tlv84yb7n: Build the sign-in screen and signed-in placeholder shell

src/lib/auth-client.ts

@@ -0,0 +1,51 @@
+// Browser-side calls to this app's own /api/session. No token, password or
+// session id is stored or logged here; the session lives in an httpOnly cookie.
+
+export type Person = { name: string; email: string; pictureUrl: string | null };
+
+export const WRONG_CREDENTIALS = "Email or password is incorrect.";
+export const GENERIC_FAILURE = "Could not sign you in. Try again.";
+
+type Fetch = typeof fetch;
+
+function toPerson(body: unknown): Person | null {
+  if (!body || typeof body !== "object") return null;
+  const r = body as Record<string, unknown>;
+  if (typeof r.email !== "string") return null;
+  return {
+    name: typeof r.name === "string" ? r.name : "",
+    email: r.email,
+    pictureUrl: typeof r.pictureUrl === "string" ? r.pictureUrl : null,
+  };
+}
+
+/** GET /api/session: the person, or null when signed out or unreachable. */
+export async function loadSession(f: Fetch = fetch): Promise<Person | null> {
+  try {
+    const res = await f("/api/session", { credentials: "same-origin", cache: "no-store" });
+    if (!res.ok) return null;
+    return toPerson(await res.json());
+  } catch {
+    return null;
+  }
+}
+
+export type SignInResult = { ok: true; person: Person } | { ok: false; message: string };
+
+/** POST /api/session. A 401 is always the one wrong-credentials message. */
+export async function signIn(email: string, password: string, f: Fetch = fetch): Promise<SignInResult> {
+  try {
+    const res = await f("/api/session", {
+      method: "POST",
+      credentials: "same-origin",
+      headers: { "content-type": "application/json" },
+      body: JSON.stringify({ email, password }),
+    });
+    if (res.status === 401) return { ok: false, message: WRONG_CREDENTIALS };
+    if (!res.ok) return { ok: false, message: GENERIC_FAILURE };
+    const person = toPerson(await res.json());
+    return person ? { ok: true, person } : { ok: false, message: GENERIC_FAILURE };
+  } catch {
+    return { ok: false, message: GENERIC_FAILURE };
+  }
+}