/***** manifest.json *****/

{
  "manifest_version": 3,
  "name": "Clipboard Alert",
  "version": "1.0",
  "description": "Shows the current clipboard contents in an alert.",
  "permissions": [
    "activeTab",
    "scripting",
    "clipboardRead"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_title": "Show Clipboard"
  }
}

/***** background.js *****/

browser.action.onClicked.addListener(async (tab) => {
  if (!tab.id) return;

  try {
    await browser.scripting.executeScript({
      target: { tabId: tab.id },
      func: async () => {
        try {
          const text = await navigator.clipboard.readText();
          alert("Clipboard contents:\n\n" + text);
        } catch (err) {
          alert("Failed to read clipboard:\n" + err);
        }
      }
    });
  } catch (e) {
    console.error("Script injection failed:", e);
  }
});