add: background.js for automatic code input

public/scripts/background.js

@@ -0,0 +1,23 @@
+import * as OTPAuth from 'otpauth';
+
+// eslint-disable-next-line no-undef
+const api = typeof browser !== "undefined" ? browser : chrome;
+
+api.runtime.onMessage.addListener((request, _sender, sendResponse) => {
+  if (request.action === "GENERATE_TOKEN") {
+    api.storage.local.get(['shasecret'], (data) => {
+      if (data.shasecret) {
+        const totp = new OTPAuth.TOTP({
+          issuer: 'US',
+          label: '2FA',
+          algorithm: 'SHA1',
+          digits: 6,
+          period: 30,
+          secret: OTPAuth.Secret.fromBase32(data.shasecret.trim().toUpperCase()),
+        });
+        sendResponse({ token: totp.generate() });
+      }
+    });
+    return true;
+  }
+});

public/scripts/content.js

@@ -0,0 +1,39 @@
+(async function() {
+  // eslint-disable-next-line no-undef
+  const api = typeof browser !== "undefined" ? browser : chrome;
+
+  const fillCode = (code) => {
+    const input = document.getElementById("input2factor");
+    const button = document.getElementById('btn-login') || document.querySelector("#notification_2factor_button_ok");
+    const error = document.querySelector("#otp_authn_wrong_code")?.offsetHeight > 0;
+
+    if (!input || error) return;
+
+    input.value = code;
+    input.dispatchEvent(new Event('input', { bubbles: true }));
+    
+    setTimeout(() => {
+      if (button) button.click();
+    }, 200);
+    console.log("Autofill");
+  };
+
+  api.runtime.onMessage.addListener((request, sender, sendResponse) => {
+    if (request.action === "autofill") {
+      fillCode(request.code);
+      sendResponse({ status: "ok" });
+    }
+  });
+
+  const data = await api.storage.local.get(['shasecret']);
+  if (data.shasecret) {
+    const input = document.getElementById("input2factor");
+    if (input && input.value.length === 0) {
+      api.runtime.sendMessage({ action: "GENERATE_TOKEN" }, response => {
+        if (response?.token) {
+          fillCode(response.token);
+        }
+      });
+    }
+  }
+})();