require 'twilio-ruby'
require 'securerandom'

module Agents
  class TwilioAgent < Agent
    cannot_be_scheduled!

    description <<-MD
      The TwilioAgent receives and collects events and sends them via text message or gives you a call when scheduled.

      It is assumed that events have a `:message`, `:text`, or `:sms` key, the value of which is sent as the content of the text message/call. You can use Event Formatting Agent if your event does not provide these keys.

      Set `receiver_cell` to the number to receive text messages/call and `sender_cell` to the number sending them.

      `expected_receive_period_in_days` is maximum number of days that you would expect to pass between events being received by this agent.

      If you would like to receive calls, then set `receive_call` to true. `server_url` needs to be 
      filled only if you are making calls. Dont forget to include http/https in `server_url`.

    MD

    def default_options
      {
        :account_sid => 'ACxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',
        :auth_token => 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',
        :sender_cell => 'xxxxxxxxxx',
        :receiver_cell => 'xxxxxxxxxx',
        :server_url    => 'http://somename.com:3000',
        :receive_text  => 'true',
        :receive_call  => 'false',
        :expected_receive_period_in_days => '1'
      }
    end

    def validate_options
      unless options[:account_sid].present? && options[:auth_token].present? && options[:sender_cell].present? && options[:receiver_cell].present? && options[:expected_receive_period_in_days].present? && options[:receive_call].present? && options[:receive_text].present?
        errors.add(:base, 'account_sid, auth_token, sender_cell, receiver_cell, receive_text, receive_call and expected_receive_period_in_days are all required')
      end
    end

    def receive(incoming_events)
      @client = Twilio::REST::Client.new options[:account_sid], options[:auth_token]
      memory[:pending_calls] ||= {}
      incoming_events.each do |event|
        message = (event.payload[:message] || event.payload[:text] || event.payload[:sms]).to_s
        if message != ""
          if options[:receive_call].to_s == 'true'
            secret = SecureRandom.hex 3
            memory[:pending_calls][secret] = message
            make_call secret
          end
          if options[:receive_text].to_s == 'true'
            message = message.slice 0..160
            send_message message
          end
        end
      end
    end

    def working?
      last_receive_at && last_receive_at > options[:expected_receive_period_in_days].to_i.days.ago
    end

    def send_message(message)
      @client.account.sms.messages.create :from => options[:sender_cell],
                                          :to => options[:receiver_cell],
                                          :body => message
    end

    def make_call(secret)
      @client.account.calls.create :from => options[:sender_cell],
                                   :to => options[:receiver_cell],
                                   :url => post_url(options[:server_url],secret)
    end

    def post_url(server_url,secret)
      "#{server_url}/users/#{self.user.id}/webhooks/#{self.id}/#{secret}"
    end

    def receive_webhook(params)
      if memory[:pending_calls].has_key? params[:secret].to_sym
        response = Twilio::TwiML::Response.new {|r| r.Say memory[:pending_calls][params[:secret].to_sym], :voice => 'woman'}
        memory[:pending_calls].delete params[:secret].to_sym
        [response.text, 200]
      end
    end
  end
end