import { Hono } from 'hono'
import * as Timing from './Timing.js'

describe('middleware', () => {
  test('emits request and operation server timings', async () => {
    const app = new Hono<{ Variables: Timing.Variables }>()

    app.use('*', Timing.middleware())
    app.get('/', async (c) => {
      await Timing.time(c, 'example.work', () => Promise.resolve())
      return c.text('ok')
    })

    const response = await app.request('/')
    const timing = response.headers.get('server-timing')

    expect(response.status).toMatchInlineSnapshot(`200`)
    expect(response.headers.get('content-type')).toMatchInlineSnapshot(`"text/plain;charset=UTF-8"`)
    expect(timing?.includes('example.work;dur=')).toMatchInlineSnapshot(`true`)
    expect(timing?.includes('request;dur=')).toMatchInlineSnapshot(`true`)
  })

  test('appends outer timings without replacing app timings', () => {
    const response = new Response('ok', { headers: { 'Server-Timing': 'request;dur=10' } })

    expect(
      Timing.append(response, [
        { duration: 2.25, name: 'edge rate limit' },
        { duration: 12.5, name: 'worker' },
      ]),
    ).toBe(response)
    expect(response.headers.get('server-timing')).toBe(
      'request;dur=10, edge_rate_limit;dur=2.3, worker;dur=12.5',
    )
  })

  test('merges timings seeded before the app receives the request', async () => {
    const app = new Hono<{ Variables: Timing.Variables }>()
    app.use('*', Timing.middleware())
    app.get('/', (c) => c.text('ok'))
    const request = new Request('http://localhost/')
    Timing.seed(request, {
      active: [{ name: 'worker', start: performance.now() }],
      metrics: [{ duration: 3, name: 'edge_rate_limit' }],
    })

    const response = await app.fetch(request)

    expect(response.headers.get('server-timing')).toContain('edge_rate_limit;dur=3.0')
    expect(response.headers.get('server-timing')).toContain('request;dur=')
    expect(response.headers.get('server-timing')).toContain('worker;dur=')
  })

  test('accumulates repeated work under one server timing metric', async () => {
    vi.useFakeTimers()
    try {
      const app = new Hono<{ Variables: Timing.Variables }>()
      app.use('*', Timing.middleware())
      app.get('/', async (c) => {
        await Timing.sum(c, 'page_work', () => vi.advanceTimersByTime(20))
        await Timing.sum(c, 'page_work', () => vi.advanceTimersByTime(5))
        return c.text('ok')
      })

      const response = await app.request('/')
      const timing = response.headers.get('server-timing')

      expect(timing?.match(/page_work/g)).toHaveLength(1)
      expect(timing).toContain('page_work;dur=25.0')
    } finally {
      vi.useRealTimers()
    }
  })

  test('counts overlapping work once', async () => {
    vi.useFakeTimers()
    try {
      const app = new Hono<{ Variables: Timing.Variables }>()
      app.use('*', Timing.middleware())
      app.get('/', async (c) => {
        const releases: (() => void)[] = []
        const work = () => new Promise<void>((resolve) => releases.push(resolve))
        const pending = [Timing.sum(c, 'parallel_work', work), Timing.sum(c, 'parallel_work', work)]
        vi.advanceTimersByTime(20)
        for (const release of releases) release()
        await Promise.all(pending)
        return c.text('ok')
      })

      const response = await app.request('/')
      const timing = response.headers.get('server-timing')

      expect(timing?.match(/parallel_work/g)).toHaveLength(1)
      expect(timing).toContain('parallel_work;dur=20.0')
    } finally {
      vi.useRealTimers()
    }
  })
})