const express = require('express')
const statusCodes = require('http-status-codes').StatusCodes
const calcQueueSvc = require('../src/services/calc-queue')
const CalcQueueExceptions = require('../src/services/calc-queue/exceptions.js')

const router = express.Router()

// Return busy/not busy flag
router.get('/busy', function(req, res) {
  res.send({ busy: calcQueueSvc.isBusy() })
})

// Get the current queue of tasks
router.get('/queue', function(req, res) {
  res.send({ 'queue': calcQueueSvc.getQueue() })
})

// Add a calc task to the queue
router.put('/queue/:id/:calcFn', function(req, res) {
  try {
    calcQueueSvc.enqueue(req.params.id, req.params.calcFn)
    res.send({ success: true })
  } catch(ex) {
    if (ex instanceof CalcQueueExceptions.AlreadyQueued
      || ex instanceof CalcQueueExceptions.AlreadyInProgress
      || ex instanceof CalcQueueExceptions.CalculationUnknown) {
      res.status(
        statusCodes.BAD_REQUEST
      ).send(
        { success: false, error: ex.message }
      )
    } else {
      throw ex
    }
  }
})

// Remove a task or collection of tasks from the queue
router.delete('/queue/:id', function(req, res) {
  calcQueueSvc.dequeue(req.params.id, null)
  res.send({ success: true })
})
// Remove a task from the queue
router.delete('/queue/:id/:calcFn', function(req, res) {
  calcQueueSvc.dequeue(req.params.id, req.params.calcFn)
  res.send({ success: true })
})


// Poll the status of a task as a text string
const processStatus = function(id, calcFn) {
  if (calcQueueSvc.isInProgress(id, calcFn)) {
    return 'in_progress'
  } else if (calcQueueSvc.isQueued(id, calcFn)) {
    return 'queued'
  } else if (calcQueueSvc.isFinished(id, calcFn)) {
    return 'finished'
  } else {
    return 'not_queued'
  }
}

// Poll the status of an individual task
router.get('/poll/:id', function(req, res) {
  const status = processStatus(req.params.id, null)
  if (status == 'finished') {
    res.status(statusCodes.OK).send({
      id: req.params.id,
      status: status,
      retCode: calcQueueSvc.retCode(req.params.id, null)
    })
  } else {
    res.status(statusCodes.OK).send({
      id: req.params.id,
      status: status
    })
  }
})

// Poll the status of an individual task
router.get('/poll/:id/:calcFn', function(req, res) {
  const status = processStatus(req.params.id, req.params.calcFn)
  if (status == 'finished') {
    res.status(statusCodes.OK).send({
      id: req.params.id,
      calcFn: req.params.calcFn,
      status: status,
      retCode: calcQueueSvc.retCode(req.params.id, req.params.calcFn)
    })
  } else {
    res.status(statusCodes.OK).send({
      id: req.params.id,
      calcFn: req.params.calcFn,
      status: status
    })
  }
})


// Get the status of the queue and all tasks
router.get('/status', function(req, res) {
  res.status(statusCodes.OK).send({
    'queued': calcQueueSvc.getQueue(),
    'in_progress': calcQueueSvc.getInProgress(),
    'finished': calcQueueSvc.getFinished()
  })
})

// Get the status of all tasks with by id
router.get('/status/:id', function(req, res) {
  const status = calcQueueSvc.getStatus(req.params.id, null)
  if (status.length == 0) {
    res.status(statusCodes.BAD_REQUEST).send()
  } else {
    res.status(statusCodes.OK).send(status)
  }
})

// Get the status of an individual task
router.get('/status/:id/:calcFn', function(req, res) {
  const status = calcQueueSvc.getStatus(req.params.id, req.params.calcFn)
  if (status.length == 0) {
    res.status(statusCodes.BAD_REQUEST).send()
  } else {
    res.status(statusCodes.OK).send(status)
  }
})

module.exports = router