const root = document.querySelector('[data-notifications]');
const toastRegion = document.querySelector('[data-toast-region]');

const levelStyles = {
    info: { bar: 'bg-sky-400', dot: 'bg-sky-400' },
    success: { bar: 'bg-emerald-400', dot: 'bg-emerald-400' },
    warning: { bar: 'bg-amber-400', dot: 'bg-amber-400' },
    danger: { bar: 'bg-rose-500', dot: 'bg-rose-500' },
};

if (root && toastRegion) {
    const pollSeconds = 15;
    const toggle = root.querySelector('[data-notifications-toggle]');
    const panel = root.querySelector('[data-notifications-panel]');
    const list = root.querySelector('[data-notifications-list]');
    const empty = root.querySelector('[data-notifications-empty]');
    const badge = root.querySelector('[data-notifications-badge]');
    const desktop = root.querySelector('[data-notifications-desktop]');
    const csrf = document.querySelector('meta[name="csrf-token"]')?.content ?? '';
    const known = new Set();
    let firstLoad = true;

    const post = (url) => fetch(url, {
        method: 'POST',
        headers: { 'X-CSRF-TOKEN': csrf, Accept: 'application/json' },
        credentials: 'same-origin',
    });

    const readUrl = (id) => root.dataset.readUrl.replace('__id__', encodeURIComponent(id));
    const style = (level) => levelStyles[level] ?? levelStyles.info;

    const element = (tag, className, text) => {
        const node = document.createElement(tag);
        if (className) node.className = className;
        if (text !== undefined) node.textContent = text;
        return node;
    };

    const openItem = async (item) => {
        if (!item.read) {
            item.read = true;
            await post(readUrl(item.id)).catch(() => {});
        }
        if (item.url) window.location.assign(item.url);
        else refresh();
    };

    const renderPanel = (items, unread) => {
        list.replaceChildren(...items.map((item) => {
            const row = element('li');
            const button = element('button', 'flex w-full gap-3 px-4 py-3 text-left transition hover:bg-slate-800/60 focus-visible:outline focus-visible:outline-2 focus-visible:outline-white');
            button.type = 'button';
            button.append(element('span', `mt-1.5 size-2 shrink-0 rounded-full ${item.read ? 'bg-slate-700' : style(item.level).dot}`));
            const text = element('span', 'min-w-0 flex-1');
            text.append(
                element('span', `block text-sm ${item.read ? 'text-slate-300' : 'font-semibold text-white'}`, item.title),
                element('span', 'mt-0.5 block text-xs text-slate-400', item.body),
                element('span', 'mt-1 block text-[11px] text-slate-500', item.time),
            );
            button.append(text);
            button.addEventListener('click', () => openItem(item));
            row.append(button);
            return row;
        }));
        empty.hidden = items.length > 0;
        badge.hidden = unread === 0;
        badge.textContent = unread > 99 ? '99+' : String(unread);
        toggle.setAttribute('aria-label', unread ? `Notifications, ${unread} unread` : 'Notifications');
    };

    const dismiss = (toast) => {
        toast.classList.add('opacity-0', 'translate-y-2');
        setTimeout(() => toast.remove(), 200);
    };

    const showToast = (item) => {
        const { bar } = style(item.level);
        const toast = element('div', 'pointer-events-auto relative flex overflow-hidden rounded-xl border border-slate-700 bg-slate-900 shadow-xl shadow-black/40 transition duration-200');
        toast.setAttribute('role', item.level === 'danger' ? 'alert' : 'status');
        toast.append(element('span', `w-1.5 shrink-0 ${bar}`));
        const body = element('button', 'min-w-0 flex-1 px-4 py-3 text-left focus-visible:outline focus-visible:outline-2 focus-visible:outline-white');
        body.type = 'button';
        body.append(element('span', 'block text-sm font-semibold text-white', item.title), element('span', 'mt-0.5 block text-xs text-slate-300', item.body));
        body.addEventListener('click', () => { dismiss(toast); openItem(item); });
        const close = element('button', 'px-3 text-slate-400 hover:text-white focus-visible:outline focus-visible:outline-2 focus-visible:outline-white', '✕');
        close.type = 'button';
        close.setAttribute('aria-label', 'Dismiss notification');
        close.addEventListener('click', () => dismiss(toast));
        toast.append(body, close);
        toastRegion.append(toast);
        setTimeout(() => dismiss(toast), item.level === 'danger' ? 15000 : 8000);
    };

    const showDesktop = (item) => {
        if (!('Notification' in window) || Notification.permission !== 'granted' || !document.hidden) return;
        const note = new Notification(item.title, { body: item.body, tag: item.id });
        note.addEventListener('click', () => { window.focus(); openItem(item); });
    };

    const refresh = async () => {
        try {
            const response = await fetch(root.dataset.feedUrl, { headers: { Accept: 'application/json' }, credentials: 'same-origin' });
            if (!response.ok) return;
            const { items, unread } = await response.json();
            renderPanel(items, unread);
            items.filter((item) => !known.has(item.id)).reverse().forEach((item) => {
                known.add(item.id);
                if (!firstLoad && !item.read) {
                    showToast(item);
                    showDesktop(item);
                }
            });
            firstLoad = false;
        } catch (error) {
            // Network blips are expected; the next poll retries.
        }
    };

    const setPanel = (open) => {
        panel.hidden = !open;
        toggle.setAttribute('aria-expanded', String(open));
    };

    toggle.addEventListener('click', () => setPanel(panel.hidden));
    document.addEventListener('click', (event) => { if (!root.contains(event.target)) setPanel(false); });
    document.addEventListener('keydown', (event) => { if (event.key === 'Escape') setPanel(false); });
    root.querySelector('[data-notifications-read-all]').addEventListener('click', async () => {
        await post(root.dataset.readAllUrl).catch(() => {});
        refresh();
    });

    if ('Notification' in window && Notification.permission === 'default') {
        desktop.hidden = false;
        root.querySelector('[data-notifications-enable-desktop]').addEventListener('click', async () => {
            await Notification.requestPermission();
            desktop.hidden = Notification.permission !== 'default';
        });
    }

    refresh();
    setInterval(() => { if (!document.hidden) refresh(); }, pollSeconds * 1000);
    document.addEventListener('visibilitychange', () => { if (!document.hidden) refresh(); });
}