const fs = require('fs').promises
const path = require('path')
const Koa = require('koa')
const { pathToRegexp } = require('path-to-regexp')
const cors = require('@koa/cors')
const logger = require('koa-logger')
const { Random, mock } = require('mockjs')
const randexp = require('randexp').randexp
const installSerializers = require('./serializers')

const PORT = 4000
const DATA_ROOT = 'api'

const app = new Koa()

Random.extend({
  phone: () => randexp(/^1[345798][0-9]{9}$/)
})

installSerializers(Random, mock)

app.use(cors())
app.use(logger())
app.use(async (ctx) => {
  const request = ctx.request
  const method = request.method.toLowerCase()
  const pathname = request.path
  const routes = await traverseDir(DATA_ROOT)

  const matchedRoute = routes.find((route) => {
    const regexp = pathToRegexp(`/${route}`.replace(/\/_/g, '/:'))
    return regexp.test(pathname)
  })

  if (matchedRoute) {
    const filePath = path.join(__dirname, matchedRoute, `${method}.json`)
    const rawData = await fs.readFile(filePath)
    // ctx.append('authorization', 'basic test-token')
    ctx.body = mock(JSON.parse(rawData))
  } else {
    ctx.throw(404, `pathname or method not found: ${method} ${pathname}`)
  }
})

app.listen(PORT)
// eslint-disable-next-line no-console
console.log(`mock start at http://localhost:${PORT} port`)

/**
 * list all dir path
 * @param {string} dir root path
 */
async function traverseDir(dir) {
  const basePath = path.join(__dirname, `${dir}`)
  const fileList = await fs.readdir(basePath)
  const allFiles = []
  let hasCurrentDir = false

  for (const filename of fileList) {
    const filepath = path.join(basePath, filename)
    const stat = await fs.lstat(filepath)
    const unixFilePath = `${dir}/${filename}`
    if (stat.isDirectory()) {
      const subFiles = await traverseDir(unixFilePath)
      allFiles.push(...subFiles)
    } else if (!hasCurrentDir) {
      hasCurrentDir = true
      allFiles.push(dir)
    }
  }
  return allFiles
}