async function currentEndpoint() {
    const subscription = await self.registration.pushManager.getSubscription();
    return subscription ? subscription.endpoint : '';
}

async function windowClientCount() {
    const allClients = await clients.matchAll({
        type: 'window',
        includeUncontrolled: true,
    });
    return allClients.length;
}

function logPushEvent(eventName, payload = {}, extra = {}) {
    return Promise.all([
        currentEndpoint().catch(() => ''),
        windowClientCount().catch(() => 0),
    ]).then(([endpoint, clientCount]) => fetch('/api/push_event.php', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        },
        credentials: 'include',
        cache: 'no-store',
        body: JSON.stringify({
            event: eventName,
            endpoint,
            push_id: payload.push_id || '',
            tag: payload.tag || '',
            client_count: clientCount,
            meta: extra,
        }),
    })).catch(() => {});
}

self.addEventListener('push', event => {
    let payload = {};

    try {
        payload = event.data ? event.data.json() : {};
    } catch (e) {
        payload = {
            body: event.data ? event.data.text() : '',
        };
    }

    const title = payload.title || 'Seoul Control Center';
    const vibrate = Array.isArray(payload.vibrate)
        ? payload.vibrate.map(value => Number(value)).filter(value => Number.isFinite(value) && value >= 0)
        : undefined;
    const options = {
        body: payload.body || 'System notice detected',
        icon: '/assets/icon-192.png',
        badge: '/assets/icon-192.png',
        tag: payload.tag || 'control-push',
        renotify: payload.renotify === true,
        requireInteraction: payload.require_interaction === true || payload.requireInteraction === true,
        silent: payload.silent === true,
        vibrate,
        data: {
            url: payload.url || '/',
            push_id: payload.push_id || '',
            tag: payload.tag || 'control-push',
        },
    };

    event.waitUntil((async () => {
        await logPushEvent('push_received', payload);
        try {
            await self.registration.showNotification(title, options);
            await logPushEvent('notification_shown', payload);
        } catch (error) {
            await logPushEvent('notification_show_failed', payload, {
                reason: error && error.message ? error.message : 'show_failed',
            });
            throw error;
        }
    })());
});

self.addEventListener('notificationclick', event => {
    event.notification.close();

    const url = event.notification.data?.url || '/';
    const payload = {
        push_id: event.notification.data?.push_id || '',
        tag: event.notification.data?.tag || event.notification.tag || '',
    };

    event.waitUntil((async () => {
        await logPushEvent('notification_click', payload, {
            action: event.action || '',
        });

        const allClients = await clients.matchAll({
            type: 'window',
            includeUncontrolled: true,
        });

        for (const client of allClients) {
            if ('focus' in client) {
                await client.focus();
                if ('navigate' in client) {
                    return client.navigate(url);
                }
                return;
            }
        }

        if (clients.openWindow) {
            return clients.openWindow(url);
        }
    })());
});

self.addEventListener('notificationclose', event => {
    const payload = {
        push_id: event.notification.data?.push_id || '',
        tag: event.notification.data?.tag || event.notification.tag || '',
    };

    event.waitUntil(logPushEvent('notification_close', payload));
});