Class: Groupdate::Series

Inherits:
Object
  • Object
show all
Defined in:
lib/groupdate/series.rb

Instance Method Summary collapse

Constructor Details

#initialize(relation, field, column, time_zone, time_range) ⇒ Series

Returns a new instance of Series.



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# File 'lib/groupdate/series.rb', line 4

def initialize(relation, field, column, time_zone, time_range)
  @relation = relation
  if time_range.is_a?(Range)
    @relation = relation.where("#{column} BETWEEN ? AND ?", time_range.first, time_range.last)
  end
  @field = field
  @time_zone = time_zone
  @time_range = time_range
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &block) ⇒ Object 



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# File 'lib/groupdate/series.rb', line 82

def method_missing(method, *args, &block)
  # https://github.com/rails/rails/blob/master/activerecord/lib/active_record/relation/calculations.rb
  if ActiveRecord::Calculations.method_defined?(method)
    build_series(@relation.send(method, *args, &block))
  else
    raise NoMethodError, "valid methods are: #{ActiveRecord::Calculations.instance_methods.join(", ")}"
  end
end

Instance Method Details

#build_series(count) ⇒ Object 



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# File 'lib/groupdate/series.rb', line 14

def build_series(count)
  utc = ActiveSupport::TimeZone["UTC"]

  cast_method =
    case @field
    when "day_of_week", "hour_of_day"
      lambda{|k| k.to_i }
    else
      lambda{|k| (k.is_a?(Time) ? k : utc.parse(k)).utc }
    end

  count = Hash[count.map do |k, v|
    [cast_method.call(k), v]
  end]

  series =
    case @field
    when "day_of_week"
      0..6
    when "hour_of_day"
      0..23
    else
      time_range =
        if @time_range.is_a?(Range)
          @time_range
        else
          # use first and last values
          sorted_keys = count.keys.sort
          sorted_keys.first..sorted_keys.last
        end

      # determine start time
      time = time_range.first.in_time_zone(@time_zone)
      starts_at =
        case @field
        when "second"
          time.change(:usec => 0)
        when "minute"
          time.change(:sec => 0)
        when "hour"
          time.change(:min => 0)
        when "day"
          time.beginning_of_day
        when "week"
          # beginning_of_week does not support :sunday argument in activesupport < 3.2
          (time - time.wday.days).midnight
        when "month"
          time.beginning_of_month
        else # year
          time.beginning_of_year
        end

      series = [starts_at]

      step = 1.send(@field)

      while time_range.cover?(series.last + step)
        series << series.last + step
      end

      series.map{|s| s.to_time.utc }
    end

  Hash[series.map do |k|
    [k, count[k] || 0]
  end]
end