// The CloudFront function that keeps Astro's directory output at the no-slash
// addresses a standard.site document record claims.
//
// It runs at the edge on every request and is deployed as a bare source file,
// so nothing else in this tree type-checks or exercises it: a mistake here is
// found by a reader hitting a redirect loop. These are the cases that decide
// whether an address a record claims and the object serving it stay one page.

import assert from 'node:assert/strict'
import { readFileSync } from 'node:fs'
import { dirname, join } from 'node:path'
import { test } from 'node:test'
import { fileURLToPath } from 'node:url'

// 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(dirname(fileURLToPath(import.meta.url)), '../../infra/viewer-request.js'),
  'utf8',
)
const handler = new Function(`${source}; return handler;`)()

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

test('the root is left to default_root_object', () => {
  assert.equal(run('/').uri, '/')
})

test('extensionless URIs become the index.html object', () => {
  assert.equal(run('/posts').uri, '/posts/index.html')
  assert.equal(run('/posts/hello-world').uri, '/posts/hello-world/index.html')
})

test('URIs that name a file pass through untouched', () => {
  assert.equal(run('/atom.xml').uri, '/atom.xml')
  assert.equal(run('/404.html').uri, '/404.html')
  assert.equal(run('/_astro/index.abc123.css').uri, '/_astro/index.abc123.css')
  // Dots in the last segment, and no extension to add.
  assert.equal(
    run('/.well-known/site.standard.publication').uri,
    '/.well-known/site.standard.publication',
  )
})

test('a trailing slash redirects to the canonical no-slash address', () => {
  const response = run('/posts/hello-world/')
  assert.equal(response.statusCode, 301)
  assert.equal(response.headers.location.value, '/posts/hello-world')
})

test('runs of trailing slashes collapse without looping the root', () => {
  assert.equal(run('/posts///').headers.location.value, '/posts')
  assert.equal(run('///').headers.location.value, '/')
})

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