(() => {
    const textSelectors = 'p, h1, h2, h3, h4, h5, h6, span, li, label, td, th, pre, .code';
    const linkSelectors = 'a, button, [role="button"], input[type="submit"], input[type="button"]';
    const padding = 6;

    let mouseX = 0, mouseY = 0;
    let currentLinkEl = null;
    let rafId = null;
    let cursor = null;
    let cursorVisible = false;
    let lastTouchTime = 0;
    let isMouseDown = false;
    const TOUCH_MOUSE_GUARD_MS = 800;

    function showCursor() {
        if (!cursorVisible && cursor) {
            cursorVisible = true;
            cursor.classList.add('visible');
        }
    }

    function hideCursor() {
        if (cursor) {
            cursorVisible = false;
            cursor.classList.remove('visible');
            currentLinkEl = null;
            if (rafId) { cancelAnimationFrame(rafId); rafId = null; }
            cursor.classList.remove('on-link', 'on-text');
        }
    }

    function isSyntheticMouse() {
        return Date.now() - lastTouchTime < TOUCH_MOUSE_GUARD_MS;
    }

    function updateCursorForLink(el) {
        const rect = el.getBoundingClientRect();
        cursor.classList.remove('on-text');
        cursor.classList.add('on-link');
        cursor.style.transform = 'none';
        cursor.style.left   = (rect.left - padding) + 'px';
        cursor.style.top    = (rect.top  - padding) + 'px';
        cursor.style.width  = (rect.width  + padding * 2) + 'px';
        cursor.style.height = (rect.height + padding * 2) + 'px';
    }

    function trackLink() {
        if (currentLinkEl) {
            updateCursorForLink(currentLinkEl);
            rafId = requestAnimationFrame(trackLink);
        }
    }

    document.addEventListener('DOMContentLoaded', () => {
        cursor = document.getElementById('cursor');
        if (!cursor) return;

        document.addEventListener('touchstart', () => { lastTouchTime = Date.now(); hideCursor(); }, { passive: true });
        document.addEventListener('touchmove', () => { lastTouchTime = Date.now(); hideCursor(); }, { passive: true });
        document.addEventListener('touchend', () => { lastTouchTime = Date.now(); }, { passive: true });

        document.addEventListener('mousemove', (e) => {
            if (isSyntheticMouse()) return;
            if (e.sourceCapabilities && e.sourceCapabilities.firesTouchEvents) return;

            mouseX = e.clientX;
            mouseY = e.clientY;

            showCursor();

            const el = document.elementFromPoint(mouseX, mouseY);
            const linkEl = el ? el.closest(linkSelectors) : null;

            if (linkEl) {
                if (currentLinkEl !== linkEl) {
                    currentLinkEl = linkEl;
                    if (rafId) cancelAnimationFrame(rafId);
                    rafId = requestAnimationFrame(trackLink);
                }
            } else {
                if (currentLinkEl) {
                    currentLinkEl = null;
                    if (rafId) { cancelAnimationFrame(rafId); rafId = null; }
                }
                cursor.classList.remove('on-link');
                cursor.style.transform = isMouseDown ? 'translate(-50%, -50%) scale(0.9)' : 'translate(-50%, -50%)';
                cursor.style.left = mouseX + 'px';
                cursor.style.top  = mouseY + 'px';
                cursor.style.width = '';
                cursor.style.height = '';

                if (el && el.closest(textSelectors)) {
                    cursor.classList.add('on-text');
                } else {
                    cursor.classList.remove('on-text');
                }
            }
        });

        document.addEventListener('mousedown', () => {
            isMouseDown = true;
            cursor.style.transform = currentLinkEl ? 'none' : 'translate(-50%, -50%) scale(0.9)';
        });
        document.addEventListener('mouseup', () => {
            isMouseDown = false;
            cursor.style.transform = currentLinkEl ? 'none' : 'translate(-50%, -50%) scale(1)';
        });

        window.addEventListener('scroll', () => {
            if (currentLinkEl) updateCursorForLink(currentLinkEl);
        }, { passive: true });
    });

    if (document.startViewTransition) {
        document.addEventListener("click", (event) => {
        const link = event.target.closest("a");
        if (!link || link.hasAttribute('download')) return;

        const url = new URL(link.href, location.href);
        if (url.origin !== location.origin) return;
        if (link.target || event.metaKey || event.ctrlKey || event.shiftKey || event.altKey) return;

        if (url.hash && url.pathname === location.pathname) {
            event.preventDefault();
            const target = document.querySelector(url.hash);
            if (target) {
                target.scrollIntoView({ behavior: 'smooth', block: 'start' });
                history.pushState(null, '', url.hash);
            }
            return;
        }

        event.preventDefault();

            document.startViewTransition(async () => {
                const response = await fetch(url.href, {
                    headers: { "X-Requested-With": "view-transition" }
                });
                const html = await response.text();
                const doc = new DOMParser().parseFromString(html, "text/html");

                for (const tag of ['head', 'header', 'main', 'footer']) {
                    const newEl = doc.querySelector(tag);
                    const curEl = document.querySelector(tag);
                    if (!newEl || !curEl) { location.href = url.href; return; }
                    curEl.innerHTML = newEl.innerHTML;
                    curEl.querySelectorAll('script').forEach(old => {
                        const s = document.createElement('script');
                        [...old.attributes].forEach(a => s.setAttribute(a.name, a.value));
                        s.textContent = old.textContent;
                        old.replaceWith(s);
                    });
                }

                history.pushState(null, "", url.href);

                currentLinkEl = null;
                if (rafId) { cancelAnimationFrame(rafId); rafId = null; }
                cursor.classList.remove('on-link', 'on-text');
                cursor.style.transform = 'translate(-50%, -50%)';
                cursor.style.left = mouseX + 'px';
                cursor.style.top  = mouseY + 'px';
                cursor.style.width = '';
                cursor.style.height = '';

                const el = document.elementFromPoint(mouseX, mouseY);
                const newLinkEl = el ? el.closest(linkSelectors) : null;
                if (newLinkEl) {
                    currentLinkEl = newLinkEl;
                    rafId = requestAnimationFrame(trackLink);
                } else if (el && el.closest(textSelectors)) {
                    cursor.classList.add('on-text');
                }
            });
        });

        window.addEventListener("popstate", () => location.reload());
    }
})();
