import http from 'http'

import express from 'express'
import lunr from 'lunr'
import morgan from 'morgan'
import * as z from 'zod'

import idxJson from '../build/idx.json'
import { dbPost, initDatabase } from './db'

export const SERVER_PORT = 5000

export async function runServer() {
  await initDatabase()

  const app = express()
  if (process.env.NODE_ENV === 'development') {
    app.use(morgan('common'))
  }

  const router = express.Router()
  app.use('/api', router)

  const idx = lunr.Index.load(idxJson)

  router.get('/', (req, res) => {
    const { path } = z
      .object({
        path: z.string(),
      })
      .parse(req.query)

    const r = dbPost.findOne({ path })
    if (!r) {
      res.sendStatus(404)
      return
    }

    res.json(r)
  })

  router.get('/q', (req, res) => {
    const { q, tag, page: _page = '1' } = z
      .object({
        q: z.string().optional(),
        tag: z.string().optional(),
        page: z
          .string()
          .refine((s) => /^\d+$/.test(s))
          .optional(),
      })
      .parse(req.query)

    const perPage = 5
    const offset = (parseInt(_page) - 1) * perPage

    let cond = dbPost.chain().find({
      date: { $exists: true } as any,
    })

    if (q) {
      cond = cond.find({
        path: { $in: idx.search(q).map(({ ref }) => ref) },
      })
    }

    if (tag) {
      cond = cond.find({
        tag: { $contains: tag },
      })
    }

    cond = cond.simplesort('date', { desc: true })

    const count = cond.branch().count()
    const result = cond.offset(offset).limit(5).data()

    res.json({
      count,
      result,
    })
  })

  app.use((err: Error, _: express.Request, res: express.Response) => {
    // eslint-disable-next-line no-console
    console.error(err.stack)
    res.status(500).send(err)
  })

  await new Promise<http.Server | Error>((resolve) => {
    const srv = app
      .listen(SERVER_PORT, () => {
        // eslint-disable-next-line no-console
        console.info(
          `serverMiddleware is running at http://localhost:${SERVER_PORT}`
        )
        resolve(srv)
      })
      .once('error', (e) => {
        /**
         * Nuxt generate will try to spawn two process on the same SERVER_PORT.
         *
         * One of which will inevitably fail.
         *
         * ! DO NOT reject()
         */
        resolve(e)
      })
      .once('close', () => {
        // eslint-disable-next-line no-console
        console.info('serverMiddleware is closing')
      })
  })
}

if (require.main === module) {
  // eslint-disable-next-line no-console
  runServer().catch(console.error)
}