// Miracles in Motion - Service Worker
// Version 1.0.0

const CACHE_NAME = 'miracles-in-motion-v1'
const STATIC_CACHE = 'static-v1'
const DYNAMIC_CACHE = 'dynamic-v1'

// Assets to cache immediately
const STATIC_ASSETS = [
  '/',
  '/index.html',
  '/favicon.svg',
  '/robots.txt',
  '/site.webmanifest'
]

// Assets to cache on demand
const CACHE_STRATEGIES = {
  // Cache first for static assets
  CACHE_FIRST: ['.js', '.css', '.woff', '.woff2', '.ttf', '.eot'],
  // Network first for API calls
  NETWORK_FIRST: ['/api/', '/analytics/'],
  // Stale while revalidate for images
  STALE_WHILE_REVALIDATE: ['.jpg', '.jpeg', '.png', '.gif', '.webp', '.svg']
}

// Install event - cache static assets
self.addEventListener('install', event => {
  console.log('Service Worker: Installing...')
  
  event.waitUntil(
    caches.open(STATIC_CACHE)
      .then(cache => {
        console.log('Service Worker: Caching static assets')
        return cache.addAll(STATIC_ASSETS)
      })
      .then(() => {
        console.log('Service Worker: Installation complete')
        return self.skipWaiting()
      })
      .catch(error => {
        console.error('Service Worker: Installation failed', error)
      })
  )
})

// Activate event - clean up old caches
self.addEventListener('activate', event => {
  console.log('Service Worker: Activating...')
  
  event.waitUntil(
    caches.keys()
      .then(cacheNames => {
        return Promise.all(
          cacheNames.map(cacheName => {
            if (cacheName !== CACHE_NAME && cacheName !== STATIC_CACHE && cacheName !== DYNAMIC_CACHE) {
              console.log('Service Worker: Deleting old cache', cacheName)
              return caches.delete(cacheName)
            }
          })
        )
      })
      .then(() => {
        console.log('Service Worker: Activation complete')
        return self.clients.claim()
      })
  )
})

// Fetch event - handle requests with appropriate caching strategy
self.addEventListener('fetch', event => {
  const { request } = event
  const url = new URL(request.url)
  
  // Skip non-GET requests
  if (request.method !== 'GET') return
  
  // Skip cross-origin requests
  if (url.origin !== location.origin) return
  
  event.respondWith(handleFetch(request))
})

// Determine caching strategy based on file type
function getCachingStrategy(url) {
  const pathname = new URL(url).pathname.toLowerCase()
  
  // Check for cache-first assets
  if (CACHE_STRATEGIES.CACHE_FIRST.some(ext => pathname.includes(ext))) {
    return 'cache-first'
  }
  
  // Check for network-first assets
  if (CACHE_STRATEGIES.NETWORK_FIRST.some(path => pathname.includes(path))) {
    return 'network-first'
  }
  
  // Check for stale-while-revalidate assets
  if (CACHE_STRATEGIES.STALE_WHILE_REVALIDATE.some(ext => pathname.includes(ext))) {
    return 'stale-while-revalidate'
  }
  
  // Default to network-first
  return 'network-first'
}

// Handle fetch requests with appropriate strategy
async function handleFetch(request) {
  const strategy = getCachingStrategy(request.url)
  
  switch (strategy) {
    case 'cache-first':
      return cacheFirst(request)
    case 'network-first':
      return networkFirst(request)
    case 'stale-while-revalidate':
      return staleWhileRevalidate(request)
    default:
      return networkFirst(request)
  }
}

// Cache-first strategy
async function cacheFirst(request) {
  try {
    const cache = await caches.open(STATIC_CACHE)
    const cachedResponse = await cache.match(request)
    
    if (cachedResponse) {
      return cachedResponse
    }
    
    const networkResponse = await fetch(request)
    if (networkResponse.ok) {
      cache.put(request, networkResponse.clone())
    }
    return networkResponse
  } catch (error) {
    console.error('Cache-first strategy failed:', error)
    return new Response('Offline content unavailable', { status: 503 })
  }
}

// Network-first strategy
async function networkFirst(request) {
  try {
    const networkResponse = await fetch(request)
    
    if (networkResponse.ok) {
      const cache = await caches.open(DYNAMIC_CACHE)
      cache.put(request, networkResponse.clone())
    }
    
    return networkResponse
  } catch (error) {
    console.log('Network failed, trying cache:', error)
    
    const cache = await caches.open(DYNAMIC_CACHE)
    const cachedResponse = await cache.match(request)
    
    if (cachedResponse) {
      return cachedResponse
    }
    
    return new Response('Content unavailable offline', { 
      status: 503,
      headers: { 'Content-Type': 'text/plain' }
    })
  }
}

// Stale-while-revalidate strategy
async function staleWhileRevalidate(request) {
  const cache = await caches.open(DYNAMIC_CACHE)
  const cachedResponse = await cache.match(request)
  
  const networkUpdate = fetch(request).then(response => {
    if (response.ok) {
      cache.put(request, response.clone())
    }
    return response
  })
  
  return cachedResponse || networkUpdate
}

// Background sync for offline form submissions
self.addEventListener('sync', event => {
  if (event.tag === 'donation-submission') {
    event.waitUntil(syncDonations())
  }
  if (event.tag === 'assistance-request') {
    event.waitUntil(syncAssistanceRequests())
  }
})

// Sync offline donations
async function syncDonations() {
  try {
    const donations = await getOfflineData('pending-donations')
    for (const donation of donations) {
      await fetch('/api/donations', {
        method: 'POST',
        body: JSON.stringify(donation),
        headers: { 'Content-Type': 'application/json' }
      })
    }
    await clearOfflineData('pending-donations')
    console.log('Offline donations synced successfully')
  } catch (error) {
    console.error('Failed to sync donations:', error)
  }
}

// Sync offline assistance requests
async function syncAssistanceRequests() {
  try {
    const requests = await getOfflineData('pending-requests')
    for (const request of requests) {
      await fetch('/api/assistance-requests', {
        method: 'POST',
        body: JSON.stringify(request),
        headers: { 'Content-Type': 'application/json' }
      })
    }
    await clearOfflineData('pending-requests')
    console.log('Offline assistance requests synced successfully')
  } catch (error) {
    console.error('Failed to sync assistance requests:', error)
  }
}

// Helper functions for offline data management
function getOfflineData(key) {
  return new Promise((resolve, reject) => {
    const request = indexedDB.open('MiraclesInMotion', 1)
    
    request.onsuccess = () => {
      const db = request.result
      const transaction = db.transaction(['offlineData'], 'readonly')
      const store = transaction.objectStore('offlineData')
      const getRequest = store.get(key)
      
      getRequest.onsuccess = () => {
        resolve(getRequest.result?.data || [])
      }
      
      getRequest.onerror = () => reject(getRequest.error)
    }
    
    request.onerror = () => reject(request.error)
  })
}

function clearOfflineData(key) {
  return new Promise((resolve, reject) => {
    const request = indexedDB.open('MiraclesInMotion', 1)
    
    request.onsuccess = () => {
      const db = request.result
      const transaction = db.transaction(['offlineData'], 'readwrite')
      const store = transaction.objectStore('offlineData')
      const deleteRequest = store.delete(key)
      
      deleteRequest.onsuccess = () => resolve()
      deleteRequest.onerror = () => reject(deleteRequest.error)
    }
    
    request.onerror = () => reject(request.error)
  })
}

// Push notification handling
self.addEventListener('push', event => {
  const options = {
    body: event.data?.text() || 'New update available',
    icon: '/favicon.svg',
    badge: '/favicon.svg',
    vibrate: [200, 100, 200],
    data: {
      timestamp: Date.now(),
      url: '/' 
    },
    actions: [
      {
        action: 'view',
        title: 'View',
        icon: '/favicon.svg'
      },
      {
        action: 'close',
        title: 'Close'
      }
    ]
  }
  
  event.waitUntil(
    self.registration.showNotification('Miracles in Motion', options)
  )
})

// Notification click handling
self.addEventListener('notificationclick', event => {
  event.notification.close()
  
  if (event.action === 'view') {
    event.waitUntil(
      clients.openWindow(event.notification.data.url)
    )
  }
})