refactor(scripts): extract atproto session helpers to shared module

scripts/_atproto-session.ts

@@ -0,0 +1,97 @@
+// Shared helpers for admin scripts that authenticate against the Remanso API
+// using an AT Protocol session. The handle is resolved to a DID, the DID is
+// resolved to a PDS, and a session is created against that PDS — yielding an
+// access JWT the API can verify with `authenticateRequest`.
+
+type ResolveHandleResponse = { did: string };
+type DidDocument = {
+  service?: { id: string; serviceEndpoint: string }[];
+};
+export type CreateSessionResponse = { did: string; accessJwt: string };
+
+export const parseArgs = (args: string[]): Record<string, string> => {
+  const out: Record<string, string> = {};
+  for (let i = 0; i < args.length; i++) {
+    const arg = args[i];
+    if (!arg.startsWith("--")) continue;
+    const key = arg.slice(2);
+    const next = args[i + 1];
+    if (next === undefined || next.startsWith("--")) {
+      out[key] = "true";
+    } else {
+      out[key] = next;
+      i++;
+    }
+  }
+  return out;
+};
+
+export const resolveHandleToDid = async (handle: string): Promise<string> => {
+  const url =
+    `https://public.api.bsky.app/xrpc/com.atproto.identity.resolveHandle?handle=${
+      encodeURIComponent(handle)
+    }`;
+  const res = await fetch(url);
+  if (!res.ok) {
+    throw new Error(
+      `resolveHandle failed for ${handle} (${res.status}): ${await res.text()}`,
+    );
+  }
+  const { did } = await res.json() as ResolveHandleResponse;
+  return did;
+};
+
+export const resolveDidToPds = async (did: string): Promise<string> => {
+  if (!did.startsWith("did:plc:")) {
+    throw new Error(
+      `Unsupported DID method (server only handles did:plc): ${did}`,
+    );
+  }
+  const res = await fetch(`https://plc.directory/${did}`);
+  if (!res.ok) {
+    throw new Error(`plc.directory lookup failed (${res.status})`);
+  }
+  const doc = await res.json() as DidDocument;
+  const pds = doc.service?.find((s) => s.id === "#atproto_pds");
+  if (!pds) throw new Error("No #atproto_pds service in DID document");
+  return pds.serviceEndpoint;
+};
+
+export const createSession = async (
+  pds: string,
+  identifier: string,
+  password: string,
+): Promise<CreateSessionResponse> => {
+  const res = await fetch(`${pds}/xrpc/com.atproto.server.createSession`, {
+    method: "POST",
+    headers: { "Content-Type": "application/json" },
+    body: JSON.stringify({ identifier, password }),
+  });
+  if (!res.ok) {
+    throw new Error(
+      `createSession failed (${res.status}): ${await res.text()}`,
+    );
+  }
+  return await res.json();
+};
+
+// Convenience: pull credentials from flags or env, resolve the full session
+// chain in one call. Throws if required inputs are missing.
+export const sessionFromFlagsOrEnv = async (
+  flags: Record<string, string>,
+): Promise<{ session: CreateSessionResponse; api: string }> => {
+  const handle = flags.handle ?? Deno.env.get("ATPROTO_HANDLE");
+  const password = flags["app-password"] ??
+    Deno.env.get("ATPROTO_APP_PASSWORD");
+  const api = flags.api ?? Deno.env.get("REMANSO_API") ??
+    "https://api.remanso.space";
+  if (!handle) throw new Error("ATPROTO_HANDLE (or --handle) is required");
+  if (!password) {
+    throw new Error("ATPROTO_APP_PASSWORD (or --app-password) is required");
+  }
+  const did = await resolveHandleToDid(handle);
+  const pds = await resolveDidToPds(did);
+  console.log(`[resolve] ${handle} → ${did} via ${pds}`);
+  const session = await createSession(pds, handle, password);
+  return { session, api };
+};