function bindValidators() {
    let inputFields = $("form div.form-group input.form-control");

    for (let i = 0; i < inputFields.length - 1; i++) {
        let currentField = $(inputFields[i]);
        let nextField = null;
        let name = currentField.attr("name");
        if(name === "user[password]"){
            nextField = $(inputFields[i + 1]);
        }

        let validationFunction = getValidationFunction(name);
        bindValidator(validationFunction, currentField, nextField);
    }
}

function bindValidator(validationFunction, field, nextField) {
    field.on("input", function () {
        if(validationFunction(field)) {
            field.css("border-color", "green");
        } else {
            field.css("border-color", "red");
        }
    });

    if(nextField !== null) {
        nextField.on("input", function () {
            if(validateConfirmPassword(field, nextField)) {
                nextField.css("border-color", "green");
            } else {
                nextField.css("border-color", "red");
            }
        });
    }
}

function getValidationFunction(fieldName) {
    switch (fieldName) {
        case "user[username]":
            return validateUsername;
        case "user[email]":
            return validateEmail;
        case "user[password]":
            return validatePassword;
    }
}

function validateUsername(username) {
    username = username.val().trim();

    return /^[^ ]{6,25}$/.test(username);
}

function validateEmail(email) {
    email = email.val().trim();

    return /^[^ ]+@[a-z][a-z-]*(\.[a-z]+)+$/.test(email);
}

function validatePassword(password) {
    password = password.val().trim();

    return /^[^ ]{6,25}$/.test(password);
}

function validateConfirmPassword(password, confirmPassword) {
    return password.val().localeCompare(confirmPassword.val()) === 0;
}