var poolModule = require('generic-pool')
var q = require('q')
var pool = poolModule.pool({
  name: 'test-pool',
  create: createFn
})

function createFn(cb) {
  createWithPromise()
   .then(function(item) {
     return cb(null, item)
   })
  .fail(function(err) {
    return cb(err)
  })
}

function createWithPromise() {
  var deferred = q.defer()
  create()
  setTimeout(rejectOnTimeout, 1000)
  return deferred.promise

  function rejectOnTimeout() {
    var error = new Error('timeout reached')
    return deferred.reject(error)
  }
  function create() {
    var item = {}
    // some async thing that might not complete before timeout
   // as an example the deferred.resolve line below is commented out
   // return deferred.resolve(item)
  }
}

var timeoutInMilliseconds = 1000
acquireWithTimeout(timeoutInMilliseconds)
  .then(function(client) {
    console.log('got client')
    // do something with the client here
  })
  .fail(function(err) {
    console.log('failed to get client')
    console.dir(err)
  })

function acquireWithTimeout(timeout) {
  var deferred = q.defer()
  pool.acquireWithPromise()
    .then(function(client) {
      return deferred.resolve(client
    })
  }

  setTimeout(reject, timeout)

  function reject() {
    var error = new Error('timeout reached trying to acquire client from pool')
    return deferred.reject(error)
  } 
}

function acquireWithPromise() {
  var deferred = q.defer()
  pool.acquire(callback)
  return deferred.promise

  function callback(err, client) {
     if (errr) {
      return deferred.reject(err)
    }
    return deferred.resolve(client
  }
}