const fs = require('fs')
const path = require('path')
const router = require('express').Router()

const timer = (time = 300) => (req, res, next) => setTimeout(next, time)

const dataDir = path.join(__dirname, 'data')

const readJson = (fileName) => {
  const filePath = path.join(dataDir, fileName)
  const content = fs.readFileSync(filePath, 'utf-8')
  return JSON.parse(content)
}

const sendNotFound = (res, message) => {
  res.status(404).json({ error: { message }, data: null })
}

router.use(timer())
router.use((req, res, next) => {
  res.type('application/json')
  next()
})

// Challenge API endpoints
router.post('/challenge/auth', (req, res) => {
  res.json(readJson('auth.json'))
})

router.get('/challenge/chains', (req, res) => {
  res.json(readJson('chains.json'))
})

router.get('/challenge/chain/:id', (req, res) => {
  const chains = readJson('chains.json')
  const chain = chains.find((item) => item.id === req.params.id || item._id === req.params.id)
  if (!chain) {
    return sendNotFound(res, `Цепочка ${req.params.id} не найдена`)
  }
  return res.json(chain)
})

router.get('/challenge/task/:id', (req, res) => {
  const chains = readJson('chains.json')
  const task = chains
    .flatMap((chain) => chain.tasks || [])
    .find((item) => item.id === req.params.id || item._id === req.params.id)

  if (!task) {
    return sendNotFound(res, `Задание ${req.params.id} не найдено`)
  }

  return res.json(task)
})

router.post('/challenge/submit', (req, res) => {
  const response = readJson('submit.json')
  res.json(response)
})

router.get('/challenge/check-status/:queueId', (req, res) => {
  const statuses = readJson('queue-status.json')
  const status = statuses[req.params.queueId]

  if (!status) {
    return sendNotFound(res, `Статус очереди ${req.params.queueId} не найден`)
  }

  return res.json(status)
})

router.get('/challenge/user/:userId/stats', (req, res) => {
  const statsMap = readJson('user-stats.json')
  const stats = statsMap[req.params.userId]

  if (!stats) {
    return sendNotFound(res, `Статистика пользователя ${req.params.userId} не найдена`)
  }

  return res.json(stats)
})

router.get('/challenge/user/:userId/submissions', (req, res) => {
  const submissionsMap = readJson('user-submissions.json')
  const submissions = submissionsMap[req.params.userId] || []
  return res.json(submissions)
})

router.get('/challenge/stats', (req, res) => {
  res.json(readJson('system-stats.json'))
})

router.get('/challenge/submissions', (req, res) => {
  res.json(readJson('submissions.json'))
})

module.exports = router