = langData.skills.models[i];
                totalActivities += skill.attributes.num_lessons;
                doneActivities += skill.attributes.num_lessons - skill.attributes.missing_lessons;
                if (skill.attributes.missing_lessons === 0) {
                    doneSkills += 1;
                }
                if (skill.attributes.locked===false) {
                    iStartedSkills +=1;
                }
                if (skill.attributes.strength === 1) {
                    iGoldenSkills++;
                }
            }
            if (langData.bonus_skills) {
                var tBoughtSkills = duo.user.getOwnedBonusSkills();
                totalSkills +=duo.user.getOwnedBonusSkills().length;
                for (var i = 0; i < langData.bonus_skills.models.length; i++) {
                    var skill = langData.bonus_skills.models[i];
                    for (var j = 0; j < tBoughtSkills.length;j++){
                        if(tBoughtSkills[j].short_name ==skill.attributes.short) {
                            if (skill.attributes.num_missing < skill.attributes.num_lessons) {
                                iStartedSkills += 1;
                            }
                            totalActivities += skill.attributes.num_lessons;
                            doneActivities += skill.attributes.num_lessons - skill.attributes.missing_lessons;
                            if ( skill.attributes.missing_lessons === 0 ) {
                                doneSkills += 1;
                            }
                            if (skill.attributes.strength === 1) {
                                iGoldenSkills++;
                            }
                        }
                    }
                }
            }
            storeDCPItems(new Date(), doneSkills, doneActivities, language);
            var lessonPercent = Math.round(doneActivities / totalActivities * 100);
            var skillPercent = Math.round(doneSkills / totalSkills * 100);
            var iSkillsLeft = totalSkills - doneSkills; 
            var iLessonsLeft = totalActivities -doneActivities;
            var skillElem = createElem(doneSkills + "/" + totalSkills + ' ('+iSkillsLeft+')', skillPercent + "%", 'Skills', 'S');
            var lessonElem = createElem(doneActivities + "/" + totalActivities + ' ('+iLessonsLeft+')', lessonPercent + "%", 'Lessons', 'L');
            var goldElem = createElem(iGoldenSkills + "/" + doneSkills +" Golden", (doneSkills - iGoldenSkills) +" left to gild" , 'skills', 'G');
            var completeElem;
            var stats = $('<ul class="sidebar-stats lesson-progress"></ul>');
            if (doneSkills == totalSkills){
                completeElem = createElem("Tree complete",":)","","C");
                completeElem.appendTo(stats);
            }
            else{
                if (langData.next_lesson) {
                    var sNextSkillUrl = langData.next_lesson.skill_url ;
                    var sUrl = 'https://'+document.domain + "/skill/"+language+"/" +langData.next_lesson.skill_url + '/'+langData.next_lesson.lesson_number;
                    var sLink = '<a href="'+sUrl+'">'+sNextSkillUrl+'</a>'
                    var sNextSkill = createElem('Next skill ('+sLink+')','Lesson; no.:'+langData.next_lesson.lesson_number,'','N')
                    sNextSkill.appendTo(stats);
                }
                skillElem.appendTo(stats);
                lessonElem.appendTo(stats);
                var lessonDiff = (doneActivities - parseInt(getLSItem('lessons', language, 1)));
                if (lessonDiff > 0) {
                    var timeDiff = (new Date() - new Date(getLSItem('date', language, 1)));
                    var timePerLesson = timeDiff / lessonDiff;
                    var estTime = (totalActivities - doneActivities) * timePerLesson;
                    var finishDate = new Date(new Date().getTime() + estTime).toLocaleDateString();
                    var days = Math.round(estTime / (1000 * 3600 * 24));
                    if (!$('#estimate_stats').length) {
                        var estText = createElem(finishDate, days + " days remaining", "Estimate", "E" );
                        estText.appendTo(stats);
                    }
                }
            }
            goldElem.appendTo(stats);
            if ($('#app').hasClass('home') && !$('.lesson-progress').length) {
                $('.strengthen-skills-container').before(stats);
            }
        } catch (ex) {
            console.log(ex);
        }
    }
    function createElem(normalText, altText, name, icon) {
        var elemText = $('<span id="' + name + '_text"><strong>' + normalText + '</strong> ' + name + '</span>');
        var percentage = $('<span id="' + name + '_percent"><strong>' + altText + '</strong></span>');
        percentage.hide();
        var elem = $('<li style="text-align: left; display: block; margin-top: 2px;" id="' + name + '_stats" title="' + altText + '"><span class="icon icon-words-small ' + name + '-icon">' + icon + '</span></li>');
        elem.append(elemText);
        elem.append(percentage);
        $('.' + name + '-icon').mouseover(function () {
            $('#' + name + '_text').hide();
            $('#' + name + '_percent').css('display', 'inline-block');
        }).mouseout(function () {
            $('#' + name + '_percent').hide();
            $('#' + name + '_text').show();
        });
        return elem;
    }
    $(document).ready(function () {
        duolingoStats();
    });
    $(document).ajaxComplete(function () {
        duolingoStats();
    });
    function getLSItem(name, language, id) {
        if (id) {
            return localStorage['dcp_' + language + '_' + name + '_' + id];
        } else {
            return localStorage['dcp_' + language + '_' + name];
        }
    }
    function setLSItem(name, language, id, value) {
        localStorage['dcp_' + language + '_' + name + '_' + id] = value;
    }
    function storeDCPItems(date, skills, lessons, language) {
        var lastIndex = getLSItem('last_index', language);
        if (!lastIndex) {
            lastIndex = 1;
        } else {
            if (lessons <= parseInt(getLSItem('lessons', language, lastIndex)) &&
                skills <= parseInt(getLSItem('skills', language, lastIndex))) {
                return;
            }
            lastIndex++;
        }
        setLSItem('date', language, lastIndex, date);
        setLSItem('skills', language, lastIndex, skills);
        setLSItem('lessons', language, lastIndex, lessons);
        localStorage['dcp_' + language + '_last_index'] = lastIndex;
    }
}