();
+
+ function clearMessages() {
+ setErrorMessage(undefined);
+ setInfoMessage(undefined);
+ }
+
+ function applyResult(result: AuthActionResult) {
+ if (result.twoFactor && result.challenge) {
+ setChallenge(result.challenge);
+ setStep("twoFactor");
+ return;
+ }
+ if (result.ok) {
+ if (mode === "forgot") {
+ setInfoMessage(authStrings.forgot.sent);
+ return;
+ }
+ router.push("/home");
+ return;
+ }
+ setErrorMessage(result.error ?? authStrings.errors.unknown);
+ }
+
+ async function handleFormSubmit(e: React.FormEvent) {
+ e.preventDefault();
+ if (isSubmitting) return;
+ clearMessages();
+
+ const trimmedEmail = email.trim();
+
+ if (mode === "forgot") {
+ if (!isValidEmail(trimmedEmail)) {
+ setErrorMessage(authStrings.errors.invalidEmail);
+ return;
+ }
+ setIsSubmitting(true);
+ try {
+ applyResult(await submitForgot(trimmedEmail));
+ } finally {
+ setIsSubmitting(false);
+ }
+ return;
+ }
+
+ if (!isValidEmail(trimmedEmail)) {
+ setErrorMessage(authStrings.errors.invalidEmail);
+ return;
+ }
+ if (password.length < 8) {
+ setErrorMessage(authStrings.errors.passwordTooShort);
+ return;
+ }
+ if (mode === "register" && password !== confirmPassword) {
+ setErrorMessage(authStrings.errors.passwordMismatch);
+ return;
+ }
+
+ setIsSubmitting(true);
+ try {
+ const result =
+ mode === "login"
+ ? await submitLogin(trimmedEmail, password)
+ : await submitRegister(trimmedEmail, password);
+ applyResult(result);
+ } finally {
+ setIsSubmitting(false);
+ }
+ }
+
+ async function handleCodeSubmit(e: React.FormEvent) {
+ e.preventDefault();
+ if (isSubmitting || !challenge) return;
+ clearMessages();
+ setIsSubmitting(true);
+ try {
+ applyResult(await submit2FA(challenge, code));
+ } finally {
+ setIsSubmitting(false);
+ }
+ }
+
+ if (step === "twoFactor") {
+ return (
+
+ );
+ }
+
+ return (
+
+ );
+}
+
+function FormError({ message }: { message?: string }) {
+ if (!message) return null;
+ return (
+
+ {message}
+
+ );
+}
diff --git a/src/features/auth/actions.ts b/src/features/auth/actions.ts
new file mode 100644
index 0000000..a1bde2c
--- /dev/null
+++ b/src/features/auth/actions.ts
@@ -0,0 +1,75 @@
+import { authStrings } from "./strings";
+
+export interface AuthActionResult {
+ ok: boolean;
+ twoFactor?: boolean;
+ challenge?: string;
+ error?: string;
+}
+
+// Mirrors AuthError.userMessage in ios/Mercury/Features/Auth/AuthRepository.swift,
+// keyed by the `{error:{code,message}}` envelope the Go backend writes
+// (internal/transport/api/respond.go, auth_handlers.go, twofa_handlers.go).
+const ERROR_MESSAGE_BY_CODE: Record = {
+ invalid_credentials: authStrings.errors.invalidCredentials,
+ email_taken: authStrings.errors.emailTaken,
+ invalid_code: authStrings.errors.invalidCode,
+ invalid_challenge: authStrings.errors.invalidCode,
+};
+
+function messageForCode(code: string | undefined): string {
+ if (code && ERROR_MESSAGE_BY_CODE[code]) return ERROR_MESSAGE_BY_CODE[code];
+ return authStrings.errors.unknown;
+}
+
+async function postAuth(
+ path: "login" | "register" | "forgot" | "2fa",
+ body: unknown,
+): Promise {
+ let res: Response;
+ try {
+ res = await fetch(`/api/auth/${path}`, {
+ method: "POST",
+ credentials: "same-origin",
+ headers: { "Content-Type": "application/json" },
+ body: JSON.stringify(body),
+ });
+ } catch {
+ return { ok: false, error: authStrings.errors.network };
+ }
+
+ const data = await res.json().catch(() => ({}));
+
+ if (!res.ok) {
+ return { ok: false, error: messageForCode(data?.error?.code) };
+ }
+ if (data?.twoFactor) {
+ return { ok: false, twoFactor: true, challenge: data.challenge };
+ }
+ return { ok: true };
+}
+
+export function submitLogin(
+ email: string,
+ password: string,
+): Promise {
+ return postAuth("login", { email, password });
+}
+
+export function submitRegister(
+ email: string,
+ password: string,
+): Promise {
+ return postAuth("register", { email, password });
+}
+
+export function submit2FA(
+ challenge: string,
+ code: string,
+): Promise {
+ return postAuth("2fa", { challenge, code });
+}
+
+export function submitForgot(email: string): Promise {
+ return postAuth("forgot", { email });
+}
diff --git a/src/features/auth/strings.ts b/src/features/auth/strings.ts
new file mode 100644
index 0000000..445f687
--- /dev/null
+++ b/src/features/auth/strings.ts
@@ -0,0 +1,46 @@
+// Auth feature copy, ported verbatim from ios/Mercury/Features/Auth/*.swift
+// (WelcomeView, LoginView, RegisterView, ForgotPasswordView, AuthModel).
+export const authStrings = {
+ wordmark: "MERCURY",
+ welcome: {
+ title: "ONBOARDING",
+ register: "Бүртгүүлэх",
+ login: "Нэвтрэх",
+ },
+ login: {
+ email: "Имэйл хаяг",
+ password: "Нууц үг",
+ forgot: "Нууц үг марсан",
+ submit: "Нэвтрэх",
+ registerLink: "Бүртгүүлэх",
+ },
+ register: {
+ email: "Имэйл хаяг",
+ password: "Нууц үг",
+ confirmPassword: "Нууц үг давтах",
+ submit: "Бүртгүүлэх",
+ loginLink: "Нэвтрэх",
+ },
+ forgot: {
+ subtitle:
+ "Бүртгэлтэй имэйл хаягаа оруулбал нууц үг сэргээх холбоосыг илгээнэ.",
+ email: "Имэйл хаяг",
+ submit: "Сэргээх холбоос авах",
+ sent: "Хэрэв бүртгэл байгаа бол сэргээх холбоосыг имэйлээр илгээлээ.",
+ },
+ twoFactor: {
+ subtitle: "Имэйлээр илгээсэн баталгаажуулах кодоо оруулна уу.",
+ code: "Баталгаажуулах код",
+ submit: "Баталгаажуулах",
+ },
+ errors: {
+ invalidEmail: "Имэйл хаягаа зөв оруулна уу.",
+ passwordTooShort: "Нууц үг дор хаяж 8 тэмдэгт байх ёстой.",
+ passwordMismatch: "Нууц үг таарахгүй байна.",
+ invalidCredentials: "Имэйл эсвэл нууц үг буруу байна.",
+ emailTaken: "Энэ имэйл бүртгэлтэй байна.",
+ invalidCode: "Код буруу эсвэл хугацаа дууссан байна.",
+ network: "Mercury-тэй холбогдож чадсангүй — холболтоо шалгана уу.",
+ unknown: "Алдаа гарлаа. Дахин оролдоно уу.",
+ },
+} as const;