chatgpt added offline items update

static/item_update_queue.js

@@ -0,0 +1,117 @@
+(function () {
+  const STORAGE_KEY = "lapp.pendingItemUpdates";
+
+  function readQueue() {
+    try {
+      return JSON.parse(localStorage.getItem(STORAGE_KEY) || "[]");
+    } catch (error) {
+      return [];
+    }
+  }
+
+  function writeQueue(queue) {
+    localStorage.setItem(STORAGE_KEY, JSON.stringify(queue));
+  }
+
+  function queueRequest(request) {
+    const queue = readQueue();
+    const queuedRequest = {
+      url: request.url,
+      method: request.method || "GET",
+      coalesceKey: request.coalesceKey || null,
+      clientUpdatedAt: request.clientUpdatedAt || Date.now()
+    };
+
+    if (queuedRequest.coalesceKey) {
+      const existingIndex = queue.findIndex(function (item) {
+        return item.coalesceKey === queuedRequest.coalesceKey;
+      });
+      if (existingIndex >= 0) {
+        queue[existingIndex] = queuedRequest;
+      } else {
+        queue.push(queuedRequest);
+      }
+    } else {
+      queue.push(queuedRequest);
+    }
+
+    writeQueue(queue);
+  }
+
+  async function sendRequest(request) {
+    const url = new URL(request.url, window.location.origin);
+    if (request.clientUpdatedAt) {
+      url.searchParams.set("client_updated_at", request.clientUpdatedAt);
+    }
+
+    const response = await fetch(url.toString(), {
+      method: request.method || "GET",
+      cache: "no-store",
+      credentials: "same-origin"
+    });
+
+    if (response.redirected && new URL(response.url).pathname === "/login") {
+      const error = new Error("Login required");
+      error.retryable = true;
+      throw error;
+    }
+
+    if (!response.ok) {
+      const error = new Error("Request failed: " + response.status);
+      error.retryable = response.status >= 500 || response.status === 408 || response.status === 429;
+      throw error;
+    }
+    return response;
+  }
+
+  async function queueableItemRequest(url, options) {
+    const request = Object.assign({}, options || {}, {
+      url: url,
+      clientUpdatedAt: Date.now()
+    });
+    try {
+      await sendRequest(request);
+      flushItemUpdateQueue();
+      return true;
+    } catch (error) {
+      if (error.retryable !== false) {
+        queueRequest(request);
+      }
+      return false;
+    }
+  }
+
+  async function flushItemUpdateQueue() {
+    if (flushItemUpdateQueue.running) {
+      return;
+    }
+    flushItemUpdateQueue.running = true;
+
+    const queue = readQueue();
+    const remaining = [];
+
+    for (const request of queue) {
+      try {
+        await sendRequest(request);
+      } catch (error) {
+        if (error.retryable !== false) {
+          remaining.push(request);
+        }
+      }
+    }
+
+    writeQueue(remaining);
+    flushItemUpdateQueue.running = false;
+  }
+
+  window.lappQueueItemRequest = queueableItemRequest;
+  window.lappFlushItemUpdateQueue = flushItemUpdateQueue;
+
+  window.addEventListener("online", flushItemUpdateQueue);
+  document.addEventListener("visibilitychange", function () {
+    if (!document.hidden) {
+      flushItemUpdateQueue();
+    }
+  });
+  document.addEventListener("DOMContentLoaded", flushItemUpdateQueue);
+})();