document.addEventListener('DOMContentLoaded', function() {
        const form = document.querySelector('form');
        const submitButton = form.querySelector('button[type="submit"]');
        const errorElement = document.getElementById('error');

        form.addEventListener('keydown', function(event) {
            const activeElement = document.activeElement;
            const formElements = Array.from(form.elements);
            const currentIndex = formElements.indexOf(activeElement);

            if (activeElement.tagName === 'INPUT') {
                if (event.key === 'Enter') {
                    event.preventDefault();
                    if (currentIndex === formElements.length - 1) {
                        submitButton.focus();
                    } else if (currentIndex !== -1 && formElements[currentIndex + 1]) {
                        formElements[currentIndex + 1].focus();
                    }
                }
            }
        });

        submitButton.addEventListener('focus', function() {
            submitButton.classList.add('focus-visible');
        });

        submitButton.addEventListener('blur', function() {
            submitButton.classList.remove('focus-visible');
        });

        form.addEventListener('submit', function(event) {
            event.preventDefault();
            validateForm();
        });

        async function validateForm() {
            const name = document.getElementById('name').value.trim();
            const nickname = document.getElementById('nickname').value.trim();

            if (name === '' || nickname === '') {
                errorElement.textContent = 'Пожалуйста, заполните все поля';
                errorElement.style.display = 'block';
                return false;
            }
            try {
                // Отправка данных для регистрации
                let response = await fetch('/login', {
                    method: 'POST',
                    headers: {
                        'Content-Type': 'application/json'
                    },
                    body: JSON.stringify({name, nickname})
                });

                const result = await response.json();

                if (result.status === 0) {
                    window.location.href = '/';
                } else {
                    throw Error(result.error);
                }
            } catch(error) {
                errorElement.textContent = 'Попробуйте еще раз';
                errorElement.style.display = 'block';
            }

        }
    });