import { describe, expect, it } from 'vitest'
import { formatBytes } from '../src/lib/bytes'
import {
  DEFAULT_RANDOM_BYTES,
  MAX_RANDOM_BYTES,
  MIN_RANDOM_BYTES,
  secureRandomBytes,
  type RandomSource,
} from '../src/lib/random'

describe('secure random bytes', () => {
  it('uses the supplied cryptographic source and preserves requested length', () => {
    let next = 0
    const source: RandomSource = {
      getRandomValues<T extends ArrayBufferView>(array: T): T {
        const bytes = new Uint8Array(array.buffer, array.byteOffset, array.byteLength)
        bytes.forEach((_, index) => { bytes[index] = next; next += 1 })
        return array
      },
    }
    expect(DEFAULT_RANDOM_BYTES).toBe(16)
    expect(secureRandomBytes(4, source)).toEqual(Uint8Array.from([0, 1, 2, 3]))
  })

  it.each([0, -1, 1.5, Number.NaN, MAX_RANDOM_BYTES + 1])('rejects invalid length %s', (length) => {
    expect(() => secureRandomBytes(length, crypto)).toThrow(`${MIN_RANDOM_BYTES} 至 ${MAX_RANDOM_BYTES}`)
  })

  it('accepts both length boundaries without exceeding the browser call limit', () => {
    const calls: number[] = []
    const source: RandomSource = {
      getRandomValues<T extends ArrayBufferView>(array: T): T {
        calls.push(array.byteLength)
        return array
      },
    }
    expect(secureRandomBytes(MIN_RANDOM_BYTES, source)).toHaveLength(MIN_RANDOM_BYTES)
    expect(secureRandomBytes(MAX_RANDOM_BYTES, source)).toHaveLength(MAX_RANDOM_BYTES)
    expect(calls).toEqual([MIN_RANDOM_BYTES, MAX_RANDOM_BYTES])
  })

  it('fails closed when the cryptographic source is unavailable or throws', () => {
    expect(() => secureRandomBytes(DEFAULT_RANDOM_BYTES, null as unknown as RandomSource)).toThrow('不支持安全随机数')
    const failure = new Error('entropy source failed')
    const source: RandomSource = { getRandomValues: () => { throw failure } }
    expect(() => secureRandomBytes(DEFAULT_RANDOM_BYTES, source)).toThrow(failure)
  })

  it('formats the same bytes for OpenSSL and source-code styles', () => {
    const bytes = Uint8Array.from([0x0a, 0xbc, 0xff])
    expect(formatBytes(bytes)).toBe('0ABCFF')
    expect(formatBytes(bytes, { format: 'spaced-hex' })).toBe('0A BC FF')
    expect(formatBytes(bytes, { format: 'byte-array', uppercase: false })).toBe('0x0a, 0xbc, 0xff')
  })
})