foodsoft/app/models/ordergroup.rb

# encoding: utf-8
#
# Ordergroups can order, they are "children" of the class Group
# 
# Ordergroup have the following attributes, in addition to Group
# * account_balance (decimal)
# * account_updated (datetime)
class Ordergroup < Group
  acts_as_paranoid                    # Avoid deleting the ordergroup for consistency of order-results
  serialize :stats

  has_many :financial_transactions, :order => "created_on DESC"
  has_many :group_orders
  has_many :orders, :through => :group_orders

  validates_numericality_of :account_balance, :message => 'ist keine gültige Zahl'
  validate :uniqueness_of_members

  after_create :update_stats!

  def contact
    "#{contact_phone} (#{contact_person})"
  end
  def non_members
    User.all(:order => 'nick').reject { |u| (users.include?(u) || u.ordergroup) }
  end

  def value_of_open_orders(exclude = nil)
    group_orders.open.reject{|go| go == exclude}.collect(&:price).sum
  end
  
  def value_of_finished_orders(exclude = nil)
    group_orders.finished.reject{|go| go == exclude}.collect(&:price).sum
  end

  # Returns the available funds for this order group (the account_balance minus price of all non-closed GroupOrders of this group).
  # * exclude (GroupOrder): exclude this GroupOrder from the calculation
  def get_available_funds(exclude = nil)
    account_balance - value_of_open_orders(exclude) - value_of_finished_orders(exclude)
  end

  # Creates a new FinancialTransaction for this Ordergroup and updates the account_balance accordingly.
  # Throws an exception if it fails.
  def add_financial_transaction!(amount, note, user)
    transaction do      
      t = FinancialTransaction.new(:ordergroup => self, :amount => amount, :note => note, :user => user)
      t.save!
      self.account_balance = financial_transactions.sum('amount')
      self.account_updated = t.created_on
      save!
      # Notify only when order group had a positive balance before the last transaction:
      if t.amount < 0 && self.account_balance < 0 && self.account_balance - t.amount >= 0
        UserNotifier.delay.negative_balance(self.id, t.id)
      end
    end
  end

  def update_stats!
    time = 6.month.ago
    jobs = users.collect { |u| u.tasks.done.sum('duration', :conditions => ["updated_on > ?", time]) }.sum
    orders_sum = group_orders.select { |go| !go.order.ends.nil? && go.order.ends > time }.collect(&:price).sum
    update_attribute(:stats, {:jobs_size => jobs, :orders_sum => orders_sum})
  end

  def avg_jobs_per_euro
    stats[:orders_sum] != 0 ? stats[:jobs_size].to_f / stats[:orders_sum].to_f : 0
  end

  # This is the ordergroup job per euro performance 
  # in comparison to the hole foodcoop average
  def apples
    ((avg_jobs_per_euro / Ordergroup.avg_jobs_per_euro) * 100).to_i rescue 0
  end

  # Global average
  def self.avg_jobs_per_euro
    stats = Ordergroup.all.collect(&:stats)
    stats.collect {|s| s[:jobs_size].to_f }.sum / stats.collect {|s| s[:orders_sum].to_f }.sum
  end
  
  private

  # Make sure, that a user can only be in one ordergroup
  def uniqueness_of_members
    users.each do |user|
      errors.add :user_tokens, "#{user.nick} ist schon in einer anderen Bestellgruppe" if user.groups.where(:type => 'Ordergroup').size > 1
    end
  end
  
end