// 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 };
};