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# File 'lib/activerecord_chronological_records.rb', line 2
def has_chronological_records(*options)
if options.empty?
start_column, end_column = :start_date, :end_date
else
start_column, end_column = options[0], options[1]
end
dealing_with_dates = columns.select{|c| [start_column, end_column].map(&:to_s).include? c.name}.all?{|c| c.type == :date}
query_start_column = "#{table_name}.#{start_column}"
query_end_column = "#{table_name}.#{end_column}"
same_record_lookup = "#{self}.where(:#{primary_key} => self.#{primary_key})"
self.instance_eval <<-EOS
def effective_at(date)
where("(#{query_start_column} <= :date OR #{query_start_column} IS NULL) AND (#{query_end_column} >= :date OR #{query_end_column} IS NULL)", :date => #{dealing_with_dates ? 'date.to_date' : 'date'})
end
def current
effective_at(Time.now)
end
EOS
self.class_eval <<-EOS
def effective_at(date)
#{same_record_lookup}.effective_at(date).first
end
def earliest
#{same_record_lookup}.order("#{query_start_column} ASC").first
end
def latest
#{same_record_lookup}.order("#{query_start_column} DESC").first
end
def previous
effective_at(#{start_column} - 1.day)
end
def next
effective_at(#{end_column} + 1.day)
end
def current
effective_at(Time.now)
end
def current?
(#{start_column}.blank? || #{start_column}.to_time <= Time.now) && (#{end_column}.blank? || #{end_column}.to_time >= Time.now)
end
EOS
end
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