document.addEventListener('DOMContentLoaded', function () {
    // --- Client-side validation for the add contact form ---
    const addContactForm = document.getElementById('addContactForm');
    if (addContactForm) {
        addContactForm.addEventListener('submit', function (event) {
            if (!validateForm(this)) {
                event.preventDefault();
                event.stopPropagation();
            }
        });
    }

    // --- Client-side validation for the edit contact form ---
    const editContactForm = document.getElementById('editContactForm');
    if (editContactForm) {
        editContactForm.addEventListener('submit', function(event) {
            if (!validateForm(this)) {
                event.preventDefault();
                event.stopPropagation();
            }
        });
    }

    // --- Edit Modal Handler ---
    const editContactModal = document.getElementById('editContactModal');
    if (editContactModal) {
        editContactModal.addEventListener('show.bs.modal', function (event) {
            const button = event.relatedTarget;
            // Extract info from data-bs-* attributes
            const id = button.getAttribute('data-id');
            const name = button.getAttribute('data-name');
            const email = button.getAttribute('data-email');
            const phone = button.getAttribute('data-phone');

            // Update the modal's content.
            const modalTitle = editContactModal.querySelector('.modal-title');
            const contactIdInput = editContactModal.querySelector('#edit_contact_id');
            const nameInput = editContactModal.querySelector('#edit_name');
            const emailInput = editContactModal.querySelector('#edit_email');
            const phoneInput = editContactModal.querySelector('#edit_phone');

            modalTitle.textContent = 'Edit Contact: ' + name;
            contactIdInput.value = id;
            nameInput.value = name;
            emailInput.value = email;
            phoneInput.value = phone;
        });
    }

    // --- Toast notification handling ---
    const toastEl = document.getElementById('notificationToast');
    if (toastEl) {
        const toast = new bootstrap.Toast(toastEl, { delay: 5000 });
        toast.show();
    }

    // --- Feather Icons ---
    feather.replace();
});

/**
 * Validates a contact form (add or edit).
 * @param {HTMLFormElement} form The form element to validate.
 * @returns {boolean} True if valid, false otherwise.
 */
function validateForm(form) {
    const name = form.querySelector('input[name="name"]');
    const email = form.querySelector('input[name="email"]');
    let isValid = true;

    // Reset invalid states
    name.classList.remove('is-invalid');
    email.classList.remove('is-invalid');

    // Validate Name
    if (name.value.trim() === '') {
        name.classList.add('is-invalid');
        isValid = false;
    }

    // Validate Email
    const emailPattern = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
    if (email.value.trim() === '' || !emailPattern.test(email.value)) {
        email.classList.add('is-invalid');
        isValid = false;
    }

    return isValid;
}