Initial commit

lib/captcha.ts

@@ -0,0 +1,76 @@
+import crypto from "crypto";
+
+// Simple in-memory CAPTCHA store (in production, use Redis or database)
+const captchaStore: Map<string, { code: string; createdAt: number; attempts: number }> = new Map();
+
+const CAPTCHA_TTL = 5 * 60 * 1000; // 5 minutes
+const MAX_ATTEMPTS = 5;
+const CLEANUP_INTERVAL = 10 * 60 * 1000; // 10 minutes
+
+// Cleanup old captchas periodically
+setInterval(() => {
+  const now = Date.now();
+  for (const [key, value] of captchaStore.entries()) {
+    if (now - value.createdAt > CAPTCHA_TTL) {
+      captchaStore.delete(key);
+    }
+  }
+}, CLEANUP_INTERVAL);
+
+export function generateCaptcha(identifier: string): { id: string; code: string } {
+  const code = Math.random().toString().slice(2, 8); // 6-digit code
+  const id = crypto.randomBytes(16).toString("hex");
+
+  captchaStore.set(id, {
+    code,
+    createdAt: Date.now(),
+    attempts: 0,
+  });
+
+  return { id, code };
+}
+
+export interface CaptchaVerificationResult {
+  success: boolean;
+  error?: string;
+  attemptsRemaining?: number;
+}
+
+export function verifyCaptcha(id: string, code: string): CaptchaVerificationResult {
+  const captcha = captchaStore.get(id);
+
+  if (!captcha) {
+    return { success: false, error: "CAPTCHA not found or expired. Please reload and try again." };
+  }
+
+  // Check if expired
+  if (Date.now() - captcha.createdAt > CAPTCHA_TTL) {
+    captchaStore.delete(id);
+    return { success: false, error: "CAPTCHA code has expired. Please request a new one." };
+  }
+
+  // Check attempts
+  if (captcha.attempts >= MAX_ATTEMPTS) {
+    captchaStore.delete(id);
+    return { success: false, error: "Too many incorrect attempts. Please request a new CAPTCHA code." };
+  }
+
+  // Verify code
+  if (captcha.code === code) {
+    captchaStore.delete(id);
+    return { success: true };
+  }
+
+  // Increment attempts
+  captcha.attempts++;
+  const remaining = MAX_ATTEMPTS - captcha.attempts;
+  return {
+    success: false,
+    error: `Incorrect CAPTCHA code. ${remaining} attempt${remaining === 1 ? "" : "s"} remaining.`,
+    attemptsRemaining: remaining,
+  };
+}
+
+export function getMaxAttempts(): number {
+  return MAX_ATTEMPTS;
+}