v1.0.5: Offline mode with sync queue, fix symbol/text rotation on compass, polygon area display

src/lib/offline-sync.ts

@@ -0,0 +1,97 @@
+// Offline detection and sync queue for saving changes when reconnecting
+
+const SYNC_QUEUE_KEY = 'lageplan-sync-queue'
+
+interface SyncQueueItem {
+  id: string
+  url: string
+  method: string
+  body: string
+  timestamp: number
+}
+
+/** Get all queued saves */
+export function getSyncQueue(): SyncQueueItem[] {
+  try {
+    const raw = localStorage.getItem(SYNC_QUEUE_KEY)
+    return raw ? JSON.parse(raw) : []
+  } catch {
+    return []
+  }
+}
+
+/** Add a save operation to the sync queue (called when offline) */
+export function addToSyncQueue(url: string, method: string, body: any): void {
+  const queue = getSyncQueue()
+  // Deduplicate: if same URL+method exists, replace it with newer data
+  const existing = queue.findIndex(q => q.url === url && q.method === method)
+  const item: SyncQueueItem = {
+    id: `${Date.now()}-${Math.random().toString(36).slice(2, 8)}`,
+    url,
+    method,
+    body: JSON.stringify(body),
+    timestamp: Date.now(),
+  }
+  if (existing >= 0) {
+    queue[existing] = item
+  } else {
+    queue.push(item)
+  }
+  localStorage.setItem(SYNC_QUEUE_KEY, JSON.stringify(queue))
+}
+
+/** Flush the sync queue — send all queued requests to the server */
+export async function flushSyncQueue(): Promise<{ success: number; failed: number }> {
+  const queue = getSyncQueue()
+  if (queue.length === 0) return { success: 0, failed: 0 }
+
+  let success = 0
+  let failed = 0
+  const remaining: SyncQueueItem[] = []
+
+  for (const item of queue) {
+    try {
+      const res = await fetch(item.url, {
+        method: item.method,
+        headers: { 'Content-Type': 'application/json' },
+        body: item.body,
+      })
+      if (res.ok) {
+        success++
+      } else {
+        // Server error — keep in queue for retry
+        remaining.push(item)
+        failed++
+      }
+    } catch {
+      // Still offline — keep in queue
+      remaining.push(item)
+      failed++
+    }
+  }
+
+  localStorage.setItem(SYNC_QUEUE_KEY, JSON.stringify(remaining))
+  return { success, failed }
+}
+
+/** Clear the sync queue */
+export function clearSyncQueue(): void {
+  localStorage.removeItem(SYNC_QUEUE_KEY)
+}
+
+/** Check if we're online */
+export function isOnline(): boolean {
+  return navigator.onLine
+}
+
+/** Register Background Sync (if supported) */
+export async function registerBackgroundSync(): Promise<void> {
+  if ('serviceWorker' in navigator && 'SyncManager' in window) {
+    try {
+      const reg = await navigator.serviceWorker.ready
+      await (reg as any).sync.register('sync-saves')
+    } catch {
+      // Background Sync not supported or failed — will use manual flush
+    }
+  }
+}