/**
 * ATT Consent Banner UI
 *
 * Handles banner display, preferences modal, floating widget, anchor link
 * triggers, focus trapping, and user interactions.
 * Depends on AttConsent (consent-manager.js) for consent state management.
 */
(function() {
	'use strict';

	var banner = document.getElementById('att-cc-banner');
	var modal  = document.getElementById('att-cc-modal');
	var widget = document.getElementById('att-cc-widget');

	if (!banner || !modal) {
		return;
	}

	// --- Modal buttons ---

	var saveBtn  = modal.querySelector('[data-att-cc="save-preferences"]');
	var closeBtn = modal.querySelector('[data-att-cc="close-modal"]');
	var overlay  = modal.querySelector('.att-cc-modal__overlay');

	if (saveBtn) {
		saveBtn.addEventListener('click', function() {
			var categories = {
				functional: document.getElementById('att-cc-functional').checked,
				analytics:  document.getElementById('att-cc-analytics').checked,
				marketing:  document.getElementById('att-cc-marketing').checked
			};
			AttConsent.update(categories);
			closeModal();
			hideBanner();
			showWidget();
		});
	}

	if (closeBtn) {
		closeBtn.addEventListener('click', function() {
			closeModal();
		});
	}

	if (overlay) {
		overlay.addEventListener('click', function() {
			closeModal();
		});
	}

	// --- Floating widget click handler ---

	if (widget) {
		widget.addEventListener('click', function() {
			openModal();
		});
	}

	// --- Anchor link listener ---

	document.addEventListener('click', function(e) {
		var link = e.target.closest('a[href="#att-cc-preferences"]');
		if (link) {
			e.preventDefault();
			openModal();
		}
	});

	// --- Initial state ---

	if (AttConsent.hasConsent()) {
		hideBanner();
		showWidget();
	} else {
		// Move focus to banner so screen readers announce it.
		banner.focus();

		// --- Banner buttons (only needed for first-time visitors) ---

		var acceptBtn = banner.querySelector('[data-att-cc="accept-all"]');
		var rejectBtn = banner.querySelector('[data-att-cc="reject-all"]');
		var prefsBtn  = banner.querySelector('[data-att-cc="preferences"]');

		if (acceptBtn) {
			acceptBtn.addEventListener('click', function() {
				AttConsent.update({ functional: true, analytics: true, marketing: true });
				hideBanner();
				showWidget();
			});
		}

		if (rejectBtn) {
			rejectBtn.addEventListener('click', function() {
				AttConsent.update({ functional: false, analytics: false, marketing: false });
				hideBanner();
				showWidget();
			});
		}

		if (prefsBtn) {
			prefsBtn.addEventListener('click', function() {
				openModal();
			});
		}
	}

	// --- Helper functions ---

	// Tracks the current focus trap handler for cleanup.
	var activeTrapHandler = null;

	function hideBanner() {
		banner.setAttribute('aria-hidden', 'true');
		banner.classList.add('att-cc-hidden');
	}

	function showWidget() {
		if (widget) {
			widget.style.display = '';
		}
	}

	function openModal() {
		// Pre-fill checkboxes with existing consent if available.
		var existing = AttConsent.getConsent();
		if (existing) {
			setCheckbox('att-cc-functional', existing.functional);
			setCheckbox('att-cc-analytics', existing.analytics);
			setCheckbox('att-cc-marketing', existing.marketing);
		}

		modal.setAttribute('aria-hidden', 'false');
		modal.classList.add('att-cc-modal--open');
		document.body.classList.add('att-cc-modal-active');
		trapFocus(modal);
	}

	function closeModal() {
		modal.setAttribute('aria-hidden', 'true');
		modal.classList.remove('att-cc-modal--open');
		document.body.classList.remove('att-cc-modal-active');

		// Clean up focus trap listener.
		if (activeTrapHandler) {
			modal.removeEventListener('keydown', activeTrapHandler);
			activeTrapHandler = null;
		}

		// Return focus to the widget if visible, otherwise the banner prefs button.
		if (widget && widget.style.display !== 'none') {
			widget.focus();
		} else {
			var prefsBtn = banner.querySelector('[data-att-cc="preferences"]');
			if (prefsBtn) {
				prefsBtn.focus();
			}
		}
	}

	function setCheckbox(id, value) {
		var el = document.getElementById(id);
		if (el) {
			el.checked = !!value;
		}
	}

	/**
	 * Trap keyboard focus within an element.
	 *
	 * @param {HTMLElement} element The container to trap focus in.
	 */
	function trapFocus(element) {
		var focusable = element.querySelectorAll(
			'button, [href], input:not([disabled]), select, textarea, [tabindex]:not([tabindex="-1"])'
		);

		if (focusable.length === 0) {
			return;
		}

		var first = focusable[0];
		var last  = focusable[focusable.length - 1];

		first.focus();

		function handleKeydown(e) {
			if (e.key === 'Escape') {
				closeModal();
				return;
			}

			if (e.key !== 'Tab') {
				return;
			}

			if (e.shiftKey) {
				if (document.activeElement === first) {
					last.focus();
					e.preventDefault();
				}
			} else {
				if (document.activeElement === last) {
					first.focus();
					e.preventDefault();
				}
			}
		}

		activeTrapHandler = handleKeydown;
		element.addEventListener('keydown', handleKeydown);
	}
})();