Retry backoff schedule

# title: Retry backoff schedule
# category: Vibescript Showcase
# difficulty: Showcase
# summary: Build an exponential retry schedule with enums, durations, and timestamps.
# description: The retry policy names each delay and returns the exact time for every attempt.
# tags: automation, durations, time, enums
# featured: true
# feature_rank: 2
# vibe: 0.2

enum RetryProfile
  Fast
  Careful
end

def base_delay(profile: RetryProfile) -> duration
  if profile == RetryProfile::Fast
    30.seconds
  else
    5.minutes
  end
end

def retry_schedule(profile: RetryProfile, start: time, attempts: int) -> array
  delay = base_delay(profile)
  rows = []
  current = start
  multiplier = 1
  attempt = 1

  while attempt <= attempts
    window = delay * multiplier
    current = window.after(current)
    rows = rows.push({
      attempt: attempt,
      delay: window.iso8601,
      at: current.format("2006-01-02T15:04:05Z")
    })
    multiplier = multiplier * 2
    attempt = attempt + 1
  end

  rows
end

def run
  start = Time.at(1700000000)
  {
    fast: retry_schedule(RetryProfile::Fast, start, 4),
    careful: retry_schedule(RetryProfile::Careful, start, 3)
  }
end