const WINDOW_MS    = 20 * 60 * 1000; // 20 minutes
const MAX_ATTEMPTS = 20;

interface Entry
{
  count: number;
  windowStart: number;
}

const store = new Map<string, Entry>();

function delayMs( count: number ): number
{
  if ( count <= 5  ) return  5_000;
  if ( count <= 10 ) return 15_000;
  return 30_000;
}

export function checkForgotPasswordRate( ip: string ): { blocked: boolean; delay: number }
{
  const now   = Date.now();
  let   entry = store.get( ip );

  if ( !entry || now - entry.windowStart > WINDOW_MS )
    entry = { count: 0, windowStart: now };

  entry.count++;
  store.set( ip, entry );

  if ( entry.count > MAX_ATTEMPTS ) return { blocked: true, delay: 0 };
  return { blocked: false, delay: delayMs( entry.count ) };
}

export function sleep( ms: number ): Promise<void>
{
  return new Promise( resolve => setTimeout( resolve, ms ) );
}