let priceMap = ((type) => {
    if (type === "online") {
        return {
            "js-fundamentals": 170 * 0.94,
            "js-advanced": 180 * 0.94,
            "js-applications": 190 * 0.94,
            "js-web": 490 * 0.94,
        };
    } else {
        return {
            "js-fundamentals": 170,
            "js-advanced": 180,
            "js-applications": 190,
            "js-web": 490,
        };
    }
})();

function solve() {
    let listCourses = document.querySelector("#myCourses > div.courseBody > ul");

    function buttonAction() {
        let type = "";
        let selectedOptions = [];
        Array
            .from(document.querySelectorAll("input"))
            .filter(el => el.checked === true)
            .forEach(el => el.value.includes("js") ? selectedOptions.push(el.value) : type = el.value);

        let price = Math.floor(calculatePrice(selectedOptions));
        addToHTMLList(selectedOptions);

        let priceForm = document.querySelector("#myCourses > div.courseFoot > p");
        let currentPrice = Number(priceForm.innerHTML.split(" ")[1]);
        let sum = currentPrice + price;
        priceForm.innerHTML = `Cost: ${sum}.00 BGN`;
    }

    function addToHTMLList(selectedOptions) {
        selectedOptions.forEach(el => addToCourse(el));
    }

    function transformName(rawName) {
        let name = rawName.split("-")[1];
        return `JS-${name.charAt(0).toUpperCase() + name.slice(1)}`;
    }

    function addToCourse(courseName) {
        if (courseName !== "HTML and CSS") {
            courseName = transformName(courseName);
        }
        let applications = document.createElement("li");
        applications.innerHTML = courseName;
        listCourses.appendChild(applications);
    }

    function calculatePrice(selectedOptions) {
        let coursesToAdd = selectedOptions.slice(0, selectedOptions.length);
        let price = 0;
        if (coursesToAdd.indexOf("js-fundamentals") !== -1 && coursesToAdd.indexOf("js-advanced") !== -1) {
            price += priceMap[coursesToAdd.shift()] + (priceMap[coursesToAdd.shift()] * 0.90);
            if (coursesToAdd.indexOf("js-applications") !== -1) {
                price = (price + priceMap[coursesToAdd.shift()]) * 0.94;
            }
            if (coursesToAdd.length === 1) {
                price += priceMap[coursesToAdd.shift()];
                selectedOptions.push('HTML and CSS');
            }
        }
        while (coursesToAdd.length > 0) {
            price += priceMap[coursesToAdd.shift()];
        }
        return price;
    }

    document.querySelector("#availableCourses > div.courseFoot > button").addEventListener("click", buttonAction);
}

solve();