document.body.className = ((document.body.className) ? document.body.className + ' js-enabled' : 'js-enabled');
function onFormSubmit() {
    event.preventDefault();
   }

function searchCertificate() {
    try{
    const getElement = (id) => document.getElementById(id);
    const addErrorClass = (element) => element.classList.add('govuk-input--error');
    const removeErrorClass = (element) => element.classList.remove('govuk-input--error');

    const documentId = getElement("documentId");
    const birthDay = getElement("dob-day");
    const birthMonth = getElement("dob-month");
    const birthYear = getElement("dob-year");
    const docIdDiv = getElement("div-docid");
    const dobDiv = getElement("div-dob");

    const ulClass = document.getElementsByClassName("govuk-error-summary__list")[0];
    docIdDiv.classList.remove('govuk-form-group--error');
    dobDiv.classList.remove('govuk-form-group--error');

    removeErrorClass(documentId);
    removeErrorClass(birthDay);
    removeErrorClass(birthMonth);
    removeErrorClass(birthYear);

    ulClass.innerHTML = '';
    let showErrorDiv = false;
    let isChildErrorLogCreated = false;   
    let listInnerHTML = '';

    const createErrorEntry = (element, message) => {
        showErrorDiv = true;
        const entry = document.createElement('li');
        entry.innerHTML = `<a href="#${element.id}">${message}</a>`;
        ulClass.appendChild(entry);
    };   

    const createErrorChildElement = (message) => {
        isChildErrorLogCreated = true;
        const pTag = getElement("dob-error") || document.createElement('p');
        pTag.className = "govuk-error-message";
        pTag.id = 'dob-error';
        pTag.innerHTML = `<span class="govuk-visually-hidden">Error:</span> ${message}`;
        dobDiv.classList.add('govuk-form-group--error');
        dobDiv.children[0].firstElementChild.before(pTag);
        return true;
    };

    const validateEmptyField = (element, message) => {
        if (element.value === "") {
            createErrorEntry(element, `Enter ${message}`);
            addErrorClass(element);

            if (!isChildErrorLogCreated) {
                isChildErrorLogCreated = createErrorChildElement(`Enter ${message}`);
            }
        } else {
            const errorElement = getElement(`${element.id}-error`);
            if (errorElement !== null) {
                errorElement.parentNode.removeChild(errorElement);
            }
        }
    };   

    if(documentId.value == ""){
        createErrorEntry(documentId,'Enter the document ID');        
        let pDocumentTag =  document.getElementById("documentId-error"); 
        if(pDocumentTag == null){
        pDocumentTag = document.createElement('p');
        pDocumentTag.className = "govuk-error-message";
        pDocumentTag.id = 'documentId-error';
        pDocumentTag.innerHTML = '<span class="govuk-visually-hidden">Error:</span> Enter the document ID';                
        docIdDiv.insertBefore(pDocumentTag,docIdDiv.children[1]);                
        }
        docIdDiv.classList.add('govuk-form-group--error');
        documentId.classList.add('govuk-input--error');       
    }
    else{
        if(document.getElementById("documentId-error") != null){
            document.getElementById("documentId-error").parentNode.removeChild(document.getElementById("documentId-error"));
        }
    }
    validateEmptyField(birthDay, 'a day');
    validateEmptyField(birthMonth, 'a month');
    validateEmptyField(birthYear, 'a year');

    if (birthDay.value != "" && birthMonth.value != "" && birthYear.value != "") {
        const birthDate = `${birthYear.value}-${birthMonth.value}-${birthDay.value}`;     
        if (!isValidDate(birthYear.value, birthMonth.value, birthDay.value)) {
            createErrorEntry(dobDiv, 'Please enter a valid date of birth');
            if (!isChildErrorLogCreated) {
                isChildErrorLogCreated = createErrorChildElement('Please enter a valid date of birth');
            }            
        }
        else{
            const dob = new Date(parseInt(birthYear.value), parseInt(birthMonth.value) - 1, parseInt(birthDay.value));
            const currentDate = new Date();

            if (dob > currentDate) {
                createErrorEntry(dobDiv, 'Please enter a date of birth from the past');
                if (!isChildErrorLogCreated) {
                    isChildErrorLogCreated = createErrorChildElement('Please enter a date of birth from the past');
                }                  
            } 
            else{
                if(document.getElementById("dob-error") != null){
                    document.getElementById("dob-error").parentNode.removeChild(document.getElementById("dob-error"));
                }
            }      
            if(!showErrorDiv){
            
            let url = /Certificate-Search-Results/ +'?documentId=' +encodeURIComponent(documentId.value) +'&date=' + encodeURIComponent(birthDate); 
            window.open(url, '_self');            
            }
        }
    }
    else {
       createErrorEntry(dobDiv, 'Please enter a valid date of birth');
        if (!isChildErrorLogCreated) {
           isChildErrorLogCreated = createErrorChildElement('Please enter a valid date of birth');
        }  
    }
    getElement("errorDiv").style.display = showErrorDiv ? "block" : "none";
    }
    catch(err){
        console.log(err.message);
    }
}
function isValidDate(year,month,day) {
    try{
    const date = `${year}-${month}-${day}`;
    const datePattern = /^([12]\d{3}-(0?[1-9]|1[0-2])-(0?[1-9]|[12]\d|3[01]))/;
    const matchArray = date.match(datePattern);

    if (matchArray === null) {
        return false;
    }

    const dateString = date.replace(/\D/g, '');
    const parsedYear = parseInt(year);
    const parsedMonth = parseInt(month);
    const parsedDay = parseInt(day);
    const daysInMonth = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];

    if (parsedYear % 400 === 0 || (parsedYear % 100 !== 0 && parsedYear % 4 === 0)) {
        daysInMonth[1] = 29;
    }

    if (parsedMonth < 1 || parsedMonth > 12 || parsedDay < 1 || parsedDay > daysInMonth[parsedMonth - 1]) {
        return false;
    }
    return true;
    }
    catch(err){
        console.log(err.message);
        return false;
    }
}