import { expect, test, vi } from "vitest"

import { getRandomIndex, getRandomUint32, getRandomUnitValue } from "#Source/random/index.ts"

test("getRandomUint32 returns an integer within uint32 range across available random sources", () => {
  const cryptoBackedValue = getRandomUint32()
  expect(Number.isInteger(cryptoBackedValue)).toBe(true)
  expect(cryptoBackedValue).toBeGreaterThanOrEqual(0)
  expect(cryptoBackedValue).toBeLessThan(0x1_0000_0000)

  vi.stubGlobal("crypto", undefined)

  try {
    const fallbackValue = getRandomUint32()
    expect(Number.isInteger(fallbackValue)).toBe(true)
    expect(fallbackValue).toBeGreaterThanOrEqual(0)
    expect(fallbackValue).toBeLessThan(0x1_0000_0000)
  } finally {
    vi.unstubAllGlobals()
  }
})

test("getRandomUnitValue returns a unit-interval float across available random sources", () => {
  const cryptoBackedValue = getRandomUnitValue()
  expect(cryptoBackedValue).toBeGreaterThanOrEqual(0)
  expect(cryptoBackedValue).toBeLessThan(1)

  vi.stubGlobal("crypto", undefined)

  try {
    const fallbackValue = getRandomUnitValue()
    expect(fallbackValue).toBeGreaterThanOrEqual(0)
    expect(fallbackValue).toBeLessThan(1)
  } finally {
    vi.unstubAllGlobals()
  }
})

test("getRandomIndex returns an integer index within alphabet bounds across available random sources", () => {
  const cryptoBackedValue = getRandomIndex(3)
  expect(Number.isInteger(cryptoBackedValue)).toBe(true)
  expect(cryptoBackedValue).toBeGreaterThanOrEqual(0)
  expect(cryptoBackedValue).toBeLessThan(3)

  vi.stubGlobal("crypto", undefined)

  try {
    const fallbackValue = getRandomIndex(3)
    expect(Number.isInteger(fallbackValue)).toBe(true)
    expect(fallbackValue).toBeGreaterThanOrEqual(0)
    expect(fallbackValue).toBeLessThan(3)
  } finally {
    vi.unstubAllGlobals()
  }
})