refactor: adjust code injection pattern

background.js

@@ -4,6 +4,33 @@
 // Detect browser API
 const browserAPI = typeof browser !== 'undefined' ? browser : chrome;
 
+// Check if content script is loaded by trying to send a message
+const isContentScriptLoaded = async (tabId) => {
+  try {
+    await browserAPI.tabs.sendMessage(tabId, { action: 'ping' });
+    return true;
+  } catch {
+    return false;
+  }
+};
+
+// Send a message with retries (for after injection)
+const sendMessageWithRetry = async (tabId, message, maxRetries = 10) => {
+  for (let i = 0; i < maxRetries; i++) {
+    try {
+      await new Promise(resolve => setTimeout(resolve, 100 * (i + 1))); // 100ms, 200ms, 300ms...
+      await browserAPI.tabs.sendMessage(tabId, message);
+      return; // Success!
+    } catch (error) {
+      if (i === maxRetries - 1) {
+        console.error('Failed to communicate with content script:', error.message);
+        throw error;
+      }
+      // Continue to next retry
+    }
+  }
+};
+
 // Handle extension icon click
 const handleIconClick = async (tab) => {
   // Check if we're on a valid page (not chrome://, about:, file://)
@@ -16,24 +43,21 @@ const handleIconClick = async (tab) => {
     return;
   }
 
-  try {
-    // Try to send a message first to see if content script is already loaded
+  // Check if content script is already loaded
+  const isLoaded = await isContentScriptLoaded(tab.id);
+
+  if (isLoaded) {
+    // Content script already there, send message
     await browserAPI.tabs.sendMessage(tab.id, { action: 'togglePanel' });
-
-  } catch (error) {
-    // If message fails, content.js isn't loaded. Inject it, and execute the content script
+  } else {
+    // Content script not loaded yet - inject it first
     await browserAPI.scripting.executeScript({
       target: { tabId: tab.id },
       files: ['content.js']
     });
-
-    // Wait a moment for the script to initialize
-    await new Promise(resolve => setTimeout(resolve, 150));
-
-    // Send a message after injection
-    await browserAPI.tabs.sendMessage(tab.id, { action: 'togglePanel' });
 
-    console.error(`Error in handleIconClick: ${error.message}`);
+    // Wait for content script to initialize, then send message
+    await sendMessageWithRetry(tab.id, { action: 'togglePanel' });
   }
 };