import { describe, it, expect } from 'vitest'
import express from 'express'
import request from 'supertest'
import { compressionMiddleware } from '../compression.js'

function createApp() {
  const app = express()
  app.use(compressionMiddleware)

  app.get('/text', (_req, res) => {
    // Send enough data to exceed 1024 byte threshold
    res.type('text/html').send('x'.repeat(2000))
  })

  app.get('/small', (_req, res) => {
    res.type('text/html').send('small')
  })

  app.get('/image', (_req, res) => {
    res.type('image/png').send(Buffer.alloc(2000))
  })

  app.get('/json', (_req, res) => {
    res.type('application/json').send(JSON.stringify({ data: 'y'.repeat(2000) }))
  })

  return app
}

describe('compressionMiddleware', () => {
  it('compresses text responses above threshold', async () => {
    const res = await request(createApp())
      .get('/text')
      .set('Accept-Encoding', 'gzip')
    expect(res.headers['content-encoding']).toBe('gzip')
  })

  it('does not compress responses below threshold', async () => {
    const res = await request(createApp())
      .get('/small')
      .set('Accept-Encoding', 'gzip')
    expect(res.headers['content-encoding']).toBeUndefined()
  })

  it('does not compress image responses', async () => {
    const res = await request(createApp())
      .get('/image')
      .set('Accept-Encoding', 'gzip')
    expect(res.headers['content-encoding']).toBeUndefined()
  })

  it('compresses JSON responses above threshold', async () => {
    const res = await request(createApp())
      .get('/json')
      .set('Accept-Encoding', 'gzip')
    expect(res.headers['content-encoding']).toBe('gzip')
  })

  it('does not compress when client does not accept gzip', async () => {
    const res = await request(createApp())
      .get('/text')
      .set('Accept-Encoding', 'identity')
    expect(res.headers['content-encoding']).toBeUndefined()
  })
})