Module: ActsAsHistorical::ClassMethods

Defined in:
lib/acts_as_historical.rb

Instance Method Summary collapse

Instance Method Details

#acts_as_historical(opts = {}) ⇒ Object

acts_as_historical

Parameters:

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :date_column (Symbol) — default: :snapshot_date —

    the database column for the date of the record

  • :scope (Symbol) — default: nil 


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# File 'lib/acts_as_historical.rb', line 16

def acts_as_historical(opts = {})
  configuration = { 
    :date_column => "snapshot_date",
    :scope => nil
  }
  configuration.update(opts) if opts.is_a?(Hash)

  send :include, InstanceMethods
  send :extend, DynamicClassMethods
  
  self.cattr_accessor :historical_date_col, :historical_scope, :only_weekdays

  self.historical_date_col = configuration[:date_column]
  self.historical_scope    = configuration[:scope]

  order_desc = "#{self.historical_date_col_sql} DESC"
  order_asc = "#{self.historical_date_col_sql} ASC"

  # named_scopes - sortings
  named_scope :asc,  :order => order_asc
  named_scope :desc, :order => order_desc

  named_scope :oldest,        :limit => 1, :order => order_asc
  named_scope :newest,        :limit => 1, :order => order_desc
  named_scope :newest_two,    :limit => 2, :order => order_desc

  # one snapshot per week (every wednesday)      
  named_scope :weekly,
              :conditions => "DAYOFWEEK(#{self.historical_date_col_sql}) = 2"

  %w[sundays mondays tuesdays wednesdays thursdays fridays saturdays].each_with_index do |name, day_of_week|
    named_scope name,
                :conditions => "DAYOFWEEK(#{self.historical_date_col_sql}) = #{day_of_week+1}"
  end

  named_scope :within_month, lambda {{
      :conditions => ["#{self.historical_date_col_sql} > ?", Date.today - 30]
  }}

  named_scope :within_year, lambda {{
      :conditions => ["#{self.historical_date_col_sql} > ?", Date.today - 364]
  }}

  named_scope :same_scope, lambda {|record| 
    if self.historical_scope.nil?
      {}
    else
      {:conditions => {self.historical_scope => record[self.historical_scope]} }
    end
  }

  named_scope :on_date, lambda {|date| {
      :conditions => { :snapshot_date => date.to_date },
      :limit => 1
  }}

  # between(older_date, newer_date)
  #
  named_scope :between, lambda {|*args|
    from, to = args
    range = (from.to_date..to.to_date)
    { :conditions => {self.historical_date_col => range } }
  }

  # nearest(date, 1)
  # nearest(date, (date_from..date_to))
  #
  named_scope :nearest, lambda {|*args| 
    date, tolerance = args
    range = self.tolerance_to_range(date, tolerance)
    {
      :conditions => {self.historical_date_col => range},
      :order => ["ABS(DATEDIFF(#{self.historical_date_col_sql}, '#{date.to_date.to_s(:db)}')) ASC"]
    }
  }

  # Does not include date
  # 
  named_scope :upto, lambda {|date| 
    raise "passed parameter does not respond_to? to_date" unless date.respond_to?(:to_date)
    { :conditions => ["#{self.historical_date_col_sql} < ?", date.to_date] }
  }

  # Includes date
  #
  named_scope :upto_including, lambda {|date| 
    raise "passed parameter does not respond_to? to_date" unless date.respond_to?(:to_date)
    { :conditions => ["#{self.historical_date_col_sql} <= ?", date.to_date] }
  }

  named_scope :from, lambda {|date| 
    raise "passed parameter does not respond_to? to_date" unless date.respond_to?(:to_date)
    { :conditions => ["#{self.historical_date_col_sql} > ?", date.to_date] }
  }

  named_scope :from_including, lambda {|date| 
    raise "passed parameter does not respond_to? to_date" unless date.respond_to?(:to_date)
    { :conditions => ["#{self.historical_date_col_sql} >= ?", date.to_date] }
  }

  named_scope :opt, lambda {|attributes_for_select| {:select => [:snapshot_date, attributes_for_select].flatten.uniq.join(', ') } }

  # validations
  validate :valid_date?, :on => :save
  nil
end