module SmsRouter

# File lib/sms_router.rb, line 9
def self.configure(&block)
self.configuration ||= Configuration.new
yield(configuration)
end

# File lib/sms_router.rb, line 23
def self.encyrpt_message(message)
        # declaration
        app_key  = self.configuration.app_key
        app_code = self.configuration.app_code

        # encyption
        msg_and_key  = message + app_key
        md5_digest   = Digest::MD5.new
        md5_digest   = md5_digest.update(msg_and_key).to_s
        encypted_msg = "#{message}|#{md5_digest.chars.first(3).join}#{md5_digest.chars.last(3).join}"

        # return
        encypted_msg
end

# File lib/sms_router.rb, line 38
def self.validate_message(message)
        # get the configurations
        app_key   = self.configuration.app_key
        app_code  = self.configuration.app_code

        # get the original message and recvd key
        recvd_msg = message.split("|")
        orgnl_msg = recvd_msg.first
        recvd_key = recvd_msg.last

        # combine the orgininal msg & app_key
        msg_and_key = orgnl_msg + app_key
        md5_message = Digest::MD5.new
        md5_message = md5_message.update(msg_and_key).to_s

        # append the first & lat 3 char of the md5 hash
        genrtd_key  = md5_message.chars.first(3).join + md5_message.chars.last(3).join

        # return  the result by combining the recvd key to generated key
        recvd_key == genrtd_key
end