import { readFileSync } from 'node:fs'
import { join } from 'node:path'
import { describe, expect, it } from 'vitest'

// The CloudFront Functions runtime wants a bare top-level handler, so the
// source has no exports; evaluate it and pull the handler out.
const source = readFileSync(join(import.meta.dirname, 'viewer-request.js'), 'utf8')
const handler = new Function(`${source}; return handler;`)()

function run(uri, querystring = {}) {
  return handler({ request: { uri, querystring } })
}

describe('viewer-request.js', () => {
  it('leaves the root to default_root_object', () => {
    expect(run('/').uri).toBe('/')
  })

  it('rewrites extensionless URIs to the index.html object', () => {
    expect(run('/posts').uri).toBe('/posts/index.html')
    expect(run('/posts/hello-world').uri).toBe('/posts/hello-world/index.html')
  })

  it('passes file URIs through untouched', () => {
    expect(run('/atom.xml').uri).toBe('/atom.xml')
    expect(run('/client-metadata.json').uri).toBe('/client-metadata.json')
    expect(run('/_astro/index.abc123.css').uri).toBe('/_astro/index.abc123.css')
  })

  it('redirects trailing slashes to the canonical no-slash address', () => {
    const response = run('/posts/hello-world/')
    expect(response.statusCode).toBe(301)
    expect(response.headers.location.value).toBe('/posts/hello-world')
  })

  it('collapses runs of trailing slashes without redirect-looping the root', () => {
    expect(run('/posts///').headers.location.value).toBe('/posts')
    expect(run('///').headers.location.value).toBe('/')
  })

  it('keeps the query string on redirects', () => {
    const querystring = {
      ref: { value: 'feed' },
      flag: { value: '' },
      tag: { value: 'a', multiValue: [{ value: 'a' }, { value: 'b' }] },
    }
    const response = run('/posts/hello-world/', querystring)
    expect(response.headers.location.value).toBe(
      '/posts/hello-world?ref=feed&flag&tag=a&tag=b',
    )
  })
})