feat: add contact form with SMS OTP verification

server/api/send-otp.post.js

@@ -0,0 +1,56 @@
+import { generateTOTP } from "../utils/totp";
+import { createSmsGatewayClient } from "../lib/sms-gateway";
+import { isRateLimited } from "../utils/rate-limiter.js";
+import { normalizeAndValidatePhoneNumber } from "../utils/phone-validator.js";
+
+export default defineEventHandler(async (event) => {
+  const config = useRuntimeConfig();
+  const { phoneNumber: rawPhoneNumber } = await readBody(event);
+  let normalizedPhoneNumber;
+
+  try {
+    normalizedPhoneNumber = normalizeAndValidatePhoneNumber(rawPhoneNumber);
+  } catch (error) {
+    // The validator throws an error with a user-friendly message.
+    throw createError({ statusCode: 400, statusMessage: error.message });
+  }
+
+  // Prevent abuse by checking rate limit before sending an SMS
+  if (isRateLimited(normalizedPhoneNumber)) {
+    throw createError({
+      statusCode: 429,
+      statusMessage:
+        "You have already sent a message within the last week. Please try again later.",
+    });
+  }
+
+  if (!config.superSecretSalt) {
+    console.error("SUPER_SECRET_SALT is not configured on the server.");
+    throw createError({
+      statusCode: 500,
+      statusMessage: "A server configuration error occurred.",
+    });
+  }
+
+  try {
+    const api = createSmsGatewayClient(config);
+    const otp = generateTOTP(normalizedPhoneNumber, config.superSecretSalt);
+    const step_min = Math.floor(getTOTPstep() / 60);
+    const step_sec = getTOTPstep() % 60;
+
+    const message = {
+      phoneNumbers: [normalizedPhoneNumber],
+      message: `${otp} is your verification code. This code is valid for ${step_min}m${step_sec}s.`,
+    };
+
+    const state = await api.send(message);
+    return { success: true, messageId: state.id };
+  } catch (error) {
+    console.error("Failed to send OTP:", error);
+    throw createError({
+      statusCode: 500,
+      statusMessage:
+        "An error occurred while trying to send the verification code.",
+    });
+  }
+});