module ActiveMerchant
  module Billing
    class SecurePayTechGateway < Gateway
      class SecurePayTechPostData < PostData
        # Fields that will be sent even if they are blank
        self.required_fields = [ :OrderReference, :CardNumber, :CardExpiry, :CardHolderName, :CardType, :MerchantID, :MerchantKey, :Amount, :Currency ]
      end                                                  

      URL = 'https://tx.securepaytech.com/web/HttpPostPurchase'

      PAYMENT_GATEWAY_RESPONSES = {
        1 => "Transaction OK",
        2 => "Insufficient funds",
        3 => "Card expired",
        4 => "Card declined",
        5 => "Server error occurred",
        6 => "Communications error",
        7 => "Unsupported transaction type",
        8 => "Bad or malformed request",
        9 => "Invalid card number" 
      }

      # URL
      attr_reader :response
      attr_reader :options

      self.default_currency = 'NZD'
      self.supported_countries = ['NZ']
      self.supported_cardtypes = [:visa, :master, :american_express, :diners_club]
      self.homepage_url = 'http://www.securepaytech.com/'
      self.display_name = "SecurePayTech" 

      def initialize(options = {})
        requires!(options, :merchant_id, :merchant_key)
        @options = options
        super
      end

      def purchase(money, creditcard, options = {})
        post = SecurePayTechPostData.new

        add_amount(post, money, options)
        add_creditcard(post, creditcard)
        add_invoice_data(post, options)

        commit(:purchase, post)
      end  

      private                                 
      def commit(action, post)
        if result = test_result_from_cc_number(post[:card_number])
          return result
        end

        data = ssl_post(URL, post_data(action, post))

        @response = parse(data)

        success = (@response[:result_code] == 1)
        message = success ? 'Success' : message_from(@response)

        Response.new(success, message, @response, 
          :test => test?, 
          :authorization => @response[:merchant_transation_reference]
        )
      end

      def parse(body)
        response = CGI.unescape(body).split(',')

        result = {}
        result[:result_code] = response[0]

        if response.length == 2
          result[:fail_reason] = response[1]
        else
          result[:merchant_transaction_reference] = response[1]
          result[:receipt_number]                 = response[2]
          result[:transaction_number]             = response[3]
          result[:authorisation_id]               = response[4]
          result[:batch_number]                   = response[5]
        end

        result
      end     

      def post_data(action, post)
        post[:MerchantID]  = @options[:merchant_id]
        post[:MerchantKey] = @options[:merchant_key]
        post.to_s
      end

      def add_creditcard(post, creditcard)      
        post[:CardNumber]     = creditcard.number
        post[:CardExpiry]     = expdate(creditcard)
        post[:CardHolderName] = creditcard.name

        # SecurePayTech always autodetects this
        post[:CardType]       = 0
      end

      def add_invoice_data(post, options)
        post[:OrderReference] = options[:order_id]
      end

      def add_amount(post, money, options)
        post[:Amount] = amount(money)

        # SecurePayTech currently only supports NZD anyway, but for possible future expansion...
        post[:Currency] = options[:currency] || currency(money)
      end

      # Make a ruby type out of the response string
      def normalize(field)
        case field
        when "true"   then true
        when "false"  then false
        when ""       then nil
        when "null"   then nil
        else field
        end        
      end          

      def message_from(result)
        PAYMENT_GATEWAY_RESPONSES[result[:result_code]]
      end

      def expdate(creditcard)
        year  = sprintf("%.4i", creditcard.year)
        month = sprintf("%.2i", creditcard.month)

        "#{month}#{year[-2..-1]}" 
      end
    end
  end
end