sonr/pkg/gateway/config/internal/sw.js

// Cache names for different types of resources
const CACHE_NAMES = {
  wasm: 'wasm-cache-v1',
  static: 'static-cache-v1',
  dynamic: 'dynamic-cache-v1'
};

// Import required scripts
importScripts(
  "https://cdn.jsdelivr.net/gh/golang/go@go1.22.5/misc/wasm/wasm_exec.js",
  "https://cdn.jsdelivr.net/gh/nlepage/go-wasm-http-server@v1.1.0/sw.js",
);

// Initialize WASM HTTP listener
const wasmInstance = registerWasmHTTPListener("https://cdn.sonr.id/wasm/app.wasm");

// MessageChannel port for WASM communication
let wasmPort;

// Request queue for offline operations
let requestQueue = new Map();

// Setup message channel handler
self.addEventListener('message', async (event) => {
  if (event.data.type === 'PORT_INITIALIZATION') {
    wasmPort = event.data.port;
    setupWasmCommunication();
  }
});

function setupWasmCommunication() {
  wasmPort.onmessage = async (event) => {
    const { type, data } = event.data;

    switch (type) {
      case 'WASM_REQUEST':
        handleWasmRequest(data);
        break;
      case 'SYNC_REQUEST':
        processSyncQueue();
        break;
    }
  };

  // Notify that WASM is ready
  wasmPort.postMessage({ type: 'WASM_READY' });
}

// Enhanced install event
self.addEventListener("install", (event) => {
  event.waitUntil(
    Promise.all([
      skipWaiting(),
      // Cache WASM binary and essential resources
      caches.open(CACHE_NAMES.wasm).then(cache =>
        cache.addAll([
          'https://cdn.sonr.id/wasm/app.wasm',
          'https://cdn.jsdelivr.net/gh/golang/go@go1.22.5/misc/wasm/wasm_exec.js'
        ])
      )
    ])
  );
});

// Enhanced activate event
self.addEventListener("activate", (event) => {
  event.waitUntil(
    Promise.all([
      clients.claim(),
      // Clean up old caches
      caches.keys().then(keys =>
        Promise.all(
          keys.map(key => {
            if (!Object.values(CACHE_NAMES).includes(key)) {
              return caches.delete(key);
            }
          })
        )
      )
    ])
  );
});

// Intercept fetch events
self.addEventListener('fetch', (event) => {
  const request = event.request;

  // Handle API requests differently from static resources
  if (request.url.includes('/api/')) {
    event.respondWith(handleApiRequest(request));
  } else {
    event.respondWith(handleStaticRequest(request));
  }
});

async function handleApiRequest(request) {
  try {
    // Try to make the request
    const response = await fetch(request.clone());

    // If successful, pass through WASM handler
    if (response.ok) {
      return await processWasmResponse(request, response);
    }

    // If offline or failed, queue the request
    await queueRequest(request);

    // Return cached response if available
    const cachedResponse = await caches.match(request);
    if (cachedResponse) {
      return cachedResponse;
    }

    // Return offline response
    return new Response(
      JSON.stringify({ error: 'Currently offline' }),
      {
        status: 503,
        headers: { 'Content-Type': 'application/json' }
      }
    );
  } catch (error) {
    await queueRequest(request);
    return new Response(
      JSON.stringify({ error: 'Request failed' }),
      {
        status: 500,
        headers: { 'Content-Type': 'application/json' }
      }
    );
  }
}

async function handleStaticRequest(request) {
  // Check cache first
  const cachedResponse = await caches.match(request);
  if (cachedResponse) {
    return cachedResponse;
  }

  try {
    const response = await fetch(request);

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

    return response;
  } catch (error) {
    // Return offline page for navigation requests
    if (request.mode === 'navigate') {
      return caches.match('/offline.html');
    }
    throw error;
  }
}

async function processWasmResponse(request, response) {
  // Clone the response before processing
  const responseClone = response.clone();

  try {
    // Process through WASM
    const processedResponse = await wasmInstance.processResponse(responseClone);

    // Notify client through message channel
    if (wasmPort) {
      wasmPort.postMessage({
        type: 'RESPONSE',
        requestId: request.headers.get('X-Wasm-Request-ID'),
        response: processedResponse
      });
    }

    return processedResponse;
  } catch (error) {
    console.error('WASM processing error:', error);
    return response;
  }
}

async function queueRequest(request) {
  const serializedRequest = await serializeRequest(request);
  requestQueue.set(request.url, serializedRequest);

  // Register for background sync
  try {
    await self.registration.sync.register('wasm-sync');
  } catch (error) {
    console.error('Sync registration failed:', error);
  }
}

async function serializeRequest(request) {
  const headers = {};
  for (const [key, value] of request.headers.entries()) {
    headers[key] = value;
  }

  return {
    url: request.url,
    method: request.method,
    headers,
    body: await request.text(),
    timestamp: Date.now()
  };
}

// Handle background sync
self.addEventListener('sync', (event) => {
  if (event.tag === 'wasm-sync') {
    event.waitUntil(processSyncQueue());
  }
});

async function processSyncQueue() {
  const requests = Array.from(requestQueue.values());

  for (const serializedRequest of requests) {
    try {
      const response = await fetch(new Request(serializedRequest.url, {
        method: serializedRequest.method,
        headers: serializedRequest.headers,
        body: serializedRequest.body
      }));

      if (response.ok) {
        requestQueue.delete(serializedRequest.url);

        // Notify client of successful sync
        if (wasmPort) {
          wasmPort.postMessage({
            type: 'SYNC_COMPLETE',
            url: serializedRequest.url
          });
        }
      }
    } catch (error) {
      console.error('Sync failed for request:', error);
    }
  }
}

// Handle payment requests
self.addEventListener("canmakepayment", function (e) {
  e.respondWith(Promise.resolve(true));
});

// Handle periodic sync if available
self.addEventListener('periodicsync', (event) => {
  if (event.tag === 'wasm-sync') {
    event.waitUntil(processSyncQueue());
  }
});