gistfile1.rb

view:

= f.inputs :name => "Contract details", :class => "accordion" do
  = f.input :mpan
  = f.input :kva
  = f.input :voltage, :as => :radio, :collection => {"Low" => "LV", "High" => "HV"}
  = f.input :estimated_annual_consumption

model:

class ElectricityContract < Contract (MogngoMapper::EmbeddedDocument)
  plugin Joint
  
  key :mpan, Mpan # this guy!
  
  key :kva, Integer
  key :estimated_annual_consumption, Integer
  key :voltage, String
  
  attachment :half_hourly_data
end

Mpan class :

class Mpan
  attr_reader :profile, :mts, :llf, :did, :uid, :cd
  
  def initialize(profile, mts, llf, did, uid, cd)
    raise "Profile invalid" unless profile.length == 2
    raise "Meter time-switch code invalid" unless mts.length == 3
    raise "Line-loss factor invalid" unless llf.length == 3
    raise "Distributor id invalid" unless did.length == 2
    raise "Unique identifier invalid" unless uid.length == 8
    
    core = did + uid + cd
    
    primes = [3, 5, 7, 13, 17, 19, 23, 29, 31, 37, 41, 43]
    check_digit = (0..11).inject(0) { |sum, n| sum + (core[n, 1].to_i * primes[n]) } % 11 % 10
    
    raise "Check digit invalid" unless check_digit == cd[-1, 1].to_i
    
    @profile = profile
    @mts = mts
    @llf = llf
    @did = did
    @uid = uid
    @cd = cd
  end
  
  def top_line
    @profile + @mts + @llf
  end
  
  def bottom_line
    @did + @uid + @cd
  end
  
  def to_s
    "#{top_line} / #{bottom_line}"
  end
  
  def self.to_mongo(value)
    return {:profile => value.profile, :mts => value.mts, :llf => value.llf, :did => value.did, :uid => value.uid, :cd => value.cd} if value.is_a? Mpan
    value.nil? ? nil : {:profile => value["profile"], :mts => value["mts"], :llf => value["llf"], :did => value["did"], :uid => value["uid"], :cd => value["cd"]}
  end
  
  def self.from_mongo(value)
    return value if value.is_a? Mpan
    value.nil? ? nil : Mpan.new(value[:profile], value[:mts], value[:llf], value[:did], value[:uid], value[:cd])
  end
end