01. SoftUni Administration

function solve() {

    const lectureName = document.querySelector('form input[name="lecture-name"]');
    const lectureDate = document.querySelector('form input[name="lecture-date"]');
    const lectureModule = document.querySelector('form select[name="lecture-module"]');
    const lectureAddBtn = document.querySelector('form > div:nth-child(4) > button');

    const moduleListArea = document.querySelector('.user-view > .modules');

    let addedModules = {};

    lectureAddBtn.addEventListener('click', addElement);

    function addElement(e) {

        e.preventDefault();

        let condition1 = lectureName.value === '';
        let condition2 = lectureDate.value === '';
        let condition3 = lectureModule.value === 'Select module';

        if (condition1 || condition2 || condition3) {
            return;
        }

        let addModuleName = `${lectureModule.value.toUpperCase()}-MODULE`;

        if (! addedModules.hasOwnProperty(addModuleName))
            addedModules[addModuleName] = [];

        let isDuplicated = false;

        for (let element of addedModules[addModuleName]) {

            let addCondition1 = element[0] === lectureName.value;
            let addCondition2 = element[1] === lectureDate.value;

            if (addCondition1 && addCondition2) {
                isDuplicated = true;
                break;
            }
        }

        if (! isDuplicated) {

            let addValue1 = lectureName.value;
            let addValue2 = lectureDate.value;

            addedModules[addModuleName]
                .push([addValue1, addValue2]);
            }

        createHtml();
    }

    function deleteElement(e) {

        const deleteLectureName = e.target
            .parentNode
            .querySelector('h4').textContent;

        const deleteModuleName = e.target
            .parentNode.parentNode.parentNode
            .querySelector('h3').textContent;

        let [aName, aDate, aTime] = deleteLectureName.split(' - ');

        let indexFlag;

        for (let lecture of addedModules[deleteModuleName]) {

            let [bDate, bTime] = lecture[1].split('T');
            bDate = bDate.split('-').join('/');

            let delCondition1 = lecture[0] === aName;
            let delCondition2 = bDate === aDate;
            let delCondition3 = bTime === aTime;

            if (delCondition1 && delCondition2 && delCondition3) {
                indexFlag = addedModules[deleteModuleName].indexOf(lecture);
                break;
            }
        }

        addedModules[deleteModuleName].splice(indexFlag, 1);

        if (addedModules[deleteModuleName].length === 0) {
            delete addedModules[deleteModuleName];
        }

        createHtml();
    }

    function createHtml() {

        moduleListArea.innerHTML = '';

        for (let module in addedModules) {

            addedModules[module].sort((a, b) => a[1].localeCompare(b[1]));

            const divElement = document.createElement('div');
            divElement.classList.add('module');
            const h3Element = document.createElement('h3');
            h3Element.textContent = module;
            const ulElement = document.createElement('ul');

            for (let training of addedModules[module]) {

                let [date, time] = training[1].split('T');
                date = date.split('-').join('/');

                const liElement = document.createElement('li');
                liElement.classList.add('flex');
                const h4Element = document.createElement('h4');
                h4Element.textContent = `${training[0]} - ${date} - ${time}`;
                const btnElement = document.createElement('button');
                btnElement.classList.add('red');
                btnElement.textContent = 'Delete';
                btnElement.addEventListener('click', deleteElement);

                liElement.appendChild(h4Element);
                liElement.appendChild(btnElement);
                ulElement.appendChild(liElement);
            }

            divElement.appendChild(h3Element);
            divElement.appendChild(ulElement);
            moduleListArea.appendChild(divElement);
        }
    }
}