Cash Validation for review

cash_validation.rb

# The following is a Rails validation method on a model object
# Validations are pieces of code that ensure the data passed in to a model matches a defined set of rules
#   ex. presence, uniqueness, within a certain range

# The validation should ensure the following constraints are met:

# 1. 
# min_cash_pct:
#    Allow null: no
#    Value range: 0 to 100
# min_cash_dollars:
#    Allow null: no
#    Value range: 0 to 1e+17
# max_cash_pct:
#    Allow null: no
#    Value range: 0 to 100
# max_cash_dollars:
#    Allow null: no
#    Value range: 0 to 1e+17
# refill_cash_pct:
#    Allow null: yes
#    Value range: 0 to 100
# refill_cash_dollars:
#    Allow null: yes
#    Value range: 0 to 1e+17

# 2.
# effective min cash <= effective refill cash <= effective max cash

# Effective min cash is the larger of min_cash_dollars and min_cash_pct converted to a percentage of account value
# Effective max cash is the smaller of max_cash_dollars and max_cash_pct converted to a percentage of account value
# Effective refill cash is the larger of refill_cash_dollars and refill_cash_pct converted to a percentage of account value

# total_value can be assumed to be a method on the account model that returns the account value



validate do

  validates_in_range :min_cash_pct, min: 0, max: 100
  validates_in_range :max_cash_pct, min: 0, max: 100
  validates_in_range :refill_cash_pct, min: 0, max: 100

  validates_numericality_of :min_cash_dollars, greater_than_or_equal_to: 0, less_than_or_equal_to: 1e+17
  validates_numericality_of :max_cash_dollars, greater_than_or_equal_to: 0, less_than_or_equal_to: 1e+17
  validates_numericality_of :refill_cash_dollars, greater_than_or_equal_to: 0, less_than_or_equal_to: 1e+17, allow_nil: true

  min_cash_pct_converted = (!min_cash_pct.blank? ? (min_cash_pct * total_value)/100 : -1) 
  min_cash_dollars_temp = (min_cash_dollars.blank? ? -1 : min_cash_dollars) 
  max_cash_pct_converted = (!max_cash_pct.blank? ? (max_cash_pct * total_value)/100 : -1)
  effective_min_cash = [min_cash_pct_converted, min_cash_dollars_temp].max
  
  if max_cash_pct_converted < effective_min_cash 
    errors.add(:max_cash_pct, "value must be greater than or equal to Min Cash value")
  end

  # convert all % values to cash
  refill_cash_pct_converted = (!refill_cash_pct.blank? ? (refill_cash_pct * total_value)/100 : -1)
  refill_cash_dollars_temp = (refill_cash_dollars.blank? ? -1 : refill_cash_dollars)  
  max_cash_dollars_temp = (max_cash_dollars.blank? ? -1 : max_cash_dollars)

  # pick the appropriate value
  effective_max_cash = [max_cash_pct_converted, max_cash_dollars_temp].min
  effective_refill_cash = [refill_cash_pct_converted, refill_cash_dollars_temp].max

  if !max_cash_dollars.blank? && effective_max_cash < effective_min_cash
    errors.add(:max_cash_dollars, "value must be greater than Min Cash. ")
  elsif max_cash_pct_converted < effective_min_cash 
    errors.add(:max_cash_dollars, "value must be greater than Min Cash. ")
  end
  
  # Refill Cash Level validations -------------
  # 3) Refill Cash Pct can be 0 and pass
  # 4) Refill Cash Dollars can be null or 0 and pass
  # then validate refill vs min
  if (!(refill_cash_dollars.blank?) && !(refill_cash_dollars == 0)) || (!(refill_cash_pct.blank?) && !(refill_cash_pct == 0)) 
    if effective_refill_cash < effective_min_cash
      errors.add(:refill_cash_dollars, "value must be greater than or equal to Min Cash value.")
    end
    if (!min_cash_pct.nil? || !min_cash_dollars.nil?) && !(effective_refill_cash == 0) && effective_refill_cash < effective_min_cash
      errors.add(:refill_cash_dollars, "value must be greater than or equal to Min Cash value.")
    end
  end
end