require "uuid"
require "rest-client"
require "uri"
require "cgi"
require "acts_as_chain"
require "nokogiri"
require "iconv"
require "ballou_sms_gateway/request"

class BallouSmsGateway
  acts_as_chain :username, :password, :id, :request_id, :message
  
  def initialize
    # 
    # @UN Username
    # @PW Password
    # @O Sender
    # @RI Request id
    # @CR SMS id
    # @D Receiver
    # @LONGSMS Is this a long sms?
    # @M Message
    #
    @url = %w{
      http://sms2.ballou.se/http/get/SendSms.php?
      UN=%s&
      PW=%s&
      CR=%s&
      RI=%s&
      O=%s&
      D=%s&
      LONGSMS=%s&
      M=%s
    }.join
    
    @id            = UUID.new.generate
    @long          = false
    @request_id    = UUID.new.generate
    @error_message = nil
  end
  
  def long
    tap { @long = true }
  end
  
  #
  # Sends the message. Raises error if message is to long or if @send and @from isn't set.
  #
  def send!
    if @message.length > 160 and not @long
      raise "Message is to long, #{@message.length} characters."
    end
    
    [:from, :to, :password, :username].each do |method|
      var = instance_variable_get("@#{method}")
      unless var
        raise "You need to specify #{method}, using the ##{method} method."
      end
    end
    
    defaults = {
      sms_id: @id,
      request_id: @request_id
    }
    
    doc = Nokogiri::XML(do_request!)
    if response = doc.at_css("response message")
      BallouSmsGatewayModule::Request.new({
        id: response.attr("id"),
        message: response.text,
        to: response.attr("to_msisdn"), 
        status: response.attr("status"), 
        error: response.attr("error")
      }.merge(defaults))
    elsif response = doc.at_css("ballou_sms_response error")
      BallouSmsGatewayModule::Request.new({
        to: @to,
        status: -2,
        error: response.attr("code"),
        message: response.text,
      }.merge(defaults))
    else
      BallouSmsGatewayModule::Request.new({
        to: @to,
        status: -2,
        error: 7,
        message: @error_message
      }.merge(defaults))
    end
  end
    
  #
  # @to A list of phonenumbers. Can contain 0-9 and the "+" sign.
  # @return BallouSmsGateway
  def to(*to)
    to.flatten.each do |number|
      unless number.to_s.match(/^\+?[0-9]{4,}$/)
        raise "Invalid receiver."
      end
    end
    
    @to = to.flatten.map { |number| number }.join(",")
    return self
  end
  
  #
  # @from String Sender. Max length when only numbers are submitet; 15, otherwise; 10
  # @return BallouSmsGateway
  #
  def from(from)
    if from.to_s.length.zero?
      raise "Sender is invalid, to short."
    end
    
    # Max length 15 for integers and 10 for chars 
    if from.match(/^[0-9]+$/)
      if  from.length > 15
        raise "Sender is invalid, to long."
      end
    elsif from.length > 10
      raise "Sender is invalid, to long."
    end
    
    @from = from
    return self
  end
  
  private
    def url
      @url % [
        @username,
        @password,
        @id,
        @request_id,
        @from,
        @to,
        @long,
        @message
      ].map{|v| URI::escape(to_latin_1(v))}
    end
    
    def do_request!
      data = RestClient.get(url)
    rescue RestClient::Exception
      @error_message = $!.message
    ensure
      data || ""
    end
    
    def to_latin_1(string)
      Iconv.conv("ISO-8859-1", "UTF-8", string.to_s)
    end
end