import express from 'express'
import libLanguages from '../lib/languages.js'
import searchVersions from '../lib/search/versions.js'
import loadLunrResults, { QueryTermError } from '../lib/search/lunr-search.js'
import { cacheControlFactory } from './cache-control.js'

const languages = new Set(Object.keys(libLanguages))
const versions = new Set(Object.values(searchVersions))
const router = express.Router()
const cacheControl = cacheControlFactory(60 * 60 * 24)
const noCacheControl = cacheControlFactory(0)

router.get('/', async function getSearch(req, res, next) {
  const { query, version, language, filters, limit: limit_ } = req.query
  const limit = Math.min(parseInt(limit_, 10) || 10, 100)
  if (!versions.has(version)) {
    return res.status(400).json({ error: 'Unrecognized version' })
  }
  if (!languages.has(language)) {
    return res.status(400).json({ error: 'Unrecognized language' })
  }
  if (!query || !limit) {
    return res.status(200).json([])
  }

  try {
    const results = await loadLunrResults({
      version,
      language,
      query: `${query} ${filters || ''}`,
      limit,
    })
    // Only reply if the headers have not been sent and the request was not aborted...
    if (!res.headersSent && !req.aborted) {
      cacheControl(res)

      // Undo the cookie setting that CSRF sets.
      // Otherwise it can't be cached in the CDN.
      res.removeHeader('set-cookie')

      return res.status(200).json(results)
    }
  } catch (err) {
    if (err instanceof QueryTermError) {
      // Handled as an not entirely unexpected potential error
      return res.status(400).json({ error: err.toString() })
    }

    console.error(err)
    // Only reply if the headers have not been sent and the request was not aborted...
    if (!res.headersSent && !req.aborted) {
      noCacheControl(res)
      return res.status(400).json({ error: err.toString() })
    }
  }
})

export default router