function solve() {

    let username = "",
        email= "",
        password = "",
        confirmPassword = "",
        companyNumber = "";

    return function(){

        let formIsValid = false;
        let usernameValid = false;
        let emailValid = false;
        let passwordValid = false;
        let passwordConfirmValid = false;
        let companyNumberValid = false;

        $("#registerForm").submit(function(e) {
            e.preventDefault();
        });

        $("#company").on("change", function () {
            if ($("#company").is(":checked")){
                $("#companyInfo").show()
            }
            else{
                $("#companyInfo").hide();
            }
        });

         function isMatch(str, pattern) {
             let regex = new RegExp(pattern);
             let match = regex.test(str);
             return match;
         }

        let submitBtn = $("#submit");
        submitBtn.on("click", function () {

            username = {
                value: $("#username").val(),
                pattern: "^[a-zA-Z0-9]{3,20}$",
                isValid: (str, pattern) => isMatch(str, pattern)
            };

            email = {
                value: $("#email").val(),
                pattern: "^.*@.*\..*$",
                isValid: (str, pattern) => isMatch(str, pattern)
            };

            password = {
                value: $("#password").val(),
                pattern: "^[\\w]{5,15}$",
                isValid: (str, pattern) => isMatch(str, pattern)
            };

            confirmPassword = {
                value: $("#confirm-password").val(),
                pattern: "^[\\w]{5,15}$"
            };

            if ($("#company").is(":checked")){
                companyNumber = {
                    value: $("#companyNumber").val(),
                    pattern: "^[1-9][0-9]{3}$",
                    isValid: (str, pattern) => isMatch(str, pattern)
                };
            }

            if (!username.value || !username.isValid(username.value, username.pattern)){
                usernameValid = false;
                $('#username').css('border-color', 'red');
            }
            else{
                usernameValid = true;
                $('#username').css('border-color', '');
            }

            if (!email.value || !email.isValid(email.value, email.pattern)) {
                emailValid = false;
                $('#email').css('border-color', 'red');
            }
            else{
                emailValid = true;
                $('#email').css('border-color', '');
            }


            if (!password.value || !password.isValid(password.value, password.pattern)){
                passwordValid = false;
                $('#password').css('border-color', 'red');

            }
            else{
                passwordValid = true;
                $('#password').css('border-color', '');
            }
            //console.log(password.isValid(password.value, password.pattern));
            //console.log(password.pattern);


            if (!confirmPassword.value || password.value != confirmPassword.value){
                passwordConfirmValid = false;
                $('#confirm-password').css('border-color', 'red');
            }
            else{
                passwordConfirmValid = true;
                $('#confirm-password').css('border-color', '');
            }


            if (($('#company').is(":checked") &&
                !companyNumber.value) ||
                ($('#company').is(":checked") &&
                !companyNumber.isValid(companyNumber.value, companyNumber.pattern))){
                companyNumberValid = false;
                $('#companyNumber').css('border-color', 'red');
            }
                else if($('#company').is(":checked") &&
                companyNumber.isValid(companyNumber.value, companyNumber.pattern)){
                companyNumberValid = true;
                $('#companyNumber').css('border-color', '');
            }
            else if(!($('#company').is(":checked"))){
                companyNumberValid = true;
            }

            formIsValid = !!(usernameValid &&
            emailValid &&
            passwordValid &&
            passwordConfirmValid &&
            companyNumberValid);

            // console.log(usernameValid);
            // console.log(emailValid);
            // console.log(passwordValid);
            // console.log(passwordConfirmValid);
            // console.log(companyNumberValid);

            if (formIsValid){
                $('#valid').css('display', '');
            }
            else{
                $('#valid').css('display', 'none');
            }
        });
     }
}