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

import {
  CoordinationAbortError,
  CoordinationTimeoutError,
  CountDownLatch,
} from "#Source/orchestration/index.ts"

afterEach(() => {
  vi.clearAllTimers()
  vi.useRealTimers()
})

test("CountDownLatch opens when the count reaches zero and resolves waiters", async () => {
  const countDownLatch = new CountDownLatch(2)
  const firstWait = countDownLatch.wait()
  const secondWait = countDownLatch.wait()

  expect(countDownLatch.isOpen()).toBe(false)
  expect(countDownLatch.tryWait()).toBe(false)
  expect(countDownLatch.getRemainingCount()).toBe(2)
  expect(countDownLatch.getPendingCount()).toBe(2)

  expect(countDownLatch.countDown()).toBe(1)
  expect(countDownLatch.arrive()).toBe(0)

  await Promise.all([firstWait, secondWait])

  expect(countDownLatch.isOpen()).toBe(true)
  expect(countDownLatch.tryWait()).toBe(true)
  expect(countDownLatch.getRemainingCount()).toBe(0)
  expect(countDownLatch.getPendingCount()).toBe(0)
  await expect(countDownLatch.wait()).resolves.toBeUndefined()
})

test("CountDownLatch wait rejects on timeout and abort without leaking pending entries", async () => {
  vi.useFakeTimers()

  const countDownLatch = new CountDownLatch(1)
  const timeoutPromise = countDownLatch.wait({ timeout: 30 })
  const timeoutExpectation = expect(timeoutPromise).rejects.toBeInstanceOf(CoordinationTimeoutError)

  expect(countDownLatch.getPendingCount()).toBe(1)

  await vi.advanceTimersByTimeAsync(30)

  await timeoutExpectation
  expect(countDownLatch.getPendingCount()).toBe(0)

  const abortController = new AbortController()
  const abortPromise = countDownLatch.wait({ abortSignal: abortController.signal })
  const abortExpectation = expect(abortPromise).rejects.toBeInstanceOf(CoordinationAbortError)

  expect(countDownLatch.getPendingCount()).toBe(1)

  abortController.abort("cancelled")

  await abortExpectation
  expect(countDownLatch.getPendingCount()).toBe(0)
})

test("CountDownLatch ignores further countdowns after opening", () => {
  const countDownLatch = new CountDownLatch(1)

  expect(countDownLatch.countDown()).toBe(0)
  expect(countDownLatch.countDown()).toBe(0)
  expect(countDownLatch.arrive()).toBe(0)
  expect(countDownLatch.isOpen()).toBe(true)
})