export interface CrossTabRefreshOptions<T> {
  lockName: string
  observedRefreshToken: string
  currentRefreshToken: () => string
  reuseCurrentSession: () => Promise<T>
  refresh: (refreshToken: string) => Promise<T>
}

export async function coordinateCrossTabRefresh<T>(options: CrossTabRefreshOptions<T>): Promise<T> {
  const run = async () => {
    const currentRefreshToken = options.currentRefreshToken()
    if (currentRefreshToken && currentRefreshToken !== options.observedRefreshToken) {
      return options.reuseCurrentSession()
    }
    return options.refresh(currentRefreshToken || options.observedRefreshToken)
  }

  if (typeof navigator === 'undefined' || !navigator.locks) {
    try {
      return await run()
    } catch (error) {
      if (!options.currentRefreshToken()) throw error
      // Web Locks requires a secure context. On plain HTTP, briefly allow another tab's
      // successful rotation to reach shared storage before treating this session as expired.
      for (let attempt = 0; attempt < 20; attempt += 1) {
        await new Promise((resolve) => setTimeout(resolve, 50))
        const currentRefreshToken = options.currentRefreshToken()
        if (!currentRefreshToken) throw error
        if (currentRefreshToken && currentRefreshToken !== options.observedRefreshToken) {
          return options.reuseCurrentSession()
        }
      }
      throw error
    }
  }
  return navigator.locks.request(options.lockName, run)
}