import { describe, expect, it } from 'vitest'
import { NetworkError, RateLimitError, TimeoutError } from '../errors/dify-error'
import { getRetryDelayMs, shouldRetry } from './retry'

const withMockedRandom = (value: number, fn: () => void): void => {
  const original = Math.random
  Math.random = () => value
  try {
    fn()
  } finally {
    Math.random = original
  }
}

describe('retry helpers', () => {
  it('getRetryDelayMs honors retry-after header', () => {
    expect(getRetryDelayMs(1, 1, 3)).toBe(3000)
  })

  it('getRetryDelayMs uses exponential backoff with jitter', () => {
    withMockedRandom(0, () => {
      expect(getRetryDelayMs(1, 1)).toBe(1000)
      expect(getRetryDelayMs(2, 1)).toBe(2000)
      expect(getRetryDelayMs(3, 1)).toBe(4000)
    })
  })

  it('shouldRetry respects max retries', () => {
    expect(shouldRetry(new TimeoutError('timeout'), 3, 3)).toBe(false)
  })

  it('shouldRetry retries on network, timeout, and rate limit', () => {
    expect(shouldRetry(new TimeoutError('timeout'), 0, 3)).toBe(true)
    expect(shouldRetry(new NetworkError('network'), 0, 3)).toBe(true)
    expect(shouldRetry(new RateLimitError('limit'), 0, 3)).toBe(true)
    expect(shouldRetry(new Error('other'), 0, 3)).toBe(false)
  })
})