/**
 * Sales Bot - Service Worker for PWA Offline Support
 */

const CACHE_NAME = 'salesbot-v1';
const RUNTIME_CACHE = 'salesbot-runtime-v1';

// Assets to cache on install
const PRECACHE_ASSETS = [
    '/dashboard',
    '/dashboard/analytics',
    '/dashboard/executive',
    '/static/css/main.css',
    '/static/js/app.js',
    '/static/js/pwa.js',
    '/static/js/camera.js',
    '/static/js/charts.js',
    '/static/manifest.json'
];

// API endpoints to cache with network-first strategy
const API_ROUTES = [
    '/api/dashboard/resumen',
    '/api/dashboard/ranking',
    '/api/dashboard/ventas-recientes',
    '/api/analytics/trends',
    '/api/analytics/predictions'
];

// Install event - cache core assets
self.addEventListener('install', (event) => {
    event.waitUntil(
        caches.open(CACHE_NAME)
            .then(cache => {
                console.log('[SW] Precaching assets');
                return cache.addAll(PRECACHE_ASSETS);
            })
            .then(() => self.skipWaiting())
            .catch(err => console.error('[SW] Precache failed:', err))
    );
});

// Activate event - clean old caches
self.addEventListener('activate', (event) => {
    event.waitUntil(
        caches.keys()
            .then(cacheNames => {
                return Promise.all(
                    cacheNames
                        .filter(name => name !== CACHE_NAME && name !== RUNTIME_CACHE)
                        .map(name => {
                            console.log('[SW] Deleting old cache:', name);
                            return caches.delete(name);
                        })
                );
            })
            .then(() => self.clients.claim())
    );
});

// Fetch event - handle requests
self.addEventListener('fetch', (event) => {
    const { request } = event;
    const url = new URL(request.url);

    // Skip non-GET requests
    if (request.method !== 'GET') {
        return;
    }

    // Skip external requests
    if (url.origin !== location.origin) {
        return;
    }

    // API requests - Network first, fall back to cache
    if (url.pathname.startsWith('/api/')) {
        event.respondWith(networkFirst(request));
        return;
    }

    // Static assets - Cache first, fall back to network
    if (url.pathname.startsWith('/static/')) {
        event.respondWith(cacheFirst(request));
        return;
    }

    // HTML pages - Network first with cache fallback
    if (request.headers.get('Accept')?.includes('text/html')) {
        event.respondWith(networkFirst(request));
        return;
    }

    // Default - Network first
    event.respondWith(networkFirst(request));
});

// Cache first strategy
async function cacheFirst(request) {
    const cachedResponse = await caches.match(request);
    if (cachedResponse) {
        return cachedResponse;
    }

    try {
        const networkResponse = await fetch(request);
        if (networkResponse.ok) {
            const cache = await caches.open(CACHE_NAME);
            cache.put(request, networkResponse.clone());
        }
        return networkResponse;
    } catch (error) {
        console.error('[SW] Cache first failed:', error);
        return new Response('Offline', { status: 503 });
    }
}

// Network first strategy
async function networkFirst(request) {
    try {
        const networkResponse = await fetch(request);

        // Cache successful responses
        if (networkResponse.ok) {
            const cache = await caches.open(RUNTIME_CACHE);
            cache.put(request, networkResponse.clone());
        }

        return networkResponse;
    } catch (error) {
        // Network failed, try cache
        const cachedResponse = await caches.match(request);
        if (cachedResponse) {
            console.log('[SW] Serving from cache:', request.url);
            return cachedResponse;
        }

        // No cache available
        if (request.headers.get('Accept')?.includes('text/html')) {
            return caches.match('/dashboard'); // Fallback to main page
        }

        if (request.headers.get('Accept')?.includes('application/json')) {
            return new Response(JSON.stringify({
                error: 'offline',
                message: 'Sin conexion. Mostrando datos en cache.'
            }), {
                status: 503,
                headers: { 'Content-Type': 'application/json' }
            });
        }

        return new Response('Offline', { status: 503 });
    }
}

// Handle messages from clients
self.addEventListener('message', (event) => {
    if (event.data && event.data.type === 'SKIP_WAITING') {
        self.skipWaiting();
    }
});

// Background sync for offline actions (if supported)
self.addEventListener('sync', (event) => {
    if (event.tag === 'sync-sales') {
        event.waitUntil(syncSales());
    }
});

async function syncSales() {
    // Sync any pending sales when back online
    console.log('[SW] Syncing pending sales...');
    // Implementation would go here
}

// Push notifications (if implemented)
self.addEventListener('push', (event) => {
    if (!event.data) return;

    const data = event.data.json();

    const options = {
        body: data.body || 'Nueva notificacion de Sales Bot',
        icon: '/static/icons/icon-192x192.png',
        badge: '/static/icons/icon-72x72.png',
        vibrate: [100, 50, 100],
        data: {
            url: data.url || '/dashboard'
        }
    };

    event.waitUntil(
        self.registration.showNotification(data.title || 'Sales Bot', options)
    );
});

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

    event.waitUntil(
        clients.matchAll({ type: 'window' }).then(clientList => {
            // Focus existing window if available
            for (const client of clientList) {
                if (client.url.includes('/dashboard') && 'focus' in client) {
                    return client.focus();
                }
            }

            // Open new window
            if (clients.openWindow) {
                return clients.openWindow(event.notification.data?.url || '/dashboard');
            }
        })
    );
});