config = require '../../server_config'
winston = require 'winston'
mongoose = require 'mongoose'
async = require 'async'
errors = require './errors'
aws = require 'aws-sdk'
db = require './../routes/db'
mongoose = require 'mongoose'
events = require 'events'

module.exports.queueClient = undefined

module.exports.sendwithusQueue = undefined



module.exports.initializeQueueClient = (cb) ->
  module.exports.queueClient = module.exports.generateQueueClient() unless queueClient?
  cb?()

module.exports.initializeSendwithusQueue = (cb) ->
  queueClient = module.exports.generateQueueClient() unless queueClient?
  queueClient.registerQueue "sendwithus", {}, (err,data) ->
    if err?
      errorString = "There was an error registering the sendwithus queue."
      winston.error errorString
      throw new Error errorString
    module.exports.sendwithusQueue = data
    cb? err, module.exports.sendwithusQueue





module.exports.generateQueueClient = ->
  if config.queue.accessKeyId
    queueClient = new SQSQueueClient()
  else
    queueClient = new MongoQueueClient()
  return queueClient


class MessageObject
  constructor: () ->
    return

  getBody: ->
    return

  getID: ->
    return
  removeFromQueue: ->
    return

  requeue: ->
    return

  changeMessageVisibilityTimeout: (secondsFromFunctionCall) ->
    return




class SQSQueueClient
  constructor: ->
    @configure()
    @sqs = @generateSQSInstance()

  ###Public API###
  registerQueue: (queueName, options, callback) ->
    #returns new queue in data argument of callback
    @sqs.createQueue {QueueName: queueName}, (err,data) =>
      if err?
        winston.error("There was an error creating a new SQS queue, reason: #{JSON.stringify err}")
        throw new Error("Fatal SQS error, see Winston output")
      newQueue = new SQSQueue(queueName, data.QueueUrl, @sqs)
      callback err, newQueue
  ###Public API###
  configure: ->
    aws.config.update
      accessKeyId: config.queue.accessKeyId
      secretAccessKey: config.queue.secretAccessKey
      region: config.queue.region

  generateSQSInstance: ->
    new aws.SQS()


class SQSQueue extends events.EventEmitter
  constructor: (@queueName, @queueUrl, @sqs) ->

  subscribe: (eventName, callback) -> @on eventName, callback
  unsubscribe: (eventName, callback) -> @removeListener eventName, callback


  publish: (messageBody,delayInSeconds, callback) ->
    @sendMessage messageBody, delayInSeconds, callback

  receiveMessage: (callback) ->
    @sqs.receiveMessage {QueueUrl: @queueUrl, WaitTimeSeconds: 20}, (err, data) =>
      originalData = data
      data = new SQSMessage originalData, this

      if err? then @emit 'error',err,originalData else @emit 'message',err,data
      callback? err,data

  deleteMessage: (receiptHandle, callback) ->
    @sqs.deleteMessage {QueueUrl: @queueUrl, ReceiptHandle: receiptHandle}, (err, data) =>
      if err? then @emit 'error',err,data else @emit 'message',err,data
      callback? err,data

  changeMessageVisibilityTimeout: (secondsFromNow, receiptHandle, callback) ->
    @sqs.changeMessageVisibility {QueueUrl: @queueUrl, ReceiptHandle: receiptHandle, VisibilityTimeout: secondsFromNow}, (err, data) =>
      if err? then @emit 'error',err,data else @emit 'edited',err,data
      callback? err,data


  sendMessage: (messageBody, delaySeconds, callback) ->
    @sqs.sendMessage {QueueUrl: @queueUrl, MessageBody: messageBody, DelaySeconds: delaySeconds}, (err, data) =>
      if err? then @emit 'error',err,data else @emit 'sent',err, data
      callback? err,data

  listenForever: =>
    async.forever (asyncCallback) =>
      @receiveMessage (err, data) ->
        asyncCallback(null)

class SQSMessage extends MessageObject
  constructor: (@originalMessage, @parentQueue) ->

  isEmpty: -> not @originalMessage.Messages?[0]?

  getBody: -> @originalMessage.Messages[0].Body

  getID: -> @originalMessage.Messages[0].MessageId

  removeFromQueue: (callback) -> @parentQueue.deleteMessage @getReceiptHandle(), callback

  requeue: (callback) -> @parentQueue.changeMessageVisibilityTimeout 0, @getReceiptHandle(), callback

  changeMessageVisibilityTimeout: (secondsFromFunctionCall, callback) ->
    @parentQueue.changeMessageVisibilityTimeout secondsFromFunctionCall,@getReceiptHandle(), callback

  getReceiptHandle: -> @originalMessage.Messages[0].ReceiptHandle

      





class MongoQueueClient
  constructor: ->
    @configure()
    @createMongoConnection()
    @messageModel = @generateMessageModel()

  ###Public API###
  registerQueue: (queueName, options, callback) ->
    newQueue = new MongoQueue queueName,options,@messageModel
    callback(null, newQueue)
  ###Public API###

  configure: ->
    @databaseAddress = db.generateDatabaseAddress()
    @mongoDatabaseName = config.mongoQueue.queueDatabaseName;

  createMongoConnection:  ->
    @mongooseConnection = mongoose.createConnection "mongodb://#{@databaseAddress}/#{@mongoDatabaseName}"
    @mongooseConnection.on 'error', ->
      winston.error "There was an error connecting to the queue in MongoDB"
    @mongooseConnection.once 'open', ->
      winston.info "Successfully connected to MongoDB queue!"

  generateMessageModel: ->
    #do find something like: messages not processing, queue as current queue, visibility time before now, sort by insertion time, findOne
    schema = new mongoose.Schema
      messageBody: Object,
      processing: false,
      insertionTime: {type: Date, default: Date.now }
      queue: String
      scheduledVisibilityTime: Date
    @mongooseConnection.model 'Message',schema


class MongoQueue extends events.EventEmitter
  constructor: (queueName, options, messageModel) ->
    @Message = messageModel
    @queueName = queueName


  subscribe: (eventName, callback) -> @on eventName, callback
  unsubscribe: (eventName, callback) -> @removeListener eventName, callback

  publish: (messageBody, delayInSeconds, callback) ->
    @sendMessage messageBody, delayInSeconds, callback

  receieveMessage: (callback) ->
    conditions = {queue: @queueName, processing: false, scheduledVisibilityTime: {$lt:Date.now()}}
    options = {sort: 'scheduledVisibilityTime'}
    update = {$set: {processing: true}}
    @Message.findOneAndUpdate conditions, update, options, =>
      if err? then @emit 'error',err,data else @emit 'message',err,data
      callback? err,data

  deleteMessage: (receiptHandle, callback) ->
    #receiptHandle in this case is an ID
    conditions = {queue: @queueName, _id: receiptHandle}
    @Message.findOneAndRemove conditions, {}, =>
      if err? then @emit 'error',err,data else @emit 'message',err,data
      callback? err,data


  sendMessage: (messageBody, delaySeconds, callback) ->
    messageToSend = new @Message
      messageBody: messageBody
      processing: false
      queue: @queueName
      scheduledVisibilityTime: Date.now() + (delaySeconds * 1000)
    messageToSend.save (err,data) =>
      if err? then @emit 'error',err,data else @emit 'sent',err, data
      callback? err,data

  listenForever: =>
    async.forever (asyncCallback) =>
      @recieveMessage (err, data) ->
        asyncCallback(null)