import type { Connection } from '../protocol/connection.ts';
import { isLegacyFidelity } from '../protocol/fidelity.ts';
import { MESSAGE_TYPE } from '../protocol/messageTypes.ts';
import type { GenesisMessage, MockServerConfig } from '../types.ts';
import type { AuthState } from './auth.ts';

// HEARTBEAT_PONG, as genesis-router answers it
// (RouterMessageDelegator.handleHeartbeat, RouterMessageDelegator.kt:158-195
// @v8.15.29): IS_AUTHENTICATED, plus with VERBOSE:true the connection's
// USER_NAME, CREATED_AT, LAST_RECEIVED, LAST_SENT and RESOURCES
// (heartbeat.json). The router writes it straight to the socket, so it
// doesn't count as LAST_SENT.
export function handleHeartbeat(
  message: GenesisMessage,
  connection: Connection,
  config: MockServerConfig,
  auth: AuthState,
): void {
  // With the auth gate off (the default), this server accepts every data
  // message — so the pong must report IS_AUTHENTICATED: true even though the
  // WS connection itself never "logged in". HTTP-login clients (httpAutoLogin
  // included) send no SESSION_AUTH_TOKEN on WS messages, so
  // connection.authenticated stays false forever on their connections; report
  // that raw flag and the client treats the session as dead and tears it
  // down, defeating httpAutoLogin entirely. Only when a project opts into
  // auth.requireAuth does the flag reflect real connection auth state.
  const requireAuth = config.auth?.requireAuth ?? false;
  const IS_AUTHENTICATED = connection.authenticated || !requireAuth;
  if (isLegacyFidelity(config) || message.VERBOSE !== true) {
    connection.reply(
      message,
      { MESSAGE_TYPE: MESSAGE_TYPE.HEARTBEAT_PONG, IS_AUTHENTICATED },
      false,
    );
    return;
  }
  // A ping carrying a token names the session's user ('' for a dead one);
  // otherwise the connection's own login.
  const token = message.SESSION_AUTH_TOKEN;
  const USER_NAME =
    typeof token === 'string'
      ? (auth.sessions.get(token)?.username ?? '')
      : (connection.userName ?? null);
  connection.reply(
    message,
    {
      IS_AUTHENTICATED,
      USER_NAME,
      CREATED_AT: connection.createdAt,
      LAST_RECEIVED: connection.lastReceived,
      LAST_SENT: connection.lastSent,
      RESOURCES: connection.dataserverResources(),
      MESSAGE_TYPE: MESSAGE_TYPE.HEARTBEAT_PONG,
    },
    false,
  );
}